Pressure grouting of fractured basalt flows

International Nuclear Information System (INIS)

Shaw, P.; Weidner, J.; Phillips, S.; Alexander, J.

1996-04-01

This report describes a field trial of pressure grouting in basalt and the results of subsequent coring and permeability measurement activities. The objective was to show that the hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was established by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping was used to establish major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is located northwest of the INEL, was chosen for this study due to the similarity of this surface outcrop geology to that of the underlying bedrock fracture system found at the Radioactive Waste Management Complex. This study showed that hydraulic conductivity of basalt can be reduced through pressure grouting of cementitious material

Pressure grouting of fractured basalt flows

Energy Technology Data Exchange (ETDEWEB)

Shaw, P.; Weidner, J.; Phillips, S.; Alexander, J.

1996-04-01

This report describes a field trial of pressure grouting in basalt and the results of subsequent coring and permeability measurement activities. The objective was to show that the hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was established by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping was used to establish major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is located northwest of the INEL, was chosen for this study due to the similarity of this surface outcrop geology to that of the underlying bedrock fracture system found at the Radioactive Waste Management Complex. This study showed that hydraulic conductivity of basalt can be reduced through pressure grouting of cementitious material.

Fatigue Life of High Performance Grout in Dry and Wet Environment for Wind Turbine Grouted Connections

DEFF Research Database (Denmark)

Sørensen, Eigil V.

2011-01-01

The cementitious material in grouted connections of offshore monopile wind turbine structures is subjected to very high oscillating service stresses. The fatigue capacity of the grout therefore becomes essential to the performance and service life of the grouted connection. In the present work...... the fatigue life of a high performance cement based grout was tested by dynamic compressive loading of cylindrical specimens at varying levels of cyclic frequency and load. The fatigue tests were performed in two series, one with the specimens tested in air and one with the specimens submerged in water during...

Development of rock bolt grout and shotcrete for rock support and corrosion of steel in low-pH cementitious materials

Energy Technology Data Exchange (ETDEWEB)

Boden, Anders (Vattenfall Power Consultant AB, Vaellingby (Sweden)); Pettersson, Stig (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

2011-04-15

It is foreseen that cementitious products will be utilized in the construction of the final repository. The use of conventional cementitious material creates pulses in the magnitude of pH 12.13 in the leachates and release alkalis. Such a high pH is detrimental mainly to impairment of bentonite functioning, but also to possibly enhanced dissolution of spent fuel and alteration of fracture filling materials. It also complicates the safety analysis of the repository, as the effect of a high pH-plume should be considered in the evaluation. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis, although limiting the amount of low-pH cement is recommended. In earlier studies it was found that shotcreting, standard casting and rock bolting with low-pH cement (pH . 11 in the leachate) should be possible without any major development work. This report summarizes the results of development work done during 2008 and 2009 in the fields of low-pH rock bolt grout, low-pH shotcrete and steel corrosion in low-pH concrete. Development of low-pH rock bolt grout mixes and laboratory testing of the selected grout was followed by installation of twenty rock bolts for rock support at Aspo HRL using the chosen low-pH grout. The operation was successful and the bolts and grout are subject to follow up the next ten years. Low-pH shotcrete for rock support was initially developed within the ESDRED project, which was an Integrated Project within the European Commission sixth framework for research and technological development. ESDRED is an abbreviation for Engineering Studies and Demonstrations of Repository Designs. ESDRED was executed from 1st February 2004 to 31st January 2009. The development of the mix design described in this report was based on the results from ESDRED. After laboratory testing of the chosen mix, it was field tested in niche NASA 0408A at Aspo HRL. Further, some areas in the TASS-tunnel were

Development of rock bolt grout and shotcrete for rock support and corrosion of steel in low-pH cementitious materials

International Nuclear Information System (INIS)

Boden, Anders; Pettersson, Stig

2011-04-01

It is foreseen that cementitious products will be utilized in the construction of the final repository. The use of conventional cementitious material creates pulses in the magnitude of pH 12.13 in the leachates and release alkalis. Such a high pH is detrimental mainly to impairment of bentonite functioning, but also to possibly enhanced dissolution of spent fuel and alteration of fracture filling materials. It also complicates the safety analysis of the repository, as the effect of a high pH-plume should be considered in the evaluation. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis, although limiting the amount of low-pH cement is recommended. In earlier studies it was found that shotcreting, standard casting and rock bolting with low-pH cement (pH . 11 in the leachate) should be possible without any major development work. This report summarizes the results of development work done during 2008 and 2009 in the fields of low-pH rock bolt grout, low-pH shotcrete and steel corrosion in low-pH concrete. Development of low-pH rock bolt grout mixes and laboratory testing of the selected grout was followed by installation of twenty rock bolts for rock support at Aspo HRL using the chosen low-pH grout. The operation was successful and the bolts and grout are subject to follow up the next ten years. Low-pH shotcrete for rock support was initially developed within the ESDRED project, which was an Integrated Project within the European Commission sixth framework for research and technological development. ESDRED is an abbreviation for Engineering Studies and Demonstrations of Repository Designs. ESDRED was executed from 1st February 2004 to 31st January 2009. The development of the mix design described in this report was based on the results from ESDRED. After laboratory testing of the chosen mix, it was field tested in niche NASA 0408A at Aspo HRL. Further, some areas in the TASS-tunnel were

Low-ph injection grout for deep repositories. Summary report from a co-operation project between NUMO (Japan), Posiva (Finland) and SKB (Sweden)

Energy Technology Data Exchange (ETDEWEB)

Boden, A. (ed.) [SwedPower Ab, Stockholm (Sweden); Sievaenen, U. (ed.) [JP-Suoraplan Oy, Vantaa (Finland)

2006-02-15

This report summarises results achieved in the joint SKB, Posiva and NUMO project 'Injection grout for deep repositories'. The work has been carried out in four subprojects with SKB and Posiva as responsible for two sub-projects each. This report summarises the original reporting. Posiva was responsible for the studies on low-pH cementitious grout, while SKB was responsible for the studies on non-cementitious grout. The work was done by literature surveys, laboratory analyses and field tests A result of the project is that there are both low-pH cementitious material for grouting larger fractures ((>-) 100 {mu}m) and non-cementitious material for grouting smaller fractures ((<-) 100 {mu}m) that will, after further optimisation work, be recommended for grouting of deep repositories. This project concentrated on the technical development of properties for the low pH grouts. Long-term safety and environmental aspects and durability of materials were preliminarily considered. Continued evaluations have to be carried out. (orig.)

The Evaluation of Material Properties of Low-pH Cement Grout for the Application of Cementitious Materials to Deep Radioactive Waste Repository Tunnels

International Nuclear Information System (INIS)

Kim, Jin Seop; Kwon, S. K.; Cho, W. J.; Kim, G. W.

2009-12-01

Considering the current construction technology and research status of deep repository tunnels for radioactive waste disposal, it is inevitable to use cementitious materials in spite of serious concern about their long-term environmental stability. Thus, it is an emerging task to develop low pH cementitious materials. This study reviews the state of the technology on low pH cements developed in Sweden, Switzerland, France, and Japan as well as in Finland which is constructing a real deep repository site for high-level radioactive waste disposal. Considering the physical and chemical stability of bentonite which acts as a buffer material, a low pH cement limits to pH ≤11 and pozzolan-type admixtures are used to lower the pH of cement. To attain this pH requirement, silica fume, which is one of the most promising admixtures, should occupy at least 40 wt% of total dry materials in cement and the Ca/Si ratio should be maintained below 0.8 in cement. Additionally, selective super-plasticizer needs to be used because a high amount of water is demanded from the use of a large amount of silica fume. In this report, the state of the technology on application of cementitious materials to deep repository tunnels for radioactive waste disposal was analysed. And the material properties of low-pH and high-pH cement grouts were evaluated base on the grout recipes of ONKALO in Finlan

Mechanical Properties of High Cementitious Grout (I)

DEFF Research Database (Denmark)

Sørensen, Eigil V.

 The present report describes tests carried out on the high performance grout MASTERFLOW 9500, marked WMG 7145 FP, developed by BASF Construction Materials and designed for use in grouted connections of offshore windmill foundations....

106-AN grout pilot-scale test HGTP-93-0501-02

International Nuclear Information System (INIS)

Bagaasen, L.M.

1993-05-01

The Grout Treatment Facility (GTF) at Hanford, Washington will process the low-level fraction of selected double-shell tank (DST) wastes into a cementitious waste form. This facility, which is operated by Westinghouse Hanford Company (WHC), mixes liquid waste with cementitious materials to produce a waste form that immobilizes hazardous constituents through chemical reactions and/or microencapsulation. Over 1,000,000 gal of Phosphate/Sulfate Waste were solidified in the first production campaign with this facility. The next tank scheduled for treatment is 106-AN. After conducting laboratory studies to select the grout formulation, part of the normal formulation verification process is to conduct tests using the 1/4-scale pilot facilities at the Pacific Northwest Laboratory (PNL). The major objectives of these pilot-scale tests were to determine if the proposed grout formulation could be processed in the pilot-scale equipment and to collect thermal information to help determine the best way to manage the grout hydration heat

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1992-07-01

The Grout Treatment Facility (GTF) will provide permanent disposal for approximately 43 Mgal of low-level radioactive liquid waste currently being stored in underground tanks on the Hanford Site. The first step in permanent disposal is accomplished by solidifying the liquid waste with cementitious dry materials. The resulting grout is cast within underground vaults. This report on the GTF contains information on the following: Geologic data, hydrologic data, groundwater monitoring program, information, detection monitoring program, groundwater characterization drawings, building emergency plan--grout treatment facility, response action plan for grout treatment facility, Hanford Facility contingency plan, training course descriptions, overview of the Hanford Facility Grout Performance, assessment, bland use and zoning map, waste minimization plan, cover design engineering report, and clay liners (ADMIXTURES) in semiarid environments

Mechanical Properties of High Performance Cementitious Grout Masterflow 9200

DEFF Research Database (Denmark)

Sørensen, Eigil V.

The present report describes tests carried out on the high performance grout Masterflow 9200, developed by BASF Construction Chemicals A/S and designed for use in grouted connections of windmill foundations....

Characterization results for 106-AN grout produced in a pilot-scale test

International Nuclear Information System (INIS)

Lokken, R.O.; Bagaasen, L.M.; Martin, P.F.C.; Palmer, S.E.; Anderson, C.M.

1993-06-01

The Grout Treatment Facility (GTF) at Hanford. Washington, will process the low-level fraction of selected double-shell tank (DST) wastes into a cementitious waste form. This facility, which is operated by Westinghouse Hanford Company (WHC), mixes liquid waste with cementitious materials to produce a waste form that immobilizes hazardous constituents through chemical reactions and/or microencapsulation. Over one million gallons of phosphate/sulfate waste were solidified in the first production campaign with this facility. The next tank waste scheduled for treatment is 106-AN (the waste from Tank 241-AN-106). After laboratory studies were conducted to select the grout formulation, tests using the 1/4-scale pilot facilities at the Pacific Northwest Laboratory (PNL) were conducted as part of the formulation verification process. The major objectives of these pilot-scale tests were to determine if the proposed grout formulation could be processed in the pilotscale equipment. to collect thermal information to help determine the best way to manage the grout hydration heat, and to characterize the solidified grout

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1992-07-01

The Grout Treatment Facility (GTF) will provide permanent disposal for approximately 43 Mgal of radioactive liquid waste currently being stored in underground tanks on the Hanford Site. The first step in permanent disposal is accomplished by solidifying the liquid waste with cementitious dry materials. The resulting grout is cast within underground vaults. This report on the GTF contains information on the following: Vault design, run-on/run-off control design, and asphalt compatibility with 90-degree celsius double-shell slurry feed

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1992-07-01

The Grout Treatment Facility (GTF) will provide permanent disposal for approximately 43 Mgal of radioactive liquid waste currently being stored in underground tanks on the Hanford Site. The first step in permanent disposal is accomplished by solidifying the low-level liquid waste with cementitious dry materials. The resulting grout is cast within underground vaults. This report on the GTF contains information on the following: Hanford Site Maps, road evaluation for the grout treatment facility, Department of Ecology certificate of non-designation for centralia fly ash, double-shell tank waste compositional modeling, laboratory analysis reports for double-shell tank waste, stored in tanks 241-AN-103, 241-AN-106, and 241-AW-101, grout vault heat transfer results for M-106 grout formulation, test results for extraction procedure toxicity testing, test results for toxicity testing of double-shell tank grout, pilot-scale grout production test with a simulated low-level waste, characterization of simulated low-level waste grout produced in a pilot-scale test, description of the procedure for sampling nonaging waste storage tanks, description of laboratory procedures, grout campaign waste composition verification, variability in properties of grouted phosphate/sulfate N-reactor waste, engineering drawings, description of operating procedures, equipment list--transportable grout equipment, grout treatment facility--tank integrity assessment plan, long-term effects of waste solutions on concrete and reinforcing steel, vendor information, grout disposal facilities construction quality assurance plan, and flexible membrane liner/waste compatibility test results

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1988-01-01

The long-term performance of the grout disposal system for Phosphate/Sulfate Waste (PSW) was analyzed. PSW is a low-level liquid generated by activities associated with N Reactor operations. The waste will be mixed with dry solids and permanently disposed of as a cementitious grout in sub-surface concrete vaults at Hanford's 200-East Area. Two categories of scenarios were analyzed that could cause humans to be exposed to radionuclides and chemicals from the grouted waste: contaminated groundwater and direct intrusion. In the groundwater scenario, contaminants are released from the buried grout monoliths, then eventually transported via the groundwater to the Columbia River. As modeled, the contaminants are assumed to leach out of the monoliths at a constant rate over a 10,000-year period. The other category of exposure involves intruders who inadvertently contact the waste directly, either by drilling, excavating, or gardening. Long-term impacts that could result from disposal of PSW grout were expressed in terms of incremental increases of (1) chemical concentrations in the groundwater and surface waters, and (2) radiation doses. None of the calculated impacts exceeded the corresponding regulatory limits set by Washington State, Department of Energy, or the Nuclear Regulatory Commission

Durability of double-shell slurry feed grouts: FY-90 results

International Nuclear Information System (INIS)

Lokken, R.O.; Martin, P.F.C.

1992-12-01

Plans for disposal of the low-level fraction of selected double-shell tank wastes at Hanford include grouting. Grout disposal is the process of mixing low-level liquid waste with cementitious powders and pumping the slurry to near-surface, underground concrete vaults; hydration results in the formation of a solid product that binds/encapsulates the radioactive/hazardous constituents. In this durability program, previous studies have indicated a strong impact from curing temperature/time on strength and leach resistance of DSSF grouts. The current studies were expanded to determine whether these impacts could be attributed to other factors, such as dry blend composition and waste concentration. Major conclusions: grouts from dry blends with 40 wt% limestone had lower strengths; compressive strengths and leach resistance decreased with increased curing temperature/time; leach resistance increased for grouts prepared with dilute DSSF; nitrate leach resistance increased with high slag/cement ratios, dilute DSSF, and low curing temperatures; amount of drainable liquids for grouts using diluted DSSF was lowest when slag content was high; the 2 most significant factors affecting grout properties were the slag/cement ratio and waste dilution (slag-waste reactions appear to dominate the properties of DSSF grouts)

REFERENCE CASES FOR USE IN THE CEMENTITIOUS BARRIERS PARTNERSHIP

Energy Technology Data Exchange (ETDEWEB)

Langton, C

2009-01-06

The Cementitious Barriers Project (CBP) is a multidisciplinary cross cutting project initiated by the US Department of Energy (DOE) to develop a reasonable and credible set of tools to improve understanding and prediction of the structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The period of performance is >100 years for operating facilities and > 1000 years for waste management. The CBP has defined a set of reference cases to provide the following functions: (1) a common set of system configurations to illustrate the methods and tools developed by the CBP, (2) a common basis for evaluating methodology for uncertainty characterization, (3) a common set of cases to develop a complete set of parameter and changes in parameters as a function of time and changing conditions, and (4) a basis for experiments and model validation, and (5) a basis for improving conceptual models and reducing model uncertainties. These reference cases include the following two reference disposal units and a reference storage unit: (1) a cementitious low activity waste form in a reinforced concrete disposal vault, (2) a concrete vault containing a steel high-level waste tank filled with grout (closed high-level waste tank), and (3) a spent nuclear fuel basin during operation. Each case provides a different set of desired performance characteristics and interfaces between materials and with the environment. Examples of concretes, grout fills and a cementitious waste form are identified for the relevant reference case configurations.

Rheology of sludge-slurry grouts

International Nuclear Information System (INIS)

McDaniel, E.W.

1980-10-01

A series of rheograms was developed that relates the critical velocity (velocity where flow changes from laminar to turbulent) of a cementitious grout that incorporates a suspended sludge-slurry to the critical velocity of a reference grout made with a simulated waste solution. The sludge that is now in the Gunite waste tanks at the Oak Ridge National Laboratory (ORNL) will be suspended and pumped to the new waste storage tanks in Melton Valley. The sludge will then be blended with a cement mix base to form a grout which will be injected underground by the shale fracturing process. This report describes the materials, equipment, and techniques used in the laboratory studies to suspend sludges and mix sludge-slurry grouts that have flow properties similar to those of current shale fracturing grouts. Bentonite clay is an effective suspender in dilute NaNO 3 solutions; 15 wt % solids can be suspended with 2.0 wt % bentonite in a 0.1 M NaNO 3 solution. Other suspending materials were evaluated, but bentonite gave the best results. If a slurry grout becomes too viscous to pump, methods must be available to thin the mixture. A number of thinners, friction reducers, and plasticizers were examined. Q-Broxin, a thinner supplied by Baroid, reduced the velocity of a grout required for turbulent flow in a 5.0-cm (2-in.)-diam tube from 1.76 to 1.20 m/s (5.79 to 3.95 ft/s); FX-32C, a plasticizer supplied by Fox Industries, Inc., reduced the velocity from 1.76 to 0.75 m/s

Degradation of cementitious materials associated with salstone disposal units

Energy Technology Data Exchange (ETDEWEB)

Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith, F. G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2014-09-01

The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of a saltstone disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions.

Phase I - Laboratory Study Effects of Cement Grout Structures on Colloid Formation from SRS Soils

International Nuclear Information System (INIS)

Serkiz, S.M.

2001-01-01

Studies were conducted to better understand the influence of grout structures and fills on colloid formation. Low-Level Waste is disposed in concrete vaults and trenches at the E-Area Low-Level Waste Facility (LLWF). Two types of enhanced trench disposal are approved for use including; Intimately-Mixed Cement-Stabilized waste forms, such as Ashcrete and Blowcrete resulting from operation of the Consolidated Incinerator Facility, and Cement-Stabilized Encapsulated waste, where waste forms (e.g., contaminated equipment) will be surrounded by a grout or other cementitious material. The presence of concrete structures and process of grouting in trenches are expected to generate colloids, both from the grout itself and as a result of the interactions of these cementitious materials and their degradation products with the surrounding soils. The extent of occurrence, mobility, and influence on contaminant transport of colloidal materials in aquifer systems is the subject of this study. The intent of this study is not to modify the PA but to aid in our understanding of the significance of this phenomenon. Information generated in this study will help in considering whether colloid-enhanced contaminant migration should be considered in establishing waste acceptance criteria and in the design and development of waste disposal systems

Fatigue Behaviour of High Performance Cementitious Grout Masterflow 9500

DEFF Research Database (Denmark)

Sørensen, Eigil V.

The present report describes the fatigue behaviour of the high performance grout MASTERFLOW 9500 subjected to cyclic loading, in air as well as submerged in water, at various frequencies and levels of maximum stress. Part of the results were also reported in [1] together with other mechanical...

Grout Treatment Facility dangerous waste permit application

International Nuclear Information System (INIS)

1992-07-01

The Grout Treatment Facility (GTF) is an existing treatment, storage, and/or disposal (TSD) unit located in the 200 East Area and the adjacent 600 Area of the Hanford Site. The GTF mixes dry cementitious solids with liquid mixed waste (containing both dangerous and radioactive constituents) produced by Hanford Site operations. The GTF consists of the following: The 241-AP-02D and 241-AP-04D waste pump pits and transfer piping; Dry Materials Facility (DMF); Grout Disposal Facility (GDF), consisting of the disposal vault and support and monitoring equipment; and Grout Processing Facility (GPF) and Westinghouse Hanford Company on the draft Hanford Facility Dangerous Waste Permit and may not be read to conflict with those comments. The Grout Treatment Facility Dangerous Waste Permit Application consists of both a Part A and a Part B permit application. An explanation of the Part A revisions associated with this TSD unit, including the current revision, is provided at the beginning of the Part A section. The Part B consists of 15 chapters addressing the organization and content of the Part B checklist prepared by the Washington State Department of Ecology (Ecology 1987). For ease of reference, the checklist section numbers, in brackets, follow chapter headings and subheadings

Injection grout for deep repositories. Subproject 1: LowpH cementitious grout for larger fractures, leach testing of grout mixes and evaluation of the long-term safety

International Nuclear Information System (INIS)

Vuorinen, U.; Lehikoinen, J.; Imoto, Harutake; Yamamoto, Takeshi; Cruz Alonso, M.

2005-10-01

Constructing an underground disposal facility for spent nuclear fuel deep in bedrock requires lowpH cement-based injection grout, because assured data of the extent of a possible high-pH plume in saturated bedrock conditions is lacking. In this work low-pH grout mixes of new design were subjected to leach testing. Before chosen to leach testing the grout mixes had to fulfil certain technical requirements. Leach testing was performed in order to establish that the pH requirement (≤11) set for the leachates was met. For comparison reasons also one conventionally used cement based grout material was included in the tests. Two kinds of lowpH grout cement mixes were tested; mixes with added blast furnace slag (4 mixes) or added silica (6 mixes). All the mixes were not completely tested according to the test plan, because for some mixes during leach testing factors detrimental to the long-term safety of a repository were observed, e.g. too high pH or leached sulphide, which is harmful for copper. Leach testing of the grout mixes was performed in a glove-box (N 2 atmosphere) in order to avoid the interference of atmospheric CO 2 on the alkaline leachates. Two simulated groundwater solutions, saline OL-SO and fresh ALL-MR, were used as leachates. Two leach tests were applied; equilibrium and diffusion tests. In the equilibrium test at each measuring point only a part of the leachate was exchanged, whereas in the diffusion test the entire leachate was exchanged. The pH value of each leachate sample was measured, but total alkalinity was determined only for some leachates. Na, K, Ca, Mg, Al, Fe, Si, SO 4 2- , S TOT , and Cl were analysed in the leach solutions collected in the diffusion test of four grout mixes chosen. Also the corresponding solid specimens were analysed (SEM, XRD, EPMA, MIP, TG) in Japan. A few grout pore fluid pH values were measured in Spain, as well. The simplified thermodynamic model calculations were successful in qualitatively reproducing the

Effect of aluminate ions on the heat of hydration of cementitious waste forms

International Nuclear Information System (INIS)

Lokken, R.O.

1993-11-01

During the hydration and setting of high-salt content liquid waste grouts, considerable heat is generated by exothermic reactions within the grout. These reactions include hydration reactions of cementitious solids and reactions between waste constituents and the solids. Adiabatic temperature rises exceeding 80 degrees C have been estimated for grouts prepared with a dry blend of 47 wt % fly ash, 47 wt % blast furnace slag, and 6 wt % type I/II Portland cement (1) Performance criteria for grout disposal specify that the temperature of the grout waste form must not exceed 90 degrees C (2) To counter the increase in temperature, inert solids were added to the ''47/47/6'' dry blend to reduce the amount of heat-generating solids, thereby decreasing the temperature rise. Based on preliminary results from adiabatic calorimetry, a dry blend consisting of 40 wt % limestone flour, 28 wt % class F fly ash, 28 wt % ground blast furnace slag, and 4 wt % type I/II Portland cement was selected for further testing

Corrosion aspects of steel radioactive waste containers in cementitious materials

International Nuclear Information System (INIS)

Smart, Nick

2012-01-01

Nick Smart from Serco, UK, gave an overview of the effects of cementitious materials on the corrosion of steel during storage and disposal of various low- and intermediate-level radioactive wastes. Steel containers are often used as an overpack for the containment of radioactive wastes and are routinely stored in an open atmosphere. Since this is an aerobic and typically humid environment, the steel containers can start to corrode whilst in storage. Steel containers often come into contact with cementitious materials (e.g. grout encapsulants, backfill). An extensive account of different steel container designs and of steel corrosion mechanisms was provided. Steel corrosion rates under conditions buffered by cementitious materials have been evaluated experimentally. The main conclusion was that the cementitious environment generally facilitates the passivation of steel materials. Several general and localised corrosion mechanisms need to be considered when evaluating the performance of steel containers in cementitious environments, and environmental thresholds can be defined and used with this aim. In addition, the consequences of the generation of gaseous hydrogen by the corrosion of carbon steel under anoxic conditions must be taken into account. Discussion of the paper included: Is crevice corrosion really significant in cementitious systems? Crevice corrosion is unlikely in the cementitious backfill considered because it will tend to neutralise any acidic conditions in the crevice. What is the role of microbially-induced corrosion (MIC) in cementitious systems? Microbes are likely to be present in a disposal facility but their effect on corrosion is uncertain

Influence of Ultrafine 2CaO·SiO₂ Powder on Hydration Properties of Reactive Powder Concrete.

Science.gov (United States)

Sun, Hongfang; Li, Zishanshan; Memon, Shazim Ali; Zhang, Qiwu; Wang, Yaocheng; Liu, Bing; Xu, Weiting; Xing, Feng

2015-09-17

In this research, we assessed the influence of an ultrafine 2CaO·SiO₂ powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM), mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength) with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO₂. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO₂ powder has the potential to improve the performance of a reactive powder cementitious system.

Degradation Of Cementitious Materials Associated With Saltstone Disposal Units

International Nuclear Information System (INIS)

Flach, G. P; Smith, F. G. III

2013-01-01

The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed ''saltstone''. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of an SDF disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions. The nominal value (NV) is an intermediate result that is more probable than the conservative estimate

Degradation Of Cementitious Materials Associated With Saltstone Disposal Units

Energy Technology Data Exchange (ETDEWEB)

Flach, G. P; Smith, F. G. III

2013-03-19

The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of an SDF disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions. The nominal value (NV) is an intermediate result that is more probable than the conservative

The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities In Assessing The Degradation Of Cementitious Barriers

Energy Technology Data Exchange (ETDEWEB)

Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States); Burns, H. H. [Savannah River Site (SRS), Aiken, SC (United States); Langton, C. [Savannah River Site (SRS), Aiken, SC (United States); Smith, F. G. III [Savannah River Site (SRS), Aiken, SC (United States); Brown, K. G. [Vanderbilt University, Nashville, TN (United States); Kosson, D. S. [Vanderbilt University, Nashville, TN (United States); Garrabrants, A. C. [Vanderbilt University, Nashville, TN (United States); Sarkar, S. [Vanderbilt University, Nashville, TN (United States); van der Sloot, H. [Hans van der Sloot Consultancy (The Netherlands); Meeussen, J. C.L. [Nuclear Research and Consultancy Group, Petten (The Netherlands); Samson, E. [SIMCO Technologies Inc. , 1400, boul. du Parc - Technologique , Suite 203, Quebec (Canada); Mallick, P. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Esh, D. W. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Fuhrmann, M. J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Philip, J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States)

2013-01-11

The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in Kd/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP software

Influence of Ultrafine 2CaO·SiO2 Powder on Hydration Properties of Reactive Powder Concrete

Directory of Open Access Journals (Sweden)

Hongfang Sun

2015-09-01

Full Text Available In this research, we assessed the influence of an ultrafine 2CaO·SiO2 powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM, mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO2. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO2 powder has the potential to improve the performance of a reactive powder cementitious system.

Review of high and ultrahigh performance cementitious composites incorporating various combinations of fibers and ultrafines

Directory of Open Access Journals (Sweden)

M.I. Khan

2017-10-01

Full Text Available The outcomes of the research in modern cementitious composites have paved the way for their wide use in construction industry. The introduction of short, discontinuous and randomly distributed fibers to these composites has altered their inherent brittleness. Extensive research has been carried out on the effects of using of mono-fibers in a cementitious composite. However, limited reports in the approachable references on the use of hybrid fibers are available. The synergetic interaction between hybrid fibers have beneficial impact on cementitious composites. The incorporation of micro- and nano-pozzolanic materials, such as fly ash and silica fume have been used to develop high performance cementitious composites such as reactive powder concrete, DUCTAL and CEMTEC multiscale. Further developments were recently achieved by the development of ultra-high performance cementitious composites. The matter of developing high and ultrahigh cementitious composites using various kinds of fibers and particles has received enormous attention from the scientific community. This paper presents a comprehensive critical literature review on the area of high and ultra-high performance cement-based materials.

Variability Of KD Values In Cementitious Materials And Sediments

International Nuclear Information System (INIS)

Almond, P.; Kaplan, D.; Shine, E.

2012-01-01

Measured distribution coefficients (K d values) for environmental contaminants provide input data for performance assessments (PA) that evaluate physical and chemical phenomena for release of radionuclides from wasteforms, degradation of engineered components and subsequent transport of radionuclides through environmental media. Research efforts at SRNL to study the effects of formulation and curing variability on the physiochemical properties of the saltstone wasteform produced at the Saltstone Disposal Facility (SDF) are ongoing and provide information for the PA and Saltstone Operations. Furthermore, the range and distribution of plutonium K d values in soils is not known. Knowledge of these parameters is needed to provide guidance for stochastic modeling in the PA. Under the current SRS liquid waste processing system, supernate from F and H Tank Farm tanks is processed to remove actinides and fission products, resulting in a low-curie Decontaminated Salt Solution (DSS). At the Saltstone Production Facility (SPF), DSS is mixed with premix, comprised of blast furnace slag (BFS), Class F fly ash (FA), and portland cement (OPC) to form a grout mixture. The fresh grout is subsequently placed in SDF vaults where it cures through hydration reactions to produce saltstone, a hardened monolithic waste form. Variation in saltstone composition and cure conditions of grout can affect the saltstone's physiochemical properties. Variations in properties may originate from variables in DSS, premix, and water to premix ratio, grout mixing, placing, and curing conditions including time and temperature (Harbour et al. 2007; Harbour et al. 2009). There are no previous studies reported in the literature regarding the range and distribution of K d values in cementitious materials. Presently, the Savannah River Site (SRS) estimate ranges and distributions of K d values based on measurements of K d values made in sandy SRS sediments (Kaplan 2010). The actual cementitious material K d

Sealing properties of cement-based grout materials used in the rock sealing project

Energy Technology Data Exchange (ETDEWEB)

Onofrei, M; Gray, M N; Pusch, R; Boergesson, L; Karnland, O; Shenton, B; Walker, B

1993-12-01

The Task Force on Sealing Materials and Techniques of the Stripa Project recommended that work be undertaken to study the sealing properties of cement-based grout materials. A new class of cement-based grouts (high-performance grouts) with the ability to penetrate and seal fine fractures in granite was investigated. The materials were selected for their small mean particle size and the ability to be made fluid by a superplasticizer at low water/cementitious-materials ratios. The fundamental physical and chemical properties (such as the particle size and chemical composition) of the materials were evaluated. The rheological properties of freshly mixed grouts, which control the workability of the grouts, were determined together with the properties of hardened materials, which largely control the long-term performance (longevity) of the materials in repository settings. The materials selected were shown to remain gel-like during the setting period, and so the grouts may be expected to remain largely homogenous during and after injection into the rock without separating into solid and liquid phases. The hydraulic conductivity and strength of hardened grouts were determined. The microstructure of the bulk grouts was characterized by a high degree of homogeneity with extremely fine porosity. The low hydraulic conductivity and good mechanical properties are consistent with the extremely fine porosity. The ability of the fractured grouts to self-seal was also observed in tests in which the hydraulic conductivity of recompacted granulated grouts was determined. The laboratory tests were carried out in parallel with investigations of the in situ performance of the materials and with the development of geochemical and theoretical models for cement-based grout longevity. (author). 56 refs., 15 tabs., 98 figs.

Sealing properties of cement-based grout materials used in the rock sealing project

International Nuclear Information System (INIS)

Onofrei, M.; Gray, M.N.; Pusch, R.; Boergesson, L.; Karnland, O.; Shenton, B.; Walker, B.

1993-12-01

The Task Force on Sealing Materials and Techniques of the Stripa Project recommended that work be undertaken to study the sealing properties of cement-based grout materials. A new class of cement-based grouts (high-performance grouts) with the ability to penetrate and seal fine fractures in granite was investigated. The materials were selected for their small mean particle size and the ability to be made fluid by a superplasticizer at low water/cementitious-materials ratios. The fundamental physical and chemical properties (such as the particle size and chemical composition) of the materials were evaluated. The rheological properties of freshly mixed grouts, which control the workability of the grouts, were determined together with the properties of hardened materials, which largely control the long-term performance (longevity) of the materials in repository settings. The materials selected were shown to remain gel-like during the setting period, and so the grouts may be expected to remain largely homogenous during and after injection into the rock without separating into solid and liquid phases. The hydraulic conductivity and strength of hardened grouts were determined. The microstructure of the bulk grouts was characterized by a high degree of homogeneity with extremely fine porosity. The low hydraulic conductivity and good mechanical properties are consistent with the extremely fine porosity. The ability of the fractured grouts to self-seal was also observed in tests in which the hydraulic conductivity of recompacted granulated grouts was determined. The laboratory tests were carried out in parallel with investigations of the in situ performance of the materials and with the development of geochemical and theoretical models for cement-based grout longevity. (author). 56 refs., 15 tabs., 98 figs

The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities in Assessing the Degradation of Cementitious Barriers - 13487

Energy Technology Data Exchange (ETDEWEB)

Flach, G.P.; Burns, H.H.; Langton, C.; Smith, F.G. III [Savannah River National Laboratory, Savannah River Site, Aiken SC 29808 (United States); Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S. [Vanderbilt University, Nashville, TN (United States); Van der Sloot, H. [Hans Van der Sloot Consultancy (Netherlands); Meeussen, J.C.L. [Nuclear Research and Consultancy Group, Petten (Netherlands); Samson, E. [SIMCO Technologies Inc., 1400, boul. du Parc-Technologique, Suite 203, Quebec (Canada); Mallick, P.; Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW, Washington, DC (United States); Esh, D.W.; Fuhrmann, M.J.; Philip, J. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)

2013-07-01

The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in K{sub d}/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP

Acid mine drainage abatement resulting from pressure grouting of buried bituminous mine spoils

International Nuclear Information System (INIS)

Scheetz, B.; Silsbee, M.; Schueck, J.

1998-01-01

A 37 acre surface coal mine located in Clinton County, PA, USA, was mined and reclaimed between 1974 and 1977. Buried pyrite-rich pit floor cleanings and tipple refuse were found to be producing severe acid mine drainage. The pyritic material is located in discrete piles or pods in the backfill. The pods and the resulting contaminant plumes were initially defined using geophysical techniques and confirmed by drilling. The approach taken was to use a cementitious grout, composed of fluidized bed combustion ash and water, which would be placed in a manner which would prevent water and oxygen from contacting the pyritic materials. Statistically significant water quality improvements have been noted as a result of the grouting. After four years of post-grouting monitoring, reductions in concentrations of most of the mine drainage parameters range from 40 to 90%. 12 refs., 1 fig., 4 tabs

BLENDED CALCIUM ALUMINATE-CALCIUM SULFATE CEMENT-BASED GROUT FOR P-REACTOR VESSEL IN-SITU DECOMMISSIONING

Energy Technology Data Exchange (ETDEWEB)

Langton, C.; Stefanko, D.

2011-03-10

The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH {<=} 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts [Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010]. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere [Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively]. Radiolysis calculations are also provided in a separate document [Reyes-Jimenez, 2010].

Expansive stresses of a grout plug on the walls of borehole

International Nuclear Information System (INIS)

Licastro, P.H.; Malek, R.I.A.; Roy, D.M.

1985-01-01

The primary function of a concrete plug in a repository seal system is to provide a viable seal at the interface with the host rock by developing and maintaining a positive normal stress across the interface. While standards do exist for unrestrained and restrained expansion of mortar and concrete there are few systems that permit calculation of stress for a stimulated borehole geometry. A system was designed to determine the radial stresses introduced by expansive, cementitious grout on the borehole. It consists of a strain gage instrumented cell and its associated signal conditioner/amplifier. Cell material and thickness can be varied to simulate restraining conditions at given depths. Prior to sample emplacement the cell/system is calibrated by fluid pressurization. Special cell design eliminates the effects of longitudinal stresses during calibration. An analog output as a function of time is recorded, in conjunction with surface temperature of the cylinder. The cell containing grout is maintained under controlled temperature conditions which can be varied from 25 0 C to 90 0 C. Pressure can be applied to the grout column to simulate hydrostatic/geostatic load conditions. Using the equipment described, several expansive grout formulations were studied at 38 0 C. Results obtained for expansive stresses as a function of time are presented together with implications on repository-seal durability

Design of rapid hardening engineered cementitious composites for sustainable construction

Directory of Open Access Journals (Sweden)

Marushchak Uliana

2017-12-01

Full Text Available This paper deals with design of environmentally friendly Rapid Hardening Engineered Cementitious Composite (RHECC nanomodified with ultrafine mineral additives, polycarboxylate ether based superplasticizer, calcium hydrosilicate nanoparticles and dispersal reinforced by fibers. The incremental coefficient of surface activity was proposed in order to estimation of ultrafine supplementary materials (fly ash, methakaolin, microsilica efficiency. A characterization of RHECC’s compressive and flexural properties at different ages is reported in this paper. Early compressive strength of ECC is 45-50 MPa, standard strength – 84-95 MPa and parameter Rc2/Rc28 – 65–70%. The microstructure of the cement matrix and RHECC was investigated. The use of ultrafine mineral supplementary materials provides reinforcement of structure on micro- and nanoscale level (cementing matrix due to formation of sub-microreinforcing hydrate phase as AFt- and C-S-H phases in unclinker part of cement matrix, resulting in the phenomena of “self-reinforcement” on the microstructure level. Designed RHECC may be regarded as lower brittle since the crack resistance coefficient is higher comparison to conventional fine grain concrete.

Design of rapid hardening engineered cementitious composites for sustainable construction

Science.gov (United States)

Marushchak, Uliana; Sanytsky, Myroslav; Sydor, Nazar

2017-12-01

This paper deals with design of environmentally friendly Rapid Hardening Engineered Cementitious Composite (RHECC) nanomodified with ultrafine mineral additives, polycarboxylate ether based superplasticizer, calcium hydrosilicate nanoparticles and dispersal reinforced by fibers. The incremental coefficient of surface activity was proposed in order to estimation of ultrafine supplementary materials (fly ash, methakaolin, microsilica) efficiency. A characterization of RHECC's compressive and flexural properties at different ages is reported in this paper. Early compressive strength of ECC is 45-50 MPa, standard strength - 84-95 MPa and parameter Rc2/Rc28 - 65-70%. The microstructure of the cement matrix and RHECC was investigated. The use of ultrafine mineral supplementary materials provides reinforcement of structure on micro- and nanoscale level (cementing matrix) due to formation of sub-microreinforcing hydrate phase as AFt- and C-S-H phases in unclinker part of cement matrix, resulting in the phenomena of "self-reinforcement" on the microstructure level. Designed RHECC may be regarded as lower brittle since the crack resistance coefficient is higher comparison to conventional fine grain concrete.

Durability 2007. Injection grout investigations. Background description

International Nuclear Information System (INIS)

Orantie, K.; Kuosa, H.

2008-12-01

The aim of this project was to evaluate the durability risks of injection grouts. The investigations were done with respect to the application conditions, materials and service life requirements at the ONKALO underground research facility. The study encompassed injection grout mixtures made of ultrafine cement with and without silica fume. Some of the mixtures hade a low pH and thus a high silica fume content. The project includes a background description on durability literature, laboratory testing programme, detailed analysis of results and recommendations for selecting of ideal grout mixtures. The background description was made for the experimental study of low-pH and reference rock injection grouts as regards pore- and microstructure, strength, shrinkage/swelling and thus versatile durability properties. A summary of test methods is presented as well as examples, i.e. literature information or former test results, of expected range of results from the tests. Also background information about how the test results correlate to other material properties and mix designs is presented. Besides the report provides basic information on the pore structure of cement based materials. Also the correlation between the pore structure of cement based materials and permeability is shortly discussed. The test methods included in the background description are compressive strength, measurement of bulk drying, autogenous and chemical shrinkage and swelling, hydraulic conductivity / permeability, capillary water uptake test, mercury intrusion porosimetry (MIP) and thin section analysis. Three main mixtures with water-binder ratio of 0.8, 1.0 and 1.4 and silica fume content of 0, 15 and 40% were studied in the laboratory. Besides two extra mixtures were studied to provide additional information about the effect of varying water-dry-material ratio and silica fume content on durability. The evaluation of water tightness based on water permeability coefficient and micro cracking was

PSU/WES interlaboratory comparative methodology study of an experimental cementitious repository seal material

International Nuclear Information System (INIS)

Roy, D.M.; Grutzeck, M.W.; Mather, K.

1980-09-01

A study is underway in two separate laboratories to investigate possible use of portland cement grout as repository sealing material for underground isolation of nuclear waste. The labs involved are the Materials Research Laboratory of the Pennsylvania State University (PSU) and the Structures Laboratory (SL) of the US Army Engineer Waterways Experiment Station. The same cementitious (grout) mixture was prepared in each laboratory in September 1980, and tests were started. Testing included characterization of cement and fly ash by chemical, physical, and petrographic procedures. Tests of hardened specimens included restrained expansion, compressive strength, modulus of elasticity, density, permeability, x-ray diffraction, and scanning electron microscopy. Each laboratory made many of the same tests and some that were not directly comparable. This document (Report 1) contains largely 3- and 7-day results and none beyond 28-day ages

An alternative approach to the management of reactive metals: tolerant cementitious systems

International Nuclear Information System (INIS)

Swift, P.; Cox, J.; Wise, M.; McKinney, J.; Rhodes, C.

2015-01-01

In recent years research has focused on preventing or minimising corrosion of reactive metals to ensure long-term waste package integrity. An alternative approach to the encapsulation of reactive metals is being explored. The approach will identify a cementitious-based encapsulating material that will allow corrosion of reactive metals to occur in a controlled and predictable manner, rather than seeking to limit or prevent the corrosion, whilst retaining waste package integrity. A low strength grout will be developed that will be 'tolerant' to the expansive forces generated by the corrosion products of reactive metals. Novel cementitious systems (e.g. foamed cements, rubber composite cements, cenosphere composite cements, lime mortars, bentonite cements etc.) that may be tolerant to potentially expansive waste products, such as reactive metals will be considered and assessed in a series of small-scale preliminary trials (compressive strength, porosity, permeability, pore solution pH, etc.)

Geochemical performance of earthen and cementitious sealing materials for radioactive waste repositories

International Nuclear Information System (INIS)

Melchoir, D.; Glazier, R.; Marton, R.

1988-01-01

Earthen and cementitious materials are proposed as part of the sealing system for radioactive waste repositories. Compacted clay-bearing earthen materials could be used in sealing shafts and shaft entryways; and in the waste emplacement boundary areas in some repository designs. Earthen material mixtures are being considered because they can be engineered and emplaced to achieve low permeabilities, appropriate swelling characteristics, and adequate strength with little tendency to degrade during changing environmental conditions. The proposed earthen sealing materials include sodium and calcium mont-morillonites, illites, and mixtures with graded aggregates of sand. To assess the relative advantages and disadvantages of various pure and mixed materials, important geochemical processes (e.g., ion-exchange, phase transformation, dissolution, and precipitation of secondary minerals) need to be evaluated. These processes could impact seal integrity by changing permeability and/or mineral swell potential. Hydrous calcium-silicate-based cementitious materials such as grouts or concrete might also be used in some proposed sealing systems

Low-pH injection grout for deep repositories. Summary report from a co-operation project between NUMO (Japan), Posiva (Finland) and SKB (Sweden)

International Nuclear Information System (INIS)

Boden, Anders; Sievaenen, Ursula

2005-06-01

The use of standard cementitious material creates pulses of pH in the magnitude of 12-13 in the leachates and release alkalis. Such a high pH is detrimental and also unnecessarily complicates the safety analysis of the repository. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis. Also, according to current understanding, the use of low-pH cement (pH = 11) will not disturb the functioning of the bentonite, although limiting the amount of low-pH cement is recommended. A result of the project is that there are both low-pH cementitious material for grouting larger fractures (= 100 μm) and non-cementitious material for grouting smaller fractures (< 100 μm) that will, after further optimisation work, be recommended for grouting of deep repositories. This project concentrated on the technical development of properties for the low pH grouts. Long-term safety and environmental aspects and durability of materials were preliminarily considered. Continued evaluations have to be carried out. Five systems, e.g. material combinations, were studied in the project: 1. Ordinary Portland Cement + Silica Fume. 'OPC+SF' denotes a binder system that is based mainly on OPC+SF. SF was used in a few commercial forms. The OPC used in this system was mainly UF16 and in some cases Rheocem 900 or white cement. 2. Blast furnace slag. 'Slag' denotes an OPC activated slag based system. Alkali and water glass activation were not examined, because of long-term safety reasons. OPC used in this system was rapid hardening Portland cement. 3. Super sulphate cement. 'SSC' is a slag-based system activated with gypsum and OPC. The OPC used was rapid hardening Portland cement and the gypsum was a very fine grained slurry product. 4. Low-Alkali Cement 'LAC' was introduced to the project by NUMO as a product, ground to fixed fineness by the producer. Neither the mineral composition nor fineness, were modified in the present

Development and Demonstration of Material Properties Database and Software for the Simulation of Flow Properties in Cementitious Materials

Energy Technology Data Exchange (ETDEWEB)

Smith, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Flach, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-03-30

This report describes work performed by the Savannah River National Laboratory (SRNL) in fiscal year 2014 to develop a new Cementitious Barriers Project (CBP) software module designated as FLOExcel. FLOExcel incorporates a uniform database to capture material characterization data and a GoldSim model to define flow properties for both intact and fractured cementitious materials and estimate Darcy velocity based on specified hydraulic head gradient and matric tension. The software module includes hydraulic parameters for intact cementitious and granular materials in the database and a standalone GoldSim framework to manipulate the data. The database will be updated with new data as it comes available. The software module will later be integrated into the next release of the CBP Toolbox, Version 3.0. This report documents the development efforts for this software module. The FY14 activities described in this report focused on the following two items that form the FLOExcel package; 1) Development of a uniform database to capture CBP data for cementitious materials. In particular, the inclusion and use of hydraulic properties of the materials are emphasized; and 2) Development of algorithms and a GoldSim User Interface to calculate hydraulic flow properties of degraded and fractured cementitious materials. Hydraulic properties are required in a simulation of flow through cementitious materials such as Saltstone, waste tank fill grout, and concrete barriers. At SRNL these simulations have been performed using the PORFLOW code as part of Performance Assessments for salt waste disposal and waste tank closure.

Tanks 18 And 19-F Structural Flowable Grout Fill Material Evaluation And Recommendations

International Nuclear Information System (INIS)

Langton, C. A.; Stefanko, D. B.

2013-01-01

Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: 1) physically stabilize the final landfill by filling the empty volume in the tanks with a non-compressible material; 2) provide a barrier for inadvertent intrusion into the tank; 3) reduce contaminant mobility by a) limiting the hydraulic conductivity of the closed tank and b) reducing contact between the residual waste and infiltrating water; and 4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: 1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). 2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. 3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix design. 4

Tanks 18 And 19-F Structural Flowable Grout Fill Material Evaluation And Recommendations

Energy Technology Data Exchange (ETDEWEB)

Langton, C. A.; Stefanko, D. B.

2013-04-23

Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: 1) physically stabilize the final landfill by filling the empty volume in the tanks with a non-compressible material; 2) provide a barrier for inadvertent intrusion into the tank; 3) reduce contaminant mobility by a) limiting the hydraulic conductivity of the closed tank and b) reducing contact between the residual waste and infiltrating water; and 4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: 1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). 2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. 3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix design. 4

Updated Liquid Secondary Waste Grout Formulation and Preliminary Waste Form Qualification

Energy Technology Data Exchange (ETDEWEB)

Saslow, Sarah A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Russell, Renee L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Asmussen, Robert M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sahajpal, Rahul [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-07-01

This report describes the results from liquid secondary waste grout (LSWG) formulation and cementitious waste form qualification tests performed by Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions, LLC (WRPS). New formulations for preparing a cementitious waste form from a high-sulfate liquid secondary waste stream simulant, developed for Effluent Management Facility (EMF) process condensates merged with low activity waste (LAW) caustic scrubber, and the release of key constituents (e.g. ⁹⁹Tc and ¹²⁹I) from these monoliths were evaluated. This work supports a technology development program to address the technology needs for Hanford Site Effluent Treatment Facility (ETF) liquid secondary waste (LSW) solidification and supports future Direct Feed Low-Activity Waste (DFLAW) operations. High-priority activities included simulant development, LSWG formulation, and waste form qualification. The work contained within this report relates to waste form development and testing and does not directly support the 2017 integrated disposal facility (IDF) performance assessment (PA). However, this work contains valuable information for use in PA maintenance past FY17, and for future waste form development efforts. The provided data should be used by (i) cementitious waste form scientists to further understanding of cementitious dissolution behavior, (ii) IDF PA modelers who use quantified constituent leachability, effective diffusivity, and partitioning coefficients to advance PA modeling efforts, and (iii) the U.S. Department of Energy (DOE) contractors and decision makers as they assess the IDF PA program. The results obtained help fill existing data gaps, support final selection of a LSWG waste form, and improve the technical defensibility of long-term waste form performance estimates.

Tanks 18 And 19-F Structural Flowable Grout Fill Material Evaluation And Recommendations

International Nuclear Information System (INIS)

Stefanko, D.; Langton, C.

2011-01-01

Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: (1) physically stabilize the final landfill by filling the empty volume in the tanks with a non compressible material; (2) provide a barrier for inadvertent intrusion into the tank; (3) reduce contaminant mobility by (a) limiting the hydraulic conductivity of the closed tank and (b) reducing contact between the residual waste and infiltrating water; and (4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: (1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). (2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. (3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix

TANKS 18 AND 19-F STRUCTURAL FLOWABLE GROUT FILL MATERIAL EVALUATION AND RECOMMENDATIONS

Energy Technology Data Exchange (ETDEWEB)

Stefanko, D.; Langton, C.

2011-11-01

Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: (1) physically stabilize the final landfill by filling the empty volume in the tanks with a non compressible material; (2) provide a barrier for inadvertent intrusion into the tank; (3) reduce contaminant mobility by (a) limiting the hydraulic conductivity of the closed tank and (b) reducing contact between the residual waste and infiltrating water; and (4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: (1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). (2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. (3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix

Analysis of Technical Status on the Application of Cementitious Materials for Radwaste Repository

International Nuclear Information System (INIS)

Kim, Jin Seop; Kwon, Sang Ki; Cho, Won Jin

2008-12-01

In this report, technical status on the application of cementitious materials and related research trends in Sweden, Switzerland and Japan etc. is listed based on the example of ONKALO in Finland. SKB and POSIVA have defined a pH limit ≤ 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate(CSH) gel with a Ca/Si ratio ≤ 0.8(Savage D. 2007). Silica fume as a blending agent is considered to be most promising for repository low-pH grouts. When adding silica fume to enhance cement quality, it demands high water content in cement paste. Then it is necessary to use additives such as superplasticiser to improve the workability of low-pH cement. Posiva, SKB and NUMO co-operated in developing low-pH grouts for deep repositories 2002-2005. Additionally, it is needed to study more about long-term performance characteristics, interaction of bentonite buffer material with high pH plume, influence on the migration/sorption of radionuclides and their performance numerical modeling. In this regards, international co-research projects such as ESDRED and IAEA CRP are being actively performed

Bench-scale feasibility testing of pulsed-air technology for in-tank mixing of dry cementitious solids with tank liquids and settled solids

International Nuclear Information System (INIS)

Whyatt, G.A.; Hymas, C.R.

1997-09-01

This report documents the results of testing performed to determine the feasibility of using a pulsed-air mixing technology (equipment developed by Pulsair Systems, Inc., Bellevue, WA) to mix cementitious dry solids with supernatant and settled solids within a horizontal tank. The mixing technology is being considered to provide in situ stabilization of the open-quotes Vclose quotes tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). The testing was performed in a vessel roughly 1/6 the scale of the INEEL tanks. The tests used a fine soil to simulate settled solids and water to simulate tank supernatants. The cementitious dry materials consisted of Portland cement and Aquaset-2H (a product of Fluid Tech Inc. consisting of clay and Portland cement). Two scoping tests were conducted to allow suitable mixing parameters to be selected. The scoping tests used only visual observations during grout disassembly to assess mixing performance. After the scoping tests indicated the approach may be feasible, an additional two mixing tests were conducted. In addition to visual observations during disassembly of the solidified grout, these tests included addition of chemical tracers and chemical analysis of samples to determine the degree of mixing uniformity achieved. The final two mixing tests demonstrated that the pulsed-air mixing technique is capable of producing slurries containing substantially more cementitious dry solids than indicated by the formulations suggested by INEEL staff. Including additional cement in the formulation may have benefits in terms of increasing mobilization of solids, reducing water separation during curing, and increasing the strength of the solidified product. During addition to the tank, the cementitious solids had a tendency to form clumps which broke down with continued mixing

Evolution of technetium speciation in reducing grout

Energy Technology Data Exchange (ETDEWEB)

Lukens, Wayne W.; Bucher, Jerome J.; Shuh, David K.; Edelstein,Norman M.

2003-11-24

Cementitious waste forms (CWFs) are an important component of the strategy to immobilize high-level nuclear waste resulting from plutonium production by the U.S. Department of Energy (DOE). Technetium (99Tc) is an abundant fission product of particular concern in CWFs due to the high solubility and mobility of pertechnetate, TcO4-, the stable form of technetium in aerobic environments. CWFs can more effectively immobilize 99Tc if they contain additives that reduce mobile TcO4- to immobile Tc(IV) species. Leaching of 99Tc from reducing CWFs that contain Tc(IV) is much slower than for CWFs containing TcO4-. Previous X-ray absorption fine structure (XAFS) studies showed that the Tc(IV) species were oxidized to TcO4- in reducing grout samples prepared on a laboratory scale. Whether the oxidizer was atmospheric O2 or NO3- in the waste simulant was not determined. In actual CWFs, rapid oxidation of Tc(IV) by NO3- would be a concern, whereas oxidation by atmospheric O2 would be of less concern due to the slow diffusion and reaction of O2 with the reducing CWF. To address this uncertainty, two series of reducing grouts were prepared using TcO4- containing waste simulants with and without NO3-. In the first series of samples, the TcO4- was completely reduced using Na2S, and the samples were placed in containers that permitted O2 diffusion. In these samples, all of the technetium was initially present as aTc(IV) sulfide compound, TcSx, which was characterized using extended X-ray absorption fine structure (EXAFS) spectroscopy, and is likely Tc2S7. The TcSx initially present in the grout samples was steadily oxidized over 4 years. In the second series of samples, all of the TcO4- was not initially reduced, and the grout samples were placed in airtight containers. In these samples, the remaining TcO4- continued to be reduced as the samples aged, presumably due to the presence of reducing blast furnace slag. When samples in the second series were exposed to atmosphere, the

Cementitious Barriers Partnership Accomplishments And Relevance To The DOE Complex

International Nuclear Information System (INIS)

Burns, H.; Langton, C.; Flach, G.; Kosson, D.

2010-01-01

The Cementitious Barriers Partnership (CBP) was initiated to reduce risk and uncertainties in the performance assessments that directly impact U.S. Department of Energy (DOE) environmental cleanup and closure programs. The CBP is supported by the DOE Office of Environmental Management (DOE-EM) and has been specifically addressing the following critical EM program needs: (i) the long-term performance of cementitious barriers and materials in nuclear waste disposal facilities and (ii) increased understanding of contaminant transport behavior within cementitious barrier systems to support the development and deployment of adequate closure technologies. To accomplish this, the CBP has two initiatives: (1) an experimental initiative to increase understanding of changes in cementitious materials over long times (> 1000 years) over changing conditions and (2) a modeling initiative to enhance and integrate a set of computational tools validated by laboratory and field experimental data to improve understanding and prediction of the long-term performance of cementitious barriers and waste forms used in nuclear applications. In FY10, the CBP developed the initial phase of an integrated modeling tool that would serve as a screening tool which could help in making decisions concerning disposal and tank closure. The CBP experimental programs are underway to validate this tool and provide increased understanding of how CM changes over time and under changing conditions. These initial CBP products that will eventually be enhanced are anticipated to reduce the uncertainties of current methodologies for assessing cementitious barrier performance and increase the consistency and transparency of the DOE assessment process. These tools have application to low activity waste forms, high level waste tank closure, D and D and entombment of major nuclear facilities, landfill waste acceptance criteria, and in-situ grouting and immobilization of vadose zone contamination. This paper

Development of cementitious grouts for the incorporation of radioactive wastes. Part 2. Continuation of cesium and strontium leach studies. [Hydrofracture

Energy Technology Data Exchange (ETDEWEB)

Moore, J.G.

1976-09-01

Additional leach studies were completed on the leachability of cesium and strontium from simulated hydrofracture grout. These studies followed the test method proposed by IAEA or a modification which exposed smaller specimens with a higher surface-to-volume ratio to a larger volume of leachant. Results showed that the amount of cesium or strontium leached from the grout varied directly with the degree of drying during curing and inversely with the time of curing. The leachability also depends on the composition of the leachant and varies in the order: distilled water greater than tap water greater than grout water. The total waste concentration had little effect on the leachability of either cesium or strontium. The credibility of the laboratory results was substantiated by a short-term continuous leach test made on a fragment of a core sample of actual hydrofracture grout. The modified effective diffusivities (10/sup -11/ to 10/sup -10/ cm/sup 2//s) calculated from these limited data were comparable to those obtained from laboratory studies containing Grundite clay. These tests also confirmed the effect of various clays on the leachability of cesium and the importance of leachant renewal frequency on the leach rate.

Experimental Study on Fibre-reinforced Cementitious Matrix Confined Concrete Columns under Axial Compression

Directory of Open Access Journals (Sweden)

Lan Zeng

2017-03-01

Full Text Available Poor fire resistance of fibre-reinforced polymer (FRP restricts its further application in construction structures. In this paper, a novel fibre-reinforced cementitious matrix confined concrete column (FRCMCC using fireproof grout as the fibre matrix was developed, and experiments were conducted to establish its performance and analyse the mechanical properties under axial compression. The test results show that its failure mode was more moderate compared to the traditional fibre-reinforced resinous matrix confined concrete column (FRRMCC, and the concrete columns confined with multi-layer fibres and end reinforcement could provide both good strength and ductility.

Secondary Waste Cementitious Waste Form Data Package for the Integrated Disposal Facility Performance Assessment

Energy Technology Data Exchange (ETDEWEB)

Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Serne, R Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cozzi, Alex D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-05-16

A review of the most up-to-date and relevant data currently available was conducted to develop a set of recommended values for use in the Integrated Disposal Facility (IDF) performance assessment (PA) to model contaminant release from a cementitious waste form for aqueous wastes treated at the Hanford Effluent Treatment Facility (ETF). This data package relies primarily upon recent data collected on Cast Stone formulations fabricated with simulants of low-activity waste (LAW) and liquid secondary wastes expected to be produced at Hanford. These data were supplemented, when necessary, with data developed for saltstone (a similar grout waste form used at the Savannah River Site). Work is currently underway to collect data on cementitious waste forms that are similar to Cast Stone and saltstone but are tailored to the characteristics of ETF-treated liquid secondary wastes. Recommended values for key parameters to conduct PA modeling of contaminant release from ETF-treated liquid waste are provided.

Low-pH injection grout for deep repositories. Summary report from a co-operation project between NUMO (Japan), Posiva (Finland) and SKB (Sweden)

Energy Technology Data Exchange (ETDEWEB)

Boden, Anders [SwedPower AB, Stockholm (Sweden); Sievaenen, Ursula [JP-Suoraplan Oy, Vantaa (Finland)

2005-06-01

The use of standard cementitious material creates pulses of pH in the magnitude of 12-13 in the leachates and release alkalis. Such a high pH is detrimental and also unnecessarily complicates the safety analysis of the repository. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis. Also, according to current understanding, the use of low-pH cement (pH = 11) will not disturb the functioning of the bentonite, although limiting the amount of low-pH cement is recommended. A result of the project is that there are both low-pH cementitious material for grouting larger fractures (= 100 {mu}m) and non-cementitious material for grouting smaller fractures (< 100 {mu}m) that will, after further optimisation work, be recommended for grouting of deep repositories. This project concentrated on the technical development of properties for the low pH grouts. Long-term safety and environmental aspects and durability of materials were preliminarily considered. Continued evaluations have to be carried out. Five systems, e.g. material combinations, were studied in the project: 1. Ordinary Portland Cement + Silica Fume. 'OPC+SF' denotes a binder system that is based mainly on OPC+SF. SF was used in a few commercial forms. The OPC used in this system was mainly UF16 and in some cases Rheocem 900 or white cement. 2. Blast furnace slag. 'Slag' denotes an OPC activated slag based system. Alkali and water glass activation were not examined, because of long-term safety reasons. OPC used in this system was rapid hardening Portland cement. 3. Super sulphate cement. 'SSC' is a slag-based system activated with gypsum and OPC. The OPC used was rapid hardening Portland cement and the gypsum was a very fine grained slurry product. 4. Low-Alkali Cement 'LAC' was introduced to the project by NUMO as a product, ground to fixed fineness by the producer. Neither the mineral composition nor

Quality assurance consideration for cement-based grout technology programs at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

McDaniel, E.W.; Tallent, O.K.; Sams, T.L.; Delzer, D.B.

1987-01-01

Oak Ridge National Laboratory has developed and is continuing to refine a method of immobilizing low-level radioactive liquid wastes by mixing them with cementitious dry-solid blends. A quality assurance program is vital to the project because Nuclear Regulatory Commission (NRC), Environmental Protection Agency (EPA) and state environmental regulations must be demonstrably met (the work must be defensible in a court of law). The end result of quality assurance (QA) is, by definition, a product of demonstrable quality. In the laboratory, this entails traceability, repeatability, and credibility. This paper describes the application of QA in grout technology development at Oak Ridge National Laboratory

Cementitious Barriers Partnership FY2013 End-Year Report

Energy Technology Data Exchange (ETDEWEB)

Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States); Langton, C. A. [Savannah River Site (SRS), Aiken, SC (United States); Burns, H. H. [Savannah River Site (SRS), Aiken, SC (United States); Smith, F. G. [Savannah River Site (SRS), Aiken, SC (United States); Kosson, D. S. [Vanderbilt University, School of Engineering, Nashville, TN (United States); Brown, K. G. [Vanderbilt University, School of Engineering, Nashville, TN (United States); Samson, E. [SIMCO Technologies, Inc., Quebec (Canada); Meeussen, J. C.L. [Nuclear Research and Consultancy Group (NRG), Petten (The Netherlands); van der Sloot, H. A. [Hans van der Sloot Consultancy, Langedijk (The Netherlands); Garboczi, E. J. [Materials & Construction Research Division, National Institute of Standards and Technology, Gaithersburg, MD (United States)

2013-11-01

In FY2013, the Cementitious Barriers Partnership (CBP) demonstrated continued tangible progress toward fulfilling the objective of developing a set of software tools to improve understanding and prediction of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. In November 2012, the CBP released “Version 1.0” of the CBP Software Toolbox, a suite of software for simulating reactive transport in cementitious materials and important degradation phenomena. In addition, the CBP completed development of new software for the “Version 2.0” Toolbox to be released in early FY2014 and demonstrated use of the Version 1.0 Toolbox on DOE applications. The current primary software components in both Versions 1.0 and 2.0 are LeachXS/ORCHESTRA, STADIUM, and a GoldSim interface for probabilistic analysis of selected degradation scenarios. The CBP Software Toolbox Version 1.0 supports analysis of external sulfate attack (including damage mechanics), carbonation, and primary constituent leaching. Version 2.0 includes the additional analysis of chloride attack and dual regime flow and contaminant migration in fractured and non-fractured cementitious material. The LeachXS component embodies an extensive material property measurements database along with chemical speciation and reactive mass transport simulation cases with emphasis on leaching of major, trace and radionuclide constituents from cementitious materials used in DOE facilities, such as Saltstone (Savannah River) and Cast Stone (Hanford), tank closure grouts, and barrier concretes. STADIUM focuses on the physical and structural service life of materials and components based on chemical speciation and reactive mass transport of major cement constituents and aggressive species (e.g., chloride, sulfate, etc.). THAMES is a planned future CBP Toolbox component focused on simulation of the microstructure of cementitious materials and calculation of resultant

Strength of Experimental Grouts

DEFF Research Database (Denmark)

Sørensen, Eigil V.

 The present report describes tests carried out on 5 experimental grouts developed by BASF Construction Materials and designed for use in grouted connections of offshore windmill foundations....... The present report describes tests carried out on 5 experimental grouts developed by BASF Construction Materials and designed for use in grouted connections of offshore windmill foundations....

Design for rock grouting based on analysis of grout penetration. Verification using Aespoe HRL data and parameter analysis

International Nuclear Information System (INIS)

Kobayashi, Shinji; Stille, Haakan

2007-01-01

Grouting as a method to reduce the inflow of water into underground facilities will be important in both the construction and operation of the deep repository. SKB has been studying grouting design based on characterization of fractured rock and prediction of grout spread. However, as in other Scandinavian tunnels, stop criteria have been empirically set so that grouting is completed when the grout flow is less than a certain value at maximum pressure or the grout take is above a certain value. Since empirically based stop criteria are determined without a theoretical basis and are not related to grout penetration, the grouting result may be inadequate or uneconomical. In order to permit the choice of adequate and cost-effective grouting methods, stop criteria can be designed based on a theoretical analysis of grout penetration. The relationship between grout penetration and grouting time has been studied at the Royal Institute of Technology and Chalmers University of Technology. Based on these studies, the theory has been further developed in order to apply to real grouting work. Another aspect is using the developed method for parameter analysis. The purpose of parameter analysis is to evaluate the influence of different grouting parameters on the result. Since the grouting strategy is composed of many different components, the selection of a grouting method is complex. Even if the theoretically most suitable grouting method is selected, it is difficult to carry out grouting exactly as planned because grouting parameters such as grout properties can easily vary during the grouting operation. In addition, knowing the parameters precisely beforehand is impossible because there are uncertainties inherent in the rock mass. Therefore, it is important to asses the effects of variations in grouting parameters. The parameter analysis can serve as a guide in choosing an effective grouting method. The objectives of this report are to: Further develop the theory concerning

Tank closure reducing grout

International Nuclear Information System (INIS)

Caldwell, T.B.

1997-01-01

A reducing grout has been developed for closing high level waste tanks at the Savannah River Site in Aiken, South Carolina. The grout has a low redox potential, which minimizes the mobility of Sr 90 , the radionuclide with the highest dose potential after closure. The grout also has a high pH which reduces the solubility of the plutonium isotopes. The grout has a high compressive strength and low permeability, which enhances its ability to limit the migration of contaminants after closure. The grout was designed and tested by Construction Technology Laboratories, Inc. Placement methods were developed by the Savannah River Site personnel

REACTOR GROUT THERMAL PROPERTIES

Energy Technology Data Exchange (ETDEWEB)

Steimke, J.; Qureshi, Z.; Restivo, M.; Guerrero, H.

2011-01-28

Savannah River Site has five dormant nuclear production reactors. Long term disposition will require filling some reactor buildings with grout up to ground level. Portland cement based grout will be used to fill the buildings with the exception of some reactor tanks. Some reactor tanks contain significant quantities of aluminum which could react with Portland cement based grout to form hydrogen. Hydrogen production is a safety concern and gas generation could also compromise the structural integrity of the grout pour. Therefore, it was necessary to develop a non-Portland cement grout to fill reactors that contain significant quantities of aluminum. Grouts generate heat when they set, so the potential exists for large temperature increases in a large pour, which could compromise the integrity of the pour. The primary purpose of the testing reported here was to measure heat of hydration, specific heat, thermal conductivity and density of various reactor grouts under consideration so that these properties could be used to model transient heat transfer for different pouring strategies. A secondary purpose was to make qualitative judgments of grout pourability and hardened strength. Some reactor grout formulations were unacceptable because they generated too much heat, or started setting too fast, or required too long to harden or were too weak. The formulation called 102H had the best combination of characteristics. It is a Calcium Alumino-Sulfate grout that contains Ciment Fondu (calcium aluminate cement), Plaster of Paris (calcium sulfate hemihydrate), sand, Class F fly ash, boric acid and small quantities of additives. This composition afforded about ten hours of working time. Heat release began at 12 hours and was complete by 24 hours. The adiabatic temperature rise was 54 C which was within specification. The final product was hard and displayed no visible segregation. The density and maximum particle size were within specification.

Kaolinitic clay-based grouting demonstration

International Nuclear Information System (INIS)

McCloskey, A.L.; Barry, C.J.; Wilmoth, R.

1997-01-01

An innovative Kaolinitic Clay-Based Grouting Demonstration was performed under the Mine Waste Technology Program (MWTP), funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by the EPA and the U.S. Department of Energy (DOE). The objective of the technology was to demonstrate the effectiveness of kaolinitic clay-based grouting in reducing/eliminating infiltration of surface and shallow groundwater through fractured bedrock into underground mine workings. In 1993, the Mike Horse Mine was selected as a demonstration site for the field implementation and evaluation of the grouting technology. The mine portal discharge ranged between 114 to 454 liters per minute (30 to 120 gpm) of water containing iron, zinc, manganese, and cadmium at levels exceeding the National Drinking Water Maximum Contaminant Levels. The grout formulation was designed by the developer Morrison Knudsen Corporation/Spetstamponazhgeologia (MK/STG), in May 1994. Grout injection was performed by Hayward Baker, Inc. under the directive of MSE Technology Applications, Inc. (MSE-TA) during fall of 1994. The grout was injected into directionally-drilled grout holes to form a grout curtain at the project site. Post grout observations suggest the grout was successful in reducing the infiltration of the surface and shallow groundwater from entering the underground mine workings. The proceeding paper describes the demonstration and technology used to form the subsurface barrier in the fracture system

Preliminary data on rheological limits for grouts in the Transportable Grout Facility

International Nuclear Information System (INIS)

Gilliam, T.M.; McDaniel, E.W.; Dole, L.R.; West, G.A.

1987-04-01

This report describes a method for establishing rheological limits for grouts that can be pumped in the Hanford Transportable Grout Facility (TGF). This method is based on two models that require determining two key parameters - gel strength and density. This work also presents rheological data on grouts prepared with simulated customer phosphate wastes (CPW) and double shell slurry (DSS) from the Hanford complex. These data can be used to make preliminary estimates of operating rheological limits of the TFG grouts. The suggested design limits will include safety factors that will increase these limits significantly. 4 refs

Strength of High Performance Grouts

DEFF Research Database (Denmark)

Sørensen, Eigil V.

The present report describes tests carried out on 5 experimental grouts developed by BASF Construction Materials and designed for use in grouted connections of offshore windmill foundations.......The present report describes tests carried out on 5 experimental grouts developed by BASF Construction Materials and designed for use in grouted connections of offshore windmill foundations....

CEMENTITIOUS BARRIERS PARTNERSHIP FY13 MID-YEAR REPORT

Energy Technology Data Exchange (ETDEWEB)

Burns, H.; Flach, G.; Langton, C.; KOSSON, D.; BROWN, K.; SAMSON, E.; MEEUSSEN, J.; SLOOT, H.; GARBOCZI, E.

2013-05-01

In FY2013, the Cementitious Barriers Partnership (CBP) is continuing in its effort to develop and enhance software tools demonstrating tangible progress toward fulfilling the objective of developing a set of tools to improve understanding and prediction of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. In FY2012, the CBP released the initial inhouse “Beta-version” of the CBP Software Toolbox, a suite of software for simulating reactive transport in cementitious materials and important degradation phenomena. The current primary software components are LeachXS/ORCHESTRA, STADIUM, and a GoldSim interface for probabilistic analysis of selected degradation scenarios. THAMES is a planned future CBP Toolbox component (FY13/14) focused on simulation of the microstructure of cementitious materials and calculation of resultant hydraulic and constituent mass transfer parameters needed in modeling. This past November, the CBP Software Toolbox Version 1.0 was released that supports analysis of external sulfate attack (including damage mechanics), carbonation, and primary constituent leaching. The LeachXS component embodies an extensive material property measurements database along with chemical speciation and reactive mass transport simulation cases with emphasis on leaching of major, trace and radionuclide constituents from cementitious materials used in DOE facilities, such as Saltstone (Savannah River) and Cast Stone (Hanford), tank closure grouts, and barrier concretes. STADIUM focuses on the physical and structural service life of materials and components based on chemical speciation and reactive mass transport of major cement constituents and aggressive species (e.g., chloride, sulfate, etc.). The CBP issued numerous reports and other documentation that accompanied the “Version 1.0” release including a CBP Software Toolbox User Guide and Installation Guide. These documents, as well as, the

Calorimetric examination of hydrofracture grouts

International Nuclear Information System (INIS)

Stinton, D.P.; Berger, R.L.

1985-01-01

A hydrofracture grout sample obtained during the SI-10 injection campaign was studied by calorimetry. The calorimetry curve of this grout was compared with laboratory-produced grout containing simulated wastes. Initiation of the cement-water reaction for the actual grout was delayed several days by the presence of a large quantity of boron in the waste. Although the hydration of cement was delayed, eventually the cement reacted with water and the grout hardened. This test indicates the potential need to analyze sludges for compounds known to retard cement hydration. 10 references, 5 figures, 4 tables

Pressurized grout remote backfilling at AML sites near Beulah and Zap, North Dakota

International Nuclear Information System (INIS)

Weiner, E.J.; Dodd, W.E.

1999-01-01

The Abandoned Mine Lands (AML) Division of the North Dakota Public Service Commission (PSC) is charged with the reclamation of hazardous abandoned mine sites in North Dakota. Several underground lignite coalmines were operated near the cities of Beulah and Zap, North Dakota, from the early 1900's until about 1955. Coal seams in this area were relatively thick and the overburden generally shallow. As these mines have deteriorated with time, deep collapse features, or sinkholes, have surfaced in many areas. These features are very dangerous, especially when they occur at or near residential and commercial areas and public roads. In the past five years, sinkholes have surfaced beneath a commercial building (boat dealership, lounge, and gas station) and beneath a nearby occupied mobile home north of Beulah. sinkholes have also surfaced near KHOL Radio Station in Beulah and in the right of way of a public road south of Zap. The AML Division has conducted several emergency sinkhole-filling projects in these areas. In 1995--97, the AML Division conducted exploratory drilling which confirmed the presence of collapsing underground mines at these sites. The remediation of these sites around Beulah/Zap will take place over several years and involve three or more separate contracts due to budget considerations. In 1997, the AML Division began reclamation at these sties utilizing pressurized grout remote backfilling. In this technique, a cementitious grout is pumped through cased drill holes directly into the mine cavities to fill them and thereby stabilize the surface from collapse. The successful contractor for Phase One of the project was The Concrete Doctor, Inc. (TCDI). This paper will concentrate on Phase One of this work performed from June through September 1997. This project is especially interesting because grout was pumped through holes drilled inside the occupied commercial building. Grout was also pumped through angled holes that intercepted mined workings directly

Pressurized grout remote backfilling at AML sites near Beulah and Zap, North Dakota

Energy Technology Data Exchange (ETDEWEB)

Weiner, E.J.; Dodd, W.E.

1999-07-01

The Abandoned Mine Lands (AML) Division of the North Dakota Public Service Commission (PSC) is charged with the reclamation of hazardous abandoned mine sites in North Dakota. Several underground lignite coalmines were operated near the cities of Beulah and Zap, North Dakota, from the early 1900's until about 1955. Coal seams in this area were relatively thick and the overburden generally shallow. As these mines have deteriorated with time, deep collapse features, or sinkholes, have surfaced in many areas. These features are very dangerous, especially when they occur at or near residential and commercial areas and public roads. In the past five years, sinkholes have surfaced beneath a commercial building (boat dealership, lounge, and gas station) and beneath a nearby occupied mobile home north of Beulah. sinkholes have also surfaced near KHOL Radio Station in Beulah and in the right of way of a public road south of Zap. The AML Division has conducted several emergency sinkhole-filling projects in these areas. In 1995--97, the AML Division conducted exploratory drilling which confirmed the presence of collapsing underground mines at these sites. The remediation of these sites around Beulah/Zap will take place over several years and involve three or more separate contracts due to budget considerations. In 1997, the AML Division began reclamation at these sties utilizing pressurized grout remote backfilling. In this technique, a cementitious grout is pumped through cased drill holes directly into the mine cavities to fill them and thereby stabilize the surface from collapse. The successful contractor for Phase One of the project was The Concrete Doctor, Inc. (TCDI). This paper will concentrate on Phase One of this work performed from June through September 1997. This project is especially interesting because grout was pumped through holes drilled inside the occupied commercial building. Grout was also pumped through angled holes that intercepted mined workings

Study of furfural-urea grout

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

An analysis of raw materials, formulation and performance of furfural-urea grout is given. Characteristics of the grout slurry, mechanism of stabilization and examples of shaft sinking with grouting in quicksand are summarized.

Grouting Applications in Cindere Dam

Directory of Open Access Journals (Sweden)

Devrim ALKAYA

2011-01-01

Full Text Available Grouting is one of the most popular method to control the water leakage in fill dam constructions. With this regard this method is widely used in all the world. Geological and geotechnical properties of rock are important parameters affect the design of grouting. In this study, geotechnical properties of Cindere Dam's base rock and the grouting prosedure have been investigated with grouting pressure.

Grout to meet physical and chemical requirements for closure at Hanford grout vaults. Final report

International Nuclear Information System (INIS)

1994-01-01

The US Army Engineer Waterways Experiment Station (WES) developed a grout based on portland cement, Class F fly ash, and bentonite clay, for the Hanford Grout Vault Program. The purpose of this grout was to fill the void between a wasteform containing 106-AN waste and the vault cover blocks. Following a successful grout development program, heat output, volume change, and compressive strength were monitored with time in simulated repository conditions and in full-depth physical models. This research indicated that the cold-cap grout could achieve and maintain adequate volume stability and other required physical properties in the internal environment of a sealed vault. To determine if contact with 106-AN liquid waste would cause chemical deterioration of the cold-cap grout, cured specimens were immersed in simulated waste. Over a period of 21 days at 150 F, specimens increased in mass without significant changes in volume. X-ray diffraction of reacted specimens revealed crystallization of sodium aluminum silicate hydrate. Scanning electron microscopy used with X-ray fluorescence showed that clusters if this phase had formed in grout pores, increasing grout density and decreasing its effective porosity. Physical and chemical tests collectively indicate a sealing component. However, the Hanford Grout Vault Program was cancelled before completion of this research. This report summarizes close-out Waterways Experiment Station when the Program was cancelled

Repair, Evaluation, Maintenance, and Rehabilitation Research Program. State-of-the-Art Procedures for Sealing Coastal Structures with Grouts and Concretes

Science.gov (United States)

1989-04-01

the shape it had as it was ex- truded from the grout tube . Figure 3 shows the type of voids in which the ma- terial is expected to form a barrier...has promising characteristics for coastal engi- neering applications. Microfine Cement, a company which markets ultrafine ce- ment, claims the product...can penetrate fine sand, and is strong and durable with a 4- to 5-hr set time. Fifty percent of Microfine Cement’s particles are less than 4 microns

Quantitative modelling of the degradation processes of cement grout. Project CEMMOD

Energy Technology Data Exchange (ETDEWEB)

Grandia, Fidel; Galindez, Juan-Manuel; Arcos, David; Molinero, Jorge (Amphos21 Consulting S.L., Barcelona (Spain))

2010-05-15

Grout cement is planned to be used in the sealing of water-conducting fractures in the deep geological storage of spent nuclear fuel waste. The integrity of such cementitious materials should be ensured in a time framework of decades to a hundred of years as mimum. However, their durability must be quantified since grout degradation may jeopardize the stability of other components in the repository due to the potential release of hyperalkaline plumes. The model prediction of the cement alteration has been challenging in the last years mainly due to the difficulty to reproduce the progressive change in composition of the Calcium-Silicate-Hydrate (CSH) compounds as the alteration proceeds. In general, the data obtained from laboratory experiments show a rather similar dependence between the pH of pore water and the Ca-Si ratio of the CSH phases. The Ca-Si ratio decreases as the CSH is progressively replaced by Si-enriched phases. An elegant and reasonable approach is the use of solid solution models even keeping in mind that CSH phases are not crystalline solids but gels. An additional obstacle is the uncertainty in the initial composition of the grout to be considered in the calculations because only the recipe of low-pH clinker is commonly provided by the manufacturer. The hydration process leads to the formation of new phases and, importantly, creates porosity. A number of solid solution models have been reported in literature. Most of them assumed a strong non-ideal binary solid solution series to account for the observed changes in the Ca-Si ratios in CSH. However, it results very difficult to reproduce the degradation of the CSH in the whole Ca-Si range of compositions (commonly Ca/Si=0.5-2.5) by considering only two end-members and fixed nonideality parameters. Models with multiple non-ideal end-members with interaction parameters as a function of the solid composition can solve the problem but these can not be managed in the existing codes of reactive

Grouting aid for controlling the separation of water for cement grout for grouting vertical tendons in nuclear concrete pressure vessels

International Nuclear Information System (INIS)

Schupack, M.

1976-01-01

Considerable testing and development work has led to grouting procedures which can successfully grout 60 m and taller tendons in containment structures. The exaggerated water separation phenomena of strand tendons can be controlled by chemical admixtures using proper mixing and pumping procedures. Experience with both vertical six-bar tendons and large capacity strand type tendons are described. History, development work, characteristics of grout using the admixtures, mixing and pumping procedure, full scale tests and practical applications are included. (author)

In situ grouting of low-level burial trenches with a cement-based grout

International Nuclear Information System (INIS)

Francis, C.W.; Spalding, B.P.

1991-01-01

A restoration technology being evaluated for use in the closure of one of the low-level radwaste burial grounds at Oak Ridge National Laboratory (ORNL) is trench stabilization using a cement-based grout. To demonstrate the applicability and effectiveness of this technology, two interconnecting trenches in Solid Waste Storage Area 6 (SWSA 6) were selected as candidates for in situ grouting with a particulate grout. The primary objective was to demonstrate the increased trench stability and decreased potential for leachate migration following in situ injection of a particulate grout into the waste trenches. Stability against trench subsidence is a critical issue. 7 refs., 3 figs., 5 tabs

Cementitious waste option scoping study report

International Nuclear Information System (INIS)

Lee, A.E.; Taylor, D.D.

1998-02-01

A Settlement Agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) on the Idaho National Engineering and Environmental Laboratory (INEEL) will be treated so that it is ready to be moved out of Idaho for disposal by a target date of 2035. This study investigates the nonseparations Cementitious Waste Option (CWO) as a means to achieve this goal. Under this option all liquid sodium-bearing waste (SBW) and existing HLW calcine would be recalcined with sucrose, grouted, canisterized, and interim stored as a mixed-HLW for eventual preparation and shipment off-Site for disposal. The CWO waste would be transported to a Greater Confinement Disposal Facility (GCDF) located in the southwestern desert of the US on the Nevada Test Site (NTS). All transport preparation, shipment, and disposal facility activities are beyond the scope of this study. CWO waste processing, packaging, and interim storage would occur over a 5-year period between 2013 and 2017. Waste transport and disposal would occur during the same time period

Cementitious waste option scoping study report

Energy Technology Data Exchange (ETDEWEB)

Lee, A.E.; Taylor, D.D.

1998-02-01

A Settlement Agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) on the Idaho National Engineering and Environmental Laboratory (INEEL) will be treated so that it is ready to be moved out of Idaho for disposal by a target date of 2035. This study investigates the nonseparations Cementitious Waste Option (CWO) as a means to achieve this goal. Under this option all liquid sodium-bearing waste (SBW) and existing HLW calcine would be recalcined with sucrose, grouted, canisterized, and interim stored as a mixed-HLW for eventual preparation and shipment off-Site for disposal. The CWO waste would be transported to a Greater Confinement Disposal Facility (GCDF) located in the southwestern desert of the US on the Nevada Test Site (NTS). All transport preparation, shipment, and disposal facility activities are beyond the scope of this study. CWO waste processing, packaging, and interim storage would occur over a 5-year period between 2013 and 2017. Waste transport and disposal would occur during the same time period.

In situ grouting of low-level burial trenches with a cement-based grout

International Nuclear Information System (INIS)

Francis, C.W.; Spalding, B.P.

1991-01-01

A restoration technology being evaluated for use in the closure of one of the low-level radwaste burial grounds at Oak Ridge National Laboratory (ORNL) is trench stabilization using a cement-based grout. To demonstrate the applicability and effectiveness of this technology, two interconnecting trenches in Solid Waste Storage Area 6 (SWSA 6) were selected as candidates for in situ grouting with a particulate grout. The primary objective was to demonstrate the increased trench stability and decreased potential for leachate migration following in situ injection of a particulate grout into the waste trenches. Stability against trench subsidence is a critical issue. After grouting, soil-penetration tests disclosed that stability had been improved greatly. For example, refusal (defined as > 100 blows to penetrate 1 ft) was encountered in 17 of the 22 tests conducted within the trench area. Mean refusal depths for the two trenches were 3.5 and 2.6 m. Stability of the trench was significantly better than pregrout conditions, and at depths > 2.4 m, the stability was very near that observed in the native soil formation outside the trench. Tests within the trench showed lower stability within this range probably because of the presence of intermediate-sized soil voids (formed during backfilling) that were too small to be penetrated and filled by the conventional cement grout formulation. Hydraulic conductivity within the trench remained very high (>0.1 cm/s) and significantly greater than outside the trench. Postgrout air pressurization tests also revealed a large degree of intervoid linkage within and between the two trenches. To effectively reduce hydraulic conductivity and to develop stability within the upper level of the trench, injection of a clay/microfine cement grout into the upper level of the grouted trench is planned

Cost estimate of grouting the proposed test pits at Idaho National Engineering Laboratory using the ORNL-recommended grouts

International Nuclear Information System (INIS)

Spence, R.D.

1987-08-01

EG and G Idaho will construct three experimental pits to simulate the TRU waste trenches at Idaho National Engineering Laboratory (INEL). Two of these pits will be grouted and then one will be destructively examined as soon as the grout cures and the other will be monitored for 10 years. Oak Ridge National Laboratory (ORNL) is evaluating grouts and will recommend a grout to EG and G Idaho to reduce the permeability of the pit, fill the large voids, and encapsulate the waste. A previous ORNL report (ORNL/TM-9881) discusses the grouts evaluated and the grout recommended based on those evaluations. This report evaluates the economics of grouting the experimental pits. The cost of double grouting two of the EG and G Idaho design pits at the Idaho National Engineering Laboratory using lance injection was estimated to be $100,000. Jet grouting the same two pits was estimated to cost $85,000. Both should be tried as part of the test EG and G Idaho is conducting

Rheological characterization of cementitious grouts used to dispose of intermediate-level radioactive waste by hydrofracturing at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

McDaniel, E.W.; Moore, J.G.

1981-01-01

The hydrofracturing process is a waste disposal process in use at the Oak Ridge National Laboratory for the permanent disposal of locally generated waste solutions. This process is now being modified for use in the disposal of sludge that results from the sodium hydroxide neutralization of acid waste solutions. In this process, the sludges will be slurried in a bentonite clay suspension and mixed with a solids blend of cement and other additives. The amount of dry solids required for each liter of waste slurry will be determined from a rheogram that relates the viscosity of the slurry with the grams per liter recommended for grouts with desirable flow properties. A description of the process and the development of rheograms are included. Data are presented on the use of chemical additives to control the flow properties of grouts

Grout Facilities standby plan

Energy Technology Data Exchange (ETDEWEB)

Claghorn, R.D.; Kison, P.F.; Nunamaker, D.R.; Yoakum, A.K.

1994-09-29

This plan defines how the Grout Facilities will be deactivated to meet the intent of the recently renegotiated Tri-Party Agreement (TPA). The TPA calls for the use of the grout process as an emergency option only in the event that tank space is not available to resolve tank safety issues. The availability of new tanks is expected by 1997. Since a grout startup effort would take an estimated two years, a complete termination of the Grout Disposal Program is expected in December 1995. The former Tank Waste Remediation (TWRS) Strategy, adopted in 1988, called for the contents of Hanford`s 28 newer double-shell waste tanks to be separated into high-level radioactive material to be vitrified and disposed of in a geologic repository; low-level wastes were to be sent to the Grout Facility to be made into a cement-like-mixture and poured into underground vaults at Hanford for disposal. The waste in the 149 older single-shell tanks (SST) were to undergo further study and analysis before a disposal decision was made.

Grout Facilities standby plan

International Nuclear Information System (INIS)

Claghorn, R.D.; Kison, P.F.; Nunamaker, D.R.; Yoakum, A.K.

1994-01-01

This plan defines how the Grout Facilities will be deactivated to meet the intent of the recently renegotiated Tri-Party Agreement (TPA). The TPA calls for the use of the grout process as an emergency option only in the event that tank space is not available to resolve tank safety issues. The availability of new tanks is expected by 1997. Since a grout startup effort would take an estimated two years, a complete termination of the Grout Disposal Program is expected in December 1995. The former Tank Waste Remediation (TWRS) Strategy, adopted in 1988, called for the contents of Hanford's 28 newer double-shell waste tanks to be separated into high-level radioactive material to be vitrified and disposed of in a geologic repository; low-level wastes were to be sent to the Grout Facility to be made into a cement-like-mixture and poured into underground vaults at Hanford for disposal. The waste in the 149 older single-shell tanks (SST) were to undergo further study and analysis before a disposal decision was made

Autogenous healing properties of cement-based grouts

International Nuclear Information System (INIS)

Onofrei, M.; Roe, L.; Shenton, B.

1997-05-01

This report presents the results of a study conducted to provide information on the ability of cement-based grouts to self-seal. Autogenous sealing was investigated both on bulk grouts and in thin films of grouts. In both cases, the self-sealing capabilities of the cement-based grouts were investigated with water flowing through the grout. Autogenous sealing was studied through changes in pore structure (decrease in pore radius and volume of pores) and changes in the rate of water flow through the cement-based grouts. (author)

Use of Cementitious Materials for SRS Reactor Facility In-Situ Decommissioning

International Nuclear Information System (INIS)

Langton, C.A.; Stefanko, D.B.; Serrato, M.G.; Blankenship, J.K.; Griffin, W.G.; Long, J.T.

2013-01-01

The United States Department of Energy (US DOE) concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate intact, structurally sound facilities that are no longer needed for their original purpose of producing (reactor facilities), processing (isotope separation facilities) or storing radioactive materials. The Savannah River Site 105-P and 105-R Reactor Facility ISD project requires approximately 250000 cubic yards of cementitious materials to fill the below-grade structure. The fills are designed to prevent subsidence, reduce water infiltration, and isolate contaminated materials. This work is being performed as a Comprehensive Environmental Response, Compensations and Liability Act (CERCLA) action and is part of the overall soil and groundwater completion projects for P- and R-Areas. Funding is being provided under the American Recovery and Reinvestment Act (ARRA). Cementitious materials were designed for the following applications: (A) Below-grade massive voids / rooms: Portland cement-based structural flowable fills for: (A.1) Bulk filling; (A.2) Restricted placement and (A.3) Underwater placement. (B) Special below-grade applications for reduced load bearing capacity needs: (B.1) Cellular portland cement lightweight fill. (C) Reactor vessel fills that are compatible with reactive metal (aluminum metal) components in the reactor vessels (C.1) Blended calcium aluminate - calcium sulfate based flowable fill; (C.2) Magnesium potassium phosphate flowable fill. (D) Caps to prevent water infiltration and intrusion into areas with the highest levels of radionuclides: (D.1) Portland cement based shrinkage compensating concrete. A system engineering approach was used to identify functions and requirements of the fill and capping materials. Laboratory testing was performed to identify candidate formulations and develop final design mixes. Scale-up testing was performed to verify material production and placement as well as fresh and cured

Grouting mixture

Energy Technology Data Exchange (ETDEWEB)

Klyusov, A A; Bakshutov, V S; Kulyavtsev, V A

1980-10-23

A grouting mixture is proposed for low-temperature boreholes. The mixture contains cement, beta gypsum polyhydrate, and calcium chloride, so as to increase the water resistance and strength properties of expanding brick at conditions from 20 to -5/sup 0/ C, the components are in the following ratios: (by wt.-%): cement, 77.45-88.06; beta gypsum polyhydrate, 9.79-19.36; calcium chloride, 2.15-3.19. Grouting mortar for cold boreholes serves as the cement.

In situ grouting of buried transuranic waste

International Nuclear Information System (INIS)

Spalding, B.P.; Lee, S.Y.

1987-01-01

This task is a demonstration and evaluation of the in situ hydrologic stabilization of buried transuranic waste at a humid site via grout injection. Two small trenches, containing buried transuranic waste, were filled with 34,000 liters of polyacrylamide grout. Initial field results have indicated that voids within the trenches were totally filled by the grout and that the intratrench hydraulic conductivity was reduced to below field-measurable values. The grout was also completely contained within the two trenches as no grout constituents were observed in the 12 perimeter ground water monitoring wells. Polyacrylamide grout was selected for field demonstration over polyacrylate grout because of its superior performance in laboratory degradation studies. Also supporting the selection of polyacrylamide was the difficulty of controlling the set time of the acrylate polymerization process in the presence of potassium ferricyanide. Based on preliminary degradation monitoring, polyacrylamide was estimated to have a microbiological half-life of 115 years in the test soil. However, this calculated value is likely to be conservatively low because microbial degradation of the grout set accelerator or residual monomer may be contributing most to the measured microbial respiration. Addition work, using 14 C-labeled acrylate and acrylamide grouts, is being carried out to more accurately estimate the grouts' microbiological half-life

Innovative grout/retrieval demonstration final report

International Nuclear Information System (INIS)

Loomis, G.G.; Thompson, D.N.

1995-01-01

This report presents the results of an evaluation of an innovative retrieval technique for buried transuranic waste. Application of this retrieval technique was originally designed for full pit retrieval; however, it applies equally to a hot spot retrieval technology. The technique involves grouting the buried soil waste matrix with a jet grouting procedure, applying an expansive demolition grout to the matrix, and retrieving the debris. The grouted matrix provides an agglomeration of fine soil particles and contaminants resulting in an inherent contamination control during the dusty retrieval process. A full-scale field demonstration of this retrieval technique was performed on a simulated waste pit at the Idaho National Engineering Laboratory. Details are reported on all phases of this proof-of-concept demonstration including pit construction, jet grouting activities, application of the demolition grout, and actual retrieval of the grouted pit. A quantitative evaluation of aerosolized soils and rare earth tracer spread is given for all phases of the demonstration, and these results are compared to a baseline retrieval activity using conventional retrieval means. 8 refs., 47 figs., 10 tabs

Use Of Cementitious Materials For SRS Reactor Facility In-Situ Decommissioning - 11620

International Nuclear Information System (INIS)

Langton, C.; Stefanko, D.; Serrato, M.; Blankenship, J.; Griffin, W.; Waymer, J.; Matheny, D.; Singh, D.

2010-01-01

The United States Department of Energy (US DOE) concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate in tact, structurally sound facilities that are no longer needed for their original purpose of, i.e., producing (reactor facilities), processing (isotope separation facilities) or storing radioactive materials. The Savannah River Site 105-P and 105-R Reactor Facility ISD requires about 250,000 cubic yards of grout to fill the below grade structure. The fills are designed to prevent subsidence, reduce water infiltration, and isolate contaminated materials. This work is being performed as a Comprehensive Environmental Response, Compensations and Liability Act (CERCLA) action and is part of the overall soil and groundwater completion projects for P- and R-Areas. Cementitious materials were designed for the following applications: (1) Below grade massive voids/rooms: Portland cement-based structural flowable fills for - Bulk filling, Restricted placement and Underwater placement. (2) Special below grade applications for reduced load bearing capacity needs: Cellular portland cement lightweight fill (3) Reactor vessel fills that are compatible with reactive metal (aluminum metal) components in the reactor vessels: Calcium sulfoaluminate flowable fill, and Magnesium potassium phosphate flowable fill. (4) Caps to prevent water infiltration and intrusion into areas with the highest levels of radionuclides: Portland cement based shrinkage compensating concrete. A system engineering approach was used to identify functions and requirements of the fill and capping materials. Laboratory testing was performed to identify candidate formulations and develop final design mixes. Scale-up testing was performed to verify material production and placement as well as fresh and cured properties. The 105-P and 105-R ISD projects are currently in progress and are expected to be complete in 2012. The focus of this paper is to describe the (1) grout mixes

USE OF CEMENTITIOUS MATERIALS FOR SRS REACTOR FACILITY IN-SITU DECOMMISSIONING - 11620

Energy Technology Data Exchange (ETDEWEB)

Langton, C.; Stefanko, D.; Serrato, M.; Blankenship, J.; Griffin, W.; Waymer, J.; Matheny, D.; Singh, D.

2010-12-07

The United States Department of Energy (US DOE) concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate in tact, structurally sound facilities that are no longer needed for their original purpose of, i.e., producing (reactor facilities), processing (isotope separation facilities) or storing radioactive materials. The Savannah River Site 105-P and 105-R Reactor Facility ISD requires about 250,000 cubic yards of grout to fill the below grade structure. The fills are designed to prevent subsidence, reduce water infiltration, and isolate contaminated materials. This work is being performed as a Comprehensive Environmental Response, Compensations and Liability Act (CERCLA) action and is part of the overall soil and groundwater completion projects for P- and R-Areas. Cementitious materials were designed for the following applications: (1) Below grade massive voids/rooms: Portland cement-based structural flowable fills for - Bulk filling, Restricted placement and Underwater placement. (2) Special below grade applications for reduced load bearing capacity needs: Cellular portland cement lightweight fill (3) Reactor vessel fills that are compatible with reactive metal (aluminum metal) components in the reactor vessels: Calcium sulfoaluminate flowable fill, and Magnesium potassium phosphate flowable fill. (4) Caps to prevent water infiltration and intrusion into areas with the highest levels of radionuclides: Portland cement based shrinkage compensating concrete. A system engineering approach was used to identify functions and requirements of the fill and capping materials. Laboratory testing was performed to identify candidate formulations and develop final design mixes. Scale-up testing was performed to verify material production and placement as well as fresh and cured properties. The 105-P and 105-R ISD projects are currently in progress and are expected to be complete in 2012. The focus of this paper is to describe the (1) grout mixes

Feasibility of permeation grouting for constructing subsurface barriers

International Nuclear Information System (INIS)

Dwyer, B.P.

1994-04-01

Efforts are being made to devise technologies that provide interim containment of waste sites while final remediation alternatives are developed. Permeation grouting, a technique used extensively in the civil and mining engineering industry has been investigated as a method for emplacing a subsurface containment barrier beneath existing waste sites. Conceptually an underlying barrier is placed by injecting grout into the formation at less than fracturing pressure from a series of directionally drilled boreholes beneath the waste site. This study evaluated the penetration and performance characteristics in varying soil conditions of four different grout materials (two microfine cements, mineral wax, and sodium silicate) at a field scale. Field testing consisted of grout injection via sleeve (tube-a'-manchette) pipe into both vertical and horizontal borehole configurations at the Mixed Waste Landfill Integrated Demonstration site at Sandia National Laboratories. Prior to, during, and after grout injection non-intrusive geophysical techniques were used to map grout flow. Following the tests, the site was excavated to reveal details of the grout permeation, and grouted soil samples were cored for laboratory characterization. The non-intrusive and intrusive grout mapping showed preferential flow patterns, i.e., the grout tended to follow the path of least resistance. Preliminary testing indicates that permeation grouting is a feasible method for emplacing a low permeability subsurface barrier in the semi-arid unconsolidated alluvial soils common to the Southwest. Despite the success of this project, difficulties in predicting grout flow in heterogeneous soils and non-intrusive methods for imaging grout location and continuity are issues that need more attention

Quantitative modelling of the degradation processes of cement grout. Project CEMMOD

International Nuclear Information System (INIS)

Grandia, Fidel; Galindez, Juan-Manuel; Arcos, David; Molinero, Jorge

2010-05-01

Grout cement is planned to be used in the sealing of water-conducting fractures in the deep geological storage of spent nuclear fuel waste. The integrity of such cementitious materials should be ensured in a time framework of decades to a hundred of years as mimum. However, their durability must be quantified since grout degradation may jeopardize the stability of other components in the repository due to the potential release of hyperalkaline plumes. The model prediction of the cement alteration has been challenging in the last years mainly due to the difficulty to reproduce the progressive change in composition of the Calcium-Silicate-Hydrate (CSH) compounds as the alteration proceeds. In general, the data obtained from laboratory experiments show a rather similar dependence between the pH of pore water and the Ca-Si ratio of the CSH phases. The Ca-Si ratio decreases as the CSH is progressively replaced by Si-enriched phases. An elegant and reasonable approach is the use of solid solution models even keeping in mind that CSH phases are not crystalline solids but gels. An additional obstacle is the uncertainty in the initial composition of the grout to be considered in the calculations because only the recipe of low-pH clinker is commonly provided by the manufacturer. The hydration process leads to the formation of new phases and, importantly, creates porosity. A number of solid solution models have been reported in literature. Most of them assumed a strong non-ideal binary solid solution series to account for the observed changes in the Ca-Si ratios in CSH. However, it results very difficult to reproduce the degradation of the CSH in the whole Ca-Si range of compositions (commonly Ca/Si=0.5-2.5) by considering only two end-members and fixed nonideality parameters. Models with multiple non-ideal end-members with interaction parameters as a function of the solid composition can solve the problem but these can not be managed in the existing codes of reactive

Fatigue Life of High Performance Grout for Wind Turbine Grouted Connection in Wet or Dry Environment

DEFF Research Database (Denmark)

Sørensen, Eigil V.; Westhof, Luc; Yde, Elo

Grouted connections of monopile supported offshore wind turbine structures are subjected to loads leading to very high oscillating service stresses in the grout material. The fatigue capacity of a high performance cement based grout was tested by dynamic compressive loading of cylindrical specimens...... at varying levels of cyclic frequency and load. The fatigue tests were performed in two series: one with the specimens in air and one with the specimens submerged in water during the test. The fatigue life of the grout, in terms of the number of cycles to failure, was found to be significantly shorter when...... tested in water than when tested in air....

Colloidal silica-grouting in demonstration tunnel 2 in ONKALO

International Nuclear Information System (INIS)

Hollmen, K.; Sievaenen, U.; Funehag, J.; Granberg, N.; Lyytinen, T.; Syrjaenen, P.

2013-12-01

Posiva carried out grouting using colloidal silica as the grouting material and with the time stop method as the design approach.Three fans were pre-grouted at Posiva Oy's research space ONKALO demonstration tunnel 2 in autumn 2011 and early winter 2012. Colloidal silica is a mix of one-component colloidal silica and accelerator. Before gelling, colloidal silica behaves like a Newtonian liquid. Colloidal silica's efficiency of penetrating hydraulic apertures in small fractures in rock is significantly better than that of cement-based grout. The grouting design was based on an analytical calculation model. A new technique was used in the grouting implementation, which primarily differed from the previous technique in regard to vacuum pumping and packers. The goal of the first grouting fan in the demonstration tunnel was to check the functionality of the equipment and the method; therefore, the fan was drilled into rock mass with no hydraulic conducting fractures. The second grouting fan was drilled into rock mass with an observed fairly low hydraulic conductivity that was lower than the start criterion established in Posiva Oy's requirements to manage groundwater inflows. Nevertheless, the grouting was carried out. The sealing effect was estimated from the control holes, and a slight improvement in sealing was noted. The holes of the third grouting fan clearly penetrated a water conductive rock mass. The grouting was carried out in two phases, in which the new holes in the second phase were drilled between the existing ones that were drilled in the first phase. In the third fan, the grouting holes of the first phase were noted to be significantly crooked and the second phase grouting holes were drilled in locations that differed from the original design. The quantity of grouting holes was increased in the second phase. The sealing effect was estimated by monitoring the second phase holes and control holes. Based on observations from the control holes

Theoretical investigations of grout seal longevity - Final report

International Nuclear Information System (INIS)

Alcorn, S.; Coons, W.; Christian-Frear, T.; Wallace, M.

1992-04-01

Theoretical investigations into the longevity of repository seals have dealt primarily with the development of a methodology to evaluate interactions between portland cement-based grout and groundwater. Evaluation of chemical thermodynamic equilibria between grout and groundwater, and among grout, groundwater, and granitic host rock phases using the geochemical codes EQ3NR/EQ6 suggests that a fracture filled with grout and saturated with groundwater will tend to fill and 'tighten' with time. Results of these investigations suggest that cement grout seals will maintain an acceptable level of performance for tens of thousands to millions of years, provided the repository is sited where groundwater chemistry is compatible with the seals and hydrologic gradients are low. The results of the grout: groundwater: rock calculations suggest that buffering of the fracture seals chemical systems by the granite rock may be important in determining the long-term fate of grout seals and the resulting phase assemblage in the fracture. The similarity of the modelled reaction products to those observed in naturally filled fractures suggests that with time equilibrium will be approached and grouted fractures subject to low hydrologic gradients will continue to seal. If grout injected into fractures materially reduces groundwater flux, the approach to chemical equilibrium will likely be accelerated. In light of this, even very thin or imperfectly grouted fractures would tighten in suitable hydrogeologic environments. (29 refs.) (au)

Gas generation from Hanford grout samples

International Nuclear Information System (INIS)

Jonah, C.D.; Kapoor, S.; Matheson, M.S.; Mulac, W.A.; Meisel, D.

1996-01-01

In an extension of our work on the radiolytic processes that occur in the waste tanks at the Hanford site, we studied the gas generation from grout samples that contained nuclear waste simulants. Grout is one option for the long-term storage of low-level nuclear waste solutions but the radiolytic effects on grout have not been thoroughly defined. In particular, the generation of potentially flammable and hazardous gases required quantification. A research team at Argonne examined this issue and found that the total amount of gases generated radiolytically from the WHC samples was an order of magnitude higher than predicted. This implies that novel pathways fro charge migration from the solid grout to the associated water are responsible for gas evolution. The grout samples produced hydrogen, nitrous oxide, and carbon monoxide as well as nitrogen and oxygen. Yields of each of these substances were determined for doses that are equivalent to about 80 years storage of the grout. Carbon monoxide, which was produced in 2% yield, is of particular importance because even small amounts may adversely affect catalytic conversion instrumentation that has been planned for installation in the storage vaults

PHYSICAL PROPERTY MEASUREMENTS OF LABORATORY PREPARED SALTSTONE GROUT

Energy Technology Data Exchange (ETDEWEB)

Hansen, E.; Cozzi, A.; Edwards, T.

2014-05-05

The Saltstone Production Facility (SPF) built two new Saltstone Disposal Units (SDU), SDU 3 and SDU 5, in 2013. The variable frequency drive (VFD) for the grout transfer hose pump tripped due to high current demand by the motor during the initial radioactive saltstone transfer to SDU 5B on 12/5/2013. This was not observed during clean cap processing on July 5, 2013 to SDU 3A, which is a slightly longer distance from the SPF than is SDU 5B. Saltstone Design Authority (SDA) is evaluating the grout pump performance and capabilities to transfer the grout processed in SPF to SDU 3/5. To assist in this evaluation, grout physical properties are required. At this time, there are no rheological data from the actual SPF so the properties of laboratory prepared samples using simulated salt solution or Tank 50 salt solution will be measured. The physical properties of grout prepared in the laboratory with de-ionized water (DI) and salt solutions were obtained at 0.60 and 0.59 water to premix (W/P) ratios, respectively. The yield stress of the DI grout was greater than any salt grout. The plastic viscosity of the DI grout was lower than all of the salt grouts (including salt grout with admixture). When these physical data were used to determine the pressure drop and fluid horsepower for steady state conditions, the salt grouts without admixture addition required a higher pressure drop and higher fluid horsepower to transport. When 0.00076 g Daratard 17/g premix was added, both the pressure drop and fluid horsepower were below that of the DI grout. Higher concentrations of Daratard 17 further reduced the pressure drop and fluid horsepower. The uncertainty in the single point Bingham Plastic parameters is + 4% of the reported values and is the bounding uncertainty. Two different mechanical agitator mixing protocols were followed for the simulant salt grout, one having a total mixing time of three minutes and the other having a time of 10 minutes. The Bingham Plastic parameters

In situ grouting of low-level burial trenches with a cement-based grout at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Francis, C.W.; Spence, R.D.; Tamura, T.; Spalding, B.P.

1993-01-01

A technology being evaluated for use in the closure of one of the low-level radwaste burial grounds at ORNL is trench stabilization using a cement-based grout. To demonstrate the applicability and effectiveness of this technology, two interconnecting trenches in SWSA 6 were selected as candidates for in situ grouting with a particulate grout. The primary objective was to demonstrate the increased trench stability (characterized by trench penetration tests) and the decreased potential for leachate migration (characterized by hydraulic conductivity tests) following in situ injection of a particulate grout into the waste trenches. Stability against trench subsidence is a critical issue. For example, construction of impermeable covers to seal the trenches will be ineffectual unless subsequent trench subsidence is permanently suspended. A grout composed of 39% Type 1 Portland cement, 55.5% Class F fly ash, and 5.5% bentonite mixed at 12.5 lb/gal of water was selected. Before the trenches were grouted, the primary characteristics relating to physical stability, hydraulic conductivity, and void volume of the trenches were determined. Their physical stability was evaluated using soil-penetration tests

Predicting the Occurrence of Hydraulic Fracture in Grouting Operations Based on the Pressure in the Penetrated Cement Grout

Directory of Open Access Journals (Sweden)

Hassan Bakhshandeh Amnieh

2017-12-01

Full Text Available Cement grouting is an operation often carried out to consolidate and seal the rock mass in dam sites and tunnels. The quality and efficiency of a grouting operation depends on various factors such as water take, grout properties and grouting pressure. One of the parameters which have the highest effect is pressure since the application of excessive pressure causes the hydraulic fracture phenomenon to occur in the rock mass and too little pressure leads to incomplete grouting and failure to seal the site in a perfect manner. Mathematical modeling is used for the first time in this study to predict and determine the optimum pressure. Thus, the joints that exist in the rock mass are simulated using cylindrical shell model. The joint surroundings are also modeled through Pasternak environment. To obtain equations governing the joints and the surroundings, energy method is used accompanied by Hamilton principle. In the end, an analytical solution method is used to obtain the maximum grouting pressure. In order to validate the modeling, the grouting pressure values obtained by the model were used in the sites of Seymareh and Aghbolagh dams and the relative error rates were measured considering the differences between calculated and actual pressures. Modeling in the examined sections of Seymareh dam showed 29.61, 5.57, 21.98, 32.50 and 9.09 percent error rates and in the sections of Aghbolagh dam it rendered the values of 4.32, 5.40 and 2.96 percent. The results indicate that this modeling can be used to estimate the amount of pressure for hydraulic fracture in grouting, to predict it and to prevent it.

Efficiency of Micro-fine Cement Grouting in Liquefiable Sand

International Nuclear Information System (INIS)

Mirjalili, Mojtaba; Mirdamadi, Alireza; Ahmadi, Alireza

2008-01-01

In the presence of strong ground motion, liquefaction hazards are likely to occur in saturated cohesion-less soils. The risk of liquefaction and subsequent deformation can be reduced by various ground improvement methods including the cement grouting technique. The grouting method was proposed for non-disruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. In this research, a large-scale experiment was developed for assessment of micro-fine cement grouting effect on strength behavior and liquefaction potential of loose sand. Loose sand samples treated with micro-fine grout in multidirectional experimental model, were tested under cyclic and monotonic triaxial loading to investigate the influence of micro-fine grout on the deformation properties and pore pressure response. The behavior of pure sand was compared with the behavior of sand grouted with a micro-fine cement grout. The test results were shown that cement grouting with low concentrations significantly decreased the liquefaction potential of loose sand and related ground deformation

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1988-01-01

This section briefly describes the Hanford Site, provides a general description of the site operations and administration, provides an overview of the contents of this Grout Treatment Facility (GTF) Permit Application, and gives a list of acronyms and abbreviations used in the document. The decision was made to use the checklist as a locator reference instead of using the checklist section numbers as paragraph section numbers because several different types of waste management units, some of which are not addressed in the checklists, are part of the GTF. The GTF is a waste management unit within the Hanford Site facility. In May 1988, permit application was filed that identified the GTF as an existing facility. The GTF mixes dry cementitious solids with liquid mixed wastes (containing both dangerous and radioactive constituents) produced by Hanford Site operations. In addition to the design and operating features of the GTF that are intended to meet the requirements of dangerous waste regulations, many additional design and operating features are necessary to comply with radioactive waste management practices. The GTF design features and practices are intended to keep operational exposure to radionuclides and dangerous substances ''as low as reasonably achievable'' (ALARA) and to provide a disposal system that protects the environment for at least 10,000 yr. In some instances, ALARA practices present difficulties when complying with requirements of dangerous waste regulations

Grouting of uranium mill tailings piles

International Nuclear Information System (INIS)

Boegly, W.J. Jr.; Tamura, T.; Williams, J.D.

1984-03-01

A program of remedial action was initiated for a number of inactive uranium mill tailings piles. These piles result from mining and processing of uranium ores to meet the nation's defense and nuclear power needs and represent a potential hazard to health and the environment. Possible remedial actions include the application of covers to reduce radon emissions and airborne transport of the tailings, liners to prevent groundwater contamination by leachates from the piles, physical or chemical stabilization of the tailings, or moving the piles to remote locations. Conventional installation of liners would require excavation of the piles to emplace the liner; however, utilization of grouting techniques, such as those used in civil engineering to stabilize soils, might be a potential method of producing a liner without excavation. Laboratory studies on groutability of uranium mill tailings were conducted using samples from three abandoned piles and employing a number of particulate and chemical grouts. These studies indicate that it is possible to alter the permeability of the tailings from ambient values of 10 -3 cm/s to values approaching 10 -7 cm/s using silicate grouts and to 10 -8 cm/s using acrylamide and acrylate grouts. An evaluation of grouting techniques, equipment required, and costs associated with grouting were also conducted and are presented. 10 references, 1 table

Relationship Between Flowability And Tank Closure Grout Quality

International Nuclear Information System (INIS)

Langton, C. A.; Stefanko, D. B.; Hay, M. S.

2012-01-01

After completion of waste removal and chemical cleaning operations, Tanks 5-F and 6-F await final closure. The project will proceed with completing operational closure by stabilizing the tanks with grout. Savannah River Remediation's (SRR) experience with grouting Tanks 18-F and 19-F showed that slump-flow values were correlated with flow/spread inside these tanks. Less mounding was observed when using grouts with higher slump-flow. Therefore, SRNL was requested to evaluate the relationship between flowability and cured properties to determine whether the slump-flow maximum spread of Mix LP no. 8-16 could be increased from 28 inches to 30 inches without impacting the grout quality. A request was also made to evaluate increasing the drop height from 5 feet to 10 feet with the objective of enhancing the flow inside the tank by imparting more kinetic energy to the placement. Based on a review of the grout property data for Mix LP no. 8-16 collected from Tank 18-F and 19-F quality control samples, the upper limit for slump-flow measured per ASTM C 1611 can be increased from 28 to 30 inches without affecting grout quality. However, testing should be performed prior to increasing the drop height from 5 to 10 feet or observations should be made during initial filling operations to determine whether segregation occurs as a function of drop heights between 5 and 10 feet. Segregation will negatively impact grout quality. Additionally, increasing the delivery rate of grout into Tanks 5-F and 6-F by using a higher capacity concrete/grout pump will result in better grout spread/flow inside the tanks

Sludge displacement verification for reducing grout report

International Nuclear Information System (INIS)

Caldwell, T.B.; Langton, C.A.

1997-01-01

To support the closure of HLW tanks at SRS, a reducing grout was developed that is formulated to reduce the mobility of radionuclides left in each tank. During non-radioactive flow tests of the grout, it was discovered that, in addition to its desired properties, the grout has the ability to move residual waste a considerable distance across the tank floor

Demonstration Of LEACHXS(trademark)/Orchestra Capabilities By Simulating Constituent Release From A Cementitious Waste Form In A Reinforced Concrete Vault

International Nuclear Information System (INIS)

Langton, C.; Meeussen, J.; Sloot, H.

2010-01-01

The objective of the work described in this report is to demonstrate the capabilities of the current version of LeachXS(trademark)/ORCHESTRA for simulating chemical behavior and constituent release processes in a range of applications that are relevant to the CBP. This report illustrates the use of LeachXS(trademark)/ORCHESTRA for the following applications: (1) Comparing model and experimental results for leaching tests for a range of cementitious materials including cement mortars, grout, stabilized waste, and concrete. The leaching test data includes liquid-solid partitioning as a function of pH and release rates based on laboratory column, monolith, and field testing. (2) Modeling chemical speciation of constituents in cementitious materials, including liquid-solid partitioning and release rates. (3) Evaluating uncertainty in model predictions based on uncertainty in underlying composition, thermodynamic, and transport characteristics. (4) Generating predominance diagrams to evaluate predicted chemical changes as a result of material aging using the example of exposure to atmospheric conditions. (5) Modeling coupled geochemical speciation and diffusion in a three layer system consisting of a layer of Saltstone, a concrete barrier, and a layer of soil in contact with air. The simulations show developing concentration fronts over a time period of 1000 years. (6) Modeling sulfate attack and cracking due to ettringite formation. A detailed example for this case is provided in a separate article by the authors (Sarkar et al. 2010). Finally, based on the computed results, the sensitive input parameters for this type of modeling are identified and discussed. The chemical speciation behavior of substances is calculated for a batch system and also in combination with transport and within a three layer system. This includes release from a barrier to the surrounding soil as a function of time. As input for the simulations, the physical and chemical properties of the

A study of grout flow pattern analysis

International Nuclear Information System (INIS)

Lee, S. Y.; Hyun, S.

2013-01-01

A new disposal unit, designated as Salt Disposal Unit no. 6 (SDU6), is being designed for support of site accelerated closure goals and salt nuclear waste projections identified in the new Liquid Waste System plan. The unit is cylindrical disposal vault of 380 ft diameter and 43 ft in height, and it has about 30 million gallons of capacity. Primary objective was to develop the computational model and to perform the evaluations for the flow patterns of grout material in SDU6 as function of elevation of grout discharge port, and slurry rheology. A Bingham plastic model was basically used to represent the grout flow behavior. A two-phase modeling approach was taken to achieve the objective. This approach assumes that the air-grout interface determines the shape of the accumulation mound. The results of this study were used to develop the design guidelines for the discharge ports of the Saltstone feed materials in the SDU6 facility. The focusing areas of the modeling study are to estimate the domain size of the grout materials radially spread on the facility floor under the baseline modeling conditions, to perform the sensitivity analysis with respect to the baseline design and operating conditions such as elevation of discharge port, discharge pipe diameter, and grout properties, and to determine the changes in grout density as it is related to grout drop height. An axi-symmetric two-phase modeling method was used for computational efficiency. Based on the nominal design and operating conditions, a transient computational approach was taken to compute flow fields mainly driven by pumping inertia and natural gravity. Detailed solution methodology and analysis results are discussed here

Pilot-scale grout production test with a simulated low-level waste

International Nuclear Information System (INIS)

Fow, C.L.; Mitchell, D.H.; Treat, R.L.; Hymas, C.R.

1987-05-01

Plans are underway at the Hanford Site near Richland, Washington, to convert the low-level fraction of radioactive liquid wastes to a grout form for permanent disposal. Grout is a mixture of liquid waste and grout formers, including portland cement, fly ash, and clays. In the plan, the grout slurry is pumped to subsurface concrete vaults on the Hanford Site, where the grout will solidify into large monoliths, thereby immobilizing the waste. A similar disposal concept is being planned at the Savannah River Laboratory site. The underground disposal of grout was conducted at Oak Ridge National Laboratory between 1966 and 1984. Design and construction of grout processing and disposal facilities are underway. The Transportable Grout Facility (TGF), operated by Rockwell Hanford Operations (Rockwell) for the Department of Energy (DOE), is scheduled to grout Phosphate/Sulfate N Reactor Operations Waste (PSW) in FY 1988. Phosphate/Sulfate Waste is a blend of two low-level waste streams generated at Hanford's N Reactor. Other wastes are scheduled to be grouted in subsequent years. Pacific Northwest Laboratory (PNL) is verifying that Hanford grouts can be safely and efficiently processed. To meet this objective, pilot-scale grout process equipment was installed. On July 29 and 30, 1986, PNL conducted a pilot-scale grout production test for Rockwell. During the test, 16,000 gallons of simulated nonradioactive PSW were mixed with grout formers to produce 22,000 gallons of PSW grout. The grout was pumped at a nominal rate of 15 gpm (about 25% of the nominal production rate planned for the TGF) to a lined and covered trench with a capacity of 30,000 gallons. Emplacement of grout in the trench will permit subsequent evaluation of homogeneity of grout in a large monolith. 12 refs., 34 figs., 5 tabs

Cement-latex grouting mortar for cementing boreholes

Energy Technology Data Exchange (ETDEWEB)

Kateev, I S; Golyshkina, L A; Gorbunova, I V; Kurochkin, B M; Vakula, Ya V

1980-01-01

The need for the development of cement-latex grouting mortar for the purpose of separating strata when reinforcing boreholes at deposits in the Tatar Associated SSR is evaluated. Results of studies of the physical and mechanical properties of cement-latex grouting mortar systems (mortar plus brick) are presented. Formulas for preparing cement-latex grouting mortor are evaluated and results of industrial tests of such mortars shown.

Biological toxicity evaluation of Hanford Site waste grouts

International Nuclear Information System (INIS)

Rebagay, T.V. Dodd, D.A.; Voogd, J.A.

1992-10-01

Liquid wastes containing radioactive, hazardous, and regulated chemicals have been generated throughout the 50 years of operation of the Hanford Site of the US Department of Energy near Richland, Washington. These wastes are currently stored onsite in single- and double-shell carbon steel tanks. To effectively handle and treat these wastes, their degree of toxicity must be determined. The disposal of the low-level radioactive liquid portion of the wastes involves mixing the wastes with pozzolanic blends to form grout. Potential environmental hazards posed by grouts are largely unknown. Biological evaluation of grout toxicity is needed to provide information on the potential risks of animal and plant exposure to the grouts. The fish, rat, and Microtox toxicity tests described herein indicate that the grouts formed from Formulations I and 2 are nonhazardous and nondangerous. Using the Microtox solid-phase protocol, both soluble and insoluble organic and inorganic toxicants in the grouts can be detected. This protocol may be used for rapid screening of environmental pollutants and toxicants

Real Time Grouting Control Method. Development and application using Aespoe HRL data

International Nuclear Information System (INIS)

Kobayashi, Shinji; Stille, Haakan; Gustafson, Gunnar; Stille, Bjoern

2008-10-01

The spread of grout is governed by a number of complex relations. The desired results, such as grout penetration and sealing of fractures, cannot be directly measured during the grouting process. This means that the issue of how or when the injection of grout should be stopped cannot be answered by simple rules of thumb. This is also the background to the great variety of empirical rules used in the grouting sector worldwide. The research during recent years has given a better understanding of the water-bearing structures of the rock mass as well as analytical solutions. In this report the methodology has been further studied and a method for design and control of rock grouting has been proposed. The concept of what we call the 'Real Time Grouting Control Method' is to calculate the grout penetration and control grouting in real time by applying the development of the theories for grout spread. Our intention is to combine our method with a computerized logging tool to acquire an active tool in order to be able to govern the grout spread in real time during the grouting operation. The objectives of this report are: to further develop the theory concerning the relationship between grout penetration and grouting time to describe the real course of grouting, to establish the concept of 'Real Time Grouting Control Method' for design and control for rock grouting based on the developed theory, and to verify the concept by using the field data from the grouting experiment at the 450 m level in the Aespoe HRL. In this report, the approximations and analysis of dimensionality have been checked and further developments of the theory with respect to varying grouting pressure, time-dependent grout properties, changing grout mixes, and changing the flow dimension of the fracture have been carried out. The concept of 'Real Time Grouting Control Method' has been described in order to calculate the grout penetration and to control grouting in real time by applying developed

R20 Programme: The development of grouting technique. Stop criteria and field tests

International Nuclear Information System (INIS)

Hollmen, K.

2008-01-01

This work is a part of the project 'Grouting Technique' by Posiva Oy, which is responsible for the final disposal of spent nuclear fuel in Finland. This study attempts to collect disperse information about the design parameters of the grouting and about a field-test stop criterion, which differs from the prevailing practice. The literature study describes salient processes of grouting design in sufficient extent. Different methods for grouting stop criterion are described in more detail. Grouting design based on selected grouting theory, grouting and evaluating of the grouting results are presented in the experiential part of this study. This study focuses on rock tunnel grouting using cement-based grout. The requirements for water tightness, which are set down by customer, direct the grouting design. Information about fractures in rock mass, which surrounds the rock facility, is the prime initial data for grouting design. In grouting work, fracturing is generally studied by water loss measurements performed in investigation, probe and grouting holes. Besides the water loss measurement, the Posiva Flow Log -tool, which measures location and transmissivity for every single fracture, is used in ONKALO. Grouting pressure and grout must be chosen together and case-specifically. Both pressure and yield strength of grout are influencing the penetration length of grout in a fracture. Grouting pressure must be high enough to ensure sufficient penetration length, but pressure must be under the level where rock mass breaks to avoid hydraulic fracturing. Raising the water to dry material ratio reduces the yield strength of grout, in which case the grouting pressure can be lowered. Stop criterion for grouting aims to define the point, when the result of the grouting is adequate, and the grouting after that point is uneconomical. Properly specified stop criterion minimizes extra grout volume and reduces the running time of grouting work. From the references, three different

In situ grouting of buried transuranic waste with polyacrylamide

International Nuclear Information System (INIS)

Spalding, B.P.; Lee, S.Y.; Farmer, C.D.; Hyder, L.K.; Supaokit, P.

1987-01-01

This project is a demonstration and evaluation of the in situ hydrologic stabilization of buried transuranic waste at a humid site via grout injection. Two small trenches, containing buried transuranic waste, were filled with 34.000 L of polyacrylamide grout. Initial field results have indicated that voids within the trenches were totally filled by the grout and that the intratrench hydraulic conductivity was reduced to below field-measurable values. No evidence of grout constituents were observed in twelve perimeter groundwater monitoring wells indicating that grout was contained completely within the two trenches. Polyacrylamide grout was selected for field demonstration over the polyacrylate grout due to its superior performance in laboratory degradation studies. Also supporting the selection of polyacrylamide was the difficulty in controlling the set time of the acrylate polymerization. Based on preliminary degradation monitoring, the polyacrylamide was estimated to have a microbiological half-life of 362 years in the test soil. 15 refs., 9 figs., 12 tabs

In situ grouting of buried transuranic waste with polyacrylamide

Energy Technology Data Exchange (ETDEWEB)

Spalding, B.P.; Lee, S.Y.; Farmer, C.D.; Hyder, L.K.; Supaokit, P.

1987-01-01

This project is a demonstration and evaluation of the in situ hydrologic stabilization of buried transuranic waste at a humid site via grout injection. Two small trenches, containing buried transuranic waste, were filled with 34.000 L of polyacrylamide grout. Initial field results have indicated that voids within the trenches were totally filled by the grout and that the intratrench hydraulic conductivity was reduced to below field-measurable values. No evidence of grout constituents were observed in twelve perimeter groundwater monitoring wells indicating that grout was contained completely within the two trenches. Polyacrylamide grout was selected for field demonstration over the polyacrylate grout due to its superior performance in laboratory degradation studies. Also supporting the selection of polyacrylamide was the difficulty in controlling the set time of the acrylate polymerization. Based on preliminary degradation monitoring, the polyacrylamide was estimated to have a microbiological half-life of 362 years in the test soil. 15 refs., 9 figs., 12 tabs.

Description of the grout system dynamic simulation

International Nuclear Information System (INIS)

Zimmerman, B.D.

1993-07-01

The grout system dynamic computer simulation was created to allow investigation of the ability of the grouting system to meet established milestones, for various assumed system configurations and parameters. The simulation simulates the movement of tank waste through the system versus time, from initial storage tanks, through feed tanks and the grout plant, then finally to a grout vault. The simulation properly accounts for the following (1) time required to perform various actions or processes, (2) delays involved in gaining regulatory approval, (3) random system component failures, (4) limitations on equipment capacities, (5) available parallel components, and (6) different possible strategies for vault filling. The user is allowed to set a variety of system parameters for each simulation run. Currently, the output of a run primarily consists of a plot of projected grouting campaigns completed versus time, for comparison with milestones. Other outputs involving any model component can also be quickly created or deleted as desired. In particular, sensitivity runs where the effect of varying a model parameter (flow rates, delay times, number of feed tanks available, etc.) on the ability of the system to meet milestones can be made easily. The grout system simulation was implemented using the ITHINK* simulation language for Macintosh** computers

Grout formulations for nuclear-waste isolation

International Nuclear Information System (INIS)

Buck, A.D.; Mather, K.

1982-06-01

It is imperative that control parameters for a grout mixture such as flow time, setting time, compressive strength, permeability, or combinations of these or of other properties be specified before a grout mixture is formulated and used. Once such parameters have been specified, it is possible to proportion a hydraulic cement-based grout mixture to meet the applicable requirements. This may be from experience or by trial mixtures or by both. While longevity of cemetitious mixtures in nonaggressive environments is known from history, satisfactory data involving specific mixtures in selected environments are still needed. Such testing is underway. While compatibility, especially long-term compatibility, of cemetitious mixtures with various rock types is also known, it is necessary to have such evidence for specific mixtures in contact with specific rocks in a selected environment or environments. Satisfactory grout mixtures may be proportioned using the standard practice set forth in Appendix A

Grouting guidelines for Hanford Tanks Initiative cone penetrometer borings

International Nuclear Information System (INIS)

Iwatate, D.F.

1998-01-01

Grouting of an open cone penetrometer (CP) borehole is done to construct a barrier that prevents the vertical migration of fluids and contaminants between geologic units and aquifers intersected by the boring. Whether to grout, the types of grout, and the method of deployment are functions of the site-specific conditions. This report recommends the strategy that should be followed both before and during HTI [Hanford Tanks Initiative] CP deployment to decide specific borehole grouting needs at Hanford SST farms. Topics discussed in this report that bear on this strategy include: Regulatory guidance, hydrogeologic conditions, operational factors, specific CP grouting deployment recommendations

Laboratory Testing of Silica Sol Grout in Coal Measure Mudstones

Directory of Open Access Journals (Sweden)

Dongjiang Pan

2016-11-01

Full Text Available The effectiveness of silica sol grout on mudstones is reported in this paper. Using X-ray diffraction (XRD, the study investigates how the silica sol grout modifies mudstone mineralogy. Micropore sizes and mechanical properties of the mudstone before and after grouting with four different materials were determined with a surface area/porosity analyser and by uniaxial compression. Tests show that, after grouting, up to 50% of the mesopore volumes can be filled with grout, the dominant pore diameter decreases from 100 nm to 10 nm, and the sealing capacity is increased. Uniaxial compression tests of silica sol grouted samples shows that their elastic modulus is 21%–38% and their uniaxial compressive strength is 16%–54% of the non-grouted samples. Peak strain, however, is greater by 150%–270%. After grouting, the sample failure mode changes from brittle to ductile. This paper provides an experimental test of anti-seepage and strengthening properties of silica sol.

Silicate grout curtains behaviour for the protection of coastal aquifers

International Nuclear Information System (INIS)

Elektorowicz, M.; Chifrina, R.; Hesnawi, R.

1997-01-01

Tests were performed to evaluate the behaviour of silicate grout with different reagents (ethylacetate - formamide SA and calcium chloride SC) in pure silica sand and natural soils from coastal areas containing organic matter, clayey soil and silica sand. The grouted specimens were tested with simulated fresh and salt water. The setting process during chemical grouting in the soil and sand was studied. The grouting of soil and sand with SA caused a transfer to the environment of some compounds: sodium formate, sodium acetate, ammonia and part of the initial ethylacetate and formamide. This process had a tendency to decrease for approximately 4 months. The stability of specimens was low. The grouting of soil and sand with SC caused no significant contamination of the environment. The increase of pH of environmental water was even less than with SA grouting. Also, the stability of specimens is higher in comparison with SA grouting. Salt water protected the specimens grouted with SA and SC from destruction and prevented contamination

Grouting of nuclear waste vault shafts

International Nuclear Information System (INIS)

Gyenge, M.

1980-01-01

A nuclear waste vault must be designed and built to ensure adequate isolation of the nuclear wastes from human contact. Consequently, after a vault has been fully loaded it must be adequately sealed off to prevent radionuclide migration which may be provided by circulating ground water. Of particular concern in vault sealing are the physical and chemical properties of the sealing materials its long-term durability and stability and the techniques used for its emplacement. Present grouting technology and grout material are reviewed in terms of the particular needs of shaft grouting. Areas requiring research and development are indicated

Experimental Characterization of Stress- and Strain-Dependent Stiffness in Grouted Rock Masses.

Science.gov (United States)

Kim, Ji-Won; Chong, Song-Hun; Cho, Gye-Chun

2018-03-29

Grouting of fractured rock mass prior to excavation results in grout-filled discontinuities that govern the deformation characteristics of a site. The influence of joint characteristics on the properties of grouted rocks is important in assessing the effects of grouting on jointed rock mass. However, grouting remains a predominantly empirical practice and the effects of grouting on rock joint behavior and material properties have yet to be accurately assessed. Granular materials, including jointed rocks, typically display nonlinear strain-dependent responses that can be characterized by the shear modulus degradation curve. In this study, the effects of grouting on the strain-dependent shear stiffness of jointed rock mass were investigated at the small-strain (below 10 -5 ) and mid-strain (10 -5 to 10 -3 ) ranges using the quasi-static resonant column test and rock mass dynamic test devices. The effects of curing time, axial stress, initial joint roughness, and grouted joint thickness were examined. The results show that (1) grouting of rock joints leads to decreased stress sensitivity and increased small-strain shear stiffness for all tested samples; (2) the grouted rock samples display similar modulus degradation characteristics as the applied grout material; (3) the initial joint roughness determines the stress-dependent behaviors and general stiffness range of the jointed and grouted rocks, but the strain-dependent behaviors are dependent on the properties of the grout material; (4) increased grouted joint thickness results in larger contribution of the grout properties in the overall grouted rock mass.

Grout performance in support of in situ grouting of the TH4 tank sludge

Energy Technology Data Exchange (ETDEWEB)

Hunt, R.D.; Kauschinger, J.L.; Spence, R.D.

1999-04-01

The cold demonstration test proved that less water was required to pump the in situ grout formulation than had been previously tested in the laboratory. The previous in situ grout formulation was restandardized with the same relative amounts of dry blend ingredients, albeit adding a fluidized admixture, but specifying less water for the slurry mix that must by pumped through the nozzles at high pressure. Also, the target GAAT tank for demonstrating this is situ grouting technique has been shifted to Tank TH4. A chemical surrogate sludge for TH4 was developed and tested in the laboratory, meeting expectations for leach resistance and strenght at 35 wt % sludge loading. It addition, a sample of hot TH4 sludge was also tested at 35 wt % sludge loading and proved to have superior strength and leach resistance compared with the surrogate test.

R20 programme: Development of rock grouting design, techniques and procedures for ONKALO

International Nuclear Information System (INIS)

Sievaenen, U.

2009-02-01

Posiva Oy constructs an underground research facility ONKALO at Olkiluoto in Eurajoki. ONKALO is planned to be a part of the deep repository for the high level nuclear waste. Posiva Oy set up R20-programme for the years 2006-2008, with the target of having an acceptable grouting methodology in ONKALO. The programme was divided into three projects and the work and results of Technique-project is presented in this report. The implementation of the results (grouting design and execution) was outlined from the project. That work is under the responsibility of construction of the ONKALO-project. The Grouting Technique -project (INKE) studied the grouting experiences obtained from the first 2 km of the ONKALO access tunnel, searched for suitable grouting design approaches, carried out two grouting tests and one pilot grouting test with colloidal silica in ONKALO, analysed the expected grouting conditions in deep rock from the grouting point of view, studied the feasibility of so called optimal design solution in the expected grouting conditions. Based on these studies recommendations concerning the grouting design, design solutions for different rock conditions, grouting procedures, grouting stop criteria, the characterisation methods for grouting purposes, grouting materials and grouting work performance are presented. Swedish Time Stop Grouting, also named Grouting Time-Method was selected to be studied and used in this project and it was further developed. This work compiles the outcome of the project subtasks and presents the recommendations for developing the grouting in ONKALO. The key conclusion of this work are: (1) Grouting Time-method (time stop grouting) alone is not enough to be used as a grouting stop criterion due to the uncertainties related to the source parameters (fracture characteristics, rheological properties of grouts); these cause too high uncertainties when proving the sealing result via the grouting time, (2) due to the uncertainties related to

Laboratory testing of cement grouting of fractures in welded tuff

International Nuclear Information System (INIS)

Sharpe, C.J.; Daemen, J.J.

1991-03-01

Fractures in the rock mass surrounding a repository and its shafts, access drifts, emplacement rooms and holes, and exploratory or in-situ testing holes, may provide preferential flowpaths for the flow of groundwater or air, potentially containing radionuclides. Such cracks may have to be sealed. The likelihood that extensive or at least local grouting will be required as part of repository sealing has been noted in numerous publications addressing high level waste repository closing. The objective of this work is to determine the effectiveness of fracture sealing (grouting) in welded tuff. Experimental work includes measurement of intact and fracture permeability under various normal stresses and injection pressures. Grout is injected into the fractures. The effectiveness of grouting is evaluated in terms of grout penetration and permeability reduction, compared prior to and after grouting. Analysis of the results include the effect of normal stress, injection pressure, fracture roughness, grout rheology, grout bonding, and the radial extent of grout penetration. Laboratory experiments have been performed on seventeen tuff cylinders with three types of fractures: (1) tension induced cracks, (2) natural fractures, and (3) sawcuts. Prior to grouting, the hydraulic conductivity of the intact rock and of the fractures is measured under a range of normal stresses. The surface topography of the fracture is mapped, and the results are used to determine aperture distributions across the fractures. 72 refs., 76 figs., 25 tabs

Experimental Characterization of Stress- and Strain-Dependent Stiffness in Grouted Rock Masses

Directory of Open Access Journals (Sweden)

Ji-Won Kim

2018-03-01

Full Text Available Grouting of fractured rock mass prior to excavation results in grout-filled discontinuities that govern the deformation characteristics of a site. The influence of joint characteristics on the properties of grouted rocks is important in assessing the effects of grouting on jointed rock mass. However, grouting remains a predominantly empirical practice and the effects of grouting on rock joint behavior and material properties have yet to be accurately assessed. Granular materials, including jointed rocks, typically display nonlinear strain-dependent responses that can be characterized by the shear modulus degradation curve. In this study, the effects of grouting on the strain-dependent shear stiffness of jointed rock mass were investigated at the small-strain (below 10−5 and mid-strain (10−5 to 10−3 ranges using the quasi-static resonant column test and rock mass dynamic test devices. The effects of curing time, axial stress, initial joint roughness, and grouted joint thickness were examined. The results show that (1 grouting of rock joints leads to decreased stress sensitivity and increased small-strain shear stiffness for all tested samples; (2 the grouted rock samples display similar modulus degradation characteristics as the applied grout material; (3 the initial joint roughness determines the stress-dependent behaviors and general stiffness range of the jointed and grouted rocks, but the strain-dependent behaviors are dependent on the properties of the grout material; (4 increased grouted joint thickness results in larger contribution of the grout properties in the overall grouted rock mass.

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1988-01-01

This section briefly describes the Hanford Site, provides a general description of the site operations and administration, provides an overview of the contents of this Grout Treatment Facility (GTF) Permit Application, and gives a list of acronyms and abbreviations used in the document. The decision was made to use the checklist as a locator reference instead of using the checklist section numbers as paragraph section numbers because several different types of waste management units, some of which are not addressed in the checklists, are part of the GTF. The GTF is a waste management unit within the Hanford Site facility. In May 1988, a permit application was filed that identified the GTF as an existing facility. The GTF mixes dry cementitious solids with liquid mixed wastes (containing both dangerous and radioactive constituents) produced by Hanford Site operations. In addition to the design and operating features of the GTF that are intended to meet the requirements of dangerous waste regulations, many additional design and operating features are necessary to comply with radioactive waste management practices. The GTF design features and practices are intended to keep operational exposure to radionuclides and dangerous substances ''as low as reasonably achievable'' (ALARA) and to provide a disposal system that protects the environment for at least 10,000 yr. In some instances, ALARA practices present difficulties when complying with requirements of dangerous waste regulations. This volume contains 2 appendices covering engineering drawings and operating procedures

Grout treatment facility dangerous waste permit application

International Nuclear Information System (INIS)

1988-01-01

This section briefly describes the Hanford Site, provides a general description of the site operations and administration, provides an overview of the contents of this Grout Treatment Facility (GTF) Permit Application, and gives a list of acronyms and abbreviations used in the document. The decision was made to use the checklist as a locator reference instead of using the checklist section numbers as paragraph section numbers because several different types of waste management units, some of which are not addressed in the checklists, are part of the GTF. The GTF is a waste management unit within the Hanford Site facility. In May 1988, a permit application was filed that identified the GTF as an existing facility. The GTF mixes dry cementitious solids with liquid mixed wastes (containing both dangerous and radioactive constitutents) produced by Hanford Site operations. In addition to the design and operating features of the GTF that are intended to meet the requirements of dangerous waste regulations, many additional design and operating features are necessary to comply with radioactive waste management practices. The GTF design features and practices are intended to keep operational exposure to radionuclides and dangerous substances ''as low as reasonably achievable'' (ALARA) and to provide a disposal system that protects the environment for at least 10,000 yr. In some instances, ALARA practices present difficulties when complying with requirements of dangerous waste regulations. This volume contains 2 Appendices covering engineering drawings and operating procedures

Grout Treatment Facility dangerous waste permit application

International Nuclear Information System (INIS)

1988-01-01

This section briefly describes the Hanford Site, provides a general description of the site operations and administration, provides an overview of the contents of this Grout Treatment Facility (GTF) Permit Application, and gives a list of acronyms and abbreviations used in the document. The decision was made to use the checklist as a locator reference instead of using the checklist section numbers as paragraph section numbers because several different types of waste management units, some of which are not addressed in the checklists, are part of the GTF. The GTF is a waste management unit within the Hanford Site facility. In May 1988, a permit application was filed that identified the GTF as an existing facility. The GTF mixes dry cementitious solids with liquid wastes (containing both dangerous and radioactive constituents) produced by Hanford Site operations. In addition to the design and operating features of the GTF that are intended to meet the requirements of dangerous waste regulations, many additional design and operating features are necessary to comply with radioactive waste management practices. The GTF design features and practices are intended to keep operational exposure to radionuclides and dangerous substances ''as low as reasonably achievable'' (ALARA) and to provide a disposal system that protects the environment for at least 10,000 yr. In some instances, ALARA practices present difficulties when complying with requirements of dangerous waste regulations. This volume contains 14 Appendices. Topics include Engineering Drawings, Maps, Roads, Toxicity Testing, and Pilot-Scale Testing

Variability in properties of grouted Phosphate/Sulfate N-Reactor Waste

International Nuclear Information System (INIS)

Lokken, R.O.; Martin, P.F.C.; Bowen, W.M.; Harty, H.; Treat, R.L.

1987-02-01

A Transportable Grout Facility (TGF) is being constructed at the Hanford site in Washington State to convert various low-level liquid wastes to a grout waste form for onsite disposal. The TGF Project is managed by Rockwell Hanford Operations (Rockwell). Oak Ridge National Laboratory (ORNL) has provided a grout formulation for Phosphate/Sulfate N-Reactor Waste, the first waste stream scheduled for grouting beginning in late 1987. The formulation includes a blend of portland cement, fly ash, attapulgite clay, and an illitic clay. Grout will be produced by mixing the blend with Phosphate/Sulfate N-Reactor Waste. These wastes result from decontamination and ion-exchange regeneration activities at Hanford's N-Reactor. Pacific Northwest Laboratory (PNL) is conducting studies on grouted Phosphate/Sulfate N-Reactor Waste to verify that the grout can be successfully processed and, when hardened, that it will meet all performance and regulatory requirements. As part of these studies, PNL is assessing the variability that may be encountered when processing Phosphate/Sulfate N-Reactor Waste grout. Sources of variability that may affect grout properties include the composition and concentrations of the waste and dry solids, temperature, efficiency of dry solids blending, and dry blend storage time. 13 refs., 20 figs., 9 tabs

The differences between soil grouting with cement slurry and cement-water glass slurry

Science.gov (United States)

Zhu, Mingting; Sui, Haitong; Yang, Honglu

2018-01-01

Cement slurry and cement-water glass slurry are the most widely applied for soil grouting reinforcement project. The viscosity change of cement slurry is negligible during grouting period and presumed to be time-independent while the viscosity of cement-water glass slurry increases with time quickly and is presumed to be time-dependent. Due to the significantly rheology differences between them, the grouting quality and the increasing characteristics of grouting parameters may be different, such as grouting pressure, grouting surrounding rock pressure, i.e., the change of surrounding rock pressure deduced by grouting pressure. Those are main factors for grouting design. In this paper, a large-scale 3D grouting simulation device was developed to simulate the surrounding curtain grouting for a tunnel. Two series of surrounding curtain grouting experiments under different geo-stress of 100 kPa, 150 kPa and 200 kPa were performed. The overload test on tunnel was performed to evaluate grouting effect of all surrounding curtain grouting experiments. In the present results, before 240 seconds, the grouting pressure increases slowly for both slurries; after 240 seconds the increase rate of grouting pressure for cement-water glass slurry increases quickly while that for cement slurry remains roughly constant. The increasing trend of grouting pressure for cement-water glass is similar to its viscosity. The setting time of cement-water glass slurry obtained from laboratory test is less than that in practical grouting where grout slurry solidifies in soil. The grouting effect of cement-water glass slurry is better than that of cement slurry and the grouting quality decreases with initial pressure.

Protection against water or mud inrush in tunnels by grouting: A review

Directory of Open Access Journals (Sweden)

Shucai Li

2016-10-01

Full Text Available Grouting is a major method used to prevent water and mud inrush in tunnels and underground engineering. In this paper, the current situation of control and prevention of water and mud inrush is summarized and recent advances in relevant theories, grout/equipment, and critical techniques are introduced. The time-variant equations of grout viscosity at different volumetric ratios were obtained based on the constitutive relation of typical fast curing grouts. A large-scale dynamic grouting model testing system (4000 mm × 2000 mm × 5 mm was developed, and the diffusions of cement and fast curing grouts in dynamic water grouting were investigated. The results reveal that the diffusions of cement grouts and fast curing grouts are U-shaped and asymmetric elliptical, respectively. A multi-parameter real-time monitoring system (ϕ = 1.5 m, h = 1.2 m was developed for the grouting process to study the diffusion and reinforcement mechanism of grouting in water-rich faulted zone. A high early strength cream-type reinforcing/plugging grout, a high permeability nano-scale silica gel grout, and a high-expansion filling grout were proposed for the control of water hazards in weak water-rich faulted zone rocks, water inrush in karst passages, and micro-crack water inrush, respectively. Complement technologies and equipment for industrial applications were also proposed. Additionally, a novel full-life periodic dynamic water grouting with the critical grouting borehole as the core was proposed. The key techniques for the control of water inrush in water-rich faulted zone, jointed fissures and karst passages, and micro-crack water inrush were developed.

Method of producing grouting mortar

Energy Technology Data Exchange (ETDEWEB)

Shelomov, I K; Alchina, S I; Dizer, E I; Gruzdeva, G A; Nikitinskii, V I; Sabirzyanov, A K

1980-10-07

A method of producing grouting mortar by mixing the cement with an aqueous salt solution is proposed. So as to increase the quality of the mortar through an acceleration of the time for hardening, the mixture is prepared in two stages, in the first of which 20-30% of the entire cement batch hardens, and in the second of which the remainder of the cement hardens; 1-3-% of an aqueous salt solution is used in quantities of 0.5/1 wt.-% of weight of the cement. The use of this method of producing grouting mortar helps to increase the flexural strength of the cement brick up to 50% after two days ageing by comparison with the strength of cement brick produced from grouting mortar by ordinary methods utilizing identical quantities of the initial components (cement, water, chloride).

R20 Programme: Field testing of grouting materials

International Nuclear Information System (INIS)

Ranta-Korpi, R.; Karttunen, P.; Sievaenen, U.

2008-02-01

In the year 2004 Finnish nuclear waste management organisation Posiva Oy started to construct an underground rock characterisation facility in Olkiluoto, Eurajoki, Western Finland. The ONKALO was planned to be a final disposal of spent nuclear fuel in Finland. This facility is going to be finished in the end of the year 2010. In ONKALO it is important to grout the water conductive structures to minimize the leakage of the inflowing groundwater in order to keep the geohydrogical environment unchanged and the repository conditions safe. Before the construction began the development of the grouts suitable for this demanding environment was started. Especially pH, the penetration ability and rheology have been the matter of interest. One target for the grout has been that the pH is relatively low. These grouts have different properties than the normal grouts. Several laboratory and field tests have been done for low pH grouts. The suitable recipies are studied in laboratory and the properties are verified in field. This work concerns the field testing of several low pH grout recipies. The different W/DM -ratios and SPL contents were studied. Besides the customary test methods, two new measurement methods were taken into use: the sand column test for measuring the penetration ability and the stick test for determining the plastic viscosity and yield value. The relationships between different properties, the properties as a function of the time and the effect of the (orig.)

Characterization of a low-level radioactive waste grout: Sampling and test results

International Nuclear Information System (INIS)

Martin, P.F.C.; Lokken, R.O.

1992-12-01

WHC manages and operates the grout treatment facility at Hanford as part of a DOE program to clean up wastes stored at federal nuclear production sites. PNL provides support to the grout disposal program through pilot-scale tests, performance assessments, and formulation verification activities. in 1988 and 1989, over one million gallons of a low-level radioactive liquid waste was processed through the facility to produce a grout waste that was then deposited in an underground vault. The liquid waste was phosphate/sulfate waste (PSW) generated in decontamination of the N Reactor. PNL sampled and tested the grout produced during the second half of the PSW campaign to support quality verification activities prior to grout vault closure. Samples of grout were obtained by inserting nested-tube samplers into the grout slurry in the vault. After the grout had cured, the inner tube of the sampler was removed and the grout samples extracted. Tests for compressive strength, sonic velocity, and leach testing were used to assess grout quality; results were compared to those from pilot-scale test grouts made with a simulated PSW. The grout produced during the second half of the PSW campaign exceeded compressive strength and leachability formulation criteria. The nested tube samplers were effective in collecting samples of grout although their use introduced greater variability into the compressive strength data

Assessment of annual exposure for grout operations

International Nuclear Information System (INIS)

Potter, R.E.

1994-01-01

An analysis is presented of the direct radiation exposures and dose rates to personnel from assumed quantities of radioactive grout, and Double Shell Tank (DST) waste feed. This analysis was based on filling four disposal vaults per year. Whole body doses were analyzed for occupational workers assigned to the Grout Treatment Facility (GTF). The study makes assumptions that must be met by the facility. Otherwise, the GTF will meet all DOE and WHC direct radiation exposure criteria. This analysis will be published in the Grout Final Safety Analysis Report (FSAR)

Design and Control of Chemical Grouting : Volume 3 - Engineering Practice

Science.gov (United States)

1983-04-01

Recent improvements in the engineering practice of chemical grouting have provided increased confidence in this method of ground modification. Designers can significantly improve the success of chemical grouting by defining their grouting program obj...

Task plan to evaluate the effectiveness of in situ grouting of an ORNL waste burial trench with a cement-based grout

International Nuclear Information System (INIS)

Francis, C.W.

1991-11-01

This task will demonstrate the feasibility of using an in situ grouting technique with a particulate-grout formulation as a closure action to stabilize waste trenches in Solid Waste Storage Area (SWSA) 6. It also supports technology development for closure of other SWSAs. A particulate grout will be formulated using cement-bentonite and fly ash from a coal-fired power plant. The grout solids will be dry-blended, mixed with water, and injected (using ∼5 to 10 lb/in. 2 pressure) into five injection wells per trench. After 28 days for setting, soil penetration resistance and hydraulic conductivity measurements will be repeated for comparison to pregrouting measurements. The primary objective of this task is to demonstrate the feasibility and effectiveness of the in situ injection of a particulate grout into waste burial trenches. Effectiveness is defined here as increased trenched stability (characterized by trench penetration resistance tests) and decreased potential for leachate migration (characterized by hydraulic conductivity tests)

Effects of Coal Gangue on Cement Grouting Material Properties

Science.gov (United States)

Liu, J. Y.; Chen, H. X.

2018-05-01

The coal gangue is one of the most abundant industrial solid wastes and pollute source of air and water. The use of coal gangue in the production of cement grouting material comforms to the basic state policy of environment protection and the circular using of natural resources. Through coal gangue processing experiment, coal gangue cement grouting materials making test, properties detection of properties and theoretical analysis, the paper studied the effects of coal gangue on the properties of cement grouting materials. It is found that at the range of 600 to 700 °C, the fluidity and the compressive and flexural strengths of the cement grouting materials increase with the rising up of the calcination temperatures of coal gangue. The optimum calcination temperature is around 700 °C. The part substitution of cement by the calcined coal gangue in the cement grouting material will improve the mechanical properties of the cement grouting material, even thought it will decrease its fluidity. The best substitution amount of cement by coal gangue is about 30%. The fluidity and the long term strength of the ordinary silicate cement grouting material is obviously higher than that of the sulphoaluminate cement one as well as that of the silicate-sulphoaluminate complex cement one.

Non-destructive examination of grouted waste

International Nuclear Information System (INIS)

Benny, H.L.

1994-01-01

This data report contains the results of ultrasonic pulse velocity (UPV) and unconfined compressive strength (USC) measurements on a grouted simulant of 106AN tank waste. This testing program was conducted according to the requirements detailed in WHC-1993a. If successful, these methods could lead to a system for the remote verification of waste form quality. The objectives of this testing program were: to determine if a relationship exists between the velocity of ultrasonic compression waves and the unconfined compressive strength of simulated grouted waste, and if so, determine if the relationship is a valid method for grout quality assessment; and to determine if a relationship exists between the attenuation of wave amplitude and the age of test specimens. The first objective was met, in that a relationship between the UPV waves and USC was determined. This method appears to provide a valid measure of the quality of the grouted waste, as discussed in Sections 3.0 and 4.0. The second objective, to determine if the attenuation of UPV waves was related to the age of test specimens was partially met. A relationship does exist between wave amplitude and age, but it is doubtful that this method alone can be used to verify the overall quality of grouted waste. Section 2.0 describes the test methods, with the results detailed in Section 3.0. A discussion of the results are provided in Section 4.0

Direct cementitious waste option study report

International Nuclear Information System (INIS)

Dafoe, R.E.; Losinski, S.J.

1998-02-01

A settlement agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) will be treated so that it is ready to be moved out of Idaho for disposal by a target data of 2035. This study investigates the direct grouting of all ICPP calcine (including the HLW dry calcine and those resulting from calcining sodium-bearing liquid waste currently residing in the ICPP storage tanks) as the treatment method to comply with the settlement agreement. This method involves grouting the calcined waste and casting the resulting hydroceramic grout into stainless steel canisters. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory (INEEL) until they are sent to a national geologic repository. The operating period for grouting treatment will be from 2013 through 2032, and all the HLW will be treated and in interim storage by the end of 2032

Direct cementitious waste option study report

Energy Technology Data Exchange (ETDEWEB)

Dafoe, R.E.; Losinski, S.J.

1998-02-01

A settlement agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) will be treated so that it is ready to be moved out of Idaho for disposal by a target data of 2035. This study investigates the direct grouting of all ICPP calcine (including the HLW dry calcine and those resulting from calcining sodium-bearing liquid waste currently residing in the ICPP storage tanks) as the treatment method to comply with the settlement agreement. This method involves grouting the calcined waste and casting the resulting hydroceramic grout into stainless steel canisters. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory (INEEL) until they are sent to a national geologic repository. The operating period for grouting treatment will be from 2013 through 2032, and all the HLW will be treated and in interim storage by the end of 2032.

Test plan: Sealing of the Disturbed Rock Zone (DRZ), including Marker Bed 139 (MB139) and the overlying halite, below the repository horizon, at the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Ahrens, E.H.

1992-05-01

This test plan describes activities intended to demonstrate equipment and techniques for producing, injecting, and evaluating microfine cementitious grout. The grout will be injected in fractured rock located below the repository horizon at the Waste Isolation Pilot Plant (WIPP). These data are intended to support the development of the Alcove Gas Barrier System (AGBS), the design of upcoming, large-scale seal tests, and ongoing laboratory evaluations of grouting efficacy. Degradation of the grout will be studied in experiments conducted in parallel with the underground grouting experiment

Mechanical response of shock conditioned HPNS-5 (R-1) grout

International Nuclear Information System (INIS)

Plannerer, H.N.

1997-01-01

HPNS-5 (R-1) grout is a portland cement formulated mix designed for use as a rigid containment plug in vertical boreholes at the Nevada Test Site. Coincident with field testing of this grout in 1991 and 1992 , two arums of the grout mix were collected and positioned in the by pass drift of the DISTANT ZENITH event to expose the grout to passage of a nuclear driven stress wave. The drums were later retrieved to determine the mechanical behavior of the shock conditioned grout. Sealed hollow tubes positioned within the grout-filled drums to detect ductile flow on passage of the stress wave were found partially to completely filled with HPNS-5 grout following the experiment. Static mechanical tests support the evidence for ductile flow and place the transition from brittle fracture failure to ductile behavior in the shock conditioned grout at a confining stress between ambient and 5 MPa (725 psi). Uniaxial and triaxial tests delineated a stress-strain field for interstice collapse that interposes between the mechanics of linear elastic deformation and dilatancy. Hydrostatic stress loading between 25 MPa (3.6 ksi) and 60 MPa (8.7 ksi) results in a significant change of permanent set from 1% to greater than 15% volume strain

Latex-modified grouts for in-situ stabilization of buried transuranic/mixed waste

International Nuclear Information System (INIS)

Allan, M.L.

1996-06-01

The Department of Applied Science at Brookhaven national Laboratory was requested to investigate latex-modified grouts for in-situ stabilization of buried TRU/mixed waste for INEL. The waste exists in shallow trenches that were backfilled with soil. The objective was to formulate latex-modified grouts for use with the jet grouting technique to enable in-situ stabilization of buried waste. The stabilized waste was either to be left in place or retrieved for further processing. Grouting prior to retrieval reduces the potential release of contaminants. Rheological properties of latex-modified grouts were investigated and compared with those of conventional neat cement grouts used for jet grouting

Liquid Secondary Waste Grout Formulation and Waste Form Qualification

Energy Technology Data Exchange (ETDEWEB)

Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, B. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Michelle M. V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-05-23

This report describes the results from liquid secondary waste (LSW) grout formulation and waste form qualification tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate new formulations for preparing a grout waste form with high-sulfate secondary waste simulants and the release of key constituents from these grout monoliths. Specific objectives of the LSW grout formulation and waste form qualification tests described in this report focused on five activities: 1.preparing new formulations for the LSW grout waste form with high-sulfate LSW simulants and solid characterization of the cured LSW grout waste form; 2.conducting the U.S. Environmental Protection Agency (EPA) Method 1313 leach test (EPA 2012) on the grout prepared with the new formulations, which solidify sulfate-rich Hanford Tank Waste Treatment and Immobilization Plant (WTP) off-gas condensate secondary waste simulant, using deionized water (DIW); 3.conducting the EPA Method 1315 leach tests (EPA 2013) on the grout monoliths made with the new dry blend formulations and three LSW simulants (242-A evaporator condensate, Environmental Restoration Disposal Facility (ERDF) leachate, and WTP off-gas condensate) using two leachants, DIW and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water (VZPW); 4.estimating the ⁹⁹Tc desorption K_d (distribution coefficient) values for ⁹⁹Tc transport in oxidizing conditions to support the IDF performance assessment (PA); 5.estimating the solubility of ⁹⁹Tc(IV)-bearing solid phases for ⁹⁹Tc transport in reducing conditions to support the IDF PA.

Investigation of a Hardened Cement Paste Grout

DEFF Research Database (Denmark)

Esteves, Luis Pedro; Sørensen, Eigil Verner

This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S.......This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S....

Silica sol as grouting material: a physio-chemical analysis.

Science.gov (United States)

Sögaard, Christian; Funehag, Johan; Abbas, Zareen

2018-01-01

At present there is a pressing need to find an environmentally friendly grouting material for the construction of tunnels. Silica nanoparticles hold great potential of replacing the organic molecule based grouting materials currently used for this purpose. Chemically, silica nanoparticles are similar to natural silicates which are essential components of rocks and soil. Moreover, suspensions of silica nanoparticles of different sizes and desired reactivity are commercially available. However, the use of silica nanoparticles as grouting material is at an early stage of its technological development. There are some critical parameters such as long term stability and functionality of grouted silica that need to be investigated in detail before silica nanoparticles can be considered as a reliable grouting material. In this review article we present the state of the art regarding the chemical properties of silica nanoparticles commercially available, as well as experience gained from the use of silica as grouting material. We give a detailed description of the mechanisms underlying the gelling of silica by different salt solutions such as NaCl and KCl and how factors such as particle size, pH, and temperature affect the gelling and gel strength development. Our focus in this review is on linking the chemical properties of silica nanoparticles to the mechanical properties to better understand their functionality and stability as grouting material. Along the way we point out areas which need further research.

Cement based grouts - longevity laboratory studies: leaching behaviour

International Nuclear Information System (INIS)

Onofrei, M.; Gray, M.; Roe, L.

1991-12-01

This report describes a series of laboratory tests carried out to determine the possible leaching behaviour of cement-based grouts in repository environments. A reference high-performance cement-based grout, comprised of Canadian Type 50 (U.S. Type V) Sulphate Resisting Portland Cement, silica fume, potable water and superplasticizer, and a commercially available cement grout were subjected to leaching in distilled water and three simulated groundwaters of different ionic strength. Hardened, monolithic specimens of the grout were leached in static, pulsed-flow and continuous flow conditions at temperatures from 10 degrees C to 150 degrees C for periods of up to 56 days. The changes in concentration of ions in the leachants with time were determined and the changes in the morphology of the surfaces of the grout specimens were examined using electron microscopy. After a review of possible mechanisms of degradation of cement-based materials, the data from these experiments are presented. The data show that the grouts will leach when in contact with water through dissolution of more soluble phases. Comparison of the leaching performance of the two grouts indicates that, while there are some minor differences, they behaved quite similarly. The rate of the leaching processes were found to tend to decrease with time and to be accompanied by precipitation and/or growth of an assemblage of secondary alteration phases (i.e., CaCO 3 , Mg(OH) 2 ). The mechanisms of leaching depended on the environmental conditions of temperature, groundwater composition and water flow rate. Matrix dissolution occurred. However, in many of the tests leaching was shown to be limited by the precipitated/reaction layers which acted as protective surface coatings. (37 refs.) (au)

Preliminary assessment of a 'surface fusible grout' concept

International Nuclear Information System (INIS)

Sellars, B.G.

1992-03-01

The Canadian Fusion Fuels Technology Project is evaluating the uptake and release of tritium (DT, T 2 ), tritiated hydrogen (HT) and tritiated water (HTO) by building materials to be used in fusion reactor enclosures. Concrete will be an important building material and poses a special problem because of its porous microstructure and the chemical makeup of the material. One approach to reducing the uptake of HT and HTO into concrete is to apply a permeation barrier directly onto the concrete. Glazed ceramic tiles are one barrier with low HT and HTO uptake; however, the grouting between tiles is a major concern. It would be desirable to seal the grout with a glassy permeation barrier. The concept investigated in this program is based on plasma spraying: injecting a powder into a high velocity flame to melt the powder particles and project them towards a target substrate. Glass on the substrate is then to be fused by the plasma flame while a molten glass is deposited on top. Ceramic bonded grouts were developed based on fused silica or borosilicate powders and ethyl silicate or sodium silicate air-set binders. Sodium silicate grouts exhibit lower porosity after drying than ethyl silicate-based grouts, although both are porous. Careful control of the ratio of coarse to fine powder fractions is necessary to minimize or eliminate drying shrinkage. The surface of grouts based on borosilicate glass could not be fused without cracking of neighbouring tiles. When a porcelain enamel glass was plasma spray deposited and fused onto the surface of a grout line and adjacent tiles crazing was observed upon dye penetrant testing

Strength of Mock-up Trial Grout

DEFF Research Database (Denmark)

Sørensen, Eigil V.

The present report describes tests carried out on samples taken and cast during the execution of a mock-up trial placement of the high performance grout MASTERFLOW 9500 on January 21, 2009.......The present report describes tests carried out on samples taken and cast during the execution of a mock-up trial placement of the high performance grout MASTERFLOW 9500 on January 21, 2009....

Concrete with supplementary cementitious materials

OpenAIRE

Jensen, Ole M; Kovler, Konstantin; De Belie, Nele

2016-01-01

This volume contains the proceedings of the MSSCE 2016 conference segment on “Concrete with Supplementary Cementitious Materials” (SCM). The conference segment is organized by the RILEM technical committee TC 238-SCM: Hydration and microstructure of concrete with supplementary cementitious materials. TC 238-SCM started activities in 2011 and has about 50 members from all over the world. The main objective of the committee is to support the increasing utilisation of hydraulic...

Service life prediction and fibre reinforced cementitious composites

DEFF Research Database (Denmark)

Stoklund Larsen, E.

The present Ph.D.thesis addresses the service life concept on the fibre reinforced cementitious composites. The advantages and problems of adding fibre to a cementitious matrix and the influence on service life are described. In SBI Report 221, Service life prediction and cementitious somposites......, the factors affecting the pure cementitious composite are described. Different sizes and types of fibre reinforced crmentitious composites have been chosen to illustrate different ageing and deterioration mechanisms. Some ageing mechanisms can be accelerated and others cannot which is demonstrated in a test...... programme. Moisture, micro structural and mechanical properties were measured before, during and after ageing, with the purpose of giving a detailed "picture" of the materials during ageing....

Field test of ethanol/bentonite slurry grouting into rock fracture

International Nuclear Information System (INIS)

Motoyuki Asada; Hitoshi Nakashima; Takashi Ishii; Sumio Horiuchi

2006-01-01

Crystalline rocks have fractures which may cause unexpected routes of groundwater seepage. Cement grouting is one of the most effective methods to minimize seepage; however, cement materials may not be suitable for the purpose of extra-long durability, because cement is neutralized or degraded by chemical and physical influence of chemical reaction. Natural clay like bentonite is one of the most promising materials for seepage barrier; however, water/bentonite grout is so viscous that enough amount of bentonite can not be grouted into rock fractures. To increase bentonite content in grout with low viscosity, the utilization of ethanol as a mixing liquid was studied. Ethanol suppresses bentonite swelling, and more bentonite can be injected more than that of water/bentonite slurry. In this paper, grouting into in-situ rock mass fracture from the ground surface was tested to investigate the barrier performance and workability of ethanol/bentonite slurry as a grouting material. (author)

Development of an in-line grout meter for improved quality control

International Nuclear Information System (INIS)

Del Cul, G.D.; Gilliam, T.M.

1991-05-01

This report documents progress to date on the development of an in-line grout meter and demonstration of its applicability at operating temperature of 50 degree C. The grout meter, which is based on measurement of grout electrical resistance/capacitance, is intended to provide real-time measurements of grout mix ratio (ratio of dry-solids-blend materials to waste). 4 refs., 6 figs., 5 tabs

Superplasticizer function and sorption in high performance cement based grouts

International Nuclear Information System (INIS)

Onofrei, M.; Gray, M.N.; Roe, L.H.

1991-08-01

This report describes laboratory studies undertaken to determine interactions between the main components of high-performance cement-based grout. These interactions were studied with the grouts in both their unset and hardened states with the specific intention of determining the following: the mechanistic function of superplasticizer; the phase of residence of the superplasticizer in hardened materials; and the permanence of the superplasticizer in hardened grouts. In unset pastes attempts were made to extract superplasticizer by mechanical processes. In hardened grout the superplasticizer was leached from the grouts. A microautoradiographic method was developed to investigate the phases of residence of superplasticizer in hardened grouts and confirm the inferences from the leaching studies. In hardened grout the superplasticizer was located on the hydrated phases formed during the early stages of cement hydration. These include tricalcium aluminate hydrates and tricalcium silicate phases. There is some tendency for the superplasticizer to sorb on ettringite. The presence of superplasticizer did not coincide with the locations of unreacted silica fume and high silica content phases such as C 2 S-H. The observations explain the findings of the studies of unset pastes which also showed that the sorption of superplasticizer is likely to be enhanced with increased mixing water content and, hence, distribution in and exposure to the hydration reaction surfaces in the grout. Superplasticizer can be leached in very small quantities from the hardened grouts. Rapid release takes place from the unsorbed superplasticizer contained in the accessible pore space. Subsequent release likely occurs with dissolution of the cement phases and the exposure of isolated pores to groundwater. (au) (37 refs.)

Numerical Simulation and Optimization of Hole Spacing for Cement Grouting in Rocks

Directory of Open Access Journals (Sweden)

Ping Fu

2013-01-01

Full Text Available The fine fissures of V-diabase were the main stratigraphic that affected the effectiveness of foundation grout curtain in Dagang Mountain Hydropower Station. Thus, specialized in situ grouting tests were conducted to determine reasonable hole spacing and other parameters. Considering time variation of the rheological parameters of grout, variation of grouting pressure gradient, and evolution law of the fracture opening, numerical simulations were performed on the diffusion process of cement grouting in the fissures of the rock mass. The distribution of permeability after grouting was obtained on the basis of analysis results, and the grouting hole spacing was discussed based on the reliability analysis. A probability of optimization along with a finer optimization precision as 0.1 m could be adopted when compared with the accuracy of 0.5 m that is commonly used. The results could provide a useful reference for choosing reasonable grouting hole spacing in similar projects.

Leach behavior of hydrofracture grout incorporating radioactive wastes

International Nuclear Information System (INIS)

Moore, J.G.; Godbee, H.W.; Kibbey, A.H.

1976-01-01

Rates at which Sr, Cs, Pu, and Cm are leached from hydrofracture grout were measured. The fraction of an isotope leached varied with the square root of time if the leachant was replaced more frequently than once per day, but was inhibited or depressed if replacement was made less often. The amount of Sr or Cs leached from the grout varied directly with the degree of drying during curing and inversely with the time of curing. Of the clay additives studied for enhancing cesium retention, Grundite, while satisfactory, was the least effective. In general, the isotope leach rate followed the order: Cs greater than Sr greater than Cm greater than Pu. The amount leached as a function of the leachant varied in the order: distilled water greater than tap water greater than grout water. Concentrating the waste by a factor of up to 4 before grouting had little effect on the leach rate. Comparison with results for other products indicates that the grout can provide leach rates comparable to those for wastes incorporated into borosilicate glass. Theoretical relationships that consider diffusion and instantaneous reaction (an equilibrium or time-dependent relationship between mobile and immobile forms of a species) were in good agreement with the data for the 28-day-cured grout when the leachant was initially replaced twice per day. The credibility of laboratory results with simulated waste was substantiated by a short-term continuous leach test made on a fragment of a core sample of actual hydrofracture grout. The modified effective diffusivities (10 -11 to 10 -10 cm 2 /s, equivalent to a leach rate of the order of 10 -7 g cm -2 day -1 ) for Sr and Cs calculated from these data are comparable to laboratory values. 17 figures, 5 tables

Engineered cementitious composites with low volume of cementitious materials

NARCIS (Netherlands)

Zhou, J.; Quian, S.; Van Breugel, K.

2010-01-01

Engineered cementitious composite (ECC) is an ultra ductile cement-based material reinforced with fibers. It is characterized by high tensile ductility and tight crack width control. Thanks to the excellent performance, ECC is emerging in broad applications to enhance the loading capacity and the

Grout Treatment Facility Land Disposal Restriction Management Plan

International Nuclear Information System (INIS)

Hendrickson, D.W.

1991-01-01

This document establishes management plans directed to result in the land disposal of grouted wastes at the Hanford Grout Facilities in compliance with Federal, State of Washington, and Department of Energy land disposal restrictions. 9 refs., 1 fig

Chemical evolution of cementitious materials

International Nuclear Information System (INIS)

Lothenbach, Barbara; Wieland, Erich

2012-01-01

Barbara Lothenback of EMPA, Switzerland gave an overview of the status of thermodynamic modelling for cementitious systems. Thermodynamic modelling of cementitious systems has been greatly facilitated in recent years by the development of more sophisticated geochemical software, of solid solution models for various cement phases, and by the collection of thermodynamic data for minerals relevant to cementitious systems over a wide range of temperature (0 to 100 deg. C). Based on these developments, thermodynamic modelling, coupled with kinetic equations that describe the dissolution of clinker as a function of time, can be used to: - Quantify the liquid and solid phase compositions of ordinary Portland cement and blended cements during the hydration process. - Evaluate compositional changes that occur in cementitious materials due to the use of various aggregates and other mineral additives (e.g. silica fume and blast furnace slag). - Predict degradation of cement in contact with the repository environment. Discussion of the paper included: What is our understanding of where aluminium resides in low-pH cements and what is our ability to model the behaviour of aluminium in these systems? The location of aluminium in low-pH cements depends on the overall Ca/Si ratio of the system and on the pH, but some aluminium enters the CSH gel as a CASH gel phase. The Swiss disposal programme is currently conducting some experiments to investigate this topic

Cement-based grouts in geological disposal of radioactive waste

International Nuclear Information System (INIS)

Onofrei, M.

1996-01-01

The behavior and performance of a specially developed high-performance cement-based grout has been studied through a combined laboratory and in situ research program conducted under the auspices of the Canadian Nuclear Fuel Waste Management Program (CNFWMP). A new class of cement-based grouts - high-performance grouts-with the ability to penetrate and seal fine fractures was developed and investigated. These high-performance grouts, which were injected into fractures in the granitic rock at the Underground Research Laboratory (URL) in Canada, are shown to successfully reduce the hydraulic conductivity of the rock mass from -7 m s -1 to 10 -9 m s -1 and to penetrate fissures in the rock with apertures as small as 10 μm. Furthermore, the laboratory studies have shown that this high - performance grout has very low hydraulic conductivity and is highly leach resistant under repository conditions. Microcracks generated in this materials from shrinkage, overstressing or thermal loads are likely to self-seal. The results of these studies suggest that the high-performance grouts can be considered as viable materials in disposal-vault sealing applications. Further work is needed to fully justify extrapolation of the results of the laboratory studies to time scales relevant to performance assessment

Quality assurance plan for placement of cold-cap grout, demonstration vault, Hanford Grout Vault Program. Final report

Energy Technology Data Exchange (ETDEWEB)

Harrington, P.T.; Wakeley, L.D.; Ernzen, J.J.; Walley, D.M.

1992-08-01

During FY 91, the U.S. Army Engineer Waterways Experiment Station (WES) developed a grout to be used as a cold cap, a nonradioactive layer, between the solidified waste and the cover blocks of a demonstration waste disposal vault at the U.S. Department of Energy Hanford Facility. This document recommends requirements for a quality assurance (QA) plan for field mixing and placing of the cold-cap grout during final closure of the demonstration vault. Preplacement activities emphasize selection and testing of materials that will match the performance of materials used in the WES grout. Materials sources and applicable American Society of Testing and Materials, American Concrete Institute, and American Petroleum Institute specifications and requirements are provided. Archiving of physical samples of materials is essential, in addition to careful maintenance of test reports and laboratory data. Full-scale field trial mixing and a detailed preconstruction conference are recommended. Placement activities focus on production and placement of a grout that remains sufficiently constant throughout all batches and meets performance requirements. QA activities must be coordinated between the batch plant and delivery site. Recommended sampling during placement includes cylinders cast for subsequent tests of compressive strength and for nondestructive evaluation and prisms cast for monitoring volume stability. A minimum of two lifts is recommended. Postplacement activities include long-term monitoring of the properties of grout specimens cast during placement. Minimum testing of cylinders includes pulse velocity, fundamental frequency, and unconfined compressive strength. Monitoring characteristics of the microstructure also are recommended. The QA plan should designate an organization to have responsibility for maintaining complete records, reports, and archived samples, including details of deviations from plans written before field placement.

Disassembly Properties of Cementitious Finish Joints Using an Induction Heating Method

Science.gov (United States)

Ahn, Jaecheol; Noguchi, Takafumi; Kitagaki, Ryoma

2015-01-01

Efficient maintenance and upgrading of a building during its lifecycle are difficult because a cementitious finish uses materials and parts with low disassembly properties. Additionally, the reuse and recycling processes during building demolition also present numerous problems from the perspective of environmental technology. In this study, an induction heating (IH) method was used to disassemble cementitious finish joints, which are widely used to join building members and materials. The IH rapidly and selectively heated and weakened these joints. The temperature elevation characteristics of the cementitious joint materials were measured as a function of several resistor types, including wire meshes and punching metals, which are usually used for cementitious finishing. The disassembly properties were evaluated through various tests using conductive resistors in cementitious joints such as mortar. When steel fiber, punching metal, and wire mesh were used as conductive resistors, the cementitious modifiers could be weakened within 30 s. Cementitious joints with conductive resistors also showed complete disassembly with little residual bond strength.

Rock fracture grouting with microbially induced carbonate precipitation

Science.gov (United States)

Minto, James M.; MacLachlan, Erica; El Mountassir, Gráinne; Lunn, Rebecca J.

2016-11-01

Microbially induced carbonate precipitation has been proposed for soil stabilization, soil strengthening, and permeability reduction as an alternative to traditional cement and chemical grouts. In this paper, we evaluate the grouting of fine aperture rock fractures with calcium carbonate, precipitated through urea hydrolysis, by the bacteria Sporosarcina pasteurii. Calcium carbonate was precipitated within a small-scale and a near field-scale (3.1 m2) artificial fracture consisting of a rough rock lower surfaces and clear polycarbonate upper surfaces. The spatial distribution of the calcium carbonate precipitation was imaged using time-lapse photography and the influence on flow pathways revealed from tracer transport imaging. In the large-scale experiment, hydraulic aperture was reduced from 276 to 22 μm, corresponding to a transmissivity reduction of 1.71 × 10-5 to 8.75 × 10-9 m2/s, over a period of 12 days under constantly flowing conditions. With a modified injection strategy a similar three orders of magnitude reduction in transmissivity was achieved over a period of 3 days. Calcium carbonate precipitated over the entire artificial fracture with strong adhesion to both upper and lower surfaces and precipitation was controlled to prevent clogging of the injection well by manipulating the injection fluid velocity. These experiments demonstrate that microbially induced carbonate precipitation can successfully be used to grout a fracture under constantly flowing conditions and may be a viable alternative to cement based grouts when a high level of hydraulic sealing is required and chemical grouts when a more durable grout is required.

Hanford grout: predicting long-term performance

International Nuclear Information System (INIS)

Sewart, G.H.; Mitchell, D.H.; Treat, R.L.; McMakin, A.H.

1987-01-01

Grouted disposal is being planned for the low-level portion of liquid radioactive wastes at the Hanford site in Washington state. The performance of the disposal system must be such that it will protect people and the environment for thousands of years after disposal. To predict whether a specific grout disposal system will comply with existing and foreseen regulations, a performance assessment (PA) is performed. Long-term PAs are conducted for a range of performance conditions. Performance assessment is an inexact science. Quantifying projected impacts is especially difficult when only scant data exist on the behavior of certain components of the disposal system over thousands of years. To develop defensible results, we are honing the models and obtaining experimental data. The combination of engineered features and PA refinements is being used to ensure that Hanford grout will meet its principal goal: to protect people and the environment in the future

Experimental assessment of the sealing effectiveness of rock fracture grouting

International Nuclear Information System (INIS)

Schaffer, A.; Daemen, J.J.K.

1987-03-01

The objective of this investigation is to determine the effectiveness of cement grouts as sealants of fractures in rock. Laboratory experiments have been conducted on seven 15-cm granite cubes containing saw cuts, three 23-cm diameter andesite cores containing induced tension cracks, and one 15-cm diameter marble core containing a natural fracture. Prior to grouting, the hydraulic conductivity of the fractures is determined under a range of normal stresses, applied in loading and unloading cycles, from 0 to 14 MPa (2000 psi). Grout is injected through an axial borehole, at a pressure of 1.2 to 8.3 MPa (180 to 1200 psi), pressure selected to provide a likely groutable fracture aperture, while the fracture is stressed at a constant normal stress. The fracture permeability is measured after grouting. Flow tests on the ungrouted samples confirm the inverse relation between normal stress and fracture permeability. The equivalent aperture determined by these tests is a reliable indicator of groutability. Postgrouting permeability measurements as performed here, and frequently in practice, can be misleading, since incomplete grouting of fractures can result in major apparent reductions in permeability. The apparent permeability reduction is caused by grouting of a small area of a highly preferential flowpath directly adjacent to the hole used for grouting and for permeability testing. Experimental results confirm claims in the literature that ordinary portland cement inadequately penetrates fine fractures

Durability of low-pH injection grout. A literature survey

International Nuclear Information System (INIS)

Holt, E.

2008-01-01

This publication provides an overview of the durability of injection grouts. It is intended for use during planning and construction at the ONKALO underground research facility. The review has been done with respect to the application conditions, materials and service life requirements expressed by Posiva Oy. The publication describes all types of cement-based material durability, with an emphasis on the key issues of shrinkage cracking, leaching and sulphate attack. The second part of the report provides information on how durability expectations have changed with the history of injection grout development. The report gives information specific to low-pH injection grouts containing high amounts of silica fume performance and how their durability is expected to differ from traditional normal cement-based mixtures. The final part of the report provides suggestions for future research needs for ensuring the service life of injection grouts. The key finding from this study is that the low-pH grout material is not expected to have worse durability performance compared to the standard injection grout. Combining high amounts of silica fume with the cement to produce low-pH grout should result in a material having lower permeability and thus greater resistance to leaching and chemical attack. Further laboratory testing is needed to quantitatively verify these findings and to provide inputs for future service life modeling. (orig.)

Solubility of krypton in hydrofracture grout at elevated pressures

International Nuclear Information System (INIS)

Fitzgerald, C.L.; Mailen, J.C.

1982-01-01

The solubilities of krypton in water, simulated waste solution, and simulated grout at about 25 0 C and to pressures of 150 atm have been determined. The results of these studies show that preliminary calculations of krypton solubility based on the aqueous component of the hydrofracture grout were overly pessimistic. The volume of noble gas generated annually by the reference reprocessing plant would be soluble in the annual hydrofracture grout injection at ORNL at about 10 atm. The amount of krypton in the gas phase would depend on the amount of air in the hydrofracture grout mixture. At 34 atm, and with a small air volume relative to the injected krypton, the krypton would constitute about 30% of the gas bubbles. The disposal of krypton via injection with hydrofracture grout seems to be a viable process. The next logical steps would be to determine the krypton diffusion rate at injection conditions, and possibly to perform a test injection. At present, the schedule for future work is uncertain since funds for this project have been reduced significantly

Mixing conditions in application of bentonite grouting to radioactive waste disposal

International Nuclear Information System (INIS)

Kobayakawa, Hiroaki; Ito, Hiroshi

2007-01-01

The purpose of this study was to understand the flow properties and permeability of bentonite grout with NaCl added, using laboratory tests, and to clarify the mixing conditions of bentonite as a material. Given that the required permeability of clay grout is 10 -9 (m/s), the combination of grout (W/B) becomes 6 or less. The viscosity of the grout was measured, and because the viscosity was higher than the thickest cement milk on dam grouting, it was found that grout with a W/B of less than 10 was difficult to inject into rock joints. We then added NaCl to grout with a W/B is 6, and its viscosity decreased as the amount of NaCl increased. A grout of viscosity able to be injected into rock joints was achieved by adding NaCl in a density higher than 'W:NaCl=40:1'. Next, the permeability of a bentonite suspension with NaCl was examined using the falling head permeability test. Testing the sample 'B:W:NaCl=20:20:1' for 10 days revealed that the initial permeability 10 -8 (m/s) decreased to 10 -10 - 10 -11 (m/s). These results showed that a suspension to inject into rock joints could be made by adding NaCl, and clarified that permeation of groundwater into the suspension causes a decline in permeability. (author)

Grouting of karstic arch dam foundation

Energy Technology Data Exchange (ETDEWEB)

Young, J.; Rigbey, S. [Acres International, Niagara Falls, ON (Canada)

2002-07-01

A 200 m high arch dam and a 2000 MW underground power house complex is under development in the Middle East. The project is located in a highly seismic area in rugged, mountainous terrain. The arch dam is constructed on good quality limestone and dolomitic limestone rock mass, but it contains several zones of disturbed or sheared rock. The basement rock is slightly karstic with hydraulic conductivities in the order of 100 Lugeons. In order to get a satisfactory foundation surface for the dam, it will be necessary to excavate extensively and backfill with concrete. Because of the presence of many clay infilled cavities and fractures, geotechnicians are considering the installation of a multiple row grout curtain to a depth of 150 m below the dam foundation to ensure adequate seepage and uplift parameters when the reservoir is impounded. Initial grouting water pressure test results suggested that the grouting and drainage curtain should be extended to the left abutment beyond the current design. However, when horizontal slide models of the dam abutment were developed using the finite element program SEEPW, it was shown that there is no benefit to extending the length of grout curtains unless they are tied to an area of much lower hydraulic conductivity much deeper in the abutment. 1 tab., 5 figs.

Rock grouting. Current competence and development for the final repository

International Nuclear Information System (INIS)

Emmelin, Ann; Brantberger, Martin; Eriksson, Magnus; Gustafson, Gunnar; St ille, Haakan

2007-06-01

The report aims at presenting the overall state of grouting competence and development relating to the final repository and at motivating and giving detail to the grouting sections presented in the 2007 version of the overall SKB report 'Programme for research, development and demonstration of methods for the management and disposal of nuclear waste' that is presented to the government every three years. The report offers suggestions for principles for planning, design and execution of grouting and describes the further work thought to be necessary in order to meet the requirements of the final repository, that are currently given as working premises. This report does not aim to, and cannot, describe the grouting processes in detail. For details of current concepts, experience and development work, a list of references is provided. In Chapter 2, the task of sealing the underground repository is examined and an overall approach presented. Although the requirements related to this task are preliminary, it is made evident that they concern both the actual grouting results and the process leading to the achievement of these results. Chapter 3 is a conceptual description of grouting and the factors that govern the spreading of grout in the rock mass. It is intended as an introduction to Chapters 4-6, which describe the state of grouting competence and the tools available for the sealing of the final repository facility. Both common practice and cutting-edge research are dealt with in these chapters, mainly relying on references where available. Chapters 4 and 5 focus on the system consisting of the fundamental components the rock mass, the grout materials and the grouting technology, and how these system components interact whilst, in Chapter 6, the rock/grout technical system is viewed in a brief organizational context. Based on the requirements on results and the overall grouting process on the one hand and the current competence in grouting theory and practice on the

Rock grouting. Current competence and development for the final repository

Energy Technology Data Exchange (ETDEWEB)

Emmelin, Ann (Swedish Nuclear Fuel and Waste Management Co., Stockholm (SE)); Brantberger, Martin (Ramboell (SE)); Eriksson, Magnus (Vattenfall Power Consultant (SE)); Gustafson, Gunnar (Chalmers Univ. of Technology, Goeteborg (SE)); Stille, Haakan (Royal Inst. of Technology, Stockholm (SE))

2007-06-15

The report aims at presenting the overall state of grouting competence and development relating to the final repository and at motivating and giving detail to the grouting sections presented in the 2007 version of the overall SKB report 'Programme for research, development and demonstration of methods for the management and disposal of nuclear waste' that is presented to the government every three years. The report offers suggestions for principles for planning, design and execution of grouting and describes the further work thought to be necessary in order to meet the requirements of the final repository, that are currently given as working premises. This report does not aim to, and cannot, describe the grouting processes in detail. For details of current concepts, experience and development work, a list of references is provided. In Chapter 2, the task of sealing the underground repository is examined and an overall approach presented. Although the requirements related to this task are preliminary, it is made evident that they concern both the actual grouting results and the process leading to the achievement of these results. Chapter 3 is a conceptual description of grouting and the factors that govern the spreading of grout in the rock mass. It is intended as an introduction to Chapters 4-6, which describe the state of grouting competence and the tools available for the sealing of the final repository facility. Both common practice and cutting-edge research are dealt with in these chapters, mainly relying on references where available. Chapters 4 and 5 focus on the system consisting of the fundamental components the rock mass, the grout materials and the grouting technology, and how these system components interact whilst, in Chapter 6, the rock/grout technical system is viewed in a brief organizational context. Based on the requirements on results and the overall grouting process on the one hand and the current competence in grouting theory and

OCRWM Science and Technology Program Cementitious Materials Technologies

International Nuclear Information System (INIS)

DOE

2004-01-01

This potential project will develop and test cost effective cementitious materials for construction of Yucca Mountain (YM) inverts, drift liners, and bulkheads. These high silica cementitious materials will be designed to buffer the pH and Eh of the groundwater, to slow corrosion of waste packages (WP), and to retard radionuclide migration. While being compatible with YM repository systems, these materials are expected to be less expensive to produce, and as strong, and more durable than ordinary Portland Cement (OPC). Therefore, building out the repository with these cementitious materials may significantly reduce these costs and reduce uncertainty in short-( 10,000 yr) repository performance. Both laboratory development and natural analog studies are anticipated using a unique combination of expertise at ORNL, UT, UC Berkeley, and Minatom to develop and test high-silica hydraulic, cementitious binders for use at YM. The major tasks of this project are to (1) formulate and make candidate cementitious materials using high-silica hydraulic hinders, (2) measure the physical and chemical properties of these materials, (3) expose combinations of these materials and WP materials to static and flowing YM groundwater at temperatures consistent with the expected repository conditions, (4) examine specimens of both the cementitious materials and WP materials periodically for chemical and mineralogical changes to determine reaction mechanisms and kinetics, and (5) predict the long-term performance of the material by thermodynamic and transport modeling and by comparisons with natural analogs

Tensile capacity of loop connections grouted with concrete or mortar

DEFF Research Database (Denmark)

Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

2017-01-01

This paper presents a study of grout failure in symmetric U-bar loop connections loaded in tension, with focus on the performance of two grouting materials – concrete and mortar. The study contains an experimental investigation as well as a rigid-plastic modelling of the tensile capacity. The test...... to allow yielding of the U-bars. The experimental work showed that connections grouted with concrete performed better than the connections grouted with mortar. In the theoretical models, the difference in tested capacity is explained by the difference in the internal angle of friction and in the softening...... behaviour of concrete as compared with mortar....

Pilot-scale decontamination solution test results HGTP-93-0702-02

International Nuclear Information System (INIS)

Clemmer, R.G.; Allen, R.P.; Bagaasen, L.M.; Fetrow, L.K.

1993-05-01

Decontamination solution testing constitutes a task of the Hanford Grout Technology Program (HGTP) at Pacific Northwest Laboratory (PNL). The HGTP provides technical support to the Westinghouse Hanford Company (WHC) Grout Disposal Program. Cementitious grout has been identified as the waste form for low-level radioactive waste. Grout processing equipment, including mixers, pumps, and piping, will require periodic maintenance. Decontamination of components is needed to reduce radiation dose to maintenance workers. The purpose of this work was to develop and test methods for decontaminating grout processing equipment. The proposed method of decontamination is to use a mild chemical solution, such as a 6 N citric acid to dissolve the grout. The method should effectively remove grout without causing degradation of grout processing equipment

Non-cementitious compositions comprising vaterite and methods thereof

Science.gov (United States)

Devenney, Martin; Fernandez, Miguel; Morgan, Samuel O.

2015-09-15

Non-cementitious compositions and products are provided. The compositions of the invention include a carbonate additive comprising vaterite such as reactive vaterite. Additional aspects of the invention include methods of making and using the non-cementitious compositions and products.

Effluent Management Facility Evaporator Bottom-Waste Streams Formulation and Waste Form Qualification Testing

Energy Technology Data Exchange (ETDEWEB)

Saslow, Sarah A.; Um, Wooyong; Russell, Renee L.

2017-08-02

This report describes the results from grout formulation and cementitious waste form qualification testing performed by Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions, LLC (WRPS). These results are part of a screening test that investigates three grout formulations proposed for wide-range treatment of different waste stream compositions expected for the Hanford Effluent Management Facility (EMF) evaporator bottom waste. This work supports the technical development need for alternative disposition paths for the EMF evaporator bottom wastes and future direct feed low-activity waste (DFLAW) operations at the Hanford Site. High-priority activities included simulant production, grout formulation, and cementitious waste form qualification testing. The work contained within this report relates to waste form development and testing, and does not directly support the 2017 Integrated Disposal Facility (IDF) performance assessment (PA). However, this work contains valuable information for use in PA maintenance past FY 2017 and future waste form development efforts. The provided results and data should be used by (1) cementitious waste form scientists to further the understanding of cementitious leach behavior of contaminants of concern (COCs), (2) decision makers interested in off-site waste form disposal, and (3) the U.S. Department of Energy, their Hanford Site contractors and stakeholders as they assess the IDF PA program at the Hanford Site. The results reported help fill existing data gaps, support final selection of a cementitious waste form for the EMF evaporator bottom waste, and improve the technical defensibility of long-term waste form risk estimates.

Microbial analyses of cement and grouting additives

International Nuclear Information System (INIS)

Hallbeck, L.; Jaegevall, S.; Paeaejaervi, A.; Rabe, L.; Edlund, J.; Eriksson, S.

2012-01-01

During sampling in the ONKALO tunnel in 2006, heavy growth of a slimy material was observed in connection with grouting. It was suggested to be microbial growth on organic additives leaching from the grout. Two sampling campaigns resulted in the isolation of several aerobic bacterial strains. Some of these strains were used in biodegradation studies of three solid cement powders, eight liquid grout additives, and six plastic drainage materials. Degradation was also studied using ONKALO groundwaters as inoculums. The isolated strains were most closely related to hydrocarbon-degrading microorganisms. The biodegradation of seven of the products was tested using microorganisms isolated from the ONKALO slime in 2006; none of these strains could degrade the tested products. When ONKALO drillhole groundwaters were used as inoculums in the degradation studies, it was demonstrated that Structuro 111X, Mighty 150, and Super-Parmix supported growth of the groundwater microorganisms. Structuro 111X is a polycarboxylate condensate while Mighty 150 and Super-Parmix are condensates with formaldehyde and naphthalene. Some of the isolated microorganisms belonged to the genus Pseudomonas, many strains of which can degrade organic molecules. None of the plastic drainage materials supported growth during the degradation studies. Microorganisms were present in two of the liquid products when delivered, GroutAid and Super-Parmix. The potential of the organic compounds in grout additives to be degraded by microorganisms, increasing the risk of biofilm formation and complexing compound production, must be considered. Microbial growth will also increase the possibility of hydrogen sulphide formation. (orig.)

Review of durability of cementitious engineered barriers in repository environments

International Nuclear Information System (INIS)

Parrott, L.J.; Lawrence, C.D.

1992-01-01

This report is concerned with the durability of cementitious engineered barriers in a repository for low and intermediate level nuclear waste. Following the introduction the second section of the review identifies the environmental conditions associated with a deep, hard rock repository for ILW and LLW that are relevant to the durability of cementitious barriers. Section three examines the microstructure and macrostructure of cementitious materials and considers the physical and chemical processes of radionuclide immobilization. Potential repository applications and compositions of cementitious materials are reviewed in Section four. The main analysis of durability is dealt with in Section five. The different types of cementitious barrier are considered separately and their most probable modes of degradation are analysed. Concluding remarks that highlight critical technical matters are given in Section six. (author)

Entombment Using Cementitious Materials: Design Considerations and International Experience

Energy Technology Data Exchange (ETDEWEB)

Seitz, Roger Ray

2002-08-01

Cementitious materials have physical and chemical properties that are well suited for the requirements of radioactive waste management. Namely, the materials have low permeability and durability that is consistent with the time frame required for short-lived radionuclides to decay. Furthermore, cementitious materials can provide a long-term chemical environment that substantially reduces the mobility of some long-lived radionuclides of concern for decommissioning (e.g., C-14, Ni-63, Ni-59). Because of these properties, cementitious materials are common in low-level radioactive waste disposal facilities throughout the world and are an attractive option for entombment of nuclear facilities. This paper describes design considerations for cementitious barriers in the context of performance over time frames of a few hundreds of years (directed toward short-lived radionuclides) and time frames of thousands of years (directed towards longer-lived radionuclides). The emphasis is on providing an overview of concepts for entombment that take advantage of the properties of cementitious materials and experience from the design of low-level radioactive waste disposal facilities. A few examples of the previous use of cementitious materials for entombment of decommissioned nuclear facilities and proposals for the use in future decommissioning of nuclear reactors in a few countries are also included to provide global perspective.

Entombment Using Cementitious Materials: Design Considerations and International Experience

Energy Technology Data Exchange (ETDEWEB)

Seitz, R.R.

2002-05-15

Cementitious materials have physical and chemical properties that are well suited for the requirements of radioactive waste management. Namely, the materials have low permeability and durability that is consistent with the time frame required for short-lived radionuclides to decay. Furthermore, cementitious materials can provide a long-term chemical environment that substantially reduces the mobility of some long-lived radionuclides of concern for decommissioning (e.g., C-14, Ni-63, Ni-59). Because of these properties, cementitious materials are common in low-level radioactive waste disposal facilities throughout the world and are an attractive option for entombment of nuclear facilities. This paper describes design considerations for cementitious barriers in the context of performance over time frames of a few hundreds of years (directed toward short-lived radionuclides) and time frames of thousands of years (directed towards longer-lived radionuclides). The emphasis is on providing a n overview of concepts for entombment that take advantage of the properties of cementitious materials and experience from the design of low-level radioactive waste disposal facilities. A few examples of the previous use of cementitious materials for entombment of decommissioned nuclear facilities and proposals for the use in future decommissioning of nuclear reactors in a few countries are also included to provide global perspective.

Entombment Using Cementitious Materials: Design Considerations and International Experience

International Nuclear Information System (INIS)

Seitz, R.R.

2002-01-01

Cementitious materials have physical and chemical properties that are well suited for the requirements of radioactive waste management. Namely, the materials have low permeability and durability that is consistent with the time frame required for short-lived radionuclides to decay. Furthermore, cementitious materials can provide a long-term chemical environment that substantially reduces the mobility of some long-lived radionuclides of concern for decommissioning (e.g., C-14, Ni-63, Ni-59). Because of these properties, cementitious materials are common in low-level radioactive waste disposal facilities throughout the world and are an attractive option for entombment of nuclear facilities. This paper describes design considerations for cementitious barriers in the context of performance over time frames of a few hundreds of years (directed toward short-lived radionuclides) and time frames of thousands of years (directed towards longer-lived radionuclides). The emphasis is on providing a n overview of concepts for entombment that take advantage of the properties of cementitious materials and experience from the design of low-level radioactive waste disposal facilities. A few examples of the previous use of cementitious materials for entombment of decommissioned nuclear facilities and proposals for the use in future decommissioning of nuclear reactors in a few countries are also included to provide global perspective

Monitoring of Grouting Compactness in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers

Directory of Open Access Journals (Sweden)

Tianyong Jiang

2016-08-01

Full Text Available A post-tensioning tendon duct filled with grout can effectively prevent corrosion of the reinforcement, maintain bonding behavior between the reinforcement and concrete, and enhance the load bearing capacity of concrete structures. In practice, grouting of the post-tensioning tendon ducts always causes quality problems, which may reduce structural integrity and service life, and even cause accidents. However, monitoring of the grouting compactness is still a challenge due to the invisibility of the grout in the duct during the grouting process. This paper presents a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real time. A segment of a commercial tendon duct was used as research object in this study. One lead zirconate titanate (PZT piezoceramic transducer with marble protection, called a smart aggregate (SA, was bonded on the tendon and installed in the tendon duct. Two PZT patch sensors were mounted on the top outside surface of the duct, and one PZT patch sensor was bonded on the bottom outside surface of the tendon duct. In the active sensing approach, the SA was used as an actuator to generate a stress wave and the PZT sensors were utilized to detect the wave response. Cement or grout in the duct functions as a wave conduit, which can propagate the stress wave. If the cement or grout is not fully filled in the tendon duct, the top PZT sensors cannot receive much stress wave energy. The experimental procedures simulated four stages during the grout pouring process, which includes empty status, half grouting, 90% grouting, and full grouting of the duct. Experimental results show that the bottom PZT sensor can detect the signal when the grout level increases towards 50%, when a conduit between the SA and PZT sensor is formed. The top PZT sensors cannot receive any signal until the grout process is completely finished. The wavelet packet-based energy analysis was adopted in this

The use of cement grouts for the immobilisation of solid radioactive waste

International Nuclear Information System (INIS)

Brown, D.J.; Smith, D.L.

1982-06-01

The use of cement grouts is being considered for the immobilisation of solid items of radioactive waste. In this report the factors which influence the selection of a grout for use in an active plant are identified. The properties and limitations of standard cement grouts are summarised. Inactive grouting trials carried out in the period September 1981 to June 1982 on the 220 dm 3 scale are described. (author)

Elevated temperature grouts and radioactive waste inventory

International Nuclear Information System (INIS)

Constable, M.; Fenton, A.; Lee, D.J.; Jones, D.V.C.; Wilding, C.R.

1990-01-01

The objective of this year's programme was to quantify the total volumes of cementitious immobilising material required to package radioactive waste arisings in the UK to 2010. These data form the basis for selection of cementitious matrices for further investigation of storage at likely repository temperatures, including the effect of γ irradiation and resaturation to determine their effects on the physical and chemical performance of the cement systems. (Author)

Leaching of radioactive nuclides from cement grouts. Part II

International Nuclear Information System (INIS)

Stanley, W.T.; Avgerinos, G.F.; Gonzalez, B.; Hemley, P.J.

1974-01-01

The determination of the leaching rate of radioactive 137 Cs from a cement grout should the grout be contacted by water is necessary for environmental protection. The effect of the leachant turnover rate on 137 Cs leaching rates was evaluated with batch and continuous (modified Soxhlet extractor) modes of experimentation. Three additives (Grundite, potter's clay, and Conasauga shale) were compared in terms of capability of radioactive isotope retention, while two leachants (tap and distilled water) were investigated. The Soxhlet extractor experiment resulted in the highest rate of leaching, and Conasauga shale was found the best additive for 137 Cs immobilization. Tap water used as leachant was more effective than distilled water. Data were analyzed using models involving isotopic diffusion in the grout and involving diffusion plus a time dependent boundary condition at the interface of grout specimen and leachant

On the Interaction between Superabsorbent Hydrogels and Cementitious Materials

Science.gov (United States)

Farzanian, Khashayar

Autogenous shrinkage induced cracking is a major concern in high performance concretes (HPC), which are produced with low water to cement ratios. Internal curing to maintain high relative humidity in HPC with the use of an internal water reservoir has proven effective in mitigating autogenous shrinkage in HPC. Superabsorbent polymers (SAP) or hydrogels have received increasing attention as an internal curing agent in recent years. A key advantage of SAP is its versatility in size distribution and absorption/desorption characteristics, which allow it to be adapted to specific mix designs. Understanding the behavior of superabsorbent hydrogels in cementitious materials is critical for accurate design of internal curing. The primary goal of this study is to fundamentally understand the interaction between superabsorbent hydrogels and cementitious materials. In the first step, the effect of chemical and mechanical conditions on the absorption of hydrogels is investigated. In the second step, the desorption of hydrogels in contact with porous cementitious materials is examined to aid in understanding the mechanisms of water release from superabsorbent hydrogels (SAP) into cementitious materials. The dependence of hydrogel desorption on the microstructure of cementitious materials and relative humidity is studied. It is shown that the capillary forces developed at the interface between the hydrogel and cementitious materials increased the desorption of the hydrogels. The size of hydrogels is shown to influence desorption, beyond the known size dependence of bulk diffusion, through debonding from the cementitious matrix, thereby decreasing the effect of the Laplace pressure on desorption. In the third step, the desorption of hydrogels synthesized with varied chemical compositions in cementitious materials are investigated. The absorption, chemical structure and mechanical response of hydrogels swollen in a cement mixture are studied. The effect of the capillary forces on

Control of water inflow and use of cement in ONKALO after penetration of fracture zone R19

International Nuclear Information System (INIS)

Ahokas, H.; Hellae, P.; Ahokas, T.

2006-07-01

The construction of ONKALO, the underground rock characterisation facility at Olkiluoto, started in summer 2004. The potential disturbances due to construction of ONKALO, which were assessed prior to construction, have been reassessed in this report. The reassessment is based on observations and experiences from construction work, in situ and surface based monitoring, and numerical flow modelling. The implications of the construction of ONKALO and the repository on hydrogeochemical disturbances and the technical development of grouts are considered. Based on the new assessment, the recommendations of the practises to be adapted after the penetration of RH19B at the depth between 70 and 170 m are presented. The identified disturbances due to the construction of ONKALO were the drawdown of the groundwater table, and intrusion of surface water and upcoming of deep saline groundwater. The intrusion of surface water would lead to reduced pH and redox buffering capacity of the rock. The latter would lead to locally high salinity levels that may negatively impact the performance of the buffer bentonite and backfill. If the rock were sealed with ordinary cementitious grout, the formation of a high-pH plume originating from cement would affect transport processes in the geosphere and the performance of the Engineered Barrier System, especially of the bentonite buffer around the canisters. This report comprises the observations for the first 670 m of access tunnel (reached in September 2005). The measured water inflow (1.7 l/min/100 m of tunnel) has remained well within the set target (1 - 2 l/min/100 m of tunnel). Grouting has been used as a measure to minimize water inflow. So far, the use of cement has been about the same as the amount estimated prior to construction. No significant changes in hydrogeochemistry have been observed, except for the highpH plume due to the effect of cement in the monitoring of some of the boreholes. The numerical flow model used to analyse

Microbiological activities in a shallow-ground repository with cementitious wasteform

International Nuclear Information System (INIS)

Varlakova, G.A.; Dyakonova, A.T.; Netrusov, A.I.; Ojovan, M.I.

2012-01-01

Cementitious wasteform with immobilised nuclear power plant operational radioactive waste disposed in a near surface testing repository for about 20 years have been analysed for microbiological activities. Clean cultures were selected from the main metabolic groups expected within repository environment e.g. anaerobic de-nitrifying, fermenting, sulphur-reducing, iron-reducing, and oxidizing, thio-bacterium and mushrooms. Microbiological species were identified within cementitious wasteform, in the clayey soil near the wasteform and in the contacting water. The most populated medium was the soil with microbial populations Bacillus, Pseudomonas and Micrococcus, and densities of populations up to 3.6*10 5 colony/g. Microbial populations of generic type Bacillus, Pseudomonas, Rhodococcus, Alcaligenes, Micrococcus, Mycobacterium, and Arthrobacter were identified within cementitious wasteform. Populations of Arthrobacter, Pseudomonas, Alcaligenes, Rhodococcus, Bacillus and Flavobacterium were identified in the water samples contacting the cementitious wasteform. Microbiological species identified are potential destructors of cementitious wasteform and containers. (authors)

Acute toxicity screening of Hanford Site waste grouts using aquatic invertebrates

International Nuclear Information System (INIS)

Rebagay, T.V.; Dodd, D.A.; Lockrem, L.L.; Voogd, J.A.

1993-01-01

Liquid wastes containing radioactive, hazardous, and regulated chemicals have been generated throughout the 50 years operation of the Hanford Site of the US Department of Energy near Richland, Washington. The current strategy for the disposal of the low-level radioactive portion of these wastes involves immobilization of the waste in the form of grout. Because the potential risk of animal and plant exposure to grouts is unknown, acute toxicity screening of grouts is needed. Grouts were prepared by mixing a surrogate nonradioactive liquid waste with a blend consisting of cement, fly ash, and clay. Aqueous extracts of the grout were then screened for acute toxicity using aquatic invertebrates as test organisms and a fluorogenic substrate as the toxic stress indicator. After a 1-hour exposure of juvenile daphnids (D, magna, D. pulex, and C. dubia) to the grout extracts followed by a 15-minute reaction with the fluorogenic substrate, the degree of in vivo enzymatic inhibition was measured by the number of resulting fluorescent daphnids. The EC50 values calculated by probit analysis were 2,877 mg/L, 2,983 mg/L, and 3,174 mg/L for D. pulex, D. magna, and C. dubia, respectively. The slight difference in the responses may be attributed to the subjective pass-fail scoring of the fluorescence criterion. The results indicated that the grout studied is nonhazardous and nondangerous

Performance of Grouted Splice Sleeve Connector under Tensile Load

Directory of Open Access Journals (Sweden)

A. Alias

2016-05-01

Full Text Available The grouted splice sleeve connector system takes advantage of the bond-slip resistance of the grout and the mechanical gripping of reinforcement bars to provide resistance to tensile force. In this system, grout acts as a load-transferring medium and bonding material between the bars and sleeve. This study adopted the end-to-end rebars connection method to investigate the effect of development length and sleeve diameter on the bonding performance of the sleeve connector. The end-to-end method refers to the condition where reinforcement bars are inserted into the sleeve from both ends and meet at the centre before grout is filled. Eight specimens of grouted splice sleeve connector were tested under tensile load to determine their performance. The sleeve connector was designed using 5 mm thick circular hollow section (CHS steel pipe and consisted of one external and two internal sleeves. The tensile test results show that connectors with a smaller external and internal sleeve diameter appear to provide better bonding performance. Three types of failure were observed in this research, which are bar fracture (outside the sleeve, bar pullout, and internal sleeve pullout. With reference to these failure types, the development length of 200 mm is the optimum value due to its bar fracture type, which indicates that the tensile capacity of the connector is higher than the reinforcement bar. It is found that the performance of the grouted splice sleeve connector is influenced by the development length of the reinforcement bar and the diameter of the sleeve.

Service life prediction and cementitious composites

DEFF Research Database (Denmark)

Stoklund Larsen, E.

The present Ph.D.thesis describes and discusses the applicability of a systematic methodology recommended by CIB W80/RILEM-PSL for sevice life prediction. The report describes the most important inherent and environmental factors affecting the service life of structures of cementitious composites....... On the basis of this discription of factors and experience from a test programme described in SBI Report 222, Service life prediction and fibre reinforced cementitious composites, the applicabillity of the CIB/RILEM methodology is discussed....

Improvement of Shear Strength of Sandy Soil by Cement Grout with Fly Ash

Directory of Open Access Journals (Sweden)

Haifaa Abdulrasool Ali

2018-12-01

Full Text Available The effects of the permeation cement grout with fly ash on the sandy soil skeleton were studied in the present work in two phase; first phase the shear strength parameters, and the second phase effect of these grouted materials on volume grouted zone by injection (51 cm³ of slurry in sandy soil placed in steel cylinder model with dimension 15 cm in diameter and 30 cm in height. The soil sample was obtained from Karbala city and it is classified as poorly graded sand (SP according to USCS. The soil samples were improved by cement grout with three percentages weight of water cement ratio (w:c; (0.1w:0.9c, 0.8w:0.2c, and 0.7w:0.3c, while the soil samples were dehydrated for one day curing time. Fly ash class (F was used with cement grout as filler material; it was added to the mixture as a replacement material for cement in weight percentages; 10%, 25% and 40%. According to the results of tests, both shear strength and approximate volume of the effective grouted zone for treated samples soil with cement grout was increased when the water cement ratio decreased. Fly ash with cement grout needs to increase the water demand for the grout mixing to give best results in both shear strength and filling the soil voids.

Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles

Directory of Open Access Journals (Sweden)

Wang Duanduan

2015-01-01

Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.

Innovative technology summary report: Innovative grouting and retrieval

International Nuclear Information System (INIS)

1998-10-01

Innovative grouting and retrieval (IGR) technology provides an innovative and cost-effective approach for full-pit and hot-spot retrieval of buried transuranic (TRU) waste sites and in situ disposal of buried waste with improved confinement. Innovative grouting technology: minimizes spreading of contamination by agglomerating the soil particles containing plutonium/americium particulates into nonaerosolizable particles; minimizes worker risks and exposure; is more effective in controlling the spread of contamination than common mining practices such as directed air flow, misting, and fixant sprays; eliminates further treatment because the grouted, rubberized waste is ready for shipment to the Waste Isolation Pilot Project (WIPP); reduces capital expenditures, operating costs, and containment structure requirements; and is an estimated five times faster than the baseline technology of removal, packaging, and storage

Solidification/stabilization of technetium in cement-based grouts

International Nuclear Information System (INIS)

Gilliam, T.M.; Bostick, W.D.; Spence, R.D.; Shoemaker, J.L.

1990-01-01

Mixed low-level radioactive and chemically hazardous process treatment wastes from the Portsmouth Gaseous Diffusion Plant are stabilized by solidification in cement-based grouts. Conventional portland cement and fly ash grouts have been shown to be effective for retention of hydrolyzable metals (e.g., lead, cadmium, uranium and nickel) but are marginally acceptable for retention of radioactive Tc-99, which is present in the waste as the highly mobile pertechnate anion. Addition of ground blast furnace slag to the grout is shown to reduce the leachability of technetium by several orders of magnitude. The selective effect of slag is believed to be due to its ability to reduce Tc(VII) to the less soluble Tc(IV) species. 12 refs., 4 tabs

77 FR 69508 - Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons

Science.gov (United States)

2012-11-19

... Containment Structures With Grouted Tendons AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory guide... (RG) 1.90, ``Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons... appropriate surveillance program for prestressed concrete containment structures with grouted tendons...

Properties of cement-fly ash grout admixed with bentonite, silica fume, or organic fiber

International Nuclear Information System (INIS)

Huang, W.H.

1997-01-01

A detailed laboratory study was conducted to investigate the properties of cement-fly ash grout mixtures as barriers for isolation of hazardous and low-level radioactive wastes. In the grout studied, fly ash was used to replace 30 percent by mass of cement. Three additives including bentonite, silica fume, and polypropylene fiber were used individually in the grout mixes to improve the properties of the grouts in different aspects. The flowability, bleeding, and setting time of freshly mixed grouts were determined; and the unconfined compressive strength, pore size distribution, and water permeability were determined for hardened grouts at various curing durations up to 120 days. Finally, the durability of cement-fly ash grouts was carefully examined in terms of the changes in their physical properties after different levels of exposure to sulfate attack and wet-dry cycles

Grouting design based on characterization of the fractured rock. Presentation and demonstration of a methodology

Energy Technology Data Exchange (ETDEWEB)

Fransson, Aasa (SWECO Environment, Stockholm (Sweden); Chalmers Univ. of Technology, Goeteborg (Sweden))

2008-12-15

The design methodology presented in this document is based on an approach that considers the individual fractures. The observations and analyses made during production enable the design to adapt to the encountered conditions. The document is based on previously published material and overview flow charts are used to show the different steps. Parts of or the full methodology has been applied for a number of tunneling experiments and projects. SKB projects in the Aespoe tunnel include a pillar experiment and pre-grouting of a 70 meter long tunnel (TASQ). Further, for Hallandsas railway tunnel (Skaane south Sweden), a field pre-grouting experiment and design and post-grouting of a section of 133 meters have been made. For the Nygard railway tunnel (north of Goeteborg, Sweden), design and grouting of a section of 86 meters (pre-grouting) and 60 meters (post-grouting) have been performed. Finally, grouting work at the Tornskog tunnel (Stockholm, Sweden) included design and grouting along a 100 meter long section of one of the two tunnel tubes. Of importance to consider when doing a design and evaluating the result are: - The identification of the extent of the grouting needed based on inflow requirements and estimates of tunnel inflow before grouting. - The selection of grout and performance of grouting materials including penetration ability and length. The penetration length is important for the fan geometry design. - The ungrouted compared to the grouted and excavated rock mass conditions: estimates of tunnel inflow and (if available) measured inflows after grouting and excavation. Identify if possible explanations for deviations. For the Hallandsas, Nygard and Tornskog tunnel sections, the use of a Pareto distribution and the estimate of tunnel inflow identified a need for sealing small aperture fractures (< 50 - 100 mum) to meet the inflow requirements. The tunneling projects show that using the hydraulic aperture as a basis for selection of grout is a good

Grouting design based on characterization of the fractured rock. Presentation and demonstration of a methodology

International Nuclear Information System (INIS)

Fransson, Aasa

2008-12-01

The design methodology presented in this document is based on an approach that considers the individual fractures. The observations and analyses made during production enable the design to adapt to the encountered conditions. The document is based on previously published material and overview flow charts are used to show the different steps. Parts of or the full methodology has been applied for a number of tunneling experiments and projects. SKB projects in the Aespoe tunnel include a pillar experiment and pre-grouting of a 70 meter long tunnel (TASQ). Further, for Hallandsas railway tunnel (Skaane south Sweden), a field pre-grouting experiment and design and post-grouting of a section of 133 meters have been made. For the Nygard railway tunnel (north of Goeteborg, Sweden), design and grouting of a section of 86 meters (pre-grouting) and 60 meters (post-grouting) have been performed. Finally, grouting work at the Tornskog tunnel (Stockholm, Sweden) included design and grouting along a 100 meter long section of one of the two tunnel tubes. Of importance to consider when doing a design and evaluating the result are: - The identification of the extent of the grouting needed based on inflow requirements and estimates of tunnel inflow before grouting. - The selection of grout and performance of grouting materials including penetration ability and length. The penetration length is important for the fan geometry design. - The ungrouted compared to the grouted and excavated rock mass conditions: estimates of tunnel inflow and (if available) measured inflows after grouting and excavation. Identify if possible explanations for deviations. For the Hallandsas, Nygard and Tornskog tunnel sections, the use of a Pareto distribution and the estimate of tunnel inflow identified a need for sealing small aperture fractures (< 50 - 100 μm) to meet the inflow requirements. The tunneling projects show that using the hydraulic aperture as a basis for selection of grout is a good

Design, construction and performance of the Oldman River Dam grout curtain

Energy Technology Data Exchange (ETDEWEB)

Hartmaier, H.; Davachi, M. [Acres International Ltd., Calgary, AB (Canada); Dharmawardene, W. [Alberta Environment, Edmonton, AB (Canada); Sinclair, B. [Acres International Ltd., Niagara Falls, ON (Canada)

2002-07-01

The 76 m high Oldman River Dam was constructed between 1986 and 1991 near Pincher Creek, Alberta to provide flow regulation and on-stream storage of water for multi-purpose use and irrigation services as well as hydroelectric development. The dam's main structure includes an earth- and rockfill dam, a low earthfill dyke 1500 m long, twin diversion/low level outlet tunnels, a gated spillways structure, and 2 drainage tunnels. A 1.3 km long, three-line grout curtain up to 100 m deep extends below the foundation of the dam and spillway. The grout curtain was built in undeformed Paleocene sedimentary rocks affected by stress relief due to river valley erosion. 80 per cent of the grout consumption was from bedrock structural features. Piezometers, slope indicators and flow measurement weirs were installed in the dam and abutment areas both during and after construction to monitor the performance of the grout curtain. Instrument readings indicate that the grout curtain is successfully preventing the transmission of reservoir pressures to the foundation beneath the downstream shell of the dam. The piezometric pressures downstream of the grout curtain are the same as they were in the foundation before impounding. A small amount of seepage has appeared at the end of the grout curtain at the eastern end of the abutment of the spillway but it is not considered to be significant. 3 refs., 4 figs.

Design procedure for formulating and assessing the durability of particulate grouts

International Nuclear Information System (INIS)

Okonkwo, I.O.; Altschaeff, A.G.

1989-01-01

The current disposal plans for low-level wastes call for stabilizing or encapsulating and storing of these wastes in steel drums which in turn are buried in shallow trenches. Complete sealing is accomplished with grout, a liquid injection comprising principally of cement and fly ash, etc. Upon solidification, the grout forms a rigid mass around the drum, thereby eliminating access of groundwater into or out of the waste barrier, or leaching of radionuclides. Since the primary mechanism for the likely introduction of hazardous and/or radioactive elements into the biosphere in this situation, is through physical or chemical deterioration of the waste barrier, it is necessary that the effect of adverse environments on the durability of the grouts be examined and incorporated in barrier design. Currently, procedures for formulating grout mixes to assure a given impermeability or durability of the grout over its service period is lacking, and so are the techniques for monitoring the in-service performance of waste barrier systems. This paper depicts a serious limitation in waste barrier system technology, for it is time that optimization in design be possible. To allow this, a method is needed that creates the grout formulation specification for an optimization of behavior parameters in the resulting product. These considerations suggest a strong need for improvement in the grout formulation specification to allow a focus upon behavior properties desired by the engineer in the creation of optimum performance. This paper addresses these problems

Gamma irradiation test report of simulated grout specimens for gas generation/liquid advection

International Nuclear Information System (INIS)

Hinman, C.A.

1994-01-01

This report presents the results from an irradiation test performed on four specimens of grout that were fabricated from synthetic Double Shell Slurry Feed (DSSF) liquid waste. The objective was to investigate the radiolytic generation of gases and the potential for advective rejection of waste liquids from the grout matrix and to provide experimental information for the validation of the C-Cubed calculated model. It has been demonstrated that a number of gases can be formed within the grout due to radiolytic decomposition of various chemical components that make up the grout. This observation leads to the conjecture that the potential exists for the rejection of a portion of the 60 vol% free liquid from the grout matrix driven by pressurization by these gases. It was found that, for the specimen geometries used in this test series, and for peak radiation dose accumulation rates on the order of 4 to 60 times of the initial rate expected in the grout vaults (300 Rads/hr), no liquid rejection was observed from 2% to 35% of the target exposure expected in the grout vaults (1E+08 Rads). When the irradiation rate exceeded the projected grout vault dose rate by a factor of 200 a small amount of liquid rejection was observed from one of two specimens that had received 20% more than the goal exposure. Because of the differences in the magnitudes of the relative radiation field strengths between this study and an actual grout vault, it is concluded that the potential for liquid rejection by internal gas pressurization from presently configured grout waste forms is very low for the expected conditions

Pullout Performances of Grouted Rockbolt Systems with Bond Defects

Science.gov (United States)

Xu, Chang; Li, Zihan; Wang, Shanyong; Wang, Shuren; Fu, Lei; Tang, Chunan

2018-03-01

This paper presents a numerical study on the pullout behaviour of fully grouted rockbolts with bond defects. The cohesive zone model (CZM) is adopted to model the bond-slip behaviour between the rockbolt and grout material. Tensile tests were also conducted to validate the numerical model. The results indicate that the defect length can obviously influence the load and stress distributions along the rockbolt as well as the load-displacement response of the grouted system. Moreover, a plateau in the stress distribution forms due to the bond defect. The linear limit and peak load of the load-displacement response decrease as the defect length increases. A bond defect located closer to the loaded end leads to a longer nonlinear stage in the load-displacement response. However, the peak loads measured from the specimens made with various defect locations are almost approximately the same. The peak load for a specimen with the defects equally spaced along the bolt is higher than that for a specimen with defects concentrated in a certain zone, even with the same total defect length. Therefore, the dispersed pattern of bond defects would be much safer than the concentrated pattern. For the specimen with dispersed defects, the peak load increases with an increase in the defect spacing, even if the total defect length is the same. The peak load for a grouted rockbolt system with defects increases with an increases in the bolt diameter. This work leads to a better understanding of the load transfer mechanism for grouted rockbolt systems with bond defects, and paves the way towards developing a general evaluation method for damaged rockbolt grouted systems.

Microfibres and hydrogels to promote autogenous healing in cementitious materials

OpenAIRE

Snoeck, Didier; Dubruel, Peter; De Belie, Nele

2013-01-01

Cementitious materials are sensitive to crack formation and it would be beneficial if the material could stop the crack propagation, repair the damage and reach again the original liquid-tightness and/or strength. Therefore, a cementitious material with synthetic microfibres and superabsorbent polymers (SAPs) is proposed. Upon crack formation, the microfibres will become active and due to the bridging action, they will stop the opening of a crack, forcing the cementitious material to crack so...

Rock mass joint treated by jet grouting at Diavik A418 dike south abutment

Energy Technology Data Exchange (ETDEWEB)

Baisre, C.A. [SNC-Lavalin, Montreal, PQ (Canada); Hatch Energy, Montreal, PQ (Canada)

2009-07-01

In order to exploit the diamond pipes at the Diavik mines, located in the Northwest Territories, two dikes were built into the Lac de Gras, dikes A154 and A418. However, during the construction of the curtain grouting of the A418 Dike, the pressure grouting technique did not achieve the desired closure of a subhorizontal joint located at variable depth beneath the dike foundation into the granite rock mass at the south abutment. The joint was filled mainly with silt, sand and gravel. This paper reviewed the problems with the pressure grouting treatment methodology, and the final decision of the designers and construction manager to treat the joint by jet grouting. The paper outlined pressure grouting, with particular reference to technical specifications; curtain grouting analysis; and joint grouting investigation. The joint treatment by jet grouting was described and the most important features of the core drilling after jetting were outlined. The permeability of the joint was reduced significantly in the treated area, according to observations made during jetting and in the recovered cores and the permeability tests. 1 tab., 7 figs.

In situ grouting of a low-level radioactive waste trench

International Nuclear Information System (INIS)

Spence, R.D.; Godsey, T.T.; McDaniel, E.W.

1987-11-01

A shallow land burial trench containing low level radioactive waste was injected with a particulate grout to help control subsidence and radionuclide migration. The trench's accessible voids have been estimated at 20 vol %, and most of these voids appear to have been filled with grout. This injection was accomplished with a simple, labor intensive technique, and an inexperienced crew at an estimated cost of about $55,000. The grout costs $0.21/gal and 8081 gal was injected into the trench. 5 refs., 10 figs., 4 tabs

Field lysimeter studies for performance evaluation of grouted Hanford defense wastes

International Nuclear Information System (INIS)

Last, G.V.; Serne, R.J.; LeGore, V.L.

1995-02-01

The Grout Waste Test Facility (GWTF) consisted of four large field lysimeters designed to test the leaching and migration rates of grout-solidified low-level radioactive wastes generated by Hanford Site operations. Each lysimeter was an 8-m-deep by 2-media closed-bottom caisson that was placed in the ground such that the uppermost rim remained just above grade. Two of these lysimeters were used; the other two remained empty. The two lysimeters that were used (A-1 and B-1) were backfilled with a two-layer soil profile representative of the proposed grout disposal site. The proposed grout disposal site (termed the Grout Treatment Facility Landfill) is located immediately east of the Hanford Site's 200 East Area. This soil profile consisted of a coarse sand into which the grout waste forms were placed and covered by 4 m of a very fine sand. The A-1 lysimeter was backfilled in March 1985, with a grout-solidified phosphate/sulfate liquid waste from N Reactor decontamination and ion exchange resin regeneration. The B-1 lysimeter was backfilled in September 1985 and received a grout-solidified simulated cladding removal waste representative of waste generated from fuel reprocessing operations at the head end of the Plutonium Uranium Extraction (PUREX) plant. Routine monitoring and leachate collection activities were conducted for over three years, terminating in January 1989. Drainage was collected sporadically between January 1989 and December 1992. Decontamination and decommissioning of these lysimeters during the summer of 1994, confirmed the presence of a 15 to 20-cm-long hairline crack in one of the bottom plate welds. This report discusses the design and construction of the GWTF, presents the routine data collected from this facility through January 1989 and subsequent data collected sporadically between 1989 and 1993, and provides a brief discussion concerning preliminary interpretation of the results

Corrosion performance of prestressing strands in contact with dissimilar grouts.

Science.gov (United States)

2013-01-01

To improve the corrosion protection provided to prestressing strands, anti-bleed grouts are used to fill voids in post-tensioning : ducts that result from bleeding and shrinkage of older Portland Cement grouts. Environmental differences caused by exp...

Examination of sample of grout after 63 years exposure underground. Technical report

International Nuclear Information System (INIS)

Rhoderick, J.E.

1981-05-01

During an investigation of the Troy Lock and Dam, New York, a core was recovered that contained part of a metal anchor that had been grouted into foundation rock. Since this grout was about 63 years old and had presumably been continuously below the water table, it provided an opportunity to study the effect of this environment for this period of time on the phase composition and microstructure of this grout. The phase composition of the grout was studied by x-ray diffraction; its microstructure was studied by scanning electron microscopy. It was found that the grout had a normal composition and microstructure; the environmental conditions had not had a significant effect on either composition or microstructure. The original water content had been fairly high as would be expected

Rheological Characteristics of Cement Grout and its Effect on Mechanical Properties of a Rock Fracture

Science.gov (United States)

Liu, Quansheng; Lei, Guangfeng; Peng, Xingxin; Lu, Chaobo; Wei, Lai

2018-02-01

Grouting reinforcement, which has an obvious strengthening effect on fractured rock mass, has been widely used in various fields in geotechnical engineering. The rheological properties of grout will greatly affect its diffusion radius in rock fractures, and the water-cement ratio is an important factor in determining the grouting flow patterns. The relationship between shear stress and shear rate which could reflect the grout rheological properties, the effects of water-cement ratio, and temperature on the rheological properties of grouting was studied in the laboratory. Besides, a new method for producing fractured rock specimens was proposed and solved the problem of producing natural fractured rock specimens. To investigate the influences of grouting on mechanical properties of a rock fracture, the fractured rock specimens made using the new method were reinforced by grouting on the independent designed grouting platform, and then normal and tangential mechanical tests were carried out on fractured rock specimens. The results showed that the mechanical properties of fractured rock mass are significantly improved by grouting, the peak shear strength and residual strength of rock fractures are greatly improved, and the resistance to deformation is enhanced after grouting. Normal forces affect the tangential behavior of the rock fracture, and the tangential stress strength increases with normal forces. The strength and stability of fractured rock mass are increased by grouting reinforcement.

Grout testing and characterization for shallow-land burial trenches at the Idaho National Engineering Laboratory

International Nuclear Information System (INIS)

Tallent, O.K.; Sams, T.L.; Tamura, T.; Godsey, T.T.; Francis, C.L.; McDaniel, E.W.

1986-10-01

An investigation was conducted to develop grout formulations suitable for in situ stabilization of low-level and transuranic (TRU) waste in shallow-land burial trenches at Idaho National Engineering Laboratory (INEL). The acceptabilities of soil, ordinary particulate, and fine particulate grouts were evaluated based on phase separation, compressive strength, freeze/thaw, penetration resistance, rheological, water permeability, column, and other tests. Soil grouts with soil-to-cement weight ratios from 0.91 to 1.60 were found to be suitable for open trench or drum disposal. Ordinary particulate grouts containing type I,II Portland cement, class C fly ash, bentonite, water, and a fluidizer were formulated to fill large voids within the soil/waste matrix of a closed shallow-land burial trench. Fine particulate grouts containing fine (mean particle size, 9.6 m) cement and water were formulated to fill smaller voids and to establish a grout-soil barrier to prevent water intrusion into the grouted waste trench. Solution, or chemical grouts, were evaluated as possible substitutes for the fine particulate grouts

Jet grouting for a groundwater cutoff wall in difficult glacial soil deposits

International Nuclear Information System (INIS)

Flanagan, R.F.; Pepe, F. Jr.

1997-01-01

Jet grouting is being used as part of a groundwater cutoff wall system in a major New York City subway construction project to limit drawdowns in an adjacent PCB contamination plume. A circular test shaft of jet grout columns was conducted during the design phase to obtain wall installation parameters. The test program also included shaft wall mapping, and measurements of; inflows, piezometric levels, ground heave and temperature, and jet grout hydraulic conductivity. An axisymmetric finite element method groundwater model was established to back calculate the in-situ hydraulic conductivities of both the surrounding glacial soils and the jet grout walls by matching observed inflows and piezometric levels. The model also verified the use of packer permeability test as a tool in the field to evaluate the hydraulic conductivities of jet grout columns. Both the test program and analytic studies indicated that adjustments to the construction procedures would be required to obtain lower hydraulic conductivities of the jet grout walls for construction. A comparison is made with the conductivities estimated from the test program/analytic studies with those from the present construction

Grouting as a remedial technique for buried low-level radioactive wastes

International Nuclear Information System (INIS)

Spalding, B.P.; Hyder, L.K.; Munro, I.L.

1985-01-01

Seven grout formulations were tested in the laboratory for their ability to penetrate and to reduce the hydraulic conductivities of soils used as backfills for shallow land burial trenches. Soils from two sites, in Oak Ridge, TN, and Maxey Flats, KY were used and both are classified as Typic Dystrochrepts. Three soluble grout formulations (sodium silicate, polypropenamide [polyacrylamide], and 1,3-Benzenediol [resorcinol]-formaldehyde) were able to both penetrate soil and sand columns and reduce hydraulic conductivities from initial values of ca. 10 -4 m s -1 to -8 m s -1 . Three particulate grouts (lime [calcium oxide]-fly ash, fly ash-cement-bentonite, and bentonite alone) could not penetrate columns; such formulations would, therefore, be difficult to inject into closed burial trenches. Field demonstrations with both sodium silicate and polyacrylamide showed that grout could be distributed throughout a burial trench and that waste-backfill hydraulic conductivity could be reduced several orders of magnitude. Field grouting with polyacrylamide reduced the mean hydraulic conductivity of nine intratrench monitoring wells from 10 -4 to 10 -8 m s -1 . Grouting of low-level radioactive solid waste in situ, therefore, should be an effective technique to correct situations where leaching of buried wastes has or will result in groundwater contamination

Engineering feasibility for the fabrication and emplacement of cementitious repository materials: results from the EC-ESDRED project

International Nuclear Information System (INIS)

Alonso, Maria Cruz; Garcia-Sineriz, Jose Luis

2012-01-01

Maria Cruz Alonso of the Spanish National Research Council gave a presentation that summarised relevant findings on cementitious materials from the EC ESDRED (Engineering Studies and Demonstration of Repository Designs) Project. Concrete will be used for different purposes during the construction of geologic repositories for radioactive waste. These purposes include grouting, tunnel and drift lining, and tunnel plugging and sealing. Although some of the concrete may be removed before repository closure, a significant amount of concrete will remain in the repository. An important concern regarding the use of cementitious materials in geologic repositories for HLW and spent fuel is their interaction with the bentonite buffer, backfill material, and the host rock close to the repository near-field. For this reason, the ESDRED project has developed a low-pH concrete formulation as an alternative to standard ordinary Portland cement (OPC) concrete formulations with the aim of reducing the interaction of the cementitious materials with the near-field components. The main functional requirement required in the development of the low-pH material was a pore fluid pH < 11, which is considered acceptable for preventing or reducing the alteration of the bentonite EBS. Other functional requirements considered in the development of the low-pH concrete were: - Hydraulic conductivity. - Mechanical properties. - Durability. - Workability and pumpability. - Slumping. - Peak hydration temperature. - Thermal conductivity. - Use of organic components. - Use of other products. The development of the low-pH concrete involved laboratory work, as well as field testing at the Aespoe underground research laboratory (URL) in Sweden, and in the Grimsel URL and at the Hagerbach site in Switzerland. The ESDRED project demonstrated that low-pH cements can be formulated and used for production of concrete plugs and rock support. OPC can be used as the cement included in low-pH blends, but at least

Liquid return from gas pressurization of grouted waste

International Nuclear Information System (INIS)

Powell, W.J.; Benny, H.L.

1994-05-01

The ability to force pore liquids out of a simulated waste grout matrix using air pressure was measured. Specimens cured under various conditions were placed in a permeameter and subjected to increasing air pressure. The pressure was held constant for 24 hours and then stepped up until either liquid was released or 150 psi was reached. One specimen was taken to 190 psi with no liquid release. Permeability to simulated tank waste was then measured. Compressive strength was measured following these tests. This data is to assess the amount of fluid that might be released from grouted waste resulting from the buildup of radiolytically generated hydrogen and other gasses within the waste form matrix. A plot of the unconfined compressive strength versus breakthrough pressures identifies a region of ''good'' grout, which will resist liquid release

Geochemical modelling of grout-groundwater-rock interactions at the seal-rock interface

International Nuclear Information System (INIS)

Alcorn, S.; Christian-Frear, T.

1992-02-01

Theoretical investigations into the longevity of repository seals have dealt primarily with the development of a methodology to evaluate interactions between portland cement-based grout and groundwater. Evaluation of chemical thermodynamic equilibria among grout, groundwater, and granitic host rock phases using the geochemical codes EQ3NR/EQ6 suggests that a fracture filled with grout and saturated with groundwater will tend to fill and 'tighten' with time. These calculations predict that some grout and rock phases will dissolve, and that there will be precipitation of secondary phases which collectively have a larger overall volume than that of the material dissolved. Model assumptions include sealing of the fracture in a sluggish hydrologic regime (low gradient) characterized by a saline groundwater environment. The results of the calculations suggest that buffering of the fracture seals chemical system by the granitic rock may be important in determining the long-term fate of grout seals and the resulting phase assemblage in the fracture. The similarity of the predicted reaction product phases to those observed in naturally filled fractures suggests that with time equilibrium will be approached and grouted fractures subject to low hydrologic gradients will continue to seal. If grout injected into fractures materially reduces groundwater flux, the approach to chemical equilibrium will likely be accelerated. In light of this, even very thin or imperfectly grouted fractures would tighten in suitable hydrogeologic environments. In order to determine the period of time necessary to approach equilibrium, data on reaction rates are required. (au)

Engineering grouts - materials and applications with specific examples from Ra asthan Atomic Power Pro ect

International Nuclear Information System (INIS)

Singha Roy, P.K.; Sachchidanand; Sukhthankar, K.D.

1978-01-01

Grouting, though not very significant costwise, is an important aspect6 of construction in most of the major projects. According to modern construction technology, grouts have very stringent and diverse uses. The materials and practices generally found in India for grouting, mainly for structural grouts upto the middle of this decade are outlined along with details of specific grouts used in the construction of the twin reactor (440 MWe) of Rajasthan Atomic Power Station, one reactor of which is already operational. Some guidance and tables for selection of grout for a specific use have also been given. (auth.)

Micro- and macroscale coefficients of friction of cementitious materials

International Nuclear Information System (INIS)

Lomboy, Gilson; Sundararajan, Sriram; Wang, Kejin

2013-01-01

Millions of metric tons of cementitious materials are produced, transported and used in construction each year. The ease or difficulty of handling cementitious materials is greatly influenced by the material friction properties. In the present study, the coefficients of friction of cementitious materials were measured at the microscale and macroscale. The materials tested were commercially-available Portland cement, Class C fly ash, and ground granulated blast furnace slag. At the microscale, the coefficient of friction was determined from the interaction forces between cementitious particles using an Atomic Force Microscope. At the macroscale, the coefficient of friction was determined from stresses on bulk cementitious materials under direct shear. The study indicated that the microscale coefficient of friction ranged from 0.020 to 0.059, and the macroscale coefficient of friction ranged from 0.56 to 0.75. The fly ash studied had the highest microscale coefficient of friction and the lowest macroscale coefficient of friction. -- Highlights: •Microscale (interparticle) coefficient of friction (COF) was determined with AFM. •Macroscale (bulk) COF was measured under direct shear. •Fly ash had the highest microscale COF and the lowest macroscale COF. •Portland cement against GGBFS had the lowest microscale COF. •Portland cement against Portland cement had the highest macroscale COF

Coupled Viscous Fluid Flow and Joint Deformation Analysis for Grout Injection in a Rock Joint

Science.gov (United States)

Kim, Hyung-Mok; Lee, Jong-Won; Yazdani, Mahmoud; Tohidi, Elham; Nejati, Hamid Reza; Park, Eui-Seob

2018-02-01

Fluid flow modeling is a major area of interest within the field of rock mechanics. The main objective of this study is to gain insight into the performance of grout injection inside jointed rock masses by numerical modeling of grout flow through a single rock joint. Grout flow has been widely simulated using non-Newtonian Bingham fluid characterized by two main parameters of dynamic viscosity and shear yield strength both of which are time dependent. The increasing value of these properties with injection time will apparently affect the parameters representing the grouting performance including grout penetration length and volumetric injection rate. In addition, through hydromechanical coupling a mutual influence between the injection pressure from the one side and the joint opening/closing behavior and the aperture profile variation on the other side is anticipated. This is capable of producing a considerable impact on grout spread within the rock joints. In this study based on the Bingham fluid model, a series of numerical analysis has been conducted using UDEC to simulate the flow of viscous grout in a single rock joint with smooth parallel surfaces. In these analyses, the time-dependent evolution of the grout fluid properties and the hydromechanical coupling have been considered to investigate their impact on grouting performance. In order to verify the validity of these simulations, the results of analyses including the grout penetration length and the injection flow rate were compared with a well-known analytical solution which is available for the simple case of constant grout properties and non-coupled hydraulic analysis. The comparison demonstrated that the grout penetration length can be overestimated when the time-dependent hardening of grout material is not considered. Moreover, due to the HM coupling, it was shown that the joint opening induced by injection pressure may have a considerable increasing impression on the values of penetration length and

Study on grout-filled coupling steel sleeve; Kokan sleeve wo mochiita grout jutenshiki tekkin tsugite ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Y. [Osaka University, Osaka (Japan)

1997-06-01

Newly designed grout-filled coupling sleeve is discussed, which uses as the sleeve an electric resistance welded tube with protrusions formed in a checker pattern on its inner wall and is capable of using various premixed grouting materials available on the market. Specimens are subjected to uniaxial tensile loading and positive/negative cyclic loading, and the impact of various factors on the basic performance of the specimens and their stress/distortion characteristics at local spots in the reinforcing bar are disclosed. In the positive/negative cyclic loading in the plastic region, however, such findings are not obtained. In view of the stress/distortion characteristics at local spots in the reinforcing bar, a method is proposed for estimating the coupling strength and fracture type. A method for estimating the deformation behavior of the coupling, however, is not proposed. Investigations are conducted into the manufacture and installation of the grout holding framework, coupling fixing jigs, plugs, etc., and it is found that precasting should be studied in the future. 38 refs., 156 figs., 30 tabs.

Sealing properties of cement-based grout materials. Final report on the Rock sealing project

International Nuclear Information System (INIS)

Onofrei, M.; Gray, Malcolm; Shenton, B.; Walker, Brad; Pusch, R.; Boergesson, L.; Karnland, O.

1992-10-01

This report presents the results of laboratory studies of material properties. A number of different high performance grouts were investigated. The laboratory studies focused on mixtures of sulphate resistant portland cement, silica fume, superplasticizer and water. The ability of the thin films to self seal was confirmed. The surface reactions were studied in specimens of hardened grouts. The leach rates were found to vary with grout and water composition and with temperature. The short-term hydraulic and strength or properties of the hardened grout were determined. These properties were determined for the grouts both in-bulk and as thin-films. The hydraulic conductivities of the bulk, hardened material were found to be less than 10 -14 m/s. The hydraulic conductivities of thin films were found to be less than 10 -11 m/s. Broken, the hydraulic conductivity of the thin films could be increased to 10 -7 m/s. Examination of the leached grout specimens revealed a trend for the pore sizes to decrease with time. The propensity for fractured grouts to self seal was also observed in tests in which the hydraulic conductivity of recompacted mechanically disrupted, granulated grouts was determined. These tests showed that the hydraulic conductivity decreased rapidly with time. The decreases were associated with decreases in mean pore size. In view of the very low hydraulic conductivity it is likely that surface leaching at the grout/groundwater interface will be that major process by which bulk high-performance grouts may degrade. With the completion of the laboratory, in situ and modelling studies it appears that high-performance cement based grouts can be considered as viable materials for some repository sealing applications. Some of the uncertainties that remain are identified in this report. (54 refs.)

Characterisation, design and execution of two grouting fans at 450 m level, Aespoe HRL

Energy Technology Data Exchange (ETDEWEB)

Emmelin, Ann [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Eriksson, Magnus [Royal Inst. of Technology, Stockholm (Sweden); Fransson, Aasa [Chalmers Univ. of Technology, Goeteborg (Sweden)

2004-09-01

During June 2003 a grouting field experiment was carried out at Aespoe HRL, in connection with the construction of a tunnel (TASQ) for the Aespoe Pillar Stability Experiment (APSE). The tunnel is situated in connection to the elevator shaft landing at 450 m depth and runs in direction N/E. The grouting was carried out as part of the ordinary construction work, but was accompanied by extra investigations and analyses during operations and an active adaptation of a basic grouting design to the encountered conditions. The main objectives of this set-up were to Investigate what can be achieved with best available technology, material and knowledge under the current conditions, i.e. a relatively tight crystalline rock mass at great depth; Collect data and evaluate theories resulting from previous research projects on characterisation and predictions on grout spread; Collect data to further develop those above mentioned theories; Contribute to the achievement of good conditions at the experimental site for the pillar stability experiments. The characterization method is based on analyses of stepwise investigations consisting of investigations in an initially drilled core-drill hole followed by probe and grouting boreholes with pressure-build-up tests and measuring of inflow during drilling, all aiming at identifying the singular fractures that are to be sealed. The decision about grouting design is based on the successively up-dated rock description from the characterization and iterative selection and testing of grouting design and grout in a numeric model, resulting in an expected grout spread and sealing effect. Based on investigations and analysis of results from investigations of a core-drilled hole at the site, a basic design was set up, together with conditions for application. Probe boreholes covering the first anticipated fan gave substantially larger inflows than expected, and subsequently the design was changed. A first round was drilled and grouted, sealing

Characterisation, design and execution of two grouting fans at 450 m level, Aespoe HRL

International Nuclear Information System (INIS)

Emmelin, Ann; Eriksson, Magnus; Fransson, Aasa

2004-09-01

During June 2003 a grouting field experiment was carried out at Aespoe HRL, in connection with the construction of a tunnel (TASQ) for the Aespoe Pillar Stability Experiment (APSE). The tunnel is situated in connection to the elevator shaft landing at 450 m depth and runs in direction N/E. The grouting was carried out as part of the ordinary construction work, but was accompanied by extra investigations and analyses during operations and an active adaptation of a basic grouting design to the encountered conditions. The main objectives of this set-up were to Investigate what can be achieved with best available technology, material and knowledge under the current conditions, i.e. a relatively tight crystalline rock mass at great depth; Collect data and evaluate theories resulting from previous research projects on characterisation and predictions on grout spread; Collect data to further develop those above mentioned theories; Contribute to the achievement of good conditions at the experimental site for the pillar stability experiments. The characterization method is based on analyses of stepwise investigations consisting of investigations in an initially drilled core-drill hole followed by probe and grouting boreholes with pressure-build-up tests and measuring of inflow during drilling, all aiming at identifying the singular fractures that are to be sealed. The decision about grouting design is based on the successively up-dated rock description from the characterization and iterative selection and testing of grouting design and grout in a numeric model, resulting in an expected grout spread and sealing effect. Based on investigations and analysis of results from investigations of a core-drilled hole at the site, a basic design was set up, together with conditions for application. Probe boreholes covering the first anticipated fan gave substantially larger inflows than expected, and subsequently the design was changed. A first round was drilled and grouted, sealing

Grout for closure of the demonstration vault at the US DOE Hanford Facility. Final report

International Nuclear Information System (INIS)

Wakeley, L.D.; Ernzen, J.J.

1992-08-01

The Waterways Experiment Station (WES) developed a grout to be used as a cold- (nonradioactive) cap or void-fill grout between the solidified low-level waste and the cover blocks of a demonstration vault for disposal of phosphate-sulfate waste (PSW) at the US Department of Energy (DOE) Hanford Facility. The project consisted of formulation and evaluation of candidate grouts and selection of the best candidate grout, followed by a physical scale-model test to verify grout performance under project-specific conditions. Further, the project provided data to verify numerical models (accomplished elsewhere) of stresses and isotherms inside the Hanford demonstration vault. Evaluation of unhardened grout included obtaining data on segregation, bleeding, flow, and working time. For hardened grout, strength, volume stability, temperature rise, and chemical compatibility with surrogate wasteform grout were examined. The grout was formulated to accommodate unique environmental boundary conditions (vault temperature = 45 C) and exacting regulatory requirements (mandating less than 0.1% shrinkage with no expansion and no bleeding); and to remain pumpable for a minimum of 2 hr. A grout consisting of API Class H oil-well cement, an ASTM C 618 Class F fly ash, sodium bentonite clay, and a natural sand from the Hanford area met performance requirements in laboratory studies. It is recommended for use in the DOE Hanford demonstration PSW vault

Probabilistic structural assessment of conical grouted joint using numerical modelling

DEFF Research Database (Denmark)

Njomo-Wandji, Wilfried; Natarajan, Anand; Dimitrov, Nikolay

2018-01-01

Conical grouted joints have been proposed as a solution for the relative settlement observed between the sleeve and the pile on monopiles for wind turbines. In this paper, the influence of the design parameters such as steel wall thicknesses and conical angle on the failure modes associated...... to continual loadings are assessed based on finite element analysis. It is found that both the sleeve's and pile's wall thicknesses have a significant impact on the grouted joint health. Namely, the larger are the wall thicknesses, the more vulnerable the grout is with respect to fatigue and material...

Modeling of Cementitious Representative Volume Element with Additives

Science.gov (United States)

Shahzamanian, M. M.; Basirun, W. J.

CEMHYD3D has been employed to simulate the representative volume element (RVE) of cementitious systems (Type I cement) containing fly ash (Class F) through a voxel-based finite element analysis (FEA) approach. Three-dimensional microstructures composed of voxels are generated for a heterogeneous cementitious material consisting of various constituent phases. The primary focus is to simulate a cementitious RVE containing fly ash and to present the homogenized macromechanical properties obtained from its analysis. Simple kinematic uniform boundary conditions as well as periodic boundary conditions were imposed on the RVE to obtain the principal and shear moduli. Our current work considers the effect of fly ash percentage on the elastic properties based on the mass and volume replacements. RVEs with lengths of 50, 100 and 200μm at different degrees of hydration are generated, and the elastic properties are modeled and simulated. In general, the elastic properties of a cementitious RVE with fly ash replacement for cement based on mass and volume differ from each other. Moreover, the finite element (FE) mesh density effect is studied. Results indicate that mechanical properties decrease with increasing mesh density.

Heat transfer analyses for grout disposal of radioactive double-shell slurry and customer wastes

International Nuclear Information System (INIS)

Robinson, S.M.; Gilliam, T.M.; McDaniel, E.W.

1987-04-01

Grout immobilization is being considered by Rockwell Hanford Operations (Rockwell Hanford) as a permanent disposal method for several radioactive waste streams. These include disposal of customer and double-shell slurry wastes in earthen trenches and in single-shell underground waste storage tanks. Heat transfer studies have previously been made to determine the maximum heat loading for grout disposal of various wastes under similar conditions, but a sensitivity analysis of temperature profiles to input parameters was needed. This document presents the results of heat transfer calculations for trenches containing grouted customer and double-shell slurry wastes and for in situ disposal of double-shell wastes in single-shell, domed concrete storage tanks. It discusses the conditions that lead to maximum grout temperatures of 250 0 F during the curing stage and 350 0 F thereafter and shows the dependence of these temperatures on input parameters such as soil and grout thermal conductivity, grout specific heat, waste loading, and disposal geometries. Transient heat transfer calculations were made using the HEATING6 computer code to predict temperature profiles in solidified low-level radioactive waste disposal scenarios at the Rockwell Hanford site. The calculations provide guidance for the development of safe, environmentally acceptable grout formulas for the Transportable Grout Facility. 11 refs

Study on the mechanism of seepage flow in the grouting for multiple fractured model

International Nuclear Information System (INIS)

Nishigaki, Makoto; Mikake, Shin-ichiro

2002-01-01

The purpose of study is to improve the grouting method for fractured rock masses. In this paper, the results on the fundamental phenomenon for grasping the properties of grouting injection and seepage flow are discussed. The case of grouting stage is studied about the multiple hydraulic fractured apertures in the injected borehole. So the theory on the mechanism is constructed, and experiment is executed in order to verify the availability of the theory. From the results, it is shown that Bernoulli's law is able to prove the behavior of the grouting. And the theoretical evaluation is executed on the experiential procedure of the grouting. (author)

Cementitious backfill in mining

Energy Technology Data Exchange (ETDEWEB)

Taute, A; Spice, J; Wingrove, A C [Van Niekerk, Kleyn Edwards (South Africa)

1993-03-01

This article describes the need for increased usage of backfill material in mining and presents some of the considerations for use of cemented materials. Laboratory test results obtained using a variety of cementitious binders and mine tailings are presented. 3 figs., 1 tab.

Parameters Optimization of Curtain Grouting Reinforcement Cycle in Yonglian Tunnel and Its Application

Directory of Open Access Journals (Sweden)

Qingsong Zhang

2015-01-01

Full Text Available For practical purposes, the curtain grouting method is an effective method to treat geological disasters and can be used to improve the strength and permeability resistance of surrounding rock. Selection of the optimal parameters of grouting reinforcement cycle especially reinforcement cycle thickness is one of the most interesting areas of research in curtain grouting designs. Based on the fluid-structure interaction theory and orthogonal analysis method, the influence of reinforcement cycle thickness, elastic modulus, and permeability on water inflow of tunnel after grouting and stability of surrounding rock was analyzed. As to the water inflow of tunnel after grouting used as performance evaluation index of grouting reinforcement cycle, it can be concluded that the permeability was the most important factor followed by reinforcement cycle thickness and elastic modulus. Furthermore, pore water pressure field, stress field, and plastic zone of surrounding rock were calculated by using COMSOL software under different conditions of reinforcement cycle thickness. It also can be concluded that the optimal thickness of reinforcement cycle and permeability can be adopted as 8 m and 1/100 of the surrounding rock permeability in the curtain grouting reinforcement cycle. The engineering case provides a reference for similar engineering.

The use of alkali-activated fly ash grouts for the remediation of AMD from underground mines

International Nuclear Information System (INIS)

Eaker, C.A.; Longley, R.D.; Michaud, L.H.; Silsbee, M.R.

1996-01-01

In preparation for a field demonstration, laboratory studies were conducted using several fly ash grout formulations to determine the optimum grout for an underground mine environment. This paper discusses the portion of the overall project designed to examine grout-acid mine drainage (AMD) interactions including neutralization, leaching and armoring of the grouts. Leaching tests were performed to study the effects of fly ash grout on AMD, including the effects of armoring. The goal of this project is to study the feasibility of in-situ acid mine drainage treatment by injecting alkali-activated fly ash grout into an underground mine

Grouting applications in civil engineering. Volume I and II

International Nuclear Information System (INIS)

Einstein, H.H.; Barvenik, M.J.

1975-01-01

A comprehensive description of grouting applications in civil engineering is presented that can serve as a basis for the selection of grouting methods in the borehole sealing problem. The breadth and depth of the study was assured by conducting the main part of the review, the collection and evaluation of information, without specifically considering the borehole sealing problem (but naturally incorporating any aspect of civil engineering applications that could be of potential use). Grouting is very much an art and not a science. In most cases, it is a trial and error procedure where an inexpensive method is initially tried and then a more expensive one is used until the desired results are obtained. Once a desired effect is obtained, it is difficult to credit any one procedure with the success because the results are due to the summation of all the methods used. In many cases, the method that proves successful reflects a small abnormality in the ground or structure rather than its overall characteristics. Hence, successful grouting relies heavily on good engineering judgement and experience, and not on a basic set of standard correlations or equations. 800 references

Field demonstration of in situ grouting of radioactive solid waste burial trenches with polyacrylamide

International Nuclear Information System (INIS)

Spalding, B.P.; Fontaine, T.A.

1990-01-01

Demonstrations of in situ grouting with polyacrylamide were carried out on two undisturbed burial trenches and one dynamically compacted burial trench in Solid Waste Storage Area (SWSA) 6 at Oak Ridge National Laboratory (ORNL). The injection of polyacrylamide was achieved quite facilely for the two undisturbed burial trenches which were filled with grout, at typical pumping rates of 95 L/min, in several batches injected over several days. The compacted burial trench, however, failed to accept grout at more than 1.9 L/min even when pressure was applied. Thus, it appears that burial trenches, stabilized by dynamic compaction, have a permeability too low to be considered groutable. The water table beneath the burial trenches did not respond to grout injections indicating a lack of hydrologic connection between fluid grout and the water table which would have been observed if the grout failed to set. Because grout set times were adjusted to less than 60 min, the lack of hydrologic connection was not surprising. Postgrouting penetration testing revealed that the stability of the burial trenches was increased from 26% to 79% that measured in the undisturbed soil surrounding the trenches. In situ permeation tests on the grouted trenches indicated a significant reduction in hydraulic conductivity of the trench contents from a mean of 2.1 x 10 -3 to 1.85 x 10 -5 cm/s. Preliminary observations indicated that grouting with polyacrylamide is an excellent method for both improved stability and hydrologic isolation of radioactive waste and its incidental hazardous constituents

Ultrasonic assessment of early age property development in hydrating cementitious materials

Science.gov (United States)

Wang, Xiaojun

The internal structure (microstructure) of cementitious materials, such as cement paste, mortar and concrete, evolves over time because of cement hydration. The microstructure of the cementitious phase plays a very important role in determining the strength, the mechanical properties and the long-term durability of cementitious materials. Therefore any understanding of the strength gain and the long-term durability of cementitious materials requires a proper assessment of the microstructure of its cementitious phase. Current methods for evaluating the microstructure of the cement are invasive and primarily laboratory-based. These methods are not conducive for studying the pore structure changes in the first few hours after casting since the changes in microstructure occur on a time scale that is an order of magnitude faster than the time required for sample preparation. The primary objective of the research presented in this thesis is to contribute towards advancing the current state-of-the-art in assessing the microstructure of cementitious systems. An ultrasonic wave reflection technique which allows for real-time assessment of the porosity and the elastic modulus of cementitious materials is developed. The test procedure for monitoring changes in the amplitude of horizontally polarized ultrasonic shear waves from the surface of hydrating cement paste is presented. A theoretical framework based on a poro-elastic idealization of the hydrating cementitious material is developed for interpreting the ultrasonic reflection data. The poro-elastic representation of hydrating cementitious material is shown to provide simultaneous, realistic estimates of porosity and shear modulus for hydrating cement paste and mortar through setting and early strength gain. The porosity predicted by the poro-elastic representation is identical to the capillary water content within the cement paste predicted by Powers' model. The shear modulus of the poro-elastic skeleton was compares

Development of ductile cementitious composites incorporating microencapsulated phase change materials

NARCIS (Netherlands)

Savija, B.; Lukovic, M.; Chaves Figueiredo, S.; de Mendoca Filho, Fernando Franca; Schlangen, H.E.J.G.

2017-01-01

Abstract In the past two decades, much research has been devoted to overcoming the inherent brittleness of cementitious materials. To that end, several solutions have been proposed, mainly utilizing fibres. One of the most promising classes of materials is strain hardening cementitious composite

R20 Programme: Grout setting and strength development in ONKALO. Literature review, observations and experiments

International Nuclear Information System (INIS)

Karttunen, P.; Raivio, P.

2008-12-01

ONKALO is an underground rock characterisation facility planned to be a part of nuclear waste repository in future. ONKALO is located in Olkiluoto Finland. Posiva Oy owned by Teollisuuden Voima Oy and Fortum Power and Heat Oy is responsible for the repository, research, construction and use of the ONKALO and closing of the underground facility after use. During construction of ONKALO it has been observed that the setting and strength of grouting materials have not sporadically developed as expected (in ONKALO). The phenomenon has been observed for the first time in the year 2005. The observations examined in this report are made in the grouting field tests and in ordinary grouting during the year 2007. The phenomenon has been observed with low pH and standard grouts and bolt grouting mortars. The reasons for this phenomenon are studied based on literature review, observations and tests in the field and laboratory. The effect of reactions between groundwater and grout, the effect of the raw materials as well as curing conditions, temperature and pressure are studied. There are several potential factors that can cause observed phenomenon. Some factors are more probable than others. Laboratory experiments for the samples of poor strength development were done. These samples were taken from the grouting holes or packers in which the strength of the grout was not developed as expected. The results of these experiments were compared to the results gained from the samples cast from the same grout batches and cured in the tunnel conditions. The purpose was to find out the factor causing slow strength development of the grouted mixes. One single reason, which can slow the setting of the grouts in ONKALO is the low temperature in the rock, but the temperature cannot cause the phenomenon alone. Locally groundwater contains compounds that can create chemically aggressive environment for (the Portland) cement based grouts. The groundwater chemistry in ONKALO has not been proved

Self-degradable Cementitious Sealing Materials

Energy Technology Data Exchange (ETDEWEB)

Sugama, T.; Butcher, T., Lance Brothers, Bour, D.

2010-10-01

A self-degradable alkali-activated cementitious material consisting of a sodium silicate activator, slag, Class C fly ash, and sodium carboxymethyl cellulose (CMC) additive was formulated as one dry mix component, and we evaluated its potential in laboratory for use as a temporary sealing material for Enhanced Geothermal System (EGS) wells. The self-degradation of alkali-activated cementitious material (AACM) occurred, when AACM heated at temperatures of {ge}200 C came in contact with water. We interpreted the mechanism of this water-initiated self-degradation as resulting from the in-situ exothermic reactions between the reactants yielded from the dissolution of the non-reacted or partially reacted sodium silicate activator and the thermal degradation of the CMC. The magnitude of self-degradation depended on the CMC content; its effective content in promoting degradation was {ge}0.7%. In contrast, no self-degradation was observed from CMC-modified Class G well cement. For 200 C-autoclaved AACMs without CMC, followed by heating at temperatures up to 300 C, they had a compressive strength ranging from 5982 to 4945 psi, which is {approx}3.5-fold higher than that of the commercial Class G well cement; the initial- and final-setting times of this AACM slurry at 85 C were {approx}60 and {approx}90 min. Two well-formed crystalline hydration phases, 1.1 nm tobermorite and calcium silicate hydrate (I), were responsible for developing this excellent high compressive strength. Although CMC is an attractive, as a degradation-promoting additive, its addition to both the AACM and the Class G well cement altered some properties of original cementitious materials; among those were an extending their setting times, an increasing their porosity, and lowering their compressive strength. Nevertheless, a 0.7% CMC-modified AACM as self-degradable cementitious material displayed the following properties before its breakdown by water; {approx}120 min initial- and {approx}180 min final

Contemporary drilling and grouting practices for dam remediation

International Nuclear Information System (INIS)

Bruce, D.A.; Naudts, A.

1998-01-01

A generic classification for the different methods used in rock drilling and overburden drilling is described, along with a classification of the range of grouting materials available and the different grouting methods that can be used. Examples are presented from two recent major dam remediation projects to demonstrate the basis for selection and use of the different methods and materials. It was shown that a high level of performance can be obtained when a project is properly designed, executed and monitored. 29 refs., 5 tabs., 5 figs

ASSESSMENT OF THE POTENTIAL FOR HYDROGEN GENERATION DURING GROUTING OPERATIONS IN THE R AND P REACTOR VESSELS

Energy Technology Data Exchange (ETDEWEB)

Wiersma, B.

2010-05-24

The R- and P-reactor buildings were retired from service and are now being prepared for deactivation and decommissioning (D and D). D and D activities consist primarily of immobilizing contaminated components and structures in a grout-like formulation. Aluminum corrodes very rapidly when it comes in contact with the alkaline grout materials and as a result produces hydrogen gas. To address this potential deflagration/explosion hazard, the Materials Science and Technology Directorate (MS and T) of the Savannah River National Laboratory (SRNL) has been requested to review and evaluate existing experimental and analytical studies of this issue to determine if any process constraints on the chemistry of the fill material and the fill operation are necessary. Various options exist for the type of grout material that may be used for D and D of the reactor vessels. The grout formulation options include ceramicrete (pH 6-8), low pH portland cement + silica fume grout (pH 10.4), or Portland cement groupt (pH 12.5). The assessment concluded that either ceramicrete or the silica fume grout may be used to safely grout the P-reactor vessel. The risk of accumulation of a flammable mixture of hydrogen between the grout-air interface and the top of the reactor is very low. Portland cement grout, on the other hand, for the same range of process parameters does not provide a margin of safety against the accumulation of flammable gas in the reactor vessel during grouting operations in the P-reactor vessel. It is recommended that this grout not be utilized for this task. The R-reactor vessel cotnains significantly less aluminum based on current facility process knowledge, surface observations, and drawings. Therefore, a Portland cement grout may be considered for grouting operations as well as the other grout formulations. For example, if the grout fill rate is less than 1 inch/min and the grout temperature is maintained at 70 C or less, the risk of hydrogen accumulation during fill

Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

Energy Technology Data Exchange (ETDEWEB)

Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

1987-12-01

An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs.

Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

International Nuclear Information System (INIS)

Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

1987-12-01

An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs

Grouting for Pile Foundation Improvement

NARCIS (Netherlands)

Van der Stoel, A.E.C.

2001-01-01

The aim of this research was to examine the use of grouting methods for pile foundation improvement, a generic term that is used here to define both foundation renovation (increasing the bearing capacity of a pile foundation that has insufficient bearing capacity) and foundation protection

The influence of clay drilling grout on the quality of well cementation

Energy Technology Data Exchange (ETDEWEB)

Romic, L; Martinko, B

1979-01-01

The influence of clay drilling grout on the behavior of the cement mixture during the cementing of casings is described. Experimental results are given which demonstrate that clay drill grout slows down the setting of the cement mixture, lowers the durability of cement stone and its adherence to the well's walls, and changes the rheological properties and viscosity of the cement mixture. Separating devices, which prevent the mixing of the clay drilling grout and the cement solutions during the cementation process, are recommended.

Use of a Paraffin Based Grout to Stabilize Buried Beryllium and Other Wastes

International Nuclear Information System (INIS)

Gretchen Matthern; Duane Hanson; Neal Yancey; Darrell Knudson

2005-01-01

The long term durability of WAXFIXi, a paraffin based grout, was evaluated for in situ grouting of activated beryllium wastes in the Subsurface Disposal Area (SDA), a radioactive landfill at the Radioactive Waste Management Complex, part of the Idaho National Laboratory (INL). The evaluation considered radiological and biological mechanisms that could degrade the grout using data from an extensive literature search and previous tests of in situ grouting at the INL. Conservative radioactive doses for WAXFIX were calculated from the ''hottest'' (i.e., highest-activity) Advanced Test Reactor beryllium block in the SDA.. These results indicate that WAXFIX would not experience extensive radiation damage for many hundreds of years. Calculation of radiation induced hydrogen generation in WAXFIX indicated that grout physical performance should not be reduced beyond the effects of radiation dose on the molecular structure. Degradation of a paraffin-based grout by microorganisms in the SDA is possible and perhaps likely, but the rate of degradation will be at a slower rate than found in the literature reviewed. The calculations showed the outer 0.46 m (18 in.) layer of each monolith, which represents the minimum expected distance to the beryllium block, was calculated to require 1,000 to 3,600 years to be consumed. The existing data and estimations of biodegradation and radiolysis rates for WAXFIX/paraffin do not indicate any immediate problems with the use of WAXFIX for grouting beryllium or other wastes in the SDA

Grouting of fly ash in sanitary landfills; Injektering av flygaska i hushaallsavfallsdeponi

Energy Technology Data Exchange (ETDEWEB)

Wikman, Karin; Berg, Magnus [AaF-Energi och Miljoe AB, Stockhom (Sweden); Andreas, Lale; Lagerkvist, Anders [Luleaa Univ. of Technology (Sweden); Jannes, Sara; Tham, Gustav [Telge Aatervinning AB, Soedertaelje (Sweden); Sjoeblom, Rolf [Tekedo AB, Nykoeping (Sweden)

2003-10-01

The purpose of the study was to investigate the potential for stabilization of sanitary landfills by injecting fly ash. The method is supposed to prevent differential settlements in landfills and by that to counteract damages in the final cover. Injecting fly ash may also affect the chemical development in a positive way and prevent metal leaching. Pilot experiments at the Tveta waste recycling center (Tveta Aatervinningsanlaeggning) have been performed in order to estimate if the grouting technology is a suitable method for sanitary landfills. Fly ashes from the combustion of bio fuels were used in these tests. A literature study and laboratory experiments in order to prepare the field experiments were also part of the project. About 100 tons of ash slurry were injected during the pilot experiments. This corresponds to a filling degree of approximately 12-16 % of the available pores in the landfill body. As a result of the pilot test, the following conclusions can be drawn: Ash can be mixed with water to a pumpable slurry which can be injected without hardening inside the equipment. Neither the waste nor the grouting material caused a backpressure during the injection and nothing indicates that the injected ash deforms the landfilled waste. The ash-water-slurry flows through the voids in the waste easily. Thus, the ash may dispread quite far from the injection holes. Using a more powerful equipment backpressure and movements in the waste might occur. It was not possible to estimate the flow required for backpressure in this study. Large variations are possible but for safety reasons the maximal pressure should be limited with regard to the expected stability in the actual area. The grouted ash will harden within the landfill body within a couple of days. It accumulates in hard but brittle lumps, which may result in an increased stability of the landfill. Further studies are necessary in order to evaluate how the stability is affected and what amounts of ash are

Grout for closure of waste-disposal vaults at the US DOE Hanford Site

International Nuclear Information System (INIS)

Wakeley, L.D.; Ernzen, J.J.; McDaniel, E.W.; Voogd, J.

1991-01-01

For permanent disposal of radioactive wastes from reprocessing, the US Department of Energy (DOE) has chosen to grout wastes in concrete vaults within a subsurface multiple-barrier system. The subject of this research is the non-radioactive, or ''cold cap'' grout, which fills the upper 120 cm of these vaults, and provides support for overlying barriers. Because of the heat evolved by the wasteform, this void-filling grout must perform at temperatures higher than those of usual large-volume grouting operations. It must have: low potential for thermal expansion and heat retention; a low modulus to withstand thermal and mechanical stresses without cracking; strength adequate to support overlying barrier-system components; and minimal potential for shrinkage. In addition, it must be pumpable, self-leveling, and non-segregating. Materials for formulation included a large percentage of Class F fly ash, and coarsely ground oil-well cement. Grout development included chemical and physical characterization, and physical and thermal modeling

Thermal energy storage based on cementitious materials: A review

Directory of Open Access Journals (Sweden)

Khadim Ndiaye

2018-01-01

Full Text Available Renewable energy storage is now essential to enhance the energy performance of buildings and to reduce their environmental impact. Many heat storage materials can be used in the building sector in order to avoid the phase shift between solar radiation and thermal energy demand. However, the use of storage material in the building sector is hampered by problems of investment cost, space requirements, mechanical performance, material stability, and high storage temperature. Cementitious material is increasingly being used as a heat storage material thanks to its low price, mechanical performance and low storage temperature (generally lower than 100 °C. In addition, cementitious materials for heat storage have the prominent advantage of being easy to incorporate into the building landscape as self-supporting structures or even supporting structures (walls, floor, etc.. Concrete solutions for thermal energy storage are usually based on sensible heat transfer and thermal inertia. Phase Change Materials (PCM incorporated in concrete wall have been widely investigated in the aim of improving building energy performance. Cementitious material with high ettringite content stores heat by a combination of physical (adsorption and chemical (chemical reaction processes usable in both the short (daily, weekly and long (seasonal term. Ettringite materials have the advantage of high energy storage density at low temperature (around 60 °C. The encouraging experimental results in the literature on heat storage using cementitious materials suggest that they could be attractive in a number of applications. This paper summarizes the investigation and analysis of the available thermal energy storage systems using cementitious materials for use in various applications.

Study of evaluation for grouting effect in a borehole; Yakueki chunyu koka hyoka gijutsu ni okeru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Nakamura, H; Matsuo, T [Fukuoka Municipal Transportation Bureau, Fukuoka (Japan); Yamauchi, Y; Imanishi, H [Osaka Soil Test, Osaka (Japan)

1996-10-01

For the foundation improvement works by grouting in a borehole, evaluation of grouting effect is one of the most important management items. The grouting design and works are sometimes reconsidered depending on the evaluation of grouting effect during the test injection. The purpose of the evaluation of grouting effect is to grasp the range of improvement and consolidation after the injection, and to judge and estimate the strength and permeability of the consolidation part. This paper describes the judgment method of the strength using PS logging results and borehole televiewer (BHTV) logging results. The reflection intensity (Ir) by the BHTV logging increased after the grouting, which showed a same tendency as that using S-wave and P-wave velocities (Vs and Vp) before and after the grouting. This was considered to demonstrate the grouting effect. A relation was obtained between the Vs, Vp and Ir before and after the grouting, which was expressed by following equation. Ir=0.143{times}Vs-70=0.093{times}Vp-110. The relation with the dynamic elastic coefficient (Ed) was also obtained as follow; Ir=0.0013{times}Ed. 9 figs.

Prediction and control of leachability of grouts used in low-level radioactive waste management. Final report

International Nuclear Information System (INIS)

Landolt, R.R.; Altschaeffl, A.G.

1987-01-01

The status of the following studies is reported: Uses of Grouting for Remedial Action and New Trench Stabilization; Water Movement and Grout Formulations; and Leachability of Grout Materials Used As Solidification Media. (LM)

A mathematical model in charactering chloride diffusivity in unsaturated cementitious material

NARCIS (Netherlands)

Zhang, Y.; Ye, G.; Pecur, I.B.; Baricevic, A.; Stirmer, N; Bjegovic, D.

2017-01-01

In this paper, a new analytic model for predicting chloride diffusivity in unsaturated cementitious materials is developed based on conductivity theory and Nernst-Einstein equation. The model specifies that chloride diffusivity in unsaturated cementitious materials can be mathematically described as

Grout compactness monitoring of concrete-filled fiber-reinforced polymer tube using electromechanical impedance

Science.gov (United States)

Shi, Yaokun; Luo, Mingzhang; Li, Weijie; Song, Gangbing

2018-05-01

The concrete-filled fiber-reinforced polymer tube (CFFT) is a type of structural element widely used in corrosive environments. Poor grout compactness results in incomplete contact or even no contact between the fiber-reinforced polymer (FRP) tube and the concrete grout, which reduces the load bearing capacity of a CFFT. The monitoring of grout compactness for CFFTs is important. The piezoceramic-based electromechanical impedance (EMI) method has emerged as an efficient and low-cost structural health monitoring technique. This paper presents a feasibility study using the EMI method to monitor grout compactness of CFFTs. In this research, CFFT specimens with different levels of compactness (empty, 1/5, 1/3, 1/2, 2/3, and full compactness) were prepared and subjected to EMI measurement by using four piezoceramic patches that were bonded circumferentially along the outer surface of the CFFT. To analyze the correlation between grout compactness and EMI signatures, a compactness index (CI) was proposed based on the root-mean-square deviation (RMSD). The experimental results show that the changes in admittance signatures are able to determine the grout compactness qualitatively. The proposed CI is able to effectively identify the compactness of the CFFT, and provides location information of the incomplete concrete infill.

Cementitious materials for radioactive waste management within IAEA coordinated research project - 59021

International Nuclear Information System (INIS)

Drace, Zoran; Ojovan, Michael I.

2012-01-01

The IAEA Coordinated Research Project (CRP) on cementitious materials for radioactive waste management was launched in 2007 [1, 2]. The objective of CRP was to investigate the behaviour and performance of cementitious materials used in radioactive waste management system with various purposes and included waste packages, waste-forms and backfills as well as investigation of interactions and interdependencies of these individual elements during long term storage and disposal. The specific research topics considered were: (i) cementitious materials for radioactive waste packaging: including radioactive waste immobilization into a solid waste form, (ii) waste backfilling and containers; (iii) emerging and alternative cementitious systems; (iv) physical-chemical processes occurring during the hydration and ageing of cement matrices and their influence on the cement matrix quality; (v) methods of production of cementitious materials for: immobilization into wasteform, backfills and containers; (vi) conditions envisaged in the disposal environment for packages (physical and chemical conditions, temperature variations, groundwater, radiation fields); (vii) testing and non-destructive monitoring techniques for quality assurance of cementitious materials; (viii) waste acceptance criteria for waste packages, waste forms and backfills; transport, long term storage and disposal requirements;and finally (ix) modelling or simulation of long term behaviours of cementations materials used for packaging, waste immobilization and backfilling, especially in the post-closure phase. The CRP has gathered overall 26 research organizations from 22 Member States aiming to share their research and practices on the use of cementitious materials [2]. The main research outcomes of the CRP were summarized in a summary report currently under preparation to be published by IAEA. The generic topical sections covered by report are: a) conventional cementitious systems; b) novel cementitious

Systematic approach for the design of pumpable cement-based grouts for immobilization of hazardous wastes

International Nuclear Information System (INIS)

Sams, T.L.; Gilliam, T.M.

1987-01-01

Cement-based grouts have been proven to be an economical and environmentally acceptable means of waste disposal. Costs can be reduced if the grout is pumped to the disposal site. This paper presents a systematic approach to guide the development of pumpable grouts. 20 refs., 2 figs

experimental study of cement grout: rheological behavior and sedimentation

OpenAIRE

Rosquoët , Frédéric; Alexis , Alain ,; Khelidj , Abdelhafid; Phelipot-Mardelé , Annabelle

2002-01-01

International audience; Three basic elements (cement, water and admixture) usually make up injectable cement grouts used for prestressed cable coating, repair and consolidation of masonry, soil grouting, etc... The present study was divided into two parts. First, in order to characterize rheologically fresh cement paste with W/C ratios (water/cement ratio) varying between 0.35 and 1, an experimental study was carried out and has revealed that the cement past behaves like a shear-thinning mate...

Jet Grouting. Control of execution and result parameters. Test fields - Experience in Chile; Jet Grouting. Control de parametros de ejecucion y de resultados. Campos de prueba-Experiencia en Chile

Energy Technology Data Exchange (ETDEWEB)

Ayarza, P. M.; Vukotic, G.

2014-07-01

This article emphasizes the importance of Test Fields in project that includes the Jet Grouting technique. In particular, the Chilean experience is analyzed, where the Jet Grouting was first introduced by Pilots Terratest S. A. in the year 2010, only, only in 2011 the first project using jet columns was constructed. The versatilely of this technique allows its use in a wide variety of projects, for example, soil capacity improvement, settlement control, reduction of soil permeability and other environmental applications. Currently, the most common applications are underpinning existing foundations, ground improvement, lateral support of excavations, hydraulic barriers, slope stabilization, liquefaction control, among others. The Jet Grouting is one of the most demanding soil improvement technique and requires excellence in designing and execution engineers and other involved specialist. It is therefore essential to ensure exhaustive control to the execution and final parameters, in order to check that the product- Jet Grouting element-have the design properties, and implement modifications if necessary. Many authors strongly advises that if there is no comparable experience and even if there is, a Test Field of Jet Grouting elements has to be executed in site. This field consists in a nearby area with similar geotechnical conditions of the project, where Jet Grouting test columns will be constructed. This Test Field will allow selecting the most effective execution parameters and verifying that the final product has he correct design properties. (Author)

Initial formulation results for in situ grouting of a waste trench at ORNL Site No. 6

International Nuclear Information System (INIS)

Tallent, O.K.; McDaniel, E.W.; Spence, R.D.; Godsey, T.T.

1987-01-01

An investigation is being conducted by the Chemical Technology Division to assist the Environmental Sciences Division in developing a grout formulation for use in testing in situ grouting in a waste trench at ORNL Site 6. This final report satisfies the milestone of Subtack 12 entitled, ''Low Level Waste (LLW) Trench Grouting Assessment,'' which was initially issued as RAP-86-7, December 31, 1985. Grouts prepared from dry-solid blends containing Type I Portland cement, ASTM Class C or Class F fly ash, and bentonite, mixed water at ratios of 10 to 15 lb/gal, were evaluated. The grouts prepared with ASTM Class C fly ash exhibited significantly better properties than those prepared with ASTM Class F fly ash. The grouts containing ASTM Class C fly ash satisfy tentative performance criteria for the project. 8 refs., 7 tabs

X-ray Computed Microtomography technique applied for cementitious materials: A review.

Science.gov (United States)

da Silva, Ítalo Batista

2018-04-01

The main objective of this article is to present a bibliographical review about the use of the X-ray microtomography method in 3D images processing of cementitious materials microstructure, analyzing the pores microstructure and connectivity network, enabling tthe possibility of building a relationship between permeability and porosity. The use of this technique enables the understanding of physical, chemical and mechanical properties of cementitious materials by publishing good results, considering that the quality and quantity of accessible information were significant and may contribute to the study of cementitious materials development. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stabilization and isolation of low-level liquid waste disposal sites

International Nuclear Information System (INIS)

Phillips, S.J.; Gilbert, T.W.

1987-01-01

Rockwell Hanford Operations is developing and testing equipment for stabilization and isolation of low-level radioactive liquid waste disposal sites. Stabilization and isolation are accomplished by a dynamic consolidation and particulate grout injection system. System equipment components include: a mobile grout plant for transport, mixing, and pumping of particulate grout; a vibratory hammer/extractor for consolidation of waste, backfill, and for emplacement of the injector; dynamic consolidation/injector probe for introducing grout into fill material; and an open-void surface injector that uses surface or subsurface mechanical or pneumatic packers and displacement gas filtration for introducing grout into disposal structure access piping. Treatment of a liquid-waste disposal site yields a physically stable, cementitious monolith. Additional testing and modification of this equipment for other applications to liquid waste disposal sites is in progress

Experimental study of cement grout : Rheological behavior and sedimentation

OpenAIRE

ROSQUOET, F; ALEXIS, A; KHELIDJ, A; PHELIPOT, A

2003-01-01

Three basic elements (cement, water and admixture) usually make up injectable cement grouts used for prestressed cable coating, repair and consolidation of masonry, soil grouting, etc. The present study was divided into two parts. First, in order to characterize rheologically fresh cement paste with water/cement ratios (W/C) varying between 0,35 and 1, an expeirmental study was carried out and has revealed that the cement past behaves like a shear-thinning material, whatever is the W/C ratio....

Ancient analogues concerning stability and durability of cementitious wasteform

International Nuclear Information System (INIS)

Jiang, W.; Roy, D.M.

1994-01-01

The history of cementitious materials goes back to ancient times. The Greeks and Romans used calcined limestone and later developed pozzolanic cement by grinding together lime and volcanic ash called open-quotes pozzolanclose quotes which was first found near Port Pozzuoli, Italy. The ancient Chinese used lime-pozzolanic mixes to build the Great Wall. The ancient Egyptians used calcined impure gypsum to build the Great Pyramid of Cheops. The extraordinary stability and durability of these materials has impressed us, when so much dramatically damaged infrastructure restored by using modern portland cement now requires rebuilding. Stability and durability of cementitious materials have attracted intensive research interest and contractors' concerns, as does immobilization of radioactive and hazardous industrial waste in cementitious materials. Nuclear waste pollution of the environment and an acceptable solution for waste management and disposal constitute among the most important public concerns. The analogy of ancient cementitious materials to modern Portland cement could give us some clues to study their stability and durability. This present study examines selected results of studies of ancient building materials from France, Italy, China, and Egypt, combined with knowledge obtained from the behavior of modern portland cement to evaluate the potential for stability and durability of such materials in nuclear waste forms

Ultrafine portland cement performance

Directory of Open Access Journals (Sweden)

C. Argiz

2018-04-01

Full Text Available By mixing several binder materials and additions with different degrees of fineness, the packing density of the final product may be improved. In this work, ultrafine cement and silica fume mixes were studied to optimize the properties of cement-based materials. This research was performed in mortars made of two types of cement (ultrafine Portland cement and common Portland cement and two types of silica fume with different particle-size distributions. Two Portland cement replacement ratios of 4% and 10% of silica fume were selected and added by means of a mechanical blending method. The results revealed that the effect of the finer silica fume mixed with the coarse cement enhances the mechanical properties and pore structure refinement at a later age. This improvement is somewhat lower in the case of ultrafine cement with silica fume.

Use of a Paraffin Based Grout to Stabilize Buried Beryllium and Other Wastes

Energy Technology Data Exchange (ETDEWEB)

Gretchen Matthern; Duane Hanson; Neal Yancey; Darrell Knudson

2005-12-01

The long term durability of WAXFIXi, a paraffin based grout, was evaluated for in situ grouting of activated beryllium wastes in the Subsurface Disposal Area (SDA), a radioactive landfill at the Radioactive Waste Management Complex, part of the Idaho National Laboratory (INL). The evaluation considered radiological and biological mechanisms that could degrade the grout using data from an extensive literature search and previous tests of in situ grouting at the INL. Conservative radioactive doses for WAXFIX were calculated from the "hottest" (i.e., highest-activity) Advanced Test Reactor beryllium block in the SDA.. These results indicate that WAXFIX would not experience extensive radiation damage for many hundreds of years. Calculation of radiation induced hydrogen generation in WAXFIX indicated that grout physical performance should not be reduced beyond the effects of radiation dose on the molecular structure. Degradation of a paraffin-based grout by microorganisms in the SDA is possible and perhaps likely, but the rate of degradation will be at a slower rate than found in the literature reviewed. The calculations showed the outer 0.46 m (18 in.) layer of each monolith, which represents the minimum expected distance to the beryllium block, was calculated to require 1,000 to 3,600 years to be consumed. The existing data and estimations of biodegradation and radiolysis rates

In-situ grouting of the low-level radioactive waste disposal silos at ORNL's Solid Waste Storage Area Six

International Nuclear Information System (INIS)

Francis, C.W.; Farmer, C.D.; Stansfield, R.G.

1993-07-01

At Oak Ridge National Laboratory (ORNL), one method of solid low-level radioactive waste disposal has been disposed of in below-grade cylindrical concrete silos. Located in Solid Waste Storage Area 6 (SWSA 6), each silo measures 8 ft in diameter and 20 ft deep. Present day operations involve loading the silos with low-level radioactive waste and grouting the remaining void space with a particulate grout of low viscosity. Initial operations involving the disposal of wastes into the below-grade silos did not include the grouting process. Grouting was stated as a standard practice (in late 1988) after discovering that ∼75% of the silos accumulated water in the bottom of the silos in the ∼2 years after capping. Silo water (leachate) contained a wide range of types and concentrations of radionuclides. The migration of contaminated leachate out of the silo into adjoining soil and groundwater was considered to be a serious environmental concern. This report describes how a specially designed particulate-base grout was used to grout 54 silos previously filled with low-level radioactive waste. Grouting involved three steps: (1) silo preparation, (2) formulation and preparation of the grout mixture, and (3) injection of the grout into the silos. Thirty-five of the 54 silos grouted were equipped with a 3-in.-diam Polyvinyl Chloride (PVC) pipe used to monitor water levels in the silos. A method for rupturing the bottom section of these PVC wells was developed so that grout could be pumped to the bottom of those silos. Holes (2-in. diam) were drilled through the ∼18 in. thick concrete to fill the remaining 19 wells without the PVC monitoring wells. The formulation of grout injected into the silos was based on a Portland Type I cement, flyash, sand, and silica fume admixture. Compressive strength of grout delivered to SWSA6 during grouting operations averaged 1,808 lb/in 2 with a bulk density of 3,549 lb/yd 3

Acoustic tomography and 3-D resistivity imaging of grout filled waste cells

International Nuclear Information System (INIS)

Morgan, F.D.; Chauvelier, C.; Shi, Weiqun; Lesmes, D.

1997-01-01

The Scientific Ecology Group, Inc., (SEG) was contracted by Martin Marietta Energy Systems, Inc., to demonstrate and evaluate four grout compounds for use in stabilizing radioactive waste trenches at the Oak Ridge National Laboratory (ORNL). The demonstration site was constructed at SEG's Gallaher Road test facility in Kingston, Tennessee. SEG's objectives in this project were to compare the effectiveness of the candidate grouts and grouting procedures to hydrologically isolate the waste contained within the trenches and to stabilize the trenches against subsequent subsidence. In a separate agreement with Martin Marietta Energy Systems, MIT was contracted to demonstrate the feasibility of using high-frequency acoustic tomographic imaging to evaluate the performance of the various grouts and grouting procedures, and to monitor the stability of the grouted test cells over time. The test trench consisted of four contiguous cells, each 14 feet long x 12 feet wide x 12 feet deep. The native soil in which the test cells were constructed consisted of fine red clay which is typical of the Oak Ridge area. A plan view of the test cells is shown in Figure 1 , and a cross-sectional view of one of the cells within the trench. Each cell within the trench was filled with approximately 75 cubic yards of simulated waste. The simulated waste, which included 55 gallon drums and HEPA filters, consisted of approximately 35% metal, 15% wood, and 50% paper/plastic. After the cells were loaded with the simulated waste, the trench was covered by three feet of soil to grade, to duplicate the trench configuration commonly found at ORNL

Preparation and Characterization of Plasma-Sprayed Ultrafine Chromium Oxide Coatings

International Nuclear Information System (INIS)

Lin Feng; Jiang Xianliang; Yu Yueguang; Zeng Keli; Ren Xianjing; Li Zhenduo

2007-01-01

Ultrafine chromium oxide coatings were prepared by plasma spraying with ultrafine feedstock. Processing parameters of plasma spraying were optimized. Optical microscope (OM) was used to observe the microstructure of the ultrafine chromium oxide coatings. Scanning electron microscopy (SEM) was used to observe the morphology and particle size of ultrafine powder feedstock as well as to examine the microstructure of the chromium oxide coating. In addition, hardness and bonding strength of the ultrafine chromium oxide coatings were measured. The results showed that the optimized plasma spraying parameters were suitable for ultrafine chromium oxide coating and the properties and microstructure of the optimized ultrafine chromium oxide coating were superior compared to conventional chromium oxide wear resistant coatings

Grouting techniques for the unfavorable geological conditions of Xiang'an subsea tunnel in China

Directory of Open Access Journals (Sweden)

Dingli Zhang

2014-10-01

Full Text Available One of the major challenges during subsea tunnel construction is to seal the potential water inflow. The paper presents a case study of Xiang'an subsea tunnel in Xiamen, the first subsea tunnel in China. During its construction, different grades of weathered geomaterials were encountered, which was the challenging issue for this project. To deal with these unfavorable geological conditions, grouting was adopted as an important measure for ground treatment. The grouting mechanism is first illustrated by introducing a typical grouting process. Then the site-specific grouting techniques employed in the Xiang'an subsea tunnel are elaborated. By using this ground reinforcement technique, the tunneling safety of the Xiang'an subsea tunnel was guaranteed.

Long-Term Mechanical Behavior of Nano Silica Sol Grouting

Science.gov (United States)

Zhang, Nong; Zhang, Chenghao; Qian, Deyu; Han, Changliang; Yang, Sen

2018-01-01

The longevity of grouting has a significant effect on the safe and sustainable operation of many engineering projects. A 500-day experiment was carried out to study the long-term mechanical behavior of nano silica sol grouting. The nano silica sol was activated with different proportions of a NaCl catalyst and cured under fluctuating temperature and humidity conditions. The mechanical parameters of the grout samples were tested using an electrohydraulic uniaxial compression tester and an improved Vicat instrument. Scanning electron microscope, X-ray diffraction, and ultrasonic velocity tests were carried out to analyze the strength change micro-mechanism. Tests showed that as the catalyst dosage in the grout mix is decreased, the curves on the graphs showing changes in the weight and geometric parameters of the samples over time could be divided into three stages, a shrinkage stage, a stable stage, and a second shrinkage stage. The catalyst improved the stability of the samples and reduced moisture loss. Temperature rise was also a driving force for moisture loss. Uniaxial compressive stress-strain curves for all of the samples were elastoplastic. The curves for uniaxial compression strength and secant modulus plotted against time could be divided into three stages. Sample brittleness increased with time and the brittleness index increased with higher catalyst dosages in the latter part of the curing time. Plastic strength-time curves exhibit allometric scaling. Curing conditions mainly affect the compactness, and then affect the strength. PMID:29337897

Long-Term Mechanical Behavior of Nano Silica Sol Grouting

Directory of Open Access Journals (Sweden)

Dongjiang Pan

2018-01-01

Full Text Available The longevity of grouting has a significant effect on the safe and sustainable operation of many engineering projects. A 500-day experiment was carried out to study the long-term mechanical behavior of nano silica sol grouting. The nano silica sol was activated with different proportions of a NaCl catalyst and cured under fluctuating temperature and humidity conditions. The mechanical parameters of the grout samples were tested using an electrohydraulic uniaxial compression tester and an improved Vicat instrument. Scanning electron microscope, X-ray diffraction, and ultrasonic velocity tests were carried out to analyze the strength change micro-mechanism. Tests showed that as the catalyst dosage in the grout mix is decreased, the curves on the graphs showing changes in the weight and geometric parameters of the samples over time could be divided into three stages, a shrinkage stage, a stable stage, and a second shrinkage stage. The catalyst improved the stability of the samples and reduced moisture loss. Temperature rise was also a driving force for moisture loss. Uniaxial compressive stress-strain curves for all of the samples were elastoplastic. The curves for uniaxial compression strength and secant modulus plotted against time could be divided into three stages. Sample brittleness increased with time and the brittleness index increased with higher catalyst dosages in the latter part of the curing time. Plastic strength-time curves exhibit allometric scaling. Curing conditions mainly affect the compactness, and then affect the strength.

Jet Grouting. Control of execution and result parameters. Test fields - Experience in Chile

International Nuclear Information System (INIS)

Ayarza, P. M.; Vukotic, G.

2014-01-01

This article emphasizes the importance of Test Fields in project that includes the Jet Grouting technique. In particular, the Chilean experience is analyzed, where the Jet Grouting was first introduced by Pilots Terratest S. A. in the year 2010, only, only in 2011 the first project using jet columns was constructed. The versatilely of this technique allows its use in a wide variety of projects, for example, soil capacity improvement, settlement control, reduction of soil permeability and other environmental applications. Currently, the most common applications are underpinning existing foundations, ground improvement, lateral support of excavations, hydraulic barriers, slope stabilization, liquefaction control, among others. The Jet Grouting is one of the most demanding soil improvement technique and requires excellence in designing and execution engineers and other involved specialist. It is therefore essential to ensure exhaustive control to the execution and final parameters, in order to check that the product- Jet Grouting element-have the design properties, and implement modifications if necessary. Many authors strongly advises that if there is no comparable experience and even if there is, a Test Field of Jet Grouting elements has to be executed in site. This field consists in a nearby area with similar geotechnical conditions of the project, where Jet Grouting test columns will be constructed. This Test Field will allow selecting the most effective execution parameters and verifying that the final product has he correct design properties. (Author)

Grouted Connections with Shear Keys

DEFF Research Database (Denmark)

Pedersen, Ronnie; Jørgensen, M. B.; Damkilde, Lars

2012-01-01

This paper presents a finite element model in the software package ABAQUS in which a reliable analysis of grouted pile-to-sleeve connections with shear keys is the particular purpose. The model is calibrated to experimental results and a consistent set of input parameters is estimated so that dif...... that different structural problems can be reproduced successfully....

Grout formulation for disposal of low-level and hazardous waste streams containing fluoride

Science.gov (United States)

McDaniel, E.W.; Sams, T.L.; Tallent, O.K.

1987-06-02

A composition and related process for disposal of hazardous waste streams containing fluoride in cement-based materials is disclosed. the presence of fluoride in cement-based materials is disclosed. The presence of fluoride in waste materials acts as a set retarder and as a result, prevents cement-based grouts from setting. This problem is overcome by the present invention wherein calcium hydroxide is incorporated into the dry-solid portion of the grout mix. The calcium hydroxide renders the fluoride insoluble, allowing the grout to set up and immobilize all hazardous constituents of concern. 4 tabs.

Discussion on the Influence of Various Technological Parameters on Jet Grouting Columns Geometry

Directory of Open Access Journals (Sweden)

Bzówka Joanna

2015-06-01

Full Text Available One of the most popular elements created by using jet grouting technology are columns. During designing such columns, it is a problem of estimating their shape and dimensions. The main factors that influence on columns geometry are soil characteristic and technological parameters. At the frame of Authors scientific research, following technological factors were taken into account: system of jet grouting, injection pressure, dimension of nozzles and rotation speed during injection. In the paper some results of the field tests of jet grouting columns are presented

Review of results from SKB R and D on grouting technology for sealing the rock, years 1996-2000

International Nuclear Information System (INIS)

Boden, A.; Eklund, D.; Eriksson, Magnus; Lagerblad, B.; Lindblom, U.

2001-05-01

In order identify the current state of the art and developments needs, SKB assembled a group of experts from universities and other research organisations. Internal plans were written for the subprojects 'Characterisation of rock for grouting purposes', 'Mechanisms that control the spreading of grout in jointed rock' and 'Cement based grouting material'. Later internal plans for the subprojects 'Demands on grouting' and 'Stabilising and sealing effect of pre-grouting' were written. The aims, which were set for the different subprojects, were in short, to summarise the technological advances, establish a method for rock characterisation from a grouting point of view, develop conceptual and numerical models for simulation of the grouting course, characterise grout in a relevant way, develop understanding and theoretical know-how of durability and chemical influence, identify and develop a number of grouting materials for different situations, develop a specification of requirements for grouting and to verify the theories in laboratory. In the subproject 'Demands on grouting' a literature review was carried out. One important conclusion from the study is that the concept is not very well dealt with in the literature. SKB are currently investigating the prerequisites for the construction of the deep repository. One part of that work is to further specify demands on maximum allowed volume of leakage water for the repository as a whole and also for each part of the deep repository. In the subproject 'Characterisation of rock for grouting purposes', the possibilities of using hydraulic tests for predictions and design have been studied. The idea of this study was to investigate correspondences and deviations to increase the understanding of what is measured in a water-loss measurement. One can draw the conclusion that hydraulic tests are useful when describing the fracture geometry. Numerical modelling and experiments indicate that the specific capacity, Q/Δh, (flow

An Experimental Study of Portland Cement and Superfine Cement Slurry Grouting in Loose Sand and Sandy Soil

OpenAIRE

Weijing Yao; Jianyong Pang; Yushan Liu

2018-01-01

Grouting technology is widely applied in the fields of geotechnical engineering in infrastructure. Loose sand and sandy soil are common poor soils in tunnel and foundation treatments. It is necessary to use superfine cement slurry grouting in the micro-cracks of soil. The different effectiveness of Portland cement slurry and superfine cement slurry in sandy soil by the laboratory grouting experiment method were presented in this paper. The grouting situations of superfine cement slurry inject...

Grouting applications in civil engineering. Volume I and II. [800 references

Energy Technology Data Exchange (ETDEWEB)

Einstein, H.H.; Barvenik, M.J.

1975-01-01

A comprehensive description of grouting applications in civil engineering is presented that can serve as a basis for the selection of grouting methods in the borehole sealing problem. The breadth and depth of the study was assured by conducting the main part of the review, the collection and evaluation of information, without specifically considering the borehole sealing problem (but naturally incorporating any aspect of civil engineering applications that could be of potential use). Grouting is very much an art and not a science. In most cases, it is a trial and error procedure where an inexpensive method is initially tried and then a more expensive one is used until the desired results are obtained. Once a desired effect is obtained, it is difficult to credit any one procedure with the success because the results are due to the summation of all the methods used. In many cases, the method that proves successful reflects a small abnormality in the ground or structure rather than its overall characteristics. Hence, successful grouting relies heavily on good engineering judgement and experience, and not on a basic set of standard correlations or equations. 800 references. (JRD)

Reduction of minimum required weight of cementitious materials in WisDOT concrete mixes.

Science.gov (United States)

2011-12-01

This project was designed to explore the feasibility of lowering the cementitious materials content : (CMC) used in Wisconsin concrete pavement construction. The cementitious materials studied included : portland cement, fly ash, and ground granulate...

Reduction of minimum required weight of cementitious materials in WisDOT concrete mixes.

Science.gov (United States)

2011-12-01

"This project was designed to explore the feasibility of lowering the cementitious materials content : (CMC) used in Wisconsin concrete pavement construction. The cementitious materials studied included : portland cement, fly ash, and ground granulat...

A new design concept of fully grouted rock bolts in underground construction

Science.gov (United States)

Phich Nguyen, Quang; Nguyen, Van Manh; Tuong Nguyen, Ke

2018-04-01

The main problem after excavating an underground excavation is to maintain the stability of the excavation for a certain period of time. Failure in meeting this demand is a threat to safety of men and equipment. Support and reinforcement are different instruments with different mechanisms. Among the common support systems in tunnelling and mining, rock bolts have been widely used to reinforce rock mass and also to reduce geological hazards. Furthermore rock bolts can be applied under varying different geological conditions with cost-effectiveness. Although different methods are developed for grouted rock bolts design until now, the interaction mechanism of the rock bolts and rock mass is still very complicated issue. The paper addresses an analytical model for the analysis and design of fully grouted rock bolts based on the reinforcement principle. According to this concept the jointed rock mass reinforced by grouted rock bolts is considered as composite material which includes rock mass, the grout material and the bolt shank. The mechanical properties of this composite material depend on the ratio of the components. The closed-form solution was developed based on the assumption that the rock mass arround a circular tunnel remained elastic after installing fully grouted rock bolts. The main parameters of the rock-bolt system (the diameter and length of bolt shank, the space between the bolts) are then easily estimated from the obtained solution.

Modeling Analysis For Grout Hopper Waste Tank

International Nuclear Information System (INIS)

Lee, S.

2012-01-01

The Saltstone facility at Savannah River Site (SRS) has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout nuclear waste slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The primary objective of the work was to evaluate the flow performance for mechanical agitators to prevent vortex pull-through for an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45 o pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. As a first step, a simple single-stage agitator model with 45 o pitched propeller blades was developed for the initial scoping analysis of the flow pattern behaviors for a range of different operating conditions. Based on the initial phase-1 results, the phase-2 model with a two-stage agitator was developed for the final performance evaluations. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. For the analysis, viscous shear was modeled by using the Bingham plastic approximation. Steady state analyses with a two-equation turbulence model were performed. All analyses were based on three-dimensional results. Recommended operational guidance was developed by using the basic concept that local shear rate profiles and flow patterns can be used as a measure of hydraulic performance and spatial stirring. Flow patterns were estimated by a Lagrangian integration technique along the flow paths

Field application of innovative grouting agents for in situ stabilization of buried waste sites

International Nuclear Information System (INIS)

Loomis, G.G.; Farnsworth, R.K.

1997-01-01

This paper presents field applications for two innovative grouting agents that were used to in situ stabilize buried waste sites, via jet grouting. The two grouting agents include paraffin and a proprietary iron oxide based cement grout called TECT. These materials were tested in specially designed cold test pits that simulate buried transuranic waste at the Idaho National Engineering Laboratory (INEL). The field demonstrations were performed at the INEL in an area referred to as the Cold Test Pit, which is adjacent to the INEL Radioactive Waste Management Complex (RWMC). At the RWMC, 56,000 m 3 of transuranic (TRU) waste is co-mingled with over 170,000 m 3 of soil in shallow land burial. Improving the confinement of this waste is one of the options for final disposition of this waste. Using jet-grouting technology to inject these materials into the pore spaces of buried waste sites results in the creation of buried monolithic waste forms that simultaneously protect the waste from subsidence, while eliminating the migratory potential of hazardous and radioactive contaminants in the waste

Development and enhancement of grouting technologies in the Mizunami Underground Research Laboratory (Contract research)

International Nuclear Information System (INIS)

Nobuto, Jun; Mikake, Shinichiro

2008-03-01

In the Tono Geoscience Center of Japan Atomic Energy Agency (hereafter, JAEA), Mizunami Underground Research Laboratory project is being advanced to develop a scientific and technological basis for geological disposal. The concept of geological disposal is based on a multi-barrier system which combines a stable geological environment with an engineered barrier system (EBS). In order to develop a engineering basis for the construction of disposal system, the enhancement of grouting technologies among engineering technologies is needed. In this study, the comprehensive performance of suspension type grouting materials to seal rock fractures encountered in excavation works at deep underground has been checked, and the clogging phenomenon at the entrance of rock fractures has been investigated following the previous year. Research issues are as follows; Study on grouting concept to secure high-level water sealing, study on the test method to check grout clogging under high injection pressure, study on grouting material which can penetrate into finer fractures. Among these, in the study on penetrability test method, prototype test instruments were made and a series of preliminary tests were conducted. (author)

Hybrid life cycle assessment comparison of colloidal silica and cement grouted soil barrier remediation technologies

Energy Technology Data Exchange (ETDEWEB)

Gallagher, Patricia M., E-mail: pmg24@drexel.edu [Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19038 (United States); Spatari, Sabrina; Cucura, Jeffrey [Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19038 (United States)

2013-04-15

Highlights: ► We use LCA to study environmental impacts of grouting techniques for site remediation. ► We consider colloidal silica permeation grouting and cement jet grouting. ► Manufacturing and transportation contribute significantly in all impact categories. ► Activity outside of direct site activity is important in assessing impacts. ► LCA can be used to consider sustainability criteria for remediation decisions. -- Abstract: Site remediation involves balancing numerous costs and benefits but often neglects the environmental impacts over the entire project life cycle. Life cycle assessment (LCA) offers a framework for inclusion of global environmental “systems-level” decision metrics in combination with technological and cost analysis. We compare colloidal silica (CS) and cement grouted soil barrier remediation technologies for soils affected by low level radionuclides at a U.S. Superfund site using hybrid LCA methods. CS is a new, high performance grouting material installed using permeation grouting techniques. Cement, a more traditional grouting material, is typically installed using jet grouting techniques. Life cycle impacts were evaluated using the US EPA TRACI 2 model. Results show the highest life cycle environmental impacts for the CS barrier occur during materials production and transportation to the site. In general, the life cycle impacts for the cement barrier were dominated by materials production; however, in the extreme scenario the life cycle impacts were dominated by truck transportation of spoils to a distant, off-site radioactive waste facility. It is only in the extreme scenario tested in which soils are transported by truck (Option 2) that spoils waste transport dominates LCIA results. Life cycle environmental impacts for both grout barriers were most sensitive to resource input requirements for manufacturing volumes and transportation. Uncertainty associated with the efficacy of new technology such as CS over its required

Hybrid life cycle assessment comparison of colloidal silica and cement grouted soil barrier remediation technologies

International Nuclear Information System (INIS)

Gallagher, Patricia M.; Spatari, Sabrina; Cucura, Jeffrey

2013-01-01

Highlights: ► We use LCA to study environmental impacts of grouting techniques for site remediation. ► We consider colloidal silica permeation grouting and cement jet grouting. ► Manufacturing and transportation contribute significantly in all impact categories. ► Activity outside of direct site activity is important in assessing impacts. ► LCA can be used to consider sustainability criteria for remediation decisions. -- Abstract: Site remediation involves balancing numerous costs and benefits but often neglects the environmental impacts over the entire project life cycle. Life cycle assessment (LCA) offers a framework for inclusion of global environmental “systems-level” decision metrics in combination with technological and cost analysis. We compare colloidal silica (CS) and cement grouted soil barrier remediation technologies for soils affected by low level radionuclides at a U.S. Superfund site using hybrid LCA methods. CS is a new, high performance grouting material installed using permeation grouting techniques. Cement, a more traditional grouting material, is typically installed using jet grouting techniques. Life cycle impacts were evaluated using the US EPA TRACI 2 model. Results show the highest life cycle environmental impacts for the CS barrier occur during materials production and transportation to the site. In general, the life cycle impacts for the cement barrier were dominated by materials production; however, in the extreme scenario the life cycle impacts were dominated by truck transportation of spoils to a distant, off-site radioactive waste facility. It is only in the extreme scenario tested in which soils are transported by truck (Option 2) that spoils waste transport dominates LCIA results. Life cycle environmental impacts for both grout barriers were most sensitive to resource input requirements for manufacturing volumes and transportation. Uncertainty associated with the efficacy of new technology such as CS over its required

Grout and Glass Performance Maximizing the Loading of ORNL Tank Sludges

International Nuclear Information System (INIS)

Burgess, M.W.; Mattus, A.J.; Spence, R.D.; Travis, J.R.

1999-01-01

Grouting and vitrification are currently two likely stabilization and solidification alternatives for radioactive and hazardous mixed wastes stored at Department of Energy (DOE) facilities. Grouting has been used to stabilize and solidify hazardous and low-level radioactive waste for decades. Vitrification has been developed as a high-level radioactive alternative for decades and has been under development recently as a mixed-waste alternative disposal technology

Laboratory stabilization/solidification of surrogate and actual mixed-waste sludge in glass and grout

International Nuclear Information System (INIS)

Spence, R.D.; Gilliam, T.M.; Mattus, C.H.; Mattus, A.J.

1998-01-01

Grouting and vitrification are currently the most likely stabilization/solidification technologies for mixed wastes. Grouting has been used to stabilize and solidify hazardous and low-level waste for decades. Vitrification has long been developed as a high-level-waste alternative and has been under development recently as an alternative treatment technology for low-level mixed waste. Laboratory testing has been performed to develop grout and vitrification formulas for mixed-waste sludges currently stored in underground tanks at Oak Ridge National Laboratory (ORNL) and to compare these waste forms. Envelopes, or operating windows, for both grout and soda-lime-silica glass formulations for a surrogate sludge were developed. One formulation within each envelope was selected for testing the sensitivity of performance to variations (±10 wt%) in the waste form composition and variations in the surrogate sludge composition over the range previously characterized in the sludges. In addition, one sludge sample of an actual mixed-waste tank was obtained, a surrogate was developed for this sludge sample, and grout and glass samples were prepared and tested in the laboratory using both surrogate and the actual sludge. The sensitivity testing of a surrogate tank sludge in selected glass and grout formulations is discussed in this paper, along with the hot-cell testing of an actual tank sludge sample

Grout Placement and Property Evaluation for Closing Hanford High-Level Waste Tanks - Scale-Up Testing

International Nuclear Information System (INIS)

LANGTON, CHRISTINE

2003-01-01

Hanford has 149 single-shell high level waste (HLW) tanks that were constructed between 1943 and 1964. Many of these tanks have leaked or are suspected of leaking HLW into the soil above the ground water. Consequently, a major effort is ongoing to transfer the liquid portion of the waste to the 28 newer, double-shell tanks. Savannah River National Laboratory (SRNL) was tasked to develop grout formulations for the three-layer closure concept selected by CH2M HILL for closing Tank C-106. These grout formulations were also evaluated for use as fill materials in the next six tanks scheduled to be closed. The overall scope consisted of both bench-scale testing to confirm mix designs and scale-up testing to confirm placement properties. This report provides results of the scale-up testing for the three-phase tank closure strategy. It also contains information on grouts for equipment and riser filling. The three-phase fill strategy is summarized as follows: Phase I fill encapsulates and minimizes dispersion of the residual waste in the tank. This fill is referred to as the Stabilization Layer and consists of the Stabilization Grout. The Phase II fill provides structural stability to the tank system and prevents subsidence. It is referred to as the Structural Layer and consists of the Structural Grout. A final Phase III fill consists of a grout designed to provide protection against intrusion and is referred to as the Capping Layer or Capping Grout

Crack Formation in Grouted Annular Composite

DEFF Research Database (Denmark)

Sørensen, Eigil V.

The objective of the present analysis is to identify the reason for extensive crack formation which occurred during an annulus grouting performance test, to evaluate possible consequences of the cracking, and to recommend measures to be taken in order to avoid similar problems in the future....

CsIX/TRU Grout Feasibility Study

Energy Technology Data Exchange (ETDEWEB)

S. J. Losinski; C. M. Barnes; B. K. Grover

1998-11-01

A settlement agreement between the Department of Energy (DOE) and the State of Idaho mandates that liquid waste now stored at the Idaho Nuclear Technology Engineering Center (INTEC - formerly the Idaho Chemical Processing Plant, ICPP) will be calcined by the end of year 2012. This study investigates an alternative treatment of the liquid waste that removes undissolved solids (UDS) by filtration and removes cesium by ion exchange followed by cement-based grouting of the remaining liquid into 55-gal drums. Operations are assumed to be from January 2008 through December 2012. The grouted waste will be contact-handled and will be shipped to the Waste Isolation Pilot Plant (WIPP) in New Mexico for disposal. The small volume of secondary wastes such as the filtered solids and cesium sorbent (resin) would remain in storage at the Idaho National Engineering and Environmental Laboratory for treatment and disposal under another project, with an option to dispose of the filtered solids as a r emote-handled waste at WIPP.

CsIX/TRU Grout Feasibility Study

International Nuclear Information System (INIS)

Losinski, S. J.; Barnes, C. M.; Grover, B. K.

1998-01-01

A settlement agreement between the Department of Energy (DOE) and the State of Idaho mandates that liquid waste now stored at the Idaho Nuclear Technology Engineering Center (INTEC - formerly the Idaho Chemical Processing Plant, ICPP) will be calcined by the end of year 2012. This study investigates an alternative treatment of the liquid waste that removes undissolved solids (UDS) by filtration and removes cesium by ion exchange followed by cement-based grouting of the remaining liquid into 55-gal drums. Operations are assumed to be FR-om January 2008 through December 2012. The grouted waste will be contact-handled and will be shipped to the Waste Isolation Pilot Plant (WIPP) in New Mexico for disposal. The small volume of secondary wastes such as the filtered solids and cesium sorbent (resin) would remain in storage at the Idaho National Engineering and Environmental Laboratory for treatment and disposal under another project, with an option to dispose of the filtered solids as a r emote-handled waste at WIPP

Ultrafine particles in concrete: Influence of ultrafine particles on concrete properties and application to concrete mix design

Energy Technology Data Exchange (ETDEWEB)

Vogt, Carsten

2010-07-01

In this work, the influence of ultrafine particles on concrete properties was investigated. In the context of this work, ultrafine particles (reactive and inert materials) are particles finer than cement. Due to the development of effective superplasticizers, the incorporation of ultrafine particles in concrete is nowadays possible. Different minerals, usually considered inert, were tested. These minerals were also used in combination with reactive silica fume. The modified Andreassen model was used to optimise the particle size distribution and thus the packing density of the complete mix composition. Heat of hydration, compressive strength, shrinkage, frost resistance and the microstructure were investigated.The influence of different ultrafine inert materials on the cement hydration was investigated. The results show that most of the minerals have an accelerating effect. They provide nucleation sites for hydration products and contribute in that way to a faster dissolution of cement grains. Minerals containing calcium were found to influence the early stage of hydration as well. These minerals shortened the dormant period of the cement hydration, the effect is known from limestone filler in self-compacting concrete. In a first test series on concrete, different ultrafine inert particles were used to replace cement. That was done in several ways; with constant water content or constant w/c. The results from this test series show that the best effect is achieved when cement is replaced by suitable ultrafines while the w/c is kept constant. In doing so, the compressive strength can be increased and shrinkage can be reduced. The microstructure is improved and becomes denser with improved packing at microlevel. Efficiency factors (k values) for the ultrafine inert materials were calculated from the compressive strength results. The k values are strongly dependent on the mode of cement replacement, fineness and type of the replacement material and curing time. Drying

Penetration of corrosion products and corrosion-induced cracking in reinforced cementitious materials

DEFF Research Database (Denmark)

Michel, Alexander; Pease, Brad J.; Peterova, Adela

2014-01-01

This paper describes experimental investigations on corrosion-induced deterioration in reinforced cementitious materials and the subsequent development and implementation of a novel conceptual model. Rejnforced mortar specimens of varying water-to-cement ratios were subjected to current-induced c......This paper describes experimental investigations on corrosion-induced deterioration in reinforced cementitious materials and the subsequent development and implementation of a novel conceptual model. Rejnforced mortar specimens of varying water-to-cement ratios were subjected to current......-dependent concentrations of corrosion products averaged through the specimen thickness. Digital image correlation (DIC) was used to measure corrosion-induced deformations including deformations between steel and cementitious matrix as well as formation and propagation of corrosion-induced cracks. Based on experimental...... observations, a conceptual model was developed to describe the penetration of solid corrosion products into capillary pores of the cementitious matrix. Only capillary pores within a corrosion accommodating region (CAR), i.e. in close proximity of the steel reinforcement, were considered accessible...

Analysis on pile testing results of post-grouting bored pile

Science.gov (United States)

Zheng, A. R.

2017-04-01

Based on static load test results, the bearing capacity of bored piles with pile-toe and pile-shaft post-grouting has been analyzed. The analysis reveals that: with post-grouting, the interface between pile and surrounding soil are strengthened and the relative sliding displacement in between is reduced; end resistance of pile is enhanced and can be mobilized at earlier stage with smaller sliding displacement. As a result, the performance of bored pile is improved with increased bearing capacity and reduced settlement.

Implications of cementitious evolution for solubility and retention of radionuclides over long timescales

International Nuclear Information System (INIS)

Williams, Steve; Norris, Simon

2012-01-01

Simon Norris of the NDA described the current status of understanding of radionuclide solubility and retention in cementitious materials based on experience in the United Kingdom. Cementitious materials play a number of roles in the long-term management and disposal of radioactive wastes. One of these roles is to contribute to the post-closure containment and retention of radionuclides within a disposal facility by imposing conditions that minimise radionuclide solubility and provide sites for radionuclide sorption. The chemical containment provided by the highly-alkaline, chemically reducing environment imposed by cementitious materials plays an important role in the long-term retention of many radionuclides. However, the mineralogy and other properties of cementitious materials that contribute to their physical and chemical barrier performance within the engineered barrier system will evolve due to several processes, including: - Leaching. - Reaction with groundwater solutes. - Hydration and crystallisation. - Reaction with wastes, their degradation products, and with non-cementitious waste forms. - Cracking. Some of these processes are better understood than others. For example, the evolution of pH within a homogeneous repository near field can be modelled based on knowledge of cement dissolution combined with expected groundwater compositions and flow rates. The calculated changes in pH can then be coupled to radionuclide solubility and sorption in safety assessment models. Other processes are not as well constrained. Reaction of cementitious materials with groundwater will lead to changes in the mineralogical composition of the cements, accompanied by changes in porosity and permeability, and cracking can lead to localised water flow along the cracks and preferential leaching or deposition of reaction products. These processes can also alter the sorption properties of the cementitious materials. Additional complexities result from the heterogeneous

Preliminary experimental study on the deterioration of cementitious materials by an acceleration method

International Nuclear Information System (INIS)

Saito, H.; Nakane, S.; Ikari, S.; Fujiwara, A.

1992-01-01

Development of a deterioration model for cementitious materials is important in assessing long-term integrity of nuclear waste repositories. The authors preliminarily examined a new test method for acceleration of aging of mortar specimens by application of electrical potential gradients and observed whether the method could throw light on the deterioration process of cementitious materials under repository conditions. As a result, it was concluded that the application of a potential gradient to a mortar specimen might be useful as an accelerated test method for assessing the deterioration behavior of cementitious materials due to leaching. (orig.)

Thin fiber and textile reinforced cementitious systems

National Research Council Canada - National Science Library

Aldea, Corina-Maria

2007-01-01

This Special Publication (SP) contains ten papers which provide insight on the topics of state of the art of thin fiber and textile-reinforced cementitious systems both in academia and the industry...

In-Situ Grouting Treatability Study for the Idaho National Engineering and Environmental Laboratory Subsurface Disposal Area-Transuranic Pits and Trenches

International Nuclear Information System (INIS)

Loomis, G. G.; Jessmore, J. J.; Sehn, A. L.; Miller, C. M.

2002-01-01

At the Idaho National Engineering and Environmental Laboratory (INEEL), a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) treatability study is being performed to examine the technology of in situ grouting for final in situ disposal of buried mixed transuranic (TRU) waste. At the INEEL, there is over 56,000 cubic meters of waste commingled with a similar amount of soil in a shallow (3-5 m) land burial referred to as Waste Area Group 7-13/14. Since this buried waste has been declared on the National Priorities List under CERCLA, it is being managed as a superfund site. Under CERCLA, options for this waste include capping and continued monitoring, retrieval and ex situ management of the retrieved waste, in situ stabilization by vitrification or grouting, in situ thermal dissorption, or some combination of these options. In situ grouting involves injecting grout at high pressures (400 bars) directly into the waste to create a solid monolith. The in situ grouting process is expected to both stabilize the waste against subsidence and provide containment against migration of waste to the Snake River Plain Aquifer lying 150-200 m below the waste. The treatability study involves bench testing, implementability testing, and field testing. The bench testing was designed to pick three grouts from six candidate grouts for the implementability field testing in full scale which were designed to down-select from those three grouts to one grout for use in a full-scale field demonstration of the technology in a simulated test pit. During the bench testing, grouts were evaluated for durability using American Nuclear Society 16.1 Leach Protocol as well as evaluating the effect on physical parameters such as hydraulic conductivity and compressive strength due to the presence of interferences such as soil, organic sludge, and nitrate salts. During full-scale implementability testing, three grouts were evaluated for groutability and monolith formation

Effect of hygrothermal conditioning on the mechanical and thermal properties of epoxy grouts for offshore pipeline rehabilitation

Directory of Open Access Journals (Sweden)

Allan Manalo

2016-07-01

Full Text Available Offshore oil and gas pipelines are susceptible to corrosion and need rehabilitation to keep them operating in-service conditions. Fibre composite filled with epoxy-based grout is emerging as an effective repair and rehabilitation system for offshore pipelines performing underwater. In such applications, the infill grout is often subjected to moisture and elevated temperature along with compressive, tensile and localised stresses at the defect. Current standards and practices for composite repairs suggest detailed investigation of the fibre reinforced sleeve, while the characterisation of the infill material is yet to be conducted for performance evaluation. The present work investigates the mechanical and thermal properties of three epoxy grouts as candidates for infill in a grouted sleeve repair for underwater pipeline. An understanding on the effect of hygrothermal ageing on the grout properties for defining the period of 1000 hours as “long-term” according to ISO/TS 24817, in comparison to their unconditioned state, is also presented. The compressive and tensile strength of the unconditioned grouts ranges from 100–120 MPa, and 19–32 MPa, respectively, which indicates that these grouts are suitable for structural rehabilitation of the pipelines. Moreover, the glass transition temperatures, Tg and Tt of the unconditioned grouts are found to be within the ranges of 50–60 °C, and 80–90 °C, respectively, which are reduced by about 20°C after conditioning.

A two-stage ceramic tile grout sealing process using a high power diode laser—Grout development and materials characteristics

Science.gov (United States)

Lawrence, J.; Li, L.; Spencer, J. T.

1998-04-01

Work has been conducted using a 60 Wcw high power diode laser (HPDL) in order to determine the feasibility and characteristics of sealing the void between adjoining ceramic tiles with a specially developed grout material having an impermeable enamel surface glaze. A two-stage process has been developed using a new grout material which consists of two distinct components: an amalgamated compound substrate and a glazed enamel surface; the amalgamated compound seal providing a tough, heat resistant bulk substrate, whilst the enamel provides an impervious surface. HPDL processing has resulted in crack free seals produced in normal atmospheric conditions. The basic process phenomena are investigated and the laser effects in terms of seal morphology, composition and microstructure are presented. Also, the resultant heat affects are analysed and described, as well as the effects of the shield gases, O 2 and Ar, during laser processing. Tiles were successfully sealed with power densities as low as 500 W/cm 2 and at rates up to 600 mm/min. Contact angle measurements revealed that due to the wettability characteristics of the amalgamated oxide compound grout (AOCG), laser surface treatment was necessary in order to alter the surface from a polycrystalline to a semi-amorphous structure, thus allowing the enamel to adhere. Bonding of the enamel to the AOCG and the ceramic tiles was identified as being principally due to van der Waals forces, and on a very small scale, some of the base AOCG material dissolving into the glaze.

Development of Freshwater Grout Subsequent to the Bell Canyon Tests (BCT).

Science.gov (United States)

1986-04-01

specimens of those grouts cured and studied in the SL, to three-years age. Selected data from earlier tests of related fresh-water grouts are...specimens were either coated with a strippable plastic momn;rane, or sealed in plastic cylinders with tightly fitting lids. Sealed in plastiC habs in...for expansion prisms, the strippable coating applied to SPDV specimens did not prevent water loss. Lower strength gain may be attributable to partial

PARTNERSHIP FOR THE DEVELOPMENT OF NEXT GENERATION SIMULATION TOOLS TO EVALUATE CEMENTITIOUS BARRIERS AND MATERIALS USED IN NUCLEAR APPLICATION - 8388

International Nuclear Information System (INIS)

Langton, C; Richard Dimenna, R

2008-01-01

The US DOE has initiated a multidisciplinary cross cutting project to develop a reasonable and credible set of tools to predict the structural, hydraulic and chemical performance of cement barriers used in nuclear applications over extended time frames (e.g., > 100 years for operating facilities and > 1000 years for waste management). A partnership that combines DOE, NRC, academia, private sector, and international expertise has been formed to accomplish the project objectives by integrating existing information and realizing advancements where necessary. The set of simulation tools and data developed under this project will be used to evaluate and predict the behavior of cementitious barriers used in near surface engineered waste disposal systems, e.g., waste forms, containment structures, entombments and environmental remediation, including decontamination and decommissioning (D and D) activities. The simulation tools will also support analysis of structural concrete components of nuclear facilities (spent fuel pools, dry spent fuel storage units, and recycling facilities, e.g., fuel fabrication, separations processes). Simulation parameters will be obtained from prior literature and will be experimentally measured under this project, as necessary, to demonstrate application of the simulation tools for three prototype applications (waste form in concrete vault, high level waste tank grouting, and spent fuel pool). Test methods and data needs to support use of the simulation tools for future applications will be defined. This is a national issue that affects all waste disposal sites that use cementitious waste forms and structures, decontamination and decommissioning activities, service life determination of existing structures, and design of future public and private nuclear facilities. The problem is difficult because it requires projecting conditions and responses over extremely long times. Current performance assessment analyses show that engineered barriers

In-situ grouting of uranium-mill-tailings piles: an assessment

International Nuclear Information System (INIS)

Tamura, T.; Boegly, W.J. Jr.

1983-05-01

Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles

In-situ grouting of uranium-mill-tailings piles: an assessment

Energy Technology Data Exchange (ETDEWEB)

Tamura, T.; Boegly, W.J. Jr.

1983-05-01

Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles.

Injection of FGD Grout to Abate Acid Mine Drainage in Underground Coal Mines

Energy Technology Data Exchange (ETDEWEB)

Mafi, S.; Damian, M.T.; Senita, R.E.; Jewitt, W.C.; Bair, S.; Chin, Y.C.; Whitlatch, E.; Traina, S.; Wolfe, W.

1997-07-01

Acid Mine Drainage (AMD) from abandoned underground coal mines in Ohio is a concern for both residents and regulatory agencies. Effluent from these mines is typically characterized by low pH and high iron and sulfate concentrations and may contaminate local drinking-water supplies and streams. The objective of this project is to demonstrate the technical feasibility of injecting cementitious alkaline materials, such as Flue Gas Desulfurization (FGD) material to mitigate current adverse environmental impacts associated with AMD in a small, abandoned deep mine in Coshocton County Ohio. The Flue Gas Desulfurization material will be provided from American Electric Power`s (AEP) Conesville Plant. It will be injected as a grout mix that will use Fixated Flue Gas Desulfurization material and water. The subject site for this study is located on the border of Coshocton and Muskingum Counties, Ohio, approximately 1.5 miles south-southwest of the town of Wills Creek. The study will be performed at an underground mine designated as Mm-127 in the Ohio Department of Natural Resources register, also known as the Roberts-Dawson Mine. The mine operated in the mid-1950s, during which approximately 2 million cubic feet of coal was removed. Effluent discharging from the abandoned mine entrances has low pH in the range of 2.8-3.0 that drains directly into Wills Creek Lake. The mine covers approximately 14.6 acres. It is estimated that 26,000 tons of FGD material will be provided from AEP`s Conesville Power Plant located approximately 3 miles northwest of the subject site.

Injection of FGD Grout to Abate Acid Mine Drainage in Underground Coal Mines

International Nuclear Information System (INIS)

Mafi, S.; Damian, M.T.; Senita, R.E.; Jewitt, W.C.; Bair, S.; Chin, Y.C.; Whitlatch, E.; Traina, S.; Wolfe, W.

1997-07-01

Acid Mine Drainage (AMD) from abandoned underground coal mines in Ohio is a concern for both residents and regulatory agencies. Effluent from these mines is typically characterized by low pH and high iron and sulfate concentrations and may contaminate local drinking-water supplies and streams. The objective of this project is to demonstrate the technical feasibility of injecting cementitious alkaline materials, such as Flue Gas Desulfurization (FGD) material to mitigate current adverse environmental impacts associated with AMD in a small, abandoned deep mine in Coshocton County Ohio. The Flue Gas Desulfurization material will be provided from American Electric Power's (AEP) Conesville Plant. It will be injected as a grout mix that will use Fixated Flue Gas Desulfurization material and water. The subject site for this study is located on the border of Coshocton and Muskingum Counties, Ohio, approximately 1.5 miles south-southwest of the town of Wills Creek. The study will be performed at an underground mine designated as Mm-127 in the Ohio Department of Natural Resources register, also known as the Roberts-Dawson Mine. The mine operated in the mid-1950s, during which approximately 2 million cubic feet of coal was removed. Effluent discharging from the abandoned mine entrances has low pH in the range of 2.8-3.0 that drains directly into Wills Creek Lake. The mine covers approximately 14.6 acres. It is estimated that 26,000 tons of FGD material will be provided from AEP's Conesville Power Plant located approximately 3 miles northwest of the subject site

Structural model testing for prestressed concrete pressure vessels: a study of grouted vs nongrouted posttensioned prestressing tendon systems

International Nuclear Information System (INIS)

Naus, D.J.

1979-04-01

Nongrouted tendons are predominantly used in this country as the prestressing system for prestressed concrete pressure vessels (PCPVs) because they are more easily surveyed to detect reductions in prestressing level and distress such as results from corrosion. Grouted tendon systems, however, offer advantages which may make them cost-effective for PCPV applications. Literature was reviewed to (1) provide insight on the behavior of grouted tendon system, (2) establish performance histories for structures utilizing grouted tendons, (3) examine corrosion protection procedures for prestressing tendons, (4) identify arguments for and against using grouted tendons, and (5) aid in the development of the experimental investigation. The experimental investigation was divided into four phases: (1) grouted-nongrouted tendon behavior, (2) evaluation of selected new material systems, (3) bench-scale corrosion studies, and (4) preliminary evaluation of acoustic emission techniques for monitoring grouted tendons in PCPVs. The groutability of large tendon systems was also investigated

Finite Element Analysis of Grouting Compactness Monitoring in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers

Directory of Open Access Journals (Sweden)

Tianyong Jiang

2017-09-01

Full Text Available With the development of the post-tensioning technique, prestressed concrete structures have been widely used in civil engineering. To ensure the long-term effectiveness of the prestressed tendon, the grouting quality of the tendon duct is one of the important factors. However, it is still a challenge to monitor the grouting quality of post-tensioning tendon ducts, due to the invisibility of the grouting. The authors’ previous work proposed a real-time method that employed a stress wave-based active sensing approach with piezoceramic transducers to monitor the grouting compactness of a Post-Tensioning Tendon Duct (PTTD. To further understand the piezoceramic induced stress wave propagation in the PTTD with different grouting levels, this paper develops a two-dimensional finite element model for monitoring the grouting compactness of the tendon duct with a piezoceramic transducer. A smart aggregate (SA developed to utilize one Lead Zirconate Titanate (PZT transducer with marble protection is installed in the center location of the tendon duct as an actuator. Two PZT patches are bonded on the bottom and top surface of the tendon duct as the sensors. The analysis results show that the finite element analysis results are in good agreement with the experimental results, which demonstrates that the finite element analysis is feasible and reliable. For the top half of the specimen, not much stress wave could be detected before the full grouting level, except for negligible signals that may propagate through the walls of the tendon duct. When the tendon duct grouting is at 100%, the stress wave propagates to the top of the specimen, and the displacements are symmetric in both left-right and top-bottom directions before the stress waves reach the boundary. The proposed two-dimensional finite element model has the potential to be implemented to simulate the stress wave propagation principle for monitoring grouting compaction of the post-tensioning tendon

Finite Element Analysis of Grouting Compactness Monitoring in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers.

Science.gov (United States)

Jiang, Tianyong; Zheng, Junbo; Huo, Linsheng; Song, Gangbing

2017-09-29

With the development of the post-tensioning technique, prestressed concrete structures have been widely used in civil engineering. To ensure the long-term effectiveness of the prestressed tendon, the grouting quality of the tendon duct is one of the important factors. However, it is still a challenge to monitor the grouting quality of post-tensioning tendon ducts, due to the invisibility of the grouting. The authors' previous work proposed a real-time method that employed a stress wave-based active sensing approach with piezoceramic transducers to monitor the grouting compactness of a Post-Tensioning Tendon Duct (PTTD). To further understand the piezoceramic induced stress wave propagation in the PTTD with different grouting levels, this paper develops a two-dimensional finite element model for monitoring the grouting compactness of the tendon duct with a piezoceramic transducer. A smart aggregate (SA) developed to utilize one Lead Zirconate Titanate (PZT) transducer with marble protection is installed in the center location of the tendon duct as an actuator. Two PZT patches are bonded on the bottom and top surface of the tendon duct as the sensors. The analysis results show that the finite element analysis results are in good agreement with the experimental results, which demonstrates that the finite element analysis is feasible and reliable. For the top half of the specimen, not much stress wave could be detected before the full grouting level, except for negligible signals that may propagate through the walls of the tendon duct. When the tendon duct grouting is at 100%, the stress wave propagates to the top of the specimen, and the displacements are symmetric in both left-right and top-bottom directions before the stress waves reach the boundary. The proposed two-dimensional finite element model has the potential to be implemented to simulate the stress wave propagation principle for monitoring grouting compaction of the post-tensioning tendon duct.

Fixation of waste materials in grouts. Part II. An empirical equation for estimating compressive strength for grouts from different wastes

International Nuclear Information System (INIS)

Tallent, O.K.; McDaniel, E.W.; Godsey, T.T.

1986-04-01

Compressive strength data for grouts prepared from three different nuclear waste materials have been correlated. The wastes include ORNL low-level waste (LLW) solution, Hanford Facility Waste (HFW) solution, and Hanford cladding removal waste (CRW) slurry. Data for the three wastes can be represented with a 0.96 coefficient of correlation by the following equation: S = -9.56 + 9.27 D/I + 18.11/C + 0.010 R, where S denotess 28-d compressive strength, in mPa; D designates Waste concentration, fraction of the original; I is ionic strength; C denotes Attapulgite-150 clay content of dry blend, in wt %; and R is the mix ratio, kg/m 3 . The equation may be used to estimate 28-d compressive strengths of grouts prepared within the compositional range of this investigation

A dynamic simulation of the Hanford site grout facility

International Nuclear Information System (INIS)

Zimmerman, B.D.; Klimper, S.C.; Williamson, G.F.

1992-01-01

Computer-based dynamic simulation can be a powerful, low-cost tool for investigating questions concerning timing, throughput capability, and ability of engineering facilities and systems to meet established milestones. The simulation project described herein was undertaken to develop a dynamic simulation model of the Hanford site grout facility and its associated systems at the US Department of Energy's (DOE's) Hanford site in Washington State. The model allows assessment of the effects of engineering design and operation trade-offs and of variable programmatic constraints, such as regulatory review, on the ability of the grout system to meet milestones established by DOE for low-level waste disposal

High-performance cement-based grouts for use in a nuclear waste disposal facility

International Nuclear Information System (INIS)

Onofrei, M.; Gray, M.N.

1992-12-01

National and international agencies have identified cement-based materials as prime candidates for sealing vaults that would isolate nuclear fuel wastes from the biosphere. Insufficient information is currently available to allow a reasonable analysis of the long-term performance of these sealing materials in a vault. A combined laboratory and modelling research program was undertaken to provide the necessary information for a specially developed high-performance cement grout. The results indicate that acceptable performance is likely for at least thousands of years and probably for much longer periods. The materials, which have been proven to be effective in field applications, are shown to be virtually impermeable and highly leach resistant under vault conditions. Special plasticizing additives used in the material formulation enhance the physical characteristics of the grout without detriment to its chemical durability. Neither modelling nor laboratory testing have yet provided a definitive assessment of the grout's longevity. However, none of the results of these studies has contraindicated the use of high-performance cement-based grouts in vault sealing applications. (Author) (24 figs., 6 tabs., 21 refs.)

Research status and future trends on surface pre-grouting technology in reforming wall rock of vertical shafts in coal mines in China

Science.gov (United States)

Wang, Hua

2018-02-01

In the mine construction, the surface pre-grouting technology is an important method to prevent water blast in excavation process of vertical shaft when the shaft must pass through the thick, water-rich and high water-pressure bedrock aquifer. It has been nearly 60 years since the technology was used to reform wall rock of vertical shaft in coal mine in China for the first time, and the existing technology can basically meet the needs of constructing 1000m deep vertical shaft. Firstly, the article introduces that in view of Magg’s spherical seepage theory and Karol’s spherical seepage theory, Chinese scholars found that the diffusion of grout from borehole into the surrounding strata in horizontal direction is irregular through a lot of research and engineering practice of using the surface pre-grouting technology to reform wall rock of vertical shafts, and put forward the selecting principles of grout’s effective diffusion radius in one grouting engineering; Secondly, according to the shape of the grouting boreholes, surface pre-grouting technology of vertical shaft is divided into two stages: vertical borehole stage and S-type borehole stage. Thirdly, the development status of grouting materials and grouting equipment for the technology is introduced. Fourthly, grouting mode, stage height and pressure of the technology are introduced. Finally, it points out that with the increasing depth of coal mining in China, the technology of reforming wall rock of 1000~2000m deep vertical shafts will face many problems, such as grouting theory, grouting equipment, grouting finishing standard, testing and evaluation of grouting effect, and so on. And it put forward a preliminary approach to solving these problems. This paper points out future research directions of the surface pre-grouting technology in China.

Strength Assessment of Broken Rock Postgrouting Reinforcement Based on Initial Broken Rock Quality and Grouting Quality

Directory of Open Access Journals (Sweden)

Hongfa Xu

2017-01-01

Full Text Available To estimate postgrouting rock mass strength growth is important for engineering design. In this paper, using self-developed indoor pressure-grouting devices, 19 groups of test cubic blocks were made of the different water cement ratio grouting into the broken rock of three kinds of particle sizes. The shear strength parameters of each group under different conditions were tested. Then this paper presents a quantitative calculation method for predicting the strength growth of grouted broken rock. Relational equations were developed to investigate the relationship between the growth rates of uniaxial compressive strength (UCS, absolute value of uniaxial tensile strength (AUTS, internal friction angle, and cohesion for post- to pregrouting broken rock based on Mohr-Coulomb strength criterion. From previous test data, the empirical equation between the growth rate of UCS and the ratio of the initial rock mass UCS to the grout concretion UCS has been determined. The equations of the growth rates of the internal friction coefficient and UCS for grouting broken rock with rock mass rating (RMR and its increment have been established. The calculated results are consistent with the experimental results. These observations are important for engineered design of grouting reinforcement for broken rock mass.

Grouting design for slope stability of kedung uling earthfill dam

Directory of Open Access Journals (Sweden)

Najib

2018-01-01

Full Text Available Kedung Uling earthfill dam locates at Wonogiri Regency, Central Java, Indonesia. The dam encountered sliding and settlement at the embankment wall. To minimize sliding and settlement and to optimize the dam, both field investigation and laboratory tests have been proceeded for slope stability analysis and remedial embankment wall. Soil and rock investigation around the dam, which is followed by 10 core drillings, have been conducted. Laboratory tests such as direct shear and index properties have also been carried on. The results were further used for dam slope stability model using slide 6.0 and were used to analyzed factor of safety (FS of Kedunguling dam. 10 conditions of dam were simulated and strengthening body of dam with grouting was designed. The results showed two conditions, which are condition of maximum water level with and without earthquake at downstream, were unsatisfy Indonesia National Standard (SNI for building and infrastructure. These conditions can be managed by using grouting for increasing stabilization of embankment wall. By setting up grouting, factor of safety increases and meet the SNI standard requirement.

A fully general and adaptive inverse analysis method for cementitious materials

DEFF Research Database (Denmark)

Jepsen, Michael S.; Damkilde, Lars; Lövgren, Ingemar

2016-01-01

The paper presents an adaptive method for inverse determination of the tensile σ - w relationship, direct tensile strength and Young’s modulus of cementitious materials. The method facilitates an inverse analysis with a multi-linear σ - w function. Usually, simple bi- or tri-linear functions...... are applied when modeling the fracture mechanisms in cementitious materials, but the vast development of pseudo-strain hardening, fiber reinforced cementitious materials require inverse methods, capable of treating multi-linear σ - w functions. The proposed method is fully general in the sense that it relies...... of notched specimens and simulated data from a nonlinear hinge model. The paper shows that the results obtained by means of the proposed method is independent on the initial shape of the σ - w function and the initial guess of the tensile strength. The method provides very accurate fits, and the increased...

Final report of the rock sealing project - Sealing properties and longevity of smectitic clay grouts

International Nuclear Information System (INIS)

Pusch, R.; Karnland, O.; Hoekmark, H.; Sanden, T.; Boergesson, L.

1991-12-01

Na and Ca bentonite clay grouts with densities that make them easily injected into fine fractures have been hydrothermally treated and investigated with respect to the hydraulic conductivity and shear strength. Exposure of the grouts to salt groundwater increased the hydraulic conductivity up to around 10 -5 m/s, which is on the same order of magnitude as the value at complete conversion of soft montmorillonite clay to hydrous mica, i.e. the major ultimate reaction product. Still, even this 'worst scenario' case will not lead to a higher bulk conductivity of the grouted rock than around 10 -10 m/s of rock with a conductivity of 10 -8 m/s before grouting. The rate of such conversion, which is entirely dependent on the potassium content of the groundwater, can be anything from a few hundred years to several thousand years depending primarily on the magnitude of prevailing hydraulic gradients. The shear strength of the grouts, which determines the resistance to piping and erosion, increases with time and temperature. The most critical situation is immediately after injection into the rock, when hydraulic gradients exceeding about 30 may produce piping. (au)

D7.21 Report on Validation of design of grouted joints Work Package 7.2

DEFF Research Database (Denmark)

Rodriguez, Alvaro; Natarajan, Anand; Santos, Benjamin

2017-01-01

components. As offshore wind turbines reach 10 MW capacities, it is extremely important to determine the reliability of grouted joints and their design configurations so as to ensure integrity of the 10 MW support structure. This report investigates two types of grouted joint connections, the conventional...... cylindrical joint with shear keys and a conical joint without shear keys. In both cases, fully coupled load simulations are made to determine the fatigue resistance and ultimate load resistance of the joint. Key recommendations are made for the reliable design of grouted joints for 10 MW wind turbines...

Rheological measurements on cement grouts

International Nuclear Information System (INIS)

Dalton, M.J.

1986-06-01

This report describes the techniques which have been developed at Winfrith for assessing the rheological properties of cement grouts. A discussion of the theory of rheology and its application to cement is given and the methodology for calibrating a special paddle measuring system for a commercial viscometer is described. The use of the system for determining flow curves, equilibrium viscosity, viscosity as a function of shearing time and structure changes is also discussed. (author)

Development and application of new composite grouting material for sealing groundwater inflow and reinforcing wall rock in deep mine.

Science.gov (United States)

Jinpeng, Zhang; Limin, Liu; Futao, Zhang; Junzhi, Cao

2018-04-04

With cement, bentonite, water glass, J85 accelerator, retarder and water as raw materials, a new composite grouting material used to seal groundwater inflow and reinforce wall rock in deep fractured rock mass was developed in this paper. Based on the reaction mechanism of raw material, the pumpable time, stone rate, initial setting time, plastic strength and unconfined compressive strength of multi-group proportion grouts were tested by orthogonal experiment. Then, the optimum proportion of composite grouting material was selected and applied to the grouting engineering for sealing groundwater inflow and reinforcing wall rock in mine shaft lining. The results show the mixing proportion of the maximum pumpable time, maximum stone rate and minimum initial setting time of grout are A K4 B K1 C K4 D K2 , A K3 B K1 C K1 D K4 and A K3 B K3 C K4 D K1 , respectively. The mixing proportion of the maximum plastic strength and unconfined compressive strength of grouts concretion bodies are A K1 B K1 C K1 D K3 and A K1 B K1 C K1 D K1 , respectively. Balanced the above 5 indicators overall and determined the optimum proportion of grouts: bentonite-cement ratio of 1.0, water-solid ratio of 3.5, accelerator content of 2.9% and retarder content of 1.45%. This new composite grouting material had good effect on the grouting engineering for sealing groundwater inflow and reinforcing wall rock in deep fractured rock mass.

A portable high-power diode laser-based single-stage ceramic tile grout sealing system

Science.gov (United States)

Lawrence, J.; Schmidt, M. J. J.; Li, L.; Edwards, R. E.; Gale, A. W.

2002-02-01

By means of a 60 W high-power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/ mm2 and at rates of up to 600 mm/ min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given.

Unraveling the atomic structure of ultrafine iron clusters

KAUST Repository

Wang, Hongtao; Li, Kun; Yao, Yingbang; Wang, Qingxiao; Cheng, Yingchun; Schwingenschlö gl, Udo; Zhang, Xixiang; Yang, Wei

2012-01-01

Unraveling the atomic structures of ultrafine iron clusters is critical to understanding their size-dependent catalytic effects and electronic properties. Here, we describe the stable close-packed structure of ultrafine Fe clusters for the first

Laboratory Evaluation of Underwater Grouting of CPP-603 Basins

International Nuclear Information System (INIS)

Johnson, V.J.; Pao, J.H.; Demmer, R.L.; Tripp, J.L.

2002-01-01

A project is underway to deactivate a Fuel Storage Basin. The project specifies the requirements and identifies the tasks that will be performed for deactivation of the CPP- 603 building at the Idaho Nuclear Technology and Engineering Center of the Idaho National Engineering and Environmental Laboratory. The Fuel Receiving and Storage Building (CPP- 603) was originally used to receive and store spent nuclear fuel from various facilities. The area to undergo deactivation includes the three spent nuclear fuel storage basins and a transfer canal (1.5 million gallons of water storage). Deactivation operations at the task site include management of the hot storage boxes and generic fuel objects, removal of the fuel storage racks, basin sludge, water evaporation and basin grouting, and interior equipment, tanks, and associated components. This includes a study to develop a grout formulation and placement process for this deactivation project. Water will be allowed to passively evaporate to r educe the spread of contamination from the walls of the basin. The basins will be filled with grout, underwater, as the water evaporates to maintain the basin water at a safe level. The objective of the deactivation project is to eliminate potential exposure to hazardous and radioactive materials and eliminate potential safety hazards associated with the CPP-603 building

The effect of using different sources of dry materials on waste-form grout properties

International Nuclear Information System (INIS)

Spence, R.D.; Gilliam, T.M.; McDaniel, E.W.

1992-01-01

A reference grout formulation had been developed for a liquid low-level radioactive waste using the following dry materials: ground limestone, ground granulated blast furnace slag, fly ash, and cement. The effect of varying the sources of these dry materials are tested. Two limestones, two fly ashes, two cements, and eight slags were tested. Varying the source of dry materials significantly affected the grout properties, but only the 28-d free-standing liquid varied outside of the preferred range. A statistical technique, Tukey's paired comparison, can be used to ascertain whether a given combination of dry materials resulted in grout properties significantly different from those of other combinations of dry materials

Grout performance in support of in situ stabilization/solidification of the GAAT tank sludges

International Nuclear Information System (INIS)

Spence, R.D.; Kauschinger, J.L.

1997-05-01

The Gunite trademark and associated tanks (GAATs) were constructed at ORNL between 1943 and 1951 and were used for many years to collect radioactive and chemical wastes. These tanks are currently inactive. Varying amounts of the sludge were removed and disposed of through the Hydrofracture Program. Thus, some tanks are virtually empty, while others still contain significant amounts of sludge and supernatant. In situ grouting of the sludges in the tanks using multi-point injection (MPI trademark), a patented, proprietary technique, is being investigated as a low-cost alternative to (1) moving the sludges to the Melton Valley Storage Tanks (MVSTs) for later solidification and disposal, (2) ex situ grouting of the sludges followed by either disposal back in the tanks or containerizing and disposal elsewhere, and (3) vitrification of the sludges. The paper discusses the chemical characteristics of the GAATs and the type of chemical surrogate that was used during the leachability tests. This is followed by the experimental work, which, consisted of scope testing and sensitivity testing. The scope testing explored the rheology of the proposed jetting slurries and the settling properties of the proposed grouts using sand-water mixes for the wet sludge. After establishing a jetting slurry and grout with an acceptable rheology and settling properties, the proposed in situ grout formulation was subjected to sensitivity testing for variations in the formulation

REFERENCE CASES FOR USE IN THE CEMENTITOUS PARTNERSHIP PROJECT

Energy Technology Data Exchange (ETDEWEB)

Langton, C.; Kosson, D.; Garrabrants, A.

2010-08-31

The Cementitious Barriers Partnership Project (CBP) is a multi-disciplinary, multi-institution cross cutting collaborative effort supported by the US Department of Energy (DOE) to develop a reasonable and credible set of tools to improve understanding and prediction of the structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The period of performance is >100 years for operating facilities and > 1000 years for waste management. The CBP has defined a set of reference cases to provide the following functions: (i) a common set of system configurations to illustrate the methods and tools developed by the CBP, (ii) a common basis for evaluating methodology for uncertainty characterization, (iii) a common set of cases to develop a complete set of parameter and changes in parameters as a function of time and changing conditions, (iv) a basis for experiments and model validation, and (v) a basis for improving conceptual models and reducing model uncertainties. These reference cases include the following two reference disposal units and a reference storage unit: (i) a cementitious low activity waste form in a reinforced concrete disposal vault, (ii) a concrete vault containing a steel high-level waste tank filled with grout (closed high-level waste tank), and (iii) a spent nuclear fuel basin during operation. Each case provides a different set of desired performance characteristics and interfaces between materials and with the environment. Examples of concretes, grout fills and a cementitious waste form are identified for the relevant reference case configurations.

REFERENCE CASES FOR USE IN THE CEMENTITOUS PARTNERSHIP PROJECT

International Nuclear Information System (INIS)

Langton, C.; Kosson, D.; Garrabrants, A.

2010-01-01

The Cementitious Barriers Partnership Project (CBP) is a multi-disciplinary, multi-institution cross cutting collaborative effort supported by the US Department of Energy (DOE) to develop a reasonable and credible set of tools to improve understanding and prediction of the structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The period of performance is >100 years for operating facilities and > 1000 years for waste management. The CBP has defined a set of reference cases to provide the following functions: (i) a common set of system configurations to illustrate the methods and tools developed by the CBP, (ii) a common basis for evaluating methodology for uncertainty characterization, (iii) a common set of cases to develop a complete set of parameter and changes in parameters as a function of time and changing conditions, (iv) a basis for experiments and model validation, and (v) a basis for improving conceptual models and reducing model uncertainties. These reference cases include the following two reference disposal units and a reference storage unit: (i) a cementitious low activity waste form in a reinforced concrete disposal vault, (ii) a concrete vault containing a steel high-level waste tank filled with grout (closed high-level waste tank), and (iii) a spent nuclear fuel basin during operation. Each case provides a different set of desired performance characteristics and interfaces between materials and with the environment. Examples of concretes, grout fills and a cementitious waste form are identified for the relevant reference case configurations.

Calcining natural zeolites to improve their effect on cementitious mixture workability

International Nuclear Information System (INIS)

Seraj, Saamiya; Ferron, Raissa D.; Juenger, Maria C.G.

2016-01-01

Despite the benefits to long-term concrete durability, the use of natural zeolites as supplementary cementitious materials (SCMs) is uncommon due to their high water demand. The motivation of the research presented here was to better understand how the physical and chemical characteristics of natural zeolites influenced the workability of cementitious mixtures and whether those properties could be modified through calcination to mitigate the high water demand of natural zeolites. In this research, three different natural zeolites were characterized in their original and calcined states using x-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface area measurements. Rheology experiments were then conducted on cementitious pastes containing these natural zeolites, in their original and calcined states, to assess mixture viscosity and yield stress. Results showed that calcination destabilized the structure of the natural zeolites and reduced their surface area, which led to an improvement in mixture viscosity and yield stress.

Pilot-scale production of grout with simulated double-shell slurry feed. Final report

Energy Technology Data Exchange (ETDEWEB)

Whyatt, G.A.

1994-08-01

This report describes the pilot-scale production of grout with simulated double-shell slurry feed (DSSF) waste performed in November 1988, and the subsequent thermal behavior of the grout as it cured in a large, insulated vessel. The report was issued in draft form in April 1989 and comments were subsequently received; however, the report was not finalized until 1994. In finalizing this report, references or information gained after the report was drafted in April 1989 have not been incorporated to preserve the report`s historical perspective. This report makes use of criteria from Ridelle (1987) to establish formulation criteria. This document has since been superseded by a document prepared by Reibling and Fadeef (1991). However, the reference to Riddelle (1987) and any analysis based on its content have been maintained within this report. In addition, grout is no longer being considered as the waste form for disposal of Hanford`s low-level waste. However, grout disposal is being maintained as an option in case there is an emergency need to provide additional tank space. Current plans are to vitrify low-level wastes into a glass matrix.

Ultrafine particles in the atmosphere

CERN Document Server

Brown, L M; Harrison, R M; Maynard, A D; Maynard, R L

2003-01-01

Following the recognition that airborne particulate matter, even at quite modest concentrations, has an adverse effect on human health, there has been an intense research effort to understand the mechanisms and quantify the effects. One feature that has shone through is the important role of ultrafine particles as a contributor to the adverse effects of airborne particles. In this volume, many of the most distinguished researchers in the field provide a state-of-the-art overview of the scientific and medical research on ultrafine particles. Contents: Measurements of Number, Mass and Size Distr

Carbonation of ternary cementitious concrete systems containing fly ash and silica fume

Directory of Open Access Journals (Sweden)

Eehab Ahmed Badreldin Khalil

2015-04-01

Full Text Available Carbonation is quite a complex physical negative effect phenomenon on concrete especially in the ones containing ternary blends of Portland Cement, fly ash, and silica fume. Nine selected concrete mixtures were prepared with various water to cementitious materials’ ratios and various cementitious contents. The concrete mixtures were adapted in such a way to have the same workability and air content. The fresh concrete properties were kept near identical in slump, air content, and unit weight. The variation was in the hardened concrete mechanical properties of compression and tension strength. The carbonation phenomenon was studied for these mixes showing at which mixes of ternary cementitious content heavy carbonation attacks maybe produced. The main components of such mixes that do affect the carbonation process with time were presented.

Hybrid life cycle assessment comparison of colloidal silica and cement grouted soil barrier remediation technologies.

Science.gov (United States)

Gallagher, Patricia M; Spatari, Sabrina; Cucura, Jeffrey

2013-04-15

Site remediation involves balancing numerous costs and benefits but often neglects the environmental impacts over the entire project life cycle. Life cycle assessment (LCA) offers a framework for inclusion of global environmental "systems-level" decision metrics in combination with technological and cost analysis. We compare colloidal silica (CS) and cement grouted soil barrier remediation technologies for soils affected by low level radionuclides at a U.S. Superfund site using hybrid LCA methods. CS is a new, high performance grouting material installed using permeation grouting techniques. Cement, a more traditional grouting material, is typically installed using jet grouting techniques. Life cycle impacts were evaluated using the US EPA TRACI 2 model. Results show the highest life cycle environmental impacts for the CS barrier occur during materials production and transportation to the site. In general, the life cycle impacts for the cement barrier were dominated by materials production; however, in the extreme scenario the life cycle impacts were dominated by truck transportation of spoils to a distant, off-site radioactive waste facility. It is only in the extreme scenario tested in which soils are transported by truck (Option 2) that spoils waste transport dominates LCIA results. Life cycle environmental impacts for both grout barriers were most sensitive to resource input requirements for manufacturing volumes and transportation. Uncertainty associated with the efficacy of new technology such as CS over its required design life indicates that barrier replacement could increase its life cycle environmental impact above that of the cement barrier. Copyright © 2013 Elsevier B.V. All rights reserved.

REVIEW OF MECHANISTIC UNDERSTANDING AND MODELING AND UNCERTAINTY ANALYSIS METHODS FOR PREDICTING CEMENTITIOUS BARRIER PERFORMANCE

Energy Technology Data Exchange (ETDEWEB)

Langton, C.; Kosson, D.

2009-11-30

Cementitious barriers for nuclear applications are one of the primary controls for preventing or limiting radionuclide release into the environment. At the present time, performance and risk assessments do not fully incorporate the effectiveness of engineered barriers because the processes that influence performance are coupled and complicated. Better understanding the behavior of cementitious barriers is necessary to evaluate and improve the design of materials and structures used for radioactive waste containment, life extension of current nuclear facilities, and design of future nuclear facilities, including those needed for nuclear fuel storage and processing, nuclear power production and waste management. The focus of the Cementitious Barriers Partnership (CBP) literature review is to document the current level of knowledge with respect to: (1) mechanisms and processes that directly influence the performance of cementitious materials (2) methodologies for modeling the performance of these mechanisms and processes and (3) approaches to addressing and quantifying uncertainties associated with performance predictions. This will serve as an important reference document for the professional community responsible for the design and performance assessment of cementitious materials in nuclear applications. This review also provides a multi-disciplinary foundation for identification, research, development and demonstration of improvements in conceptual understanding, measurements and performance modeling that would be lead to significant reductions in the uncertainties and improved confidence in the estimating the long-term performance of cementitious materials in nuclear applications. This report identifies: (1) technology gaps that may be filled by the CBP project and also (2) information and computational methods that are in currently being applied in related fields but have not yet been incorporated into performance assessments of cementitious barriers. The various

Review Of Mechanistic Understanding And Modeling And Uncertainty Analysis Methods For Predicting Cementitious Barrier Performance

International Nuclear Information System (INIS)

Langton, C.; Kosson, D.

2009-01-01

Cementitious barriers for nuclear applications are one of the primary controls for preventing or limiting radionuclide release into the environment. At the present time, performance and risk assessments do not fully incorporate the effectiveness of engineered barriers because the processes that influence performance are coupled and complicated. Better understanding the behavior of cementitious barriers is necessary to evaluate and improve the design of materials and structures used for radioactive waste containment, life extension of current nuclear facilities, and design of future nuclear facilities, including those needed for nuclear fuel storage and processing, nuclear power production and waste management. The focus of the Cementitious Barriers Partnership (CBP) literature review is to document the current level of knowledge with respect to: (1) mechanisms and processes that directly influence the performance of cementitious materials (2) methodologies for modeling the performance of these mechanisms and processes and (3) approaches to addressing and quantifying uncertainties associated with performance predictions. This will serve as an important reference document for the professional community responsible for the design and performance assessment of cementitious materials in nuclear applications. This review also provides a multi-disciplinary foundation for identification, research, development and demonstration of improvements in conceptual understanding, measurements and performance modeling that would be lead to significant reductions in the uncertainties and improved confidence in the estimating the long-term performance of cementitious materials in nuclear applications. This report identifies: (1) technology gaps that may be filled by the CBP project and also (2) information and computational methods that are in currently being applied in related fields but have not yet been incorporated into performance assessments of cementitious barriers. The various

Degree of saturation effect on the grout-soil interface shear strength of soil nailing

Directory of Open Access Journals (Sweden)

Wang Qiong

2016-01-01

Full Text Available In the grouted soil nailing system, the bonding strength of cement grout-soil interface offers the required resistance to maintain the stability of whole structure. In practice, soil nailing applications are often placed at unsaturated conditions, such as soil slopes, shallow foundations, retaining walls and pavement structures. In these cases, the water content in the soil nail zone may increase or decrease due to rain water or dry weather, and even cannot become saturated during their design service life. In this study, the effect of water content (degree of saturation on the shear strength of interface between cement grout and sand are experimentally investigated by means of direct shear test. Meanwhile the water retention curve was determined and interface microstructure was observed. Experimental results show that the shear strength of interface changes non-monotonously with degree of saturation when the interface was prepared, due to the non-monotonousness of the cohesiveness between soil particles. The less the cohesiveness between sand particles, the more grout was observed been penetrated into the voids, and thus the larger the interface shear stress.

Pretreatment of Tc-Containing Waste and Its Effect on Tc-99 Leaching From Grouts

International Nuclear Information System (INIS)

Aloy, Albert; Kovarskaya, Elena N.; Harbour, John R.; Langton, Christine A.; Holtzscheiter, E. William

2007-01-01

A salt solution (doped with Tc-99), that simulates the salt waste stream to be processed at the Saltstone Production Facility, was immobilized in grout waste forms with and without (1) ground granulated blast furnace slag and (2) pretreatment with iron salts. The degree of immobilization of Tc-99 was measured through monolithic and crushed grout leaching tests. Although Fe (+2) was shown to be effective in reducing Tc-99 to the +4 state, the strong reducing nature of the blast furnace slag present in the grout formulation dominated the reduction of Tc-99 in the cured grouts. An effective diffusion coefficient of 4.75 x 10 -12 (Leach Index of 11.4) was measured using the ANSI/ANS-16.1 protocol. The leaching results show that, even in the presence of a concentrated salt solution, blast furnace slag can effectively reduce pertechnetate to the immobile +4 oxidation state. The measured diffusivity was introduced into a flow and transport model (PORFLOW) to calculate the release of Tc-99 from a Saltstone Vault as a function of hydraulic conductivity of the matrix. (authors)

The effect of using different sources of dry materials on waste-form grout properties

International Nuclear Information System (INIS)

Spence, R.D.; Gilliam, T.M.; McDaniel, E.W.

1992-01-01

A reference grout formulation had been developed for a liquid low-level radioactive waste using the following dry materials: ground limestone, ground granulated blast furnace slag, fly ash, and cement. The effect of varying the sources of these dry materials was tested. Two limestones, two fly ashes, two cements, and eight slags were tested. Varying the source of dry materials significantly affected the grout properties, but only the 28-d free-standing liquid varied outside of the preferred range. A statistical technique, Tukey's paired comparison, can be used to ascertain whether a given combination of dry materials resulted in grout properties significantly different from those of other combinations of dry materials. (author)

Development of grouting technologies for geological disposal of high level waste in Japan (1). Overall program and application of developed technologies

International Nuclear Information System (INIS)

Fujita, Tomoo; Sasamoto, Hiroshi; Sugita, Yutaka; Matsui, Hiroya

2013-01-01

The Japan Atomic Energy Agency started a grout project for geological disposal of high-level radioactive waste (HLW) in 2007. The aim of the project was to develop new grouting technologies and grout materials and also to develop models for performance assessments, prediction of the long-term radionuclide migration and identify detrimental changes in the host rock by the grout material leachate. This study presents the overall program and the application of key engineering technologies to the construction and operation of an underground facility for the geological disposal of HLW, with particular emphasis on the long-term effects of grout materials. (author)

Size-dependent proinflammatory effects of ultrafine polystyrene particles: a role for surface area and oxidative stress in the enhanced activity of ultrafines.

Science.gov (United States)

Brown, D M; Wilson, M R; MacNee, W; Stone, V; Donaldson, K

2001-09-15

Studies into the effects of ultrafine particles in the lung have shown adverse effects considered to be due in part to the particle size. Air pollution particles (PM(10)) are associated with exacerbations of respiratory disease and deaths from cardiovascular causes in epidemiological studies and the ultrafine fraction of PM(10) has been hypothesized to play an important role. The aim of the present study was to investigate proinflammatory responses to various sizes of polystyrene particles as a simple model of particles of varying size including ultrafine. In the animal model, we demonstrated that there was a significantly greater neutrophil influx into the rat lung after instillation of 64-nm polystyrene particles compared with 202- and 535-nm particles and this was mirrored in other parameters of lung inflammation, such as increased protein and lactate dehydrogenase in bronchoalveolar lavage. When surface area instilled was plotted against inflammation, these two variables were directly proportional and the line passed through zero. This suggests that surface area drives inflammation in the short term and that ultrafine particles cause a greater inflammatory response because of the greater surface area they possess. In vitro, we measured the changes in intracellular calcium concentration in mono mac 6 cells in view of the potential role of calcium as a signaling molecule. Calcium changes after particle exposure may be important in leading to proinflammatory gene expression such as chemokines. We demonstrated that only ultrafine polystyrene particles induced a significant increase in cytosolic calcium ion concentration. Experiments using dichlorofluorescin diacetate demonstrated greater oxidant activity of the ultrafine particles, which may explain their activity in these assays. There were significant increases in IL-8 gene expression in A549 epithelial cells after treatment with the ultrafine particles but not particles of other sizes. These findings suggest

Chloride diffusion in partially saturated cementitious material

DEFF Research Database (Denmark)

Nielsen, Erik Pram; Geiker, Mette Rica

2003-01-01

The paper proposes a combined application of composite theory and Powers' model for microstructural development for the estimation of the diffusion coefficient as a function of the moisture content of a defect-free cementitious material. Measurements of chloride diffusion in mortar samples (440 kg...

Surgical smoke and ultrafine particles

Directory of Open Access Journals (Sweden)

Nowak Dennis

2008-12-01

Full Text Available Abstract Background Electrocautery, laser tissue ablation, and ultrasonic scalpel tissue dissection all generate a 'surgical smoke' containing ultrafine ( Methods To measure the amount of generated particulates in 'surgical smoke' during different surgical procedures and to quantify the particle number concentration for operation room personnel a condensation particle counter (CPC, model 3007, TSI Inc. was applied. Results Electro-cauterization and argon plasma tissue coagulation induced the production of very high number concentration (> 100000 cm-3 of particles in the diameter range of 10 nm to 1 μm. The peak concentration was confined to the immediate local surrounding of the production side. In the presence of a very efficient air conditioning system the increment and decrement of ultrafine particle occurrence was a matter of seconds, with accumulation of lower particle number concentrations in the operation room for only a few minutes. Conclusion Our investigation showed a short term very high exposure to ultrafine particles for surgeons and close assisting operating personnel – alternating with longer periods of low exposure.

Use of jet grouting to create a low permeability horizontal barrier below an incinerator ash landfill

International Nuclear Information System (INIS)

Furth, A.J.; Burke, G.K.; Deutsch, W.L. Jr.

1997-01-01

The City of Philadelphia's Division of Aviation (DOA) has begun construction of a new commuter runway, designated as Runway 8-26, at the Philadelphia International Airport. A portion of this runway will be constructed over a former Superfund site known as the Enterprise Avenue Landfill, which for many years was used to dispose of solid waste incinerator ash and other hazardous materials. The site was clay capped in the 1980's, but in order for the DOA to use the site, additional remediation was needed to meet US EPA final closure requirements. One component of the closure plan included installation of a low permeability horizontal barrier above a very thin (approximately 0.61 to 0.91 meters) natural clay stratum which underlies an approximately 1020 m 2 area of the landfill footprint so as to insure that a minimum 1.52 meter thick low permeability barrier exists beneath the entire 150,000 m 2 landfill. The new barrier was constructed using jet grouting techniques to achieve remote excavation and replacement of the bottom 0.91 meters of the waste mass with a low permeability grout. The grout was formulated to meet the low permeability, low elastic modulus and compressive strength requirements of the project design. This paper will discuss the advantages of using jet grouting for the work and details the development of the grout mixture, modeling of the grout zone under load, field construction techniques, performance monitoring and verification testing

Overview Of The U.S. Department Of Energy And Nuclear Regulatory Commission Performance Assessment Approaches: Cementitious Barriers Partnership

International Nuclear Information System (INIS)

Langton, C.; Burns, H.

2009-01-01

Engineered barriers including cementitious barriers are used at sites disposing or contaminated with low-level radioactive waste to enhance performance of the natural environment with respect to controlling the potential spread of contaminants. Drivers for using cementitious barriers include: high radionuclide inventory, radionuclide characteristics (e.g., long half-live, high mobility due to chemical form/speciation, waste matrix properties, shallow water table, and humid climate that provides water for leaching the waste). This document comprises the first in a series of reports being prepared for the Cementitious Barriers Partnership. The document is divided into two parts which provide a summary of: (1) existing experience in the assessment of performance of cementitious materials used for radioactive waste management and disposal and (2) sensitivity and uncertainty analysis approaches that have been applied for assessments. Each chapter is organized into five parts: Introduction, Regulatory Considerations, Specific Examples, Summary of Modeling Approaches and Conclusions and Needs. The objective of the report is to provide perspective on the state of the practice for conducting assessments for facilities involving cementitious barriers and to identify opportunities for improvements to the existing approaches. Examples are provided in two contexts: (1) performance assessments conducted for waste disposal facilities and (2) performance assessment-like analyses (e.g., risk assessments) conducted under other regulatory regimes. The introductory sections of each section provide a perspective on the purpose of performance assessments and different roles of cementitious materials for radioactive waste management. Significant experience with assessments of cementitious materials associated with radioactive waste disposal concepts exists in the US Department of Energy Complex and the commercial nuclear sector. Recently, the desire to close legacy facilities has created

OVERVIEW OF THE U.S. DEPARTMENT OF ENERGY AND NUCLEAR REGULATORY COMMISSION PERFORMANCE ASSESSMENT APPROACHES: CEMENTITIOUS BARRIERS PARTNERSHIP

Energy Technology Data Exchange (ETDEWEB)

Langton, C.; Burns, H.

2009-05-29

Engineered barriers including cementitious barriers are used at sites disposing or contaminated with low-level radioactive waste to enhance performance of the natural environment with respect to controlling the potential spread of contaminants. Drivers for using cementitious barriers include: high radionuclide inventory, radionuclide characteristics (e.g., long half-live, high mobility due to chemical form/speciation, waste matrix properties, shallow water table, and humid climate that provides water for leaching the waste). This document comprises the first in a series of reports being prepared for the Cementitious Barriers Partnership. The document is divided into two parts which provide a summary of: (1) existing experience in the assessment of performance of cementitious materials used for radioactive waste management and disposal and (2) sensitivity and uncertainty analysis approaches that have been applied for assessments. Each chapter is organized into five parts: Introduction, Regulatory Considerations, Specific Examples, Summary of Modeling Approaches and Conclusions and Needs. The objective of the report is to provide perspective on the state of the practice for conducting assessments for facilities involving cementitious barriers and to identify opportunities for improvements to the existing approaches. Examples are provided in two contexts: (1) performance assessments conducted for waste disposal facilities and (2) performance assessment-like analyses (e.g., risk assessments) conducted under other regulatory regimes. The introductory sections of each section provide a perspective on the purpose of performance assessments and different roles of cementitious materials for radioactive waste management. Significant experience with assessments of cementitious materials associated with radioactive waste disposal concepts exists in the US Department of Energy Complex and the commercial nuclear sector. Recently, the desire to close legacy facilities has created

Simulation of prepackaged grout bleed under field conditions.

Science.gov (United States)

2014-04-01

This report contains a summary of the research performed in the area of reproducing and determining the cause of soft : grout, which has been found in several PT (Post-Tensioned) tubes around the state of Florida. A modified version of the : Euronorm...

Sensitivity analysis of the long-term performance of the grout system for the disposal of a low-level radioactive waste stream at Hanford

International Nuclear Information System (INIS)

Huizenga, D.G.; Farris, W.T.; Treat, R.L.; McMakin, A.H.

1986-03-01

The US Department of Energy is planning to design and construct a Transportable Grout Facility at the Hanford Site near Richland, Washington. The facility will combine grout-forming materials with low-level liquid radioactive wastes to produce solidified grout monoliths for near-surface disposal. Pacific Northwest Laboratory is conducting studies to verify that the process is workable and that the waste, as disposed of in grout, will provide long-term protection for people and the environment. The long-term performance of the grout disposal system is sensitive to several parameters that affect radionuclide release and transport (e.g., local climate, leach rate, and monolith integrity). The purpose of this analysis was to investigate variations in these parameters in order to evaluate several design options for the grout system, including the proposed design for the grout startup campaign. The analysis was performed by postulating several scenarios that included conditions that could potentially compromise the effectiveness of the grout system. The grout system's performance was then evaluated, under each set of conditions, to measure its ability to reduce the transport rate of contaminants to the biosphere

An Experimental Study of Portland Cement and Superfine Cement Slurry Grouting in Loose Sand and Sandy Soil

Directory of Open Access Journals (Sweden)

Weijing Yao

2018-04-01

Full Text Available Grouting technology is widely applied in the fields of geotechnical engineering in infrastructure. Loose sand and sandy soil are common poor soils in tunnel and foundation treatments. It is necessary to use superfine cement slurry grouting in the micro-cracks of soil. The different effectiveness of Portland cement slurry and superfine cement slurry in sandy soil by the laboratory grouting experiment method were presented in this paper. The grouting situations of superfine cement slurry injected into sand and sandy soil were explored. The investigated parameters were the dry density, wet density, moisture content, internal friction angle, and cohesion force. The results show that the consolidation effect of superfine cement is better than that of Portland cement due to the small size of superfine cement particles. The superfine cement can diffuse into the sand by infiltration, extrusion, and splitting. When the water–cement ratio of superfine cement slurry is less than 2:1 grouting into loose sand, the dry and wet density decrease with the increase in the water–cement ratio, while the moisture content and cohesive force gradually increase. When the water–cement ratio of superfine cement slurry is 1:1 grouting into loose sand and sandy soil, the dry density, wet density, and cohesive force of loose sand are larger than those of sandy soil. The results of the experiment may be relevant for engineering applications.

Literature review of stabilization/solidification of volatile organic compounds and the implications for Hanford grouts

International Nuclear Information System (INIS)

Spence, R.D.; Osborne, S.C.

1993-09-01

A literature review was conducted on the stabilization/solidification of volatile organic compounds (VOCs). Based on this literature, it is likely that the limestone-containing grout will not permanently immobilize VOCs and that no presently available additives can guarantee permanent immobilization. The Westinghouse hanford company grout may be fairly effective at retarding aqueous leaching of VOCs, and commercial additives can improve this performance. Significant VOC losses do occur during stabilization/solidification, and the high temperatures of the Westinghouse Hanford Company waste and grout should exacerbate this problem. In fact, these high temperatures raise doubts about the presence of VOCs in the double-shell tanks supernates

Novel Ultrafine Fibrous Poly(tetrafluoroethylene Hollow Fiber Membrane Fabricated by Electrospinning

Directory of Open Access Journals (Sweden)

Qinglin Huang

2018-04-01

Full Text Available Novel poly(tetrafluoroethylene (PTFE hollow fiber membranes were successfully fabricated by electrospinning, with ultrafine fibrous PTFE membranes as separation layers, while a porous glassfiber braided tube served as the supporting matrix. During this process, PTFE/poly(vinylalcohol (PVA ultrafine fibrous membranes were electrospun while covering the porous glassfiber braided tube; then, the nascent PTFE/PVA hollow fiber membrane was obtained. In the following sintering process, the spinning carrier PVA decomposed; meanwhile, the ultrafine fibrous PTFE membrane shrank inward so as to further integrate with the supporting matrix. Therefore, the ultrafine fibrous PTFE membranes had excellent interface bonding strength with the supporting matrix. Moreover, the obtained ultrafine fibrous PTFE hollow fiber membrane exhibited superior performances in terms of strong hydrophobicity (CA > 140°, high porosity (>70%, and sharp pore size distribution. The comprehensive properties indicated that the ultrafine fibrous PTFE hollow fiber membranes could have potentially useful applications in membrane contactors (MC, especially membrane distillation (MD in harsh water environments.

Development of concrete mixtures containing highly reactive Pozzolans for improved durability in Florida environments

Science.gov (United States)

2008-11-01

The report describes research that evaluated the use of supplementary cementitious materials (SCM) to improve the service life of bridges constructed in severe marine environments. The SCM studied included ultra-fine fly ash, ground granulated blast ...

Radiolytic and thermal generation of gases from Hanford grout samples

Energy Technology Data Exchange (ETDEWEB)

Meisel, D.; Jonah, C.D.; Kapoor, S.; Matheson, M.S.; Mulac, W.A.

1993-10-01

Gamma irradiation of WHC-supplied samples of grouted Tank 102-AP simulated nonradioactive waste has been carried out at three dose rates, 0.25, 0.63, and 130 krad/hr. The low dose rate corresponds to that in the actual grout vaults; with the high dose rate, doses equivalent to more than 40 years in the grout vault were achieved. An average G(H{sub 2}) = 0.047 molecules/100 eV was found, independent of dose rate. The rate of H2 production decreases above 80 Mrad. For other gases, G(N{sub 2}) = 0.12, G(O{sub 2}) = 0.026, G(N{sub 2}O) = 0.011 and G(CO) = 0.0042 at 130 krad/hr were determined. At lower dose rates, N{sub 2} and O{sub 2} could not be measured because of interference by trapped air. The value of G(H{sub 2}) is higher than expected, suggesting segregation of water from nitrate and nitrite salts in the grout. The total pressure generated by the radiolysis at 130 krad/h has been independently measured, and total amounts of gases generated were calculated from this measurement. Good agreement between this measurement and the sum of all the gases that were independently determined was obtained. Therefore, the individual gas measurements account for most of the major components that are generated by the radiolysis. At 90 {degree}C, H{sub 2}, N{sub 2}, and N{sub 2}O were generated at a rate that could be described by exponential formation of each of the gases. Gases measured at the lower temperatures were probably residual trapped gases. An as yet unknown product interfered with oxygen determinations at temperatures above ambient. The thermal results do not affect the radiolytic findings.

Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

International Nuclear Information System (INIS)

Loh, Kenneth J; Gonzalez, Jesus

2015-01-01

Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens. (paper)

Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

Science.gov (United States)

Loh, Kenneth J.; Gonzalez, Jesus

2015-07-01

Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens.

Efficiency of cloud condensation nuclei formation from ultrafine particles

Directory of Open Access Journals (Sweden)

J. R. Pierce

2007-01-01

Full Text Available Atmospheric cloud condensation nuclei (CCN concentrations are a key uncertainty in the assessment of the effect of anthropogenic aerosol on clouds and climate. The ability of new ultrafine particles to grow to become CCN varies throughout the atmosphere and must be understood in order to understand CCN formation. We have developed the Probability of Ultrafine particle Growth (PUG model to answer questions regarding which growth and sink mechanisms control this growth, how the growth varies between different parts of the atmosphere and how uncertainties with respect to the magnitude and size distribution of ultrafine emissions translates into uncertainty in CCN generation. The inputs to the PUG model are the concentrations of condensable gases, the size distribution of ambient aerosol, particle deposition timescales and physical properties of the particles and condensable gases. It was found in most cases that condensation is the dominant growth mechanism and coagulation with larger particles is the dominant sink mechanism for ultrafine particles. In this work we found that the probability of a new ultrafine particle generating a CCN varies from <0.1% to ~90% in different parts of the atmosphere, though in the boundary layer a large fraction of ultrafine particles have a probability between 1% and 40%. Some regions, such as the tropical free troposphere, are areas with high probabilities; however, variability within regions makes it difficult to predict which regions of the atmosphere are most efficient for generating CCN from ultrafine particles. For a given mass of primary ultrafine aerosol, an uncertainty of a factor of two in the modal diameter can lead to an uncertainty in the number of CCN generated as high as a factor for eight. It was found that no single moment of the primary aerosol size distribution, such as total mass or number, is a robust predictor of the number of CCN ultimately generated. Therefore, a complete description of the

About the possibility of obtaining cementitious soil composites of high strength on the basis of belozems of carbonate composition

Science.gov (United States)

Karapetyan, K. A.; Hayroyan, S. G.; Manukyan, E. S.

2018-04-01

The problem of manufacturing high strength cementitious soils based on belozems of carbonate composition, which experience compression (no less than 10 MPa), without application of surface active substances is considered. The portland cement of type 400 was used as a binding agent to develop compositions of cementitious soil composites, and the ordinary pipe water was used to obtain solutions of cementitious soils. The chemical and mineralogical composition of the initial ingredients and the granulometric composition of belozems were determined. The measurements showed that the upper and lower plasticity limits, the optimum moisture content, and the maximal density of the skeleton of belozems, as well as the considered compositions of cementitious soils, are insignificant, while the plasticity index of cementitious soils is less than one for belozems. It is experimentally proved that an increase in the portland cement amount lead to an increase in the compressive strength of cementitious soils with a decreasing speed. But for the same amount of portland cement used in the cementitious soil compositions, the values of the strength ratio of the pieces tested at the age of 60 and 28 days remain the same and are approximately equal to 1.2. A comparison of experimental data showed that it seems to be real to manufacture a cementitious soil on the basis of belozems of carbonate composition, which contain 10% of cement of the weight of dry mixture and have strength more than 10 MPa, without adding any surfactants to the material composition.

Uranium Metal Reaction Behavior in Water, Sludge, and Grout Matrices

Energy Technology Data Exchange (ETDEWEB)

Delegard, Calvin H.; Schmidt, Andrew J.

2009-05-27

This report summarizes information and data on the reaction behavior of uranium metal in water, in water-saturated simulated and genuine K Basin sludge, and in grout matrices. This information and data are used to establish the technical basis for metallic uranium reaction behavior for the K Basin Sludge Treatment Project (STP). The specific objective of this report is to consolidate the various sources of information into a concise document to serve as a high-level reference and road map for customers, regulators, and interested parties outside the STP (e.g., external reviewers, other DOE sites) to clearly understand the current basis for the corrosion of uranium metal in water, sludge, and grout.

Uranium Metal Reaction Behavior in Water, Sludge, and Grout Matrices

Energy Technology Data Exchange (ETDEWEB)

Delegard, Calvin H.; Schmidt, Andrew J.

2008-09-25

This report summarizes information and data on the reaction behavior of uranium metal in water, in water-saturated simulated and genuine K Basin sludge, and in grout matrices. This information and data are used to establish the technical basis for metallic uranium reaction behavior for the K Basin Sludge Treatment Project (STP). The specific objective of this report is to consolidate the various sources of information into a concise document to serve as a high-level reference and road map for customers, regulators, and interested parties outside the STP (e.g., external reviewers, other DOE sites) to clearly understand the current basis for the corrosion of uranium metal in water, sludge, and grout.

Research on cement-based grouts for the OECD/NEA international Stripa project

International Nuclear Information System (INIS)

Onofrei, M.

1994-01-01

This paper deals with the work that has been carried out on cement-based by AECL research in Canada. The results indicate that it is possible to manufacture low water content high-performance cement-grouts, the performance of which would be acceptable for at least thousands of years and probably for much longer periods. Moreover, these grouts were shown to have negligible hydraulic conductivity, associated with very low porosity and to be highly leach resistant in repository conditions. (TEC). 18 refs., 1 tab., 6 figs

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

International Nuclear Information System (INIS)

Naus, Dan J.; Mattus, Catherine H.; Dole, Leslie Robert

2007-01-01

The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a 'primer' on factors that can affect the durability of concrete materials and structures in nuclear power plants. An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a 'bench-scale' laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the 'primer,' a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

Energy Technology Data Exchange (ETDEWEB)

Naus, Dan J [ORNL; Mattus, Catherine H [ORNL; Dole, Leslie Robert [ORNL

2007-06-01

The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a "primer" on factors that can affect the durability of concrete materials and structures in nuclear power plants. An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the "primer," a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures.

Fundamentals of fast reduction of ultrafine iron ore at low temperature

Institute of Scientific and Technical Information of China (English)

Pei Zhao; Peimin Guo

2008-01-01

Fundamentals on the fast reduction of ultrafine iron ore at low temperature, including characterization of ultrafine ore, de- oxidation thermodynamics of stored-energy ultrafine ore, kinetics of iron ore deoxidation, and deoxidation mechanism, etc., and a new ironmaking process are presented in this article. Ultrafine ore concentrate with a high amount of stored energy can be produced by mechanical milling, and can be dcoxidated fast below 700℃ by either the coal-based or gas-based process. This novel process has some advantages over others: high productivity, low energy consumption, and environmental friendliness.

INTERNATIONAL PROGRAM: SUMMARY REPORT ON THE PROPERTIES OF CEMENTITIOUS WASTE FORMS

International Nuclear Information System (INIS)

Harbour, J

2007-01-01

This report provides a summary of the results on the properties of cementitious waste forms obtained as part of the International Program. In particular, this report focuses on the results of Task 4 of the Program that was initially entitled ''Improved Retention of Key Contaminants of Concern in Low Temperature Immobilized Waste Forms''. Task 4 was a joint program between Khlopin Radium Institute and the Savannah River National Laboratory. The task evolved during this period into a study of cementitious waste forms with an expanded scope that included heat of hydration and fate and transport modeling. This report provides the results for Task 4 of the International Program as of the end of FY06 at which time funding for Task 4 was discontinued due to the needs of higher priority tasks within the International Program. Consequently, some of the subtasks were only partially completed, but it was considered important to capture the results up to this point in time. Therefore, this report serves as the closeout report for Task 4. The degree of immobilization of Tc-99 within the Saltstone waste form was measured through monolithic and crushed grout leaching tests. An effective diffusion coefficient of 4.8 x 10 -12 (Leach Index of 11.4) was measured using the ANSI/ANS-16.1 protocol which is comparable with values obtained for tank closure grouts using a dilute salt solution. The leaching results show that, in the presence of concentrated salt solutions such as those that will be processed at the Saltstone Production Facility, blast furnace slag can effectively reduce pertechnetate to the immobile +4 oxidation state. Leaching tests were also initiated to determine the degree of immobilization of selenium in the Saltstone waste form. Results were obtained for the upper bound of projected selenium concentration (∼5 x 10 -3 M) in the salt solution that will be treated at Saltstone. The ANSI/ANS 16.1 leaching tests provided a value for the effective diffusivity of ∼5 x 10

Nuclear waste viewed in a new light; a synchrotron study of uranium encapsulated in grout

Energy Technology Data Exchange (ETDEWEB)

Stitt, C.A., E-mail: Camilla.stitt@bristol.ac.uk [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Hart, M., E-mail: oxford.mike@gmail.com [Diamond Light Source Limited, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, Oxfordshire OX11 0QX (United Kingdom); Harker, N.J., E-mail: nicholas.harker@esrf.fr [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Hallam, K.R., E-mail: k.r.hallam@bristol.ac.uk [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); MacFarlane, J., E-mail: james.macfarlane@bristol.ac.uk [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Banos, A., E-mail: antonis.banos@bristol.ac.uk [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Paraskevoulakos, C., E-mail: cp13846@bristol.ac.uk [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Butcher, E., E-mail: ed.j.butcher@nnl.co.uk [National Nuclear Laboratory, Seascale, Cumbria CA20 1 PG (United Kingdom); Padovani, C., E-mail: cristiano.padovani@nda.gov.uk [Radioactive Waste Management Limited (formerly the Radioactive Waste Management Directorate of the UK Nuclear Decommissioning Authority), Curie Avenue, Didcot, Oxfordshire OX11 0RH (United Kingdom); Scott, T.B., E-mail: t.b.scott@bristol.ac.uk [Interface Analysis Centre, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

2015-03-21

Highlights: • Unirradiated Magnox uranium was encapsulated in grout and exposed to hydrogen. • Synchrotron X-ray tomography imaged the uranium corrosion before and after exposure. • Synchrotron X-ray powder diffraction identified the corrosion products; UH{sub 3} and UO{sub 2}. • Uranium encapsulated in grout oxidised via the anoxic U + H{sub 2}O regime. • Successful in-situ, non-invasive examination of pyrophoric and radioactive material - Abstract: How do you characterise the contents of a sealed nuclear waste package without breaking it open? This question is important when the contained corrosion products are potentially reactive with air and radioactive. Synchrotron X-rays have been used to perform micro-scale in-situ observation and characterisation of uranium encapsulated in grout; a simulation for a typical intermediate level waste storage packet. X-ray tomography and X-ray powder diffraction generated both qualitative and quantitative data from a grout-encapsulated uranium sample before, and after, deliberately constrained H{sub 2} corrosion. Tomographic reconstructions provided a means of assessing the extent, rates and character of the corrosion reactions by comparing the relative densities between the materials and the volume of reaction products. The oxidation of uranium in grout was found to follow the anoxic U + H{sub 2}O oxidation regime, and the pore network within the grout was observed to influence the growth of uranium hydride sites across the metal surface. Powder diffraction analysis identified the corrosion products as UO{sub 2} and UH{sub 3}, and permitted measurement of corrosion-induced strain. Together, X-ray tomography and diffraction provide means of accurately determining the types and extent of uranium corrosion occurring, thereby offering a future tool for isolating and studying the reactions occurring in real full-scale waste package systems.

Effect of different dispersants in compressive strength of carbon fiber cementitious composites

Science.gov (United States)

Lestari, Yulinda; Bahri, Saiful; Sugiarti, Eni; Ramadhan, Gilang; Akbar, Ari Yustisia; Martides, Erie; Khaerudini, Deni S.

2013-09-01

Carbon Fiber Cementitious Composites (CFCC) is one of the most important materials in smart concrete applications. CFCC should be able to have the piezoresistivity properties where its resistivity changes when there is applied a stress/strain. It must also have the compressive strength qualification. One of the important additives in carbon fiber cementitious composites is dispersant. Dispersion of carbon fiber is one of the key problems in fabricating piezoresistive carbon fiber cementitious composites. In this research, the uses of dispersants are methylcellulose, mixture of defoamer and methylcellulose and superplasticizer based polycarboxylate. The preparation of composite samples is similar as in the mortar technique according to the ASTM C 109/109M standard. The additives material are PAN type carbon fibers, methylcellulose, defoamer and superplasticizer (as water reducer and dispersant). The experimental testing conducts the compressive strength and resistivity at various curing time, i.e. 3, 7 and 28 days. The results obtained that the highest compressive strength value in is for the mortar using superplasticizer based polycarboxylate dispersant. This also shown that the distribution of carbon fiber with superplasticizer is more effective, since not reacting with the cementitious material which was different from the methylcellulose that creates the cement hydration reaction. The research also found that the CFCC require the proper water cement ratio otherwise the compressive strength becomes lower.

Research on Anchorage Performance of Grouting Anchor Connection of Precast Concrete Structure

Science.gov (United States)

Wang, Donghui; Liu, Xudong; Wang, Sheng; Cao, Xixi

2018-03-01

The bonding of grouted anchor bars is one of the vertical connection forms of steel bars in fabricated concrete structures. The performance of grouted connection is mainly affected by the anchorage length and lap length of steel bars. The mechanisms of bond and anchorage between steel bar and concrete are analyzed, and the factors that influence the anchorage performance of steel bar are systematically summarized. Results show that the bond and anchorage performance of steel and concrete have been studied widely, but there are still shortcomings, and the connection forms need to be further improved.

Development of grout formulations for 106-AN waste: Mixture-experiment results and analysis

International Nuclear Information System (INIS)

Spence, R.D.; McDaniel, E.W.; Anderson, C.M.; Lokken, R.O.; Piepel, G.F.

1993-09-01

Twenty potential ingredients were identified for use in developing a 106-AN grout formulation, and 18 were subsequently obtained and tested. Four ingredients-Type II-LA (moderate heat of hydration) Portland cement, Class F fly ash, attapulgite 150 drilling clay, and ground air-cooled blast-furnace slag (GABFS) were selected for developing the 106-AN grout formulations. A mixture experiment was designed and conducted around the following formulation: 2.5 lb of cement per gallon, 1.2 lb of fly ash per gallon, 0.8 lb of attapulgite per gallon, and 3.5 lb of GABFS per gallon. Reduced empirical models were generated from the results of the mixture experiment. These models were used to recommend several grout formulations for 106-AN. Westinghouse Hanford Company selected one of these formulations to be verified for use with 106-AN and a backup formulation in case problems arise with the first choice

Transport properties of damaged materials. Cementitious barriers partnership

Energy Technology Data Exchange (ETDEWEB)

Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2014-11-01

The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

Transport properties of damaged materials. Cementitious barriers partnership

International Nuclear Information System (INIS)

Langton, C.

2014-01-01

The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

Electrochemical migration technique to accelerate ageing of cementitious materials

Directory of Open Access Journals (Sweden)

Abbas Z.

2013-07-01

Full Text Available Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen’s micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

Electrochemical migration technique to accelerate ageing of cementitious materials

Science.gov (United States)

Babaahmadi, A.; Tang, L.; Abbas, Z.

2013-07-01

Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

Thermodynamics of Autogenous Self-healing in Cementitious Materials

NARCIS (Netherlands)

Huang, H.

2014-01-01

Concrete is a brittle composite cementitious material that easily fractures under tensile loading. Microcracks can appear throughout the concrete prior to application of any load because of temperature-induced strain and autogenous and drying shrinkage. There is no doubt that these cracks provide

Cementitious Barriers Partnership - FY2015 End-Year Report

International Nuclear Information System (INIS)

Burns, H. H.; Flach, G. P.; Langton, C. A.; Smith, F. G.; Kosson, D. S.; Meeussen, J. C. L.; Seignette, Paul; Van der Sloot, H. A.

2015-01-01

The DOE-EM Office of Tank Waste Management Cementitious Barriers Partnership (CBP) is chartered with providing the technical basis for implementing cement-based waste forms and radioactive waste containment structures for long-term disposal. Therefore, the CBP ultimate purpose is to support progress in final treatment and disposal of legacy waste and closure of High-Level Waste (HLW) tanks in the DOE complex. This status report highlights the CBP 2015 Software and Experimental Program efforts and accomplishments that support DOE needs in environmental cleanup and waste disposal. DOE needs in this area include: Long-term performance predictions to provide credibility (i.e., a defensible technical basis) for regulator and DOE review and approvals, Facility flow sheet development/enhancements, and Conceptual designs for new disposal facilities. In 2015, the CBP developed a beta release of the CBP Software Toolbox - ''Version 3.0'', which includes new STADIUM carbonation and damage models, a new SRNL module for estimating hydraulic properties and flow in fractured and intact cementitious materials, and a new LeachXS/ORCHESTRA (LXO) oxidation module. In addition, the STADIUM sulfate attack and chloride models have been improved as well as the LXO modules for sulfate attack, carbonation, constituent leaching, and percolation with radial diffusion (for leaching and transport in cracked cementitious materials). These STADIUM and LXO models are applicable to and can be used by both DOE and the Nuclear Regulatory Commission (NRC) end-users for service life prediction and long-term leaching evaluations of radioactive waste containment structures across the DOE complex.

Cementitious Barriers Partnership - FY2015 End-Year Report

Energy Technology Data Exchange (ETDEWEB)

Burns, H. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Langton, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith, F. G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kosson, D. S. [Vanderbilt Univ., Nashville, TN (United States). School of Engineering; Brown, K. G. [Vanderbilt Univ., Nashville, TN (United States). School of Engineering; Samson, E. [SIMCO Technologies, Inc., QC (Canada); Meeussen, J. C. L. [Nuclear Research and Consultancy Group (NRG); Seignette, Paul [Energy Research Center of the Netherlands; van der Sloot, H. A. [Hans van der Sloot Consultancy

2015-09-17

The DOE-EM Office of Tank Waste Management Cementitious Barriers Partnership (CBP) is chartered with providing the technical basis for implementing cement-based waste forms and radioactive waste containment structures for long-term disposal. Therefore, the CBP ultimate purpose is to support progress in final treatment and disposal of legacy waste and closure of High-Level Waste (HLW) tanks in the DOE complex. This status report highlights the CBP 2015 Software and Experimental Program efforts and accomplishments that support DOE needs in environmental cleanup and waste disposal. DOE needs in this area include: Long-term performance predictions to provide credibility (i.e., a defensible technical basis) for regulator and DOE review and approvals, Facility flow sheet development/enhancements, and Conceptual designs for new disposal facilities. In 2015, the CBP developed a beta release of the CBP Software Toolbox – “Version 3.0”, which includes new STADIUM carbonation and damage models, a new SRNL module for estimating hydraulic properties and flow in fractured and intact cementitious materials, and a new LeachXS/ORCHESTRA (LXO) oxidation module. In addition, the STADIUM sulfate attack and chloride models have been improved as well as the LXO modules for sulfate attack, carbonation, constituent leaching, and percolation with radial diffusion (for leaching and transport in cracked cementitious materials). These STADIUM and LXO models are applicable to and can be used by both DOE and the Nuclear Regulatory Commission (NRC) end-users for service life prediction and long-term leaching evaluations of radioactive waste containment structures across the DOE complex.

Water absorption of superabsorbent polymers in a cementitious environment

DEFF Research Database (Denmark)

Jensen, Ole Mejlhede

2011-01-01

This paper focuses on the water absorption of superabsorbent polymers in a cementitious environment. The paper discusses different techniques to measure the water absorption capacity, and in particular it describes a technique which enables a simple and quick estimation of the water absorption...... capacity in a cementitious environment. The challenges met in defining the concept of water absorption capacity are treated, and the appropriateness of different types of superabsorbent polymers is also briefly dealt with. The concept “water absorption capacity” and its measurement seem straightforwardly...... simple, but a closer examination of the topic discloses many, significant difficulties. However, given proper cautiousness it is possible both to quickly estimate the water absorption capacity through a simple measurement as well as to examine how it will be influenced by different factors....

Progress in Research on Carbon Nanotubes Reinforced Cementitious Composites

Directory of Open Access Journals (Sweden)

Qinghua Li

2015-01-01

Full Text Available As one-dimensional (1D nanofiber, carbon nanotubes (CNTs have been widely used to improve the performance of nanocomposites due to their high strength, small dimensions, and remarkable physical properties. Progress in the field of CNTs presents a potential opportunity to enhance cementitious composites at the nanoscale. In this review, current research activities and key advances on multiwalled carbon nanotubes (MWCNTs reinforced cementitious composites are summarized, including the effect of MWCNTs on modulus of elasticity, porosity, fracture, and mechanical and microstructure properties of cement-based composites. The issues about the improvement mechanisms, MWCNTs dispersion methods, and the major factors affecting the mechanical properties of composites are discussed. In addition, large-scale production methods of MWCNTs and the effects of CNTs on environment and health are also summarized.

Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating

International Nuclear Information System (INIS)

Zhang, H.J.; Zhang, H.T.; Wu, X.W.; Wang, Z.L.; Jia, Q.L.; Jia, X.L.

2006-01-01

Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO 4 aqueous solution by electroless plating method. The factors including concentration of NiSO 4 , bathing temperature, ratio of hydrazine hydrate to NiSO 4 , the pH of the solution, etc., on influence of the yield and average particle size of metallic Ni ultrafine powders were studied in detail. X-ray powders diffraction patterns show that the nickel powders are cubic crystallite. The average crystalline size of the ultrafine nickel powders is about 30 nm. The dielectric and magnetic loss of ultrafine Ni powders-paraffin wax composites were measured by the rectangle waveguide method in the range 8.2-12.4 GHz. The factors for Ni ultrafine powders preparation are optimized by computer pattern recognition program based on principal component analysis, the optimum factors regions with higher yield of metallic Ni ultrafine powders are indicated by this way

Fractal Prediction of Grouting Volume for Treating Karst Caverns along a Shield Tunneling Alignment

Directory of Open Access Journals (Sweden)

Wen-Chieh Cheng

2017-06-01

Full Text Available Karst geology is common in China, and buried karst formations are widely distributed in Guangdong province. In the process of shield tunneling, the abundant water resources present in karst caverns could lead to the potential for high water ingress, and a subsequent in situ stress change-induced stratum collapse. The development and distribution of karst caverns should therefore be identified and investigated prior to shield tunnel construction. Grouting is an efficient measure to stabilize karst caverns. The total volume of karst caverns along the shield tunneling alignment, and its relationship with the required volume of grouts, should be evaluated in the preliminary design phase. Conventionally, the total volume of karst caverns is empirically estimated based on limited geological drilling hole data; however, accurate results are rarely obtained. This study investigates the hydrogeology and engineering geology of Guangzhou, the capital of Guangdong province, and determines the fractal characteristics of the karst caverns along the tunnel section of Guangzhou metro line no. 9. The karst grouting coefficients (VR were found to vary from 0.11 in the case of inadequate drilling holes to 1.1 in the case where adequate drilling holes are provided. A grouting design guideline was furthermore developed in this study for future projects in karst areas.

Development of grout formulations for 106-AN waste: Mixture-experiment results and analysis

International Nuclear Information System (INIS)

Spence, R.D.; McDaniel, E.W.; Anderson, C.M.; Lokken, R.O.; Piepel, G.F.

1993-09-01

Twenty potential ingredients were identified for use in developing a 106-AN grout formulation, and 18 were subsequently obtained and tested. Four ingredients: Type II-LA (moderate heat of hydration) Portland cement, Class F fly ash, attapulgite 150 drilling clay, and ground air-cooled blast-furnace slag (GABFS) -- were selected for developing the 106-AN grout formulations. A mixture experiment was designed and conducted around the following formulation: 2.5 lb of cement per gallon, 1.2 lb of fly ash per gallon, 0.8 lb of attapulgite per gallon, and 3.5 lb of GABFS per gallon. Reduced empirical models were generated from the results of the mixture experiment. These models were used to recommend several grout formulations for 106-AN. Westinghouse Hanford Company selected one of these formulations to be verified for use with 106-AN and a backup formulation in case problems arise with the first choice. This report presents the mixture-experimental results and leach data

ORNL grouting technologies for immobilizing hazardous wastes

International Nuclear Information System (INIS)

Dole, L.R.; Trauger, D.B.

1983-01-01

The Cement and Concrete Applications Group at the Oak Ridge National Laboratory (ORNL) has developed versatile and inexpensive processes to solidify large quantities of hazardous liquids, sludges, and solids. By using standard off the shelf processing equipment, these batch or continuous processes are compatible with a wide range of disposal methods, such as above-ground storage, shallow-land burial, deep geological disposal, sea-bed dumping, and bulk in-situ solidification. Because of their economic advantages, these latter bulk in-situ disposal scenarios have received the most development. ORNL's experience has shown that tailored cement-based formulas can be developed which tolerate wide fluctuations in waste feed compositions and still maintain mixing properties that are compatible with standard equipment. In addition to cements, these grouts contain pozzolans, clays and other additives to control the flow properties, set-times, phase separations and impacts of waste stream fluctuation. The cements, fly ashes and other grout components are readily available in bulk quantities and the solids-blends typically cost less than $0.05 to 0.15 per waste gallon. Depending on the disposal scenario, total disposal costs (material, capital, and operating) can be as low as $0.10 to 0.50 per gallon

Applications of graphite-enabled phase change material composites to improve thermal performance of cementitious materials

Science.gov (United States)

Li, Mingli; Lin, Zhibin; Wu, Lili; Wang, Jinhui; Gong, Na

2017-11-01

Enhancing the thermal efficiency to decrease the energy consumption of structures has been the topic of much research. In this study, a graphite-enabled microencapsulated phase change material (GE-MEPCM) was used in the production of a novel thermal energy storage engineered cementitious composite feathering high heat storage capacity and enhanced thermal conductivity. The surface morphology and particle size of the microencapsulated phase change material (MEPCM) were investigated by scanning electron microscopy (SEM). Thermal properties of MEPCM was determined using differential scanning calorimetry (DSC). In addition, thermal and mechanical properties of the cementitious mortar with different admixtures were explored and compared with those of a cementitious composite. It was shown that the latent heat of MEPCM was 162 J/g, offering much better thermal energy storage capacity to the cementitious composite. However, MEPCM was found to decrease the thermal conductivity of the composite, which can be effectively solved by adding natural graphite (NG). Moreover, the incorporation of MEPCM has a certain decrease in the compressive strength, mainly due to the weak interfaces between MEPCM and cement matrix.

Characterisation of vibration equipment used for the immobilisation of solid items in cement grout

International Nuclear Information System (INIS)

Dalton, M.J.

1984-12-01

Processes are being developed at AEE Winfrith for the immobilisation of solid radioactive waste in cement grouts. The flow of grout during the infilling stage is assisted by vibration of the waste container. A high resolution signal analyser has been used to measure the operating frequency and amplitude characteristics of vibrating equipment used in the solid immobilisation process. In this report the commissioning of the instrument and results obtained on the equipment are described. (author)

Bolt-Grout Interactions in Elastoplastic Rock Mass Using Coupled FEM-FDM Techniques

Directory of Open Access Journals (Sweden)

Debasis Deb

2010-01-01

Full Text Available Numerical procedure based on finite element method (FEM and finite difference method (FDM for the analysis of bolt-grout interactions are introduced in this paper. The finite element procedure incorporates elasto-plastic concepts with Hoek and Brown yield criterion and has been applied for rock mass. Bolt-grout interactions are evaluated based on finite difference method and are embedded in the elasto-plastic procedures of FEM. The experimental validation of the proposed FEM-FDM procedures and numerical examples of a bolted tunnel are provided to demonstrate the efficacy of the proposed method for practical applications.

Self Cleanable Tile Grout

Directory of Open Access Journals (Sweden)

Mehmet CANBAZ

2016-03-01

Full Text Available In this study, In this study, self-cleaning tile grout and white cement specimens are produced and the effect of self-cleaning mechanism of TiO2 is tested. Effects of TiO2 amount and TiO2 type are tested and compared. Anatase form and rutile TiO2 additive are used in the study. In addition, effects of silicate additives on the self-cleaning mechanism is determined. Studies are conducted with respect to Italian UNI code. This study presents a method for solving rust between the tiles of ceramic wet floor coverings with photocatalysis method and then removing the dirt with secondary effects such as water, wind etc.

Cellulose nanomaterials as additives for cementitious materials

Science.gov (United States)

Tengfei Fu; Robert J. Moon; Pablo Zavatierri; Jeffrey Youngblood; William Jason Weiss

2017-01-01

Cementitious materials cover a very broad area of industries/products (buildings, streets and highways, water and waste management, and many others; see Fig. 20.1). Annual production of cements is on the order of 4 billion metric tons [2]. In general these industries want stronger, cheaper, more durable concrete, with faster setting times, faster rates of strength gain...

Task plan for TARA-II compaction and grouting demonstration

International Nuclear Information System (INIS)

Spalding, B.P.

1991-11-01

This task directly supports the corrective measures evaluation for the closure of Solid Waste Storage Area (SWSA) 6 but also supports technology development for the closure of other Oak Ridge National Laboratory (ORNL) SWSAs and waste management units. Previous demonstrations have established the effectiveness of dynamic compaction and in situ grouting in stabilizing burial trenches against subsidence, which would otherwise compromise the support of infiltration barrier structures designed to protect buried waste from leaching. In situ grouting with polyacrylamide has also been demonstrated to improve the hydrologic isolation of buried waste. Both of these stabilization techniques have been demonstrated on burial trenches that are situated well above the water table and, hence, are in a chronic unsaturated moisture regime. Further demonstrations of these shallow-land burial trench stabilization techniques are necessary to establish their effectiveness and safety when applied to burial trenches that are chronically inundated with groundwater

Preparation of ultrafine poly(sodium 4-styrenesulfonate) fibres via ...

Indian Academy of Sciences (India)

The ultrafine poly (sodium 4-styrenesulfonate) (NaPSS) fibres have been prepared for the first time by electrospinning. The spinning solutions (NaPSS aqueous solutions) in varied concentrations were studied for electrospinning into ultrafine fibres. The results indicated that the smooth fibre could be formed when the ...

Ultrafine ash aerosols from coal combustion: Characterization and health effects

Energy Technology Data Exchange (ETDEWEB)

William P. Linak; Jong-Ik Yoo; Shirley J. Wasson; Weiyan Zhu; Jost O.L. Wendt; Frank E. Huggins; Yuanzhi Chen; Naresh Shah; Gerald P. Huffman; M. Ian Gilmour [US Environmental Protection Agency, Research Triangle Park, NC (United States). National Risk Management Research Laboratory

2007-07-01

Ultrafine coal fly-ash particles withdiameters less than 0.5 {mu}m typically comprise less than 1% of the total fly-ash mass. This paper reports research focused on both characterization and health effects of primary ultrafine coal ash aerosols alone. Ultrafine, fine, and coarse ash particles were segregated and collected from a coal burned in a 20 kW laboratory combustor and two additional coals burned in an externally heated drop tube furnace. Extracted samples from both combustors were characterized by transmission electron microscopy (TEM), wavelength dispersive X-ray fluorescence(WD-XRF) spectroscopy, Moessbauer spectroscopy, and X-ray absorption fine structure (XAFS) spectroscopy. Pulmonary inflammation was characterized by albumin concentrations in mouse lung lavage fluid after instillation of collected particles in saline solutions and a single direct inhalation exposure. Results indicate that coal ultrafine ash sometimes contains significant amounts of carbon, probably soot originating from coal tar volatiles, depending on coal type and combustion device. Surprisingly, XAFS results revealed the presence of chromium and thiophenic sulfur in the ultrafine ash particles. The instillation results suggested potential lung injury, the severity of which could be correlated with the carbon (soot) content of the ultrafines. This increased toxicity is consistent with theories in which the presence of carbon mediates transition metal (i.e., Fe) complexes, as revealed in this work by TEM and XAFS spectroscopy, promoting reactive oxygenspecies, oxidation-reduction cycling, and oxidative stress. 24 refs., 7 figs.

Submicron and ultrafine grained hardmetals for microdrills and metal cutting inserts

International Nuclear Information System (INIS)

Gille, G.; Szesny, B.; Dreyer, K.; Berg, H. van den; Schidt, J.; Gestrich, T.; Leitner, G.

2001-01-01

Although round tools as carbide drills and mills are dominating by far the application of submicron and ultrafine hardmetals the consumption for PCB microdrills had the strongest growth rate over the last decade. This paper deals with the latest developments of ultrafine hardmetals and their application for PCB microdrills and metal cutting inserts. Based on optimized processing and properties such as hardness, hot hardness, toughness, strength and wear resistance a new generation of microdrills is presented. In particular the failure probability of the microdrills could be considerably reduced and the number of drilling strokes was nearly doubled. Combining improved pressing behavior with proper doping and optimized processing new applications of submicron and ultrafine hardmetals could be obtained by using complex shaped metal cutting inserts. Apart from these application examples the paper gives some insight into fundamental investigations an sintering and properties of ultrafine hardmetals and shows in particular the influence of milling, doping and sintering an the properties of ultrafine hardmetals. The paper also presents a new ultrafine WC grade showing a 0.1 μm WC intercept of a sintered WC - 10 wt % Co structure and a hardness of HV 30 = 2050 for a 1 wt % mixed VC/Cr 3 C 2 doping. (author)

Time-Lapse Electrical Resistivity Investigations for Imaging the Grouting Injection in Shallow Subsurface Cavities

Directory of Open Access Journals (Sweden)

Muhammad Farooq

2014-01-01

Full Text Available The highway of Yongweol-ri, Muan-gun, south-western part of the South Korean Peninsula, is underlain by the abandoned of subsurface cavities, which were discovered in 2005. These cavities lie at shallow depths with the range of 5∼15 meters below the ground surface. Numerous subsidence events have repeatedly occurred in the past few years, damaging infrastructure and highway. As a result of continuing subsidence issues, the Korean Institute of Geosciences and Mineral Resources (KIGAM was requested by local administration to resolve the issue. The KIGAM used geophysical methods to delineate subsurface cavities and improve more refined understanding of the cavities network in the study area. Cement based grouting has been widely employed in the construction industry to reinforce subsurface ground. In this research work, time-lapse electrical resistivity surveys were accomplished to monitor the grouting injection in the subsurface cavities beneath the highway, which have provided a quasi-real-time monitoring for modifying the subsurface cavities related to ground reinforcement, which would be difficult with direct methods. The results obtained from time-lapse electrical resistivity technique have satisfactory imaged the grouting injection experiment in the subsurface cavities beneath the highway. Furthermore, the borehole camera confirmed the presence of grouting material in the subsurface cavities, and hence this procedure increases the mechanical resistance of subsurface cavities below the highway.

The effect of nitrates on the alteration of the cementitious material

International Nuclear Information System (INIS)

Takei, Akihiko; Owada, Hitoshi; Fujita, Hideki; Negishi, Kumi

2002-02-01

TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. Since the temperature of the deep-underground is higher than that of the near surface and a part of the TRU waste generates the heat accompanied with the decay of the radioactive nuclides, the influences of the heat to the barrier material also should be taken into account. In this study, we estimated the influence of sodium nitrate and also that of the leachate from the ROBE-waste (borate-solidified body of concentrated low-level waste) to the degradation of the cementitious material. We also obtained the mineralogical data of cementitious mineral after alteration in elevated temperature conditions. Results in this year are described below. 1) Alteration of characteristics of cementitious material in nitrate solution were evaluated by the water permeation test using sodium nitrate solution. The enhancement of the alteration of cementitious material due to sodium nitrate was observed. The dissolution quantity of the calcium of sodium nitrate solution permeated sample was larger than that of deionized water permeated sample (denoted as 'blank' in following). Hydraulic conductivity of sodium nitrate solution permeated sample was lower than blank, but after changing permeation liquid from sodium nitrate solution to deionized water, hydraulic conductivity rose quickly. The increase of porosity and the decrease of compressive strength were observed in the case of sodium nitrate solution compared with blank. In the nitrate solution, sulfate type and carbonate type of AFm changed into the nitrate type AFm. The nitrate type AFm altered to the carbonate type AFm when the nitrate concentration was lowered. 2) The influence of the leachate from the two types of ROBE-waste on the dissolution of the cementitious material was evaluated by the leaching experiments. Dissolution of the calcium from the cementitious

The grouting handbook a step-by-step guide for foundation design and machinery installation

CERN Document Server

Harrison, Donald M

2013-01-01

Minimize loss of revenue and the downtime of critical assets by avoiding foundation cracking, poor bonds, and initial alignment changes. After their successful introduction as a maintenance material, machinery grouts are now being used for equipment placement in new construction. While certainly suitable for both markets and applications, a successful installation depends on proper grout selection, application, foundation preparation, and forming methods. Therefore, guidelines on their uses and limitations are needed for engineers and maintenance personnel. Based on 45 years of field experi

Practical Model of Cement Based Grout Mix Design, for Use into Low Level Radiation Waste Management

Directory of Open Access Journals (Sweden)

Radu Lidia

2015-12-01

Full Text Available The cement based grouts, as functional performance composite materials, are widely used for both immobilisation and encapsulation as well as for stabilization in the field of inorganic waste management. Also, to ensure that low level radioactive waste (LLW are contained for storage and ultimate disposal, they are encapsulated or immobilized in monolithic waste forms, with cement –based grouts.

Field-scale permeation testing of jet-grouted buried waste sites

International Nuclear Information System (INIS)

Loomis, G.G.; Zdinak, A.P.

1996-01-01

The Idaho National Engineering Laboratory (INEL) conducted field-scale hydraulic conductivity testing of simulated buried waste sites with improved confinement. The improved confinement was achieved by jet grouting the buried waste, thus creating solid monoliths. The hydraulic conductivity of the monoliths was determined using both the packer technique and the falling head method. The testing was performed on simulated buried waste sites utilizing a variety of encapsulating grouts, including high-sulfate-resistant Portland cement, TECT, (a proprietary iron oxide cement) and molten paraffin. By creating monoliths using in-situ jet grouting of encapsulating materials, the waste is simultaneously protected from subsidence and contained against further migration of contaminants. At the INEL alone there is 56,000 m 3 of buried transuranic waste commingled with 170,000--224,000 m 3 of soil in shallow land burial. One of the options for this buried waste is to improve the confinement and leave it in place for final disposal. Knowledge of the hydraulic conductivity for these monoliths is important for decision-makers. The packer tests involved coring the monolith, sealing off positions within the core with inflatable packers, applying pressurized water to the matrix behind the seal, and observing the water flow rate. The falling head tests were performed in full-scale 3-m-diameter, 3-m-high field-scale permeameters. In these permeameters, both water inflow and outflow were measured and equated to a hydraulic conductivity

CEMENTITIOUS BARRIERS MODELING FOR PERFORMANCE ASSESSMENTS OF SHALLOW LAND BURIAL OF LOW LEVEL RADIOACTIVE WASTE - 9243

International Nuclear Information System (INIS)

Taylor, G.

2009-01-01

The Cementitious Barriers Partnership (CBP) was created to develop predictive capabilities for the aging of cementitious barriers over long timeframes. The CBP is a multi-agency, multi-national consortium working under a U.S. Department of Energy (DOE) Environmental Management (EM-21) funded Cooperative Research and Development Agreement (CRADA) with the Savannah River National Laboratory (SRNL) as the lead laboratory. Members of the CBP are SRNL, Vanderbilt University, the U.S. Nuclear Regulatory Commission (USNRC), National Institute of Standards and Technology (NIST), SIMCO Technologies, Inc. (Canada), and the Energy Research Centre of the Netherlands (ECN). A first step in developing advanced tools is to determine the current state-of-the-art. A review has been undertaken to assess the treatment of cementitious barriers in Performance Assessments (PA). Representatives of US DOE sites which have PAs for their low level waste disposal facilities were contacted. These sites are the Idaho National Laboratory, Oak Ridge National Laboratory, Los Alamos National Laboratory, Nevada Test Site, and Hanford. Several of the more arid sites did not employ cementitious barriers. Of those sites which do employ cementitious barriers, a wide range of treatment of the barriers in a PA was present. Some sites used conservative, simplistic models that even though conservative still showed compliance with disposal limits. Other sites used much more detailed models to demonstrate compliance. These more detailed models tend to be correlation-based rather than mechanistically-based. With the US DOE's Low Level Waste Disposal Federal Review Group (LFRG) moving towards embracing a risk-based, best estimate with an uncertainties type of analysis, the conservative treatment of the cementitious barriers seems to be obviated. The CBP is creating a tool that adheres to the LFRG chairman's paradigm of continuous improvement

Self-cementitious properties of fly ashes from CFBC boilers co-firing coal and high-sulphur petroleum coke

International Nuclear Information System (INIS)

Sheng Guanghong; Li Qin; Zhai Jianping; Li Feihu

2007-01-01

Self-cementitious properties of fly ash from circulating fluidized bed combustion boiler co-firing coal and high-sulphur petroleum coke (CPFA) were investigated. CPFA was self-cementitious which was affected by its fineness and chemical compositions, especially the contents of SO 3 and free lime (f-CaO). Higher contents of SO 3 and f-CaO were beneficial to self-cementitious strength; the self-cementitious strength increases with a decrease of its 45 μm sieve residue. The expansive ratio of CPFA hardened paste was high because of generation of ettringite (AFt), which was influenced by its water to binder ratio (W/A), curing style and grinding of the ash. The paste cured in water had the highest expansive ratio, and grinding of CPFA was beneficial to its volume stability. The hydration products of CPFA detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM) were portlandite, gypsum, AFt and hydrated calcium silicate (C-S-H)

Long Term Behaviour of Cementitious Materials in the Korean Repository Environment

International Nuclear Information System (INIS)

Park, J.-W.; Kim, C.-L.

2013-01-01

The safe management of radioactive waste is a national task required for sustainable generation of nuclear power and for energy self-reliance in Korea. After the selection of the final candidate site for low- and intermediate-level waste (LILW) disposal in Korea, a construction and operation license was issued for the Wolsong LILW Disposal Center (WLDC) for the first stage of disposal. Underground silo type disposal has been determined for the initial phase. The engineered barrier system of the disposal silo consists of waste packages, disposal containers, backfills, and a concrete lining. Main objective of our study in this IAEA-CRP is to investigate closure concepts and cementitious backfill materials for the closure of silos. For this purpose, characterisation of cementitious materials, development of silo closure concept, and evaluation of long-term behaviour of cementitious materials, including concrete degradation in repository environment, have been carried out. The overall implementation plan for the CRP comprises performance testing for the physic-chemical properties of cementitious materials, degradation modelling of concrete structures, comparisons of performance for silo closure options, radionuclide transport modelling (considering concrete degradation in repository conditions), and the implementation of an input parameter database and quality assurance for safety/performance assessment. In particular, the concrete degradation modelling study has been focused on the corrosion of reinforcement steel induced by chloride attack, which was of primary concern in the safety assessment of the WLDC. A series of electrochemical experiments were conducted to investigate the effect of dissolved oxygen, pH, and Cl on the corrosion rate of reinforcing steel in a concrete structure saturated with groundwater. Laboratory-scale experiments and a thermodynamic modelling were performed to understand the porosity change of cement pastes, which were prepared using

Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag

Energy Technology Data Exchange (ETDEWEB)

Zhang, Na; Li, Hongxu [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China); Zhao, Yazhao [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Xiaoming, E-mail: liuxm@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China)

2016-04-05

Highlights: • Cementitious material was designed according to [SiO{sub 4}] polymerization degree of raw materials. • The cementitious material composed of calcium silicate slag yields excellent physical and mechanical properties. • Amorphous C–A–S–H gel and rod-like ettringite are predominantly responsible for the strength development. • Leaching toxicity and radioactivity tests show the cementitious material is environmentally acceptable. - Abstract: Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al{sub 2}O{sub 3} from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C–A–S–H gel, rod-like ettringite and hexagonal-sheet Ca(OH){sub 2} with small amount of zeolite-like minerals such as CaAl{sub 2}Si{sub 2}O{sub 8}·4H{sub 2}O and Na{sub 2}Al{sub 2}Si{sub 2}O{sub 8}·H{sub 2}O. As the predominant hydration products, rod-like ettringite and amorphous C–A–S–H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities.

Evaluation of dry-solids-blend material source for grouts containing 106-AN waste: September 1990 progress report

International Nuclear Information System (INIS)

Gilliam, T.M.; Osborne, S.C.; Francis, C.L.; Scott, T.C.

1993-09-01

Stabilization/solidification (S/S) is the most widely used technology for the treatment and ultimate disposal of both radioactive and chemically hazardous wastes. Such technology is being utilized in a Grout Treatment Facility (GTF) by the Westinghouse Hanford Company (WHC) for the disposal of various wastes, including 106-AN wastes, located on the Hanford Reservation. The WHC personnel have developed a grout formula for 106-AN disposal that is designed to meet stringent performance requirements. This formula consists of a dry-solids blend containing 40 wt % limestone, 28 wt % granulated blast furnace slag (BFS), 28 wt % ASTM Class F fly ash, and 4 wt % Type I-II-LA Portland cement. The blend is mixed with 106-AN waste at a ratio of 9 lb of dry-solids blend per gallon of waste. This report documents progress made to date on efforts at Oak Ridge National Laboratory (ORNL) in support of WHC's Grout Technology Program to assess the effects of the source of the dry-solids-blend materials on the resulting grout formula

A combined wet chemistry and EXAFS study of U(VI) uptake by cementitious materials

International Nuclear Information System (INIS)

Wieland, E.; Harfouche, M.; Tits, J.; Kunz, D.; Daehn, R.; Fujita, T.; Tsukamoto, M.

2006-01-01

The sorption behaviour and speciation of U(VI) in cementitious systems was investigated by a combination of wet chemistry experiments and synchrotron-based X-ray absorption spectroscopy (XAS) measurements. Radiotracer studies using 233 U were carried out on hardened cement paste (HCP) and calcium silicate hydrates (C-S-H), which are the major constituents of HCP, to determine the uptake kinetics and sorption isotherms. C-S-H phases were synthesized using different methods for solid phase preparation, which enabled us to study the U(VI) uptake by different types of C-S-H phases and a wide range of Ca/Si compositions, and to distinguish U(VI) sorption on the surface of C-S-H from U(VI) incorporation into the structure. XAS measurements were performed using U(VI) loaded HCP and C-S-H materials (sorption and co-precipitation samples) to gain structural information on the U(VI) speciation in these systems, i.e., the type and number of neighbouring atoms, and bond distances. Examples of studies that have utilized XAS to characterize U(VI) speciation in cementitious systems are still rare, and to the best of our knowledge, detailed XAS investigations of the U(VI)/C-S-H system are lacking. The results obtained from the combined use of wet chemical and spectroscopic techniques allow mechanistic models of the immobilization process to be proposed for cementitious waste forms containing low and high U(VI) inventories. In the latter case U(VI) immobilization is controlled by a solubility-limiting process with the U(VI) mineral predominantly formed under the conditions prevailing in cementitious systems. At low U(VI) concentrations, however, U(VI) appears to be predominantly bound onto C-S-H phases. The coordination environment of U(VI) taken up by C-S-H was found to resemble that of U(VI) in uranophane. A mechanistic understanding of the U(VI) binding by cementitious materials will allow more detailed and scientifically well founded predictions of the retention of

Application of high-strength non-shrink cement based grouting material in nuclear power installations

International Nuclear Information System (INIS)

Li Zhong; Zuo Weiwei

2011-01-01

This paper briefly describes the related technical requirement of secondary grouting during the process of equipment installation in nuclear power projects. The method and procedure are introduced in detail from the aspects of acceptance, preparation, pouring, collecting and maintenance of the high-strength non-shrinking based pouring cement material, and the cautions during the construction is also provided. The factors affecting the quality of the field grouting is analyzed, and the measures to reduce or eliminate the micro-cracks during the process is provided. (authors)

Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials

International Nuclear Information System (INIS)

Zhang, Na; Li, Hongxu; Liu, Xiaoming

2016-01-01

Highlights: • Nanocrystalline regions in size of ∼5 nm were found in the amorphous C-A-S-H gel. • A hydration model was proposed to clarify the hydration mechanism. • The developed cementitious materials are environmentally acceptable. - Abstract: A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5 nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable.

Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials

Energy Technology Data Exchange (ETDEWEB)

Zhang, Na; Li, Hongxu [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Xiaoming, E-mail: liuxm@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China)

2016-08-15

Highlights: • Nanocrystalline regions in size of ∼5 nm were found in the amorphous C-A-S-H gel. • A hydration model was proposed to clarify the hydration mechanism. • The developed cementitious materials are environmentally acceptable. - Abstract: A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5 nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable.

Flexural behavior of the fibrous cementitious composites (FCC) containing hybrid fibres

Science.gov (United States)

Ramli, Mahyuddin; Ban, Cheah Chee; Samsudin, Muhamad Fadli

2018-02-01

In this study, the flexural behavior of the fibrous cementitious composites containing hybrid fibers was investigated. Waste materials or by product materials such as pulverized fuel ash (PFA) and ground granulated blast-furnace slag (GGBS) was used as supplementary cement replacement. In addition, barchip and kenaf fiber will be used as additional materials for enhance the flexural behavior of cementitious composites. A seven mix design of fibrous cementitious composites containing hybrid fiber mortar were fabricated with PFA-GGBS as cement replacement at 50% with hybridization of barchip and kenaf fiber between 0.5% and 2.0% by total volume weight. The FCC with hybrid fibers mortar will be fabricated by using 50 × 50 × 50 mm, 40 × 40 × 160 mm and 350 × 125 × 30 mm steel mold for assessment of mechanical performances and flexural behavior characteristics. The flexural behavior and mechanical performance of the PFA-GGBS with hybrid fiber mortar block was assessed in terms of load deflection response, stress-strain response, crack development, compressive and flexural strength after water curing for 28 days. Moreover, the specimen HBK 1 and HBK 2 was observed equivalent or better in mechanical performance and flexural behavior as compared to control mortar.

Technetium Sorption By Cementitious Materials Under Reducing Conditions

International Nuclear Information System (INIS)

Kaplan, Daniel I.; Estes, Shanna L.; Arai, Yuji; Powell, Brian A.

2013-01-01

The objective of this study was to measure Tc sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. Earlier studies were conducted and the experimental conditions were found not to simulate those of the facility. Through a five month subcontract with Clemson University, sorption of 99 Tc to four cementitious materials was examined within an anaerobic glovebag targeting a 0.1% H 2 (g)/ 99.9% N 2 (g) atmosphere. Early experiments based on Tc sorption and Eh indicated that 0.1% H 2 (g) (a reductant) was necessary to preclude experimental impacts from O 2 (g) diffusion into the glovebag. Preliminary data to date (up to 56 days) indicates that sorption of 99 Tc to cementitious materials increased with increasing slag content for simulated saltstone samples. This is consistent with the conceptual model that redox active sulfide groups within the reducing slag facilitate reduction of Tc(VII) to Tc(IV). These experiments differ from previous experiments where a 2% H 2 (g) atmosphere was maintained (Kaplan et al., 2011 (SRNL-STI-2010-00668)). The impact of the 2% H 2 (g) reducing atmosphere on this data was examined and determined to cause the reduction of Tc in experimental samples without slag. In the present ongoing study, after 56 days, Tc sorption by the 50-year old cement samples (no slag) was undetectable, whereas Tc sorption in the cementitious materials containing slag continues to increase with contact time (measured after 1, 4, 8, 19 and 56 days). Sorption was not consistent with spike concentrations and steady state has not been demonstrated after 56 days. The average conditional K d value for the Vault 2 cementitious material was 873 mL/g (17% slag), for the TR547 Saltstone (45% slag) the conditional K d was 168 mL/g, and for TR545 (90% slag) the conditional K d was 1,619 mL/g. It is anticipated that additional samples will be collected until steady state conditions are established to permit measuring

Cementitious building material incorporating end-capped polyethylene glycol as a phase change material

Science.gov (United States)

Salyer, Ival O.; Griffen, Charles W.

1986-01-01

A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

A Plastic Damage Mechanics Model for Engineered Cementitious Composites

DEFF Research Database (Denmark)

Dick-Nielsen, Lars; Stang, Henrik; Poulsen, Peter Noe

2007-01-01

This paper discusses the establishment of a plasticity-based damage mechanics model for Engineered Cementitious Composites (ECC). The present model differs from existing models by combining a matrix and fiber description in order to describe the behavior of the ECC material. The model provides...

Leach and EP [extraction procedure] toxicity tests on grouted waste from Tank 106-AN

International Nuclear Information System (INIS)

Serne, R.J.; Martin, W.J.; Lokken, R.O.; LeGore, V.L.; Lindenmeier, C.W.; Martin, P.F.C.

1989-09-01

Pacific Northwest Laboratory is conducting laboratory experiments to produce leach rate data for various waste species that will be contained in grout at Hanford. In the work reported here, grout made from Tank 106-AN liquid waste was used to produce empirical leach rate data for several radionuclides ( 60 Co, 90 Sr, 99Tc, 129I, 137Cs, and 241 Am), stable major components (NO 3 - , NO 2 - , F, Cl, and Na), and trace metals (Cr, Mo, and Ni). Two types of tests were used to produce leach rate data: an intermittent replacement leach test (ANS 16.1 leach test) and a static leach test. Measured effective diffusivities of key species are as follows: 4 to 6 x 10 -8 cm 2 /sec for 99 Tc, 3 to 7 x 10 -8 cm 2 /sec for 129 I, 4 to 6 x 10 -9 cm 2 /sec for nitrate, and 6 to 7 x 10 -9 cm 2 /sec for nitrite. The leach indices of all species studied are above (more favorable than) the waste form criteria. The leach indices for 99 Tc and 129 I are 7.4 ± 1.2 and 7.6 ± 0.4, respectively, and are being further investigated in continuing studies of double-shell slurry feed grouts. An Extraction Procedure (EP) toxicity test was also conducted and the grouted water is considered nontoxic per this test protocol. 19 refs., 9 figs., 8 tabs

Cytocompatible and water stable ultrafine protein fibers for tissue engineering

Science.gov (United States)

Jiang, Qiuran

This dissertation proposal focuses on the development of cytocompatible and water stable protein ultrafine fibers for tissue engineering. The protein-based ultrafine fibers have the potential to be used for biomedicine, due to their biocompatibility, biodegradability, similarity to natural extracellular matrix (ECM) in physical structure and chemical composition, and superior adsorption properties due to their high surface to volume ratio. However, the current technologies to produce the protein-based ultrafine fibers for biomedical applications still have several problems. For instance, the current electrospinning and phase separation technologies generate scaffolds composed of densely compacted ultrafine fibers, and cells can spread just on the surface of the fiber bulk, and hardly penetrate into the inner sections of scaffolds. Thus, these scaffolds can merely emulate the ECM as a two dimensional basement membrane, but are difficult to mimic the three dimensional ECM stroma. Moreover, the protein-based ultrafine fibers do not possess sufficient water stability and strength for biomedical applications, and need modifications such as crosslinking. However, current crosslinking methods are either high in toxicity or low in crosslinking efficiency. To solve the problems mentioned above, zein, collagen, and gelatin were selected as the raw materials to represent plant proteins, animal proteins, and denatured proteins in this dissertation. A benign solvent system was developed specifically for the fabrication of collagen ultrafine fibers. In addition, the gelatin scaffolds with a loose fibrous structure, high cell-accessibility and cell viability were produced by a novel ultralow concentration phase separation method aiming to simulate the structure of three dimensional (3D) ECM stroma. Non-toxic crosslinking methods using citric acid as the crosslinker were also developed for electrospun or phase separated scaffolds from these three proteins, and proved to be

Hanford grout disposal program - an environmentally sound alternative

International Nuclear Information System (INIS)

Bergman, T.B.; Allison, J.M.

1987-01-01

The Hanford Grout Disposal Program (HGDP) is a comprehensive, integrated program to develop technology and facilities for the disposal of ∼ 3.0 x 10 5 m 3 (80 million gal) of the low-level fraction of liquid radioactive tank wastes at the Hanford site in southeastern Washington state. Environmentally sound disposal via long-term protection of the public and the environment is the principal goal of the HGDP. To accomplish this goal, several criteria have been established that guide technology and facility development activities. The key criteria are discussed. To meet the challenges posed by disposal of these wastes, the HGDP is developing a waste form using grout-forming materials, such as blast furnace slag, fly ash, clays, and Portland cement for solidification and immobilization of both the radioactive and hazardous chemical constituents. In addition to development of a final waste form, the HGDP is also developing a unique disposal system to assure long-term protection of the public and the environment. Disposal of a low-level nonhazardous waste will be initiated, as a demonstration of the disposal system concept, in June 1988. Disposal of higher activity hazardous wastes is scheduled to begin in October 1989

Durability of low-pH cementitious materials based on OPC or CAC

International Nuclear Information System (INIS)

Garcia Calvo, J.L.; Sanchez, M.; Alonso, M.C.; Fernandez Luco, L.

2015-01-01

Low pH cementitious materials are considered to be used in underground repositories for high level waste but there are still some characteristics related to their long-term durability that must be analyzed in depth. In this sense, different shrinkage tests have been made using low-pH cement formulations based on Ordinary Portland Cement (OPC) or Calcium Aluminate Cement (CAC), on mortar and concrete specimens. The obtained results show that, regarding the autogenous shrinkage, low-pH cementitious materials show similar values than those observed in the reference samples. In fact, the main shrinkage problems in the low-pH materials are related with those based on OPC with high silica fume contents in drying conditions. Besides, as the use of reinforced concrete can be required in underground repositories, the susceptibility of reinforcements to corrosion when using low-pH cementitious materials based on OPC was analyzed, using two different reinforcements: carbon steel and galvanized steel. The lower pore solution pH of the low-pH OPC based materials generates the corrosion of the carbon steel reinforcement. However, when galvanized steels are used, any corrosion problem is detected regardless of the cement formulation. (authors)

Performance of alusilica as mineral admixture in cementitious systems

DEFF Research Database (Denmark)

Chi, Lin; Jensen, Ole Mejlhede

2016-01-01

This paper presents a preliminary study of the effect of alusilica (ALS) as a mineral admixture on the fresh properties and development of mechanical properties of cementitious systems. Cement was substituted with ALS with the ratio of 10% during grinding or blended during mixing. The produced ALS...

Separation of ultrafine particles from class F fly ashes

Directory of Open Access Journals (Sweden)

Acar Ilker

2016-01-01

Full Text Available In this study, ultrafine particles were recovered from Çatalağzı (CFA and Sugözü (SFA thermal power plant fly ashes using a specific hydraulic classification technology. Since fly ashes have a high tendency to be flocculated in water, settling experiments were first designed to determine the more effective dispersant and the optimum dosage. Two different types of the superplasticizers (SP polymers based on sulphonate (NSF, Disal and carboxylate (Glenium 7500 were used as the dispersing agents in these settling experiments. Hydraulic classification experiments were then conducted to separate ultrafine fractions from the fly ash samples on the basis of the settling experiments. According to the settling experiments, better results were achieved with the use of Disal for both CFA and SFA. The classification experiments showed that the overflow products with average particle sizes of 5.2 μm for CFA and 4.4 μm for SFA were separated from the respective as-received samples with acceptable yields and high enough recoveries of -5 μm (ultrafine particles. Overall results pointed out that the hydraulic classification technology used provided promising results in the ultrafine particle separations from the fly ash samples.

Leach tests on grouts made with actual and trace metal-spiked synthetic phosphate/sulfate waste

International Nuclear Information System (INIS)

Serne, R.J.; Martin, W.J.; LeGore, V.L.; Lindenmeier, C.W.; McLaurine, S.B.; Martin, P.F.C.; Lokken, R.O.

1989-10-01

Pacific Northwest Laboratory conducted experiments to produce empirical leach rate data for phosphate-sulfate waste (PSW) grout. Effective diffusivities were measured for various radionuclides ( 90 Sr, 99 Tc, 14 C, 129 I, 137 Cs, 60 Co, 54 Mn, and U), stable major components (NO 3 - , SO 4 2- , H 3 BO 3 , K and Na) and the trace constituents Ag, As, Cd, Hg, Pb, and Se. Two types of leach tests were used on samples of actual PSW grout and synthetic PSW grout: the American Nuclear Society (ANS) 16.1 intermittent replacement leach test and a static leach test. Grout produced from both synthetic and real PSW showed low leach rates for the trace metal constituents and most of the waste radionuclides. Many of the spiked trace metals and radionuclides were not detected in any leachates. None of the effluents contained measurable quantities of 137 Cs, 60 Co, 54 Mn, 109 Cd, 51 Cr, 210 Pb, 203 Hg, or As. For those trace species with detectable leach rates, 125 I appeared to have the greatest leach rate, followed by 99 Tc, 75 Se, and finally U, 14 C, and 110m Ag. Leach rates for nitrate are between those for I and Tc, but there is much scatter in the nitrate data because of the very low nitrate inventory. 32 refs., 6 figs., 15 tabs

Nuclear waste viewed in a new light; a synchrotron study of uranium encapsulated in grout.

Science.gov (United States)

Stitt, C A; Hart, M; Harker, N J; Hallam, K R; MacFarlane, J; Banos, A; Paraskevoulakos, C; Butcher, E; Padovani, C; Scott, T B

2015-03-21

How do you characterise the contents of a sealed nuclear waste package without breaking it open? This question is important when the contained corrosion products are potentially reactive with air and radioactive. Synchrotron X-rays have been used to perform micro-scale in-situ observation and characterisation of uranium encapsulated in grout; a simulation for a typical intermediate level waste storage packet. X-ray tomography and X-ray powder diffraction generated both qualitative and quantitative data from a grout-encapsulated uranium sample before, and after, deliberately constrained H2 corrosion. Tomographic reconstructions provided a means of assessing the extent, rates and character of the corrosion reactions by comparing the relative densities between the materials and the volume of reaction products. The oxidation of uranium in grout was found to follow the anoxic U+H2O oxidation regime, and the pore network within the grout was observed to influence the growth of uranium hydride sites across the metal surface. Powder diffraction analysis identified the corrosion products as UO2 and UH3, and permitted measurement of corrosion-induced strain. Together, X-ray tomography and diffraction provide means of accurately determining the types and extent of uranium corrosion occurring, thereby offering a future tool for isolating and studying the reactions occurring in real full-scale waste package systems. Copyright © 2014 Elsevier B.V. All rights reserved.

Rigid-body-spring model numerical analysis of joint performance of engineered cementitious composites and concrete

Science.gov (United States)

Khmurovska, Y.; Štemberk, P.; Křístek, V.

2017-09-01

This paper presents a numerical investigation of effectiveness of using engineered cementitious composites with polyvinyl alcohol fibers for concrete cover layer repair. A numerical model of a monolithic concaved L-shaped concrete structural detail which is strengthened with an engineered cementitious composite layer with polyvinyl alcohol fibers is created and loaded with bending moment. The numerical analysis employs nonlinear 3-D Rigid-Body-Spring Model. The proposed material model shows reliable results and can be used in further studies. The engineered cementitious composite shows extremely good performance in tension due to the strain-hardening effect. Since durability of the bond can be decreased significantly by its degradation due to the thermal loading, this effect should be also taken into account in the future work, as well as the experimental investigation, which should be performed for validation of the proposed numerical model.

Properties of salt-saturated concrete and grout after six years in situ at the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Wakeley, L.D.; Harrington, P.T.; Weiss, C.A. Jr.

1993-06-01

Samples of concrete and grout were recovered from short boreholes in the repository floor at the Waste Isolation Pilot Plant more than six years after the concrete and grout were placed. Plugs from the Plug Test Matrix of the Plugging and Sealing Program of Sandia National Laboratories were overcored to include a shell of host rock. The cores were analyzed at the Waterways Experiment Station to assess their condition after six years of service, having potentially been exposed to those aspects of their service environment (salt, brine, fracturing, anhydrite, etc.) that could cause deterioration. Measured values of compressive strength and pulse velocity of both the grout and the concrete equaled or exceeded values from tests performed on laboratory-tested samples of the same mixtures at ages of one month to one year after casting. The phase assemblages had changed very little. Materials performed as intended and showed virtually no chemical or physical evidence of deterioration. The lowest values for strength and pulse velocity were measured for samples taken from the Disturbed Rock Zone, indicating the influence of cracking in this zone on the properties of enclosed seal materials. There was evidence of movement of brine in the system. Crystalline phases containing magnesium, potassium, sulfate, and other ions had been deposited on free surfaces in fractures and pilot holes. There was a reaction rim in the anhydrite immediately surrounding each recovered borehole plug, suggesting interaction between grout or concrete and host rock. However, the chemical changes apparent in this reaction rim were not reflected in the chemical composition of the adjacent concrete or grout. The grout and concrete studied here showed no signs of the deterioration found to have occurred in some parts of the concrete liner of the Waste Isolation Pilot Plant waste handling shaft

Grout disposal facility vault exhauster: Technical background document on demonstration of best available control technology for toxics

International Nuclear Information System (INIS)

Glissmeyer, J.A.; Glantz, C.S.; Rittman, P.D.

1994-09-01

The Grout Disposal Facility (GDF) is currently operated on the US Department of Energy's Hanford Site. The GDF is located near the east end of the Hanford Site's 200 East operations area, and is used for the treatment and disposal of low-level radioactive liquid wastes. In the grout treatment process, selected radioactive wastes from double-shell tanks are mixed with grout-forming solids; the resulting grout slurry is pumped to near-surface concrete vaults for solidification and permanent disposal. As part of this treatment process, small amounts of toxic particles and volatile organic compounds (VOCs) may be released to the atmosphere through the GDF's exhaust system. This analysis constitutes a Best Available Control Technology for Toxics (T-BACT) study, as required in the Washington Administrative Code (WAC 173-460) to support a Notice of Construction for the operation of the GDF exhaust system at a modified flow rate that exceeds the previously permitted value. This report accomplishes the following: assesses the potential emissions from the GDF; estimates air quality impacts to the public from toxic air pollutants; identifies control technologies that could reduce GDF emissions; evaluates impacts of the control technologies; and recommends appropriate emissions controls

Description of near-tip fracture processes in strain hardening cementitious composites using image-based analysis and the compact tension test

DEFF Research Database (Denmark)

Pereira, Eduardo B.; Fischer, Gregor; Barros, Joaquim A.O.

2013-01-01

The cracking mechanisms assume a key role in the composite behavior of Strain Hardening Cementitious Composites (SHCCs). Due to their importance, in previous studies the mechanical behavior of SHCC materials, as well as of other strain softening fiber reinforced cementitious composites......, was characterized under eccentric tensile loading using the Compact Tension Test (CTT). The present research further extends this investigation, with particular emphasis on cementitious composites reinforced with multiple types of fibers. The experimental tensile load-displacement results are discussed and compared...

A THERMAL MODEL OF THE IMMOBILIZATION OF LOW-LEVEL RADIOACTIVE WASTE AS GROUT IN CONCRETE VAULTS

Energy Technology Data Exchange (ETDEWEB)

Shadday, M

2008-10-27

Salt solution will be mixed with cement and flyash/slag to form a grout which will be immobilized in above ground concrete vaults. The curing process is exothermic, and a transient thermal model of the pouring and curing process is herein described. A peak temperature limit of 85 C for the curing grout restricts the rate at which it can be poured into a vault. The model is used to optimize the pouring.

Engineered cementitious composites for strengthening masonry infilled reinforced concrete frames

DEFF Research Database (Denmark)

Dehghani, Ayoub; Nateghi-Alahi, Fariborz; Fischer, Gregor

2015-01-01

The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented...

Cementitious Materials in Safety Cases for Geological Repositories for Radioactive Waste: Role, Evolution and Interactions. A Workshop organised by the OECD/NEA Integration Group for the Safety Case and hosted by ONDRAF/NIRAS. Cementitious materials in safety cases for radioactive waste: role, evolution and interactions

International Nuclear Information System (INIS)

2012-01-01

The OECD Nuclear Energy Agency (NEA) Integration Group for the Safety Case (IGSC) organised a workshop to assess current understanding on the use of cementitious materials in radioactive waste disposal. The workshop was hosted by the Belgian Agency for Radioactive Waste and Enriched Fissile Materials (Ondraf/Niras), in Brussels, Belgium on 17-19 November 2009. The workshop brought together a wide range of people involved in supporting safety case development and having an interest in cementitious materials: namely, cement and concrete experts, repository designers, scientists, safety assessors, disposal programme managers and regulators. The workshop was designed primarily to consider issues relevant to the post-closure safety of radioactive waste disposal, but also addressed some related operational issues, such as cementitious barrier emplacement. Where relevant, information on cementitious materials from analogous natural and anthropogenic systems was also considered. This report provides a synthesis of the workshop, and summarises its main results and findings. The structure of this report follows the workshop agenda: - Section 2 summarises plenary and working group discussions on the uses, functions and evolution of cementitious materials in geological disposal, and highlights key aspects and discussions points. - Section 3 summarises plenary and working group discussions on interactions of cementitious materials with other disposal system components, and highlights key aspects and discussions points. - Section 4 summarises the workshop session on the integration of issues related to cementitious materials using the safety case. - Section 5 presents the main conclusions from the workshop. - Section 6 contains a list of references. - Appendix A presents the workshop agenda. - Appendix B contains the abstracts and, where provided, technical papers supporting oral presentations at the workshop. - Appendix C contains the abstracts and, where provided, technical

Nanomaterials vs Ambient Ultrafine Particles

DEFF Research Database (Denmark)

Stone, Vicki; Miller, Mark R.; Clift, Martin J. D.

2017-01-01

BACKGROUND: A rich body of literature exists that has demonstrated adverse human health effects following exposure to ambient air particulate matter (PM), and there is strong support for an important role of ultrafine (nanosized) particles. At present, relatively few human health or epidemiology ...

X-ray computed microtomography of three-dimensional microcracks and self-healing in engineered cementitious composites

International Nuclear Information System (INIS)

Fan, Shuai; Li, Mo

2015-01-01

Concrete cracking and deterioration can potentially be addressed by innovative self-healing cementitious materials, which can autogenously regain transport properties and mechanical characteristics after the damage self-healing process. For the development of such materials, it is crucial, but challenging, to precisely characterize the extent and quality of self-healing due to a variety of factors. This study adopted x-ray computed microtomography (μCT) to derive three-dimensional morphological data on microcracks before and after healing in engineered cementitious composite (ECC). Scanning electron microscope and energy dispersive x-ray spectroscopy were also used to morphologically and chemically analyze the healing products. This work showed that the evolution of the microcrack 3D structure due to self-healing in cementitious materials can be directly and quantitatively characterized by μCT. A detailed description of the μCT image analysis method applied to ECC self-healing was presented. The results revealed that the self-healing extent and rate strongly depended on initial surface crack width, with smaller crack width favoring fast and robust self-healing. We also found that the self-healing mechanism in cementitious materials is dependent on crack depth. The region of a crack close to the surface (from 0 to around 50–150 μm below the surface) can be sealed quickly with crystalline precipitates. However, at greater depths the healing process inside the crack takes a significantly longer time to occur, with healing products more likely resulting from continued hydration and pozzolanic reactions. Finally, the μCT method was compared with other self-healing characterization methods, with discussions on its importance in generating new scientific knowledge for the development of robust self-healing cementitious materials. (paper)

Twinning interactions induced amorphisation in ultrafine silicon grains

Energy Technology Data Exchange (ETDEWEB)

Cao, Y. [School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Zhang, L.C., E-mail: liangchi.zhang@unsw.edu.au [School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Zhang, Y. [School of Mechatronics Engineering, Harbin Institute of Technology (China)

2016-03-21

Detailed transmission electron microscopy analysis on a severely deformed Al-Si composite material has revealed that partial dislocation slips and deformation twinning are the major plastic deformation carriers in ultrafine silicon grains. This resembles the deformation twinning activities and mechanisms observed in nano-crystalline face-centred-cubic metallic materials. While deformation twinning and amorphisation in Si were thought unlikely to co-exist, it is observed for the first time that excessive twinning and partial dislocation interactions can lead to localised solid state amorphisation inside ultrafine silicon grains.

Mejoramiento de cimentaciones en suelos y rocas aplicando las técnicas de grouting

OpenAIRE

Ampuero Cayo, Salomón Edgard; Ampuero Cayo, Salomón Edgard

2012-01-01

Las técnicas de inyecciones de grouting, se conocen desde el año 1802 en Francia, desde entonces se ha recopilado información y se practica esta técnica mejorando cada vez. Los diseños, procedimientos de inyección, están orientados hacia los objetivos básicos, que son el control de agua subterránea y el tratamiento de los macizos rocosos fracturados y suelos sin cohesión. La aplicación de las técnicas de grouting en rocas; reducen el flujo de agua, refuerzan las rocas y mitigan la formaci...

Micromechanical Properties of a New Polymeric Microcapsule for Self-Healing Cementitious Materials

Directory of Open Access Journals (Sweden)

Leyang Lv

2016-12-01

Full Text Available Self-healing cementitious materials containing a microencapsulated healing agent are appealing due to their great application potential in improving the serviceability and durability of concrete structures. In this study, poly(phenol–formaldehyde (PF microcapsules that aim to provide a self-healing function for cementitious materials were prepared by an in situ polymerization reaction. Size gradation of the synthesized microcapsules was achieved through a series of sieving processes. The shell thickness and the diameter of single microcapsules was accurately measured under environmental scanning electron microscopy (ESEM. The relationship between the physical properties of the synthesized microcapsules and their micromechanical properties were investigated using nanoindentation. The results of the mechanical tests show that, with the increase of the mean size of microcapsules and the decrease of shell thickness, the mechanical force required to trigger the self-healing function of microcapsules increased correspondingly from 68.5 ± 41.6 mN to 198.5 ± 31.6 mN, featuring a multi-sensitive trigger function. Finally, the rupture behavior and crack surface of cement paste with embedded microcapsules were observed and analyzed using X-ray computed tomography (XCT. The synthesized PF microcapsules may find potential application in self-healing cementitious materials.

Application of an Ultrafine Shearing Method for the Extraction of C-Phycocyanin from Spirulina platensis

Directory of Open Access Journals (Sweden)

Jianfeng Yu

2017-11-01

Full Text Available Cell disruption is an important step during the extraction of C-phycocyanin from Spirulina platensis. An ultrafine shearing method is introduced and combined with soaking and ultrasonication to disrupt the cell walls of S. platensis efficiently and economically. Five kinds of cell disruption method, including soaking, ultrasonication, freezing-thawing, soaking-ultrafine shearing and soaking-ultrafine shearing-ultrasonication were applied to break the cell walls of S. platensis. The effectiveness of cell breaking was evaluated based on the yield of the C-phycocyanin. The results show that the maximum C-phycocyanin yield was 9.02%, achieved by the soaking-ultrafine shearing-ultrasonication method, followed by soaking (8.43%, soaking-ultrafine shearing (8.89%, freezing and thawing (8.34%, and soaking-ultrasonication (8.62%. The soaking-ultrafine shearing-ultrasonication method is a novel technique for breaking the cell walls of S. platensis for the extraction of C-phycocyanin.

Preparation of Cementitious Material Using Smelting Slag and Tailings and the Solidification and Leaching of Pb2+

Directory of Open Access Journals (Sweden)

Dan Zhang

2015-01-01

Full Text Available The composite cementitious materials were prepared with lead-zinc tailings, lead-zinc smelting slag, and cement clinker. The effect of material ratio on the mechanical properties, the phase analysis, and microstructures were investigated. The effect of the pH and stripping time on the leaching amount of lead ion was discussed. The results show that the additive amount of the tailings should be minimized for the cementitious materials meeting the strength requirements, controlled within 10%. The leaching amount of cementitious materials remains low in a larger range of pH, which can effectively reduce the leaching of heavy metal lead. The leaching kinetics of lead ions in the three kinds of samples could be better described by the pseudo-second-model.

Sealing of decant structure at QCM using a tailings cement grout mix

Energy Technology Data Exchange (ETDEWEB)

Bedard, C.; Goulisty, P.; Lemieux, J. [Journeaux, Bedard and Associates Inc., Dorval, PQ (Canada)

2001-10-01

It became necessary for Quebec Cartier Mining (QCM) to transfer the decantation point at the Mont-Wright mine to the Hesse 4 dam and proceed with the permanent sealing of the decant structure at dam A, as a result of the gradual advancement of the tailings mine waste in the Hesse North primary settling basin. A study was conducted to evaluate the use of tailings incorporated in a non-shrink Portland cement grout mix to adequately seal the decant structure of the 30 m high process water earth dam, and the results are presented in this paper. Along with the existing tailings, a type I Portland cement and supplementary cementing materials including fly ash and silica fume were tested. Using a series of design criteria including durability requirements, strength, density, segregation, bleeding, initial and final set, shrinkage, expansion, underwater placement, flowability, pumpability, and others, Journeaux, Bedard and Associates Incorporated completed a series of laboratory tests and trial mixes. Air entrainment admixture, anti-washout admixture, expansion admixture, bentonite, superplasticizer, etc. were tested in the various grout mixes. The design criteria, methodology, laboratory results, various placing techniques, such as pressure grouting, pumping, tremie and others, and formwork used to seal the decant structures are all detailed in the paper. A section is also devoted to the many challenges encountered during the testing. 11 figs.

Fabrication and characterization of dual-functional ultrafine composite fibers with phase-change energy storage and luminescence properties.

Science.gov (United States)

Xi, Peng; Zhao, Tianxiang; Xia, Lei; Shu, Dengkun; Ma, Menjiao; Cheng, Bowen

2017-01-09

Ultrafine composite fibers consisting of a thermoplastic polyurethane solid-solid phase-change material and organic lanthanide luminescent materials were prepared through a parallel electrospinning technique as an innovative type of ultrafine, dual-functional fibers containing phase-change and luminescent properties. The morphology and structure, thermal energy storage, and luminescent properties of parallel electrospun ultrafine fibers were investigated. Scanning electron microscopy (SEM) images showed that the parallel electrospun ultrafine fibers possessed the desired morphologies with smaller average fiber diameters than those of traditional mixed electrospun ultrafine fibers. Transmission electron microscopy (TEM) images revealed that the parallel electrospun ultrafine fibers were composed of two parts. Polymeric phase-change materials, which can be directly produced and spun, were used to provide temperature stability, while a mixture of polymethyl methacrylate and an organic lanthanide complex acted as the luminescent unit. Differential scanning calorimetry (DSC) and luminescence measurements indicated that the unique structure of the parallel electrospun ultrafine fibers provides the products with good thermal energy storage and luminescence properties. The fluorescence intensity and the phase-change enthalpy values of the ultrafine fibers prepared by parallel electrospinning were respectively 1.6 and 2.1 times those of ultrafine fibers prepared by mixed electrospinning.