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Sample records for survey wenatchee concrete

  1. Asphaltic concrete pavement survey.

    Science.gov (United States)

    1963-04-01

    The ever increasing problem of wheel path rutting and excessive desification of asphaltic concrete pavement has been the subject of asphalt technology for quite sometime. It is known that the density of the pavement, which is significant for several ...

  2. 2009 PSLC-USGS Topographic LiDAR: Wenatchee

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WS) collected Light Detection and Ranging (LiDAR) data of the Wenatchee USGS area of interest (AOI) east of Wenatchee, WA on May 1nd ? May...

  3. 2009 PSLC-USGS Topographic LiDAR: Wenatchee

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WS) collected Light Detection and Ranging (LiDAR) data of the Wenatchee USGS area of interest (AOI) east of Wenatchee, WA on May 1nd - May...

  4. Wenatchee River steelhead reproductive success - Estimate the relative reproductive success of hatchery and wild steelhead in the Wenatchee River, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project uses genetic parentage analysis to estimate the relative reproductive success of hatchery and wild steelhead spawning in the Wenatchee River, WA. The...

  5. Wenatchee Chinook Parentage - Evaluate the reproductive success of hatchery and wild Chinook salmon in the Wenatchee River

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We are using genetic parentage analysis to measure the relative fitness of hatchery and wild spring run Chinook salmon that spawn in the Wenatchee River. In addition...

  6. Wenatchee River, Washington, Water Temperature Modeling and Assessment Using Remotely Sensed Thermal Infrared and Instream Recorded Data

    Science.gov (United States)

    Cristea, N. C.; Burges, S. J.

    2004-12-01

    The stream water spatial and temporal temperature patterns of the Wenatchee River, WA are assessed based on temperature data recorded by instream data loggers in the dry season of 2002 and thermal infrared imagery from August 16th 2002. To gain insights into the possible thermal behavior of the river, the stream temperature model Qual2K (Chapra and Pelletier, 2003) is extended beyond its calibration (10-16 August 2002) and confirmation (9-11 September 2002) periods for use with different meteorological, shade and flow conditions. The temperature longitudinal profile of the Wenatchee River is influenced by the temperature regime in Lake Wenatchee, the source of the Wenatchee River. Model simulations performed at 7-day average with 2-year return period flow conditions show that the potential (maximum average across all reaches) temperature (the temperature that would occur under natural conditions) is about 19.8 deg. C. For the 7-day average with 10-year return period flow conditions the potential temperature increases to about 21.2 deg. C. The simulation results show that under normal flow and meteorological conditions the water temperature exceeds the current water quality standards. Model simulations performed under the 7-day average with 10-year return period flow conditions and a climate change scenario show that the average potential temperature across all reaches can increase by as much as 1.3 deg. C compared to the case where climate change impact is not taken into account. Thermal infrared (TIR) derived stream temperature data were useful for describing spatial distribution patterns of the Wenatchee River water temperature. The TIR and visible band images are effective tools to map cold water refugia for fish and to detect regions that can be improved for fish survival. The images collected during the TIR survey and the TIR derived stream temperature longitudinal profile helps pinpoint additional instream monitoring locations that avoid regions of backwater

  7. Survey of four damage models for concrete.

    Energy Technology Data Exchange (ETDEWEB)

    Leelavanichkul, Seubpong (University of Utah, Salt Lake City, UT); Brannon, Rebecca Moss (University of Utah, Salt Lake City, UT)

    2009-08-01

    Four conventional damage plasticity models for concrete, the Karagozian and Case model (K&C), the Riedel-Hiermaier-Thoma model (RHT), the Brannon-Fossum model (BF1), and the Continuous Surface Cap Model (CSCM) are compared. The K&C and RHT models have been used in commercial finite element programs many years, whereas the BF1 and CSCM models are relatively new. All four models are essentially isotropic plasticity models for which 'plasticity' is regarded as any form of inelasticity. All of the models support nonlinear elasticity, but with different formulations. All four models employ three shear strength surfaces. The 'yield surface' bounds an evolving set of elastically obtainable stress states. The 'limit surface' bounds stress states that can be reached by any means (elastic or plastic). To model softening, it is recognized that some stress states might be reached once, but, because of irreversible damage, might not be achievable again. In other words, softening is the process of collapse of the limit surface, ultimately down to a final 'residual surface' for fully failed material. The four models being compared differ in their softening evolution equations, as well as in their equations used to degrade the elastic stiffness. For all four models, the strength surfaces are cast in stress space. For all four models, it is recognized that scale effects are important for softening, but the models differ significantly in their approaches. The K&C documentation, for example, mentions that a particular material parameter affecting the damage evolution rate must be set by the user according to the mesh size to preserve energy to failure. Similarly, the BF1 model presumes that all material parameters are set to values appropriate to the scale of the element, and automated assignment of scale-appropriate values is available only through an enhanced implementation of BF1 (called BFS) that regards scale effects to be coupled to

  8. Precast concrete unit assessment through GPR survey and FDTD modelling

    Science.gov (United States)

    Campo, Davide

    2017-04-01

    Precast concrete elements are widely used within United Kingdom house building offering ease in assembly and added values as structural integrity, sound and thermal insulation; most common concrete components include walls, beams, floors, panels, lintels, stairs, etc. The lack of respect of the manufacturer instruction during assembling, however, may induce cracking and short/long term loss of bearing capacity. GPR is a well-established not destructive technique employed in the assessment of structural elements because of real-time imaging, quickness of data collecting and ability to discriminate finest structural details. In this work, GPR has been used to investigate two different precast elements: precast reinforced concrete planks constituting the roof slab of a school and precast wood-cement blocks with insulation material pre-fitted used to build a perimeter wall of a private building. Visible cracks affected both constructions. For the assessment surveys, a GSSI 2.0 GHz GPR antenna has been used because of the high resolution required and the small size of the antenna case (155 by 90 by 105mm) enabling scanning up to 45mm from any obstruction. Finite Difference Time Domain (FDTD) numerical modelling was also performed to build a scenario of the expected GPR signal response for a preliminary real-time interpretation and to help solve uncertainties due to complex reflection patterns: simulated radargrams were built using Reflex Software v. 8.2, reproducing the same GPR pulse used for the surveys in terms of wavelet, nominal frequency, sample frequency and time window. Model geometries were derived from the design projects available both for the planks and the blocks; the electromagnetic properties of the materials (concrete, reinforcing bars, air-filled void, insulation and wooden concrete) were inferred from both values reported in literature and a preliminary interpretation of radargrams where internal layer interfaces were clearly recognizable and

  9. 75 FR 81560 - Buckhorn Exploration Project 2010, Okanogan-Wenatchee National Forest, Okanogan County, Washington

    Science.gov (United States)

    2010-12-28

    ... Forest Service Buckhorn Exploration Project 2010, Okanogan-Wenatchee National Forest, Okanogan County... Agencies: Forest Service, Department of Agriculture; and Department of Natural Resources, Washington State. Cooperating Agencies: Bureau of Land Management, Department of the Interior; and Department of Ecology...

  10. Final Critical Habitat for the Wenatchee Mountains Checkermallow (Sidalcea oregana var. calva)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — To provide the user with a general idea of areas where final critical habitat for Wenatchee Mountains checker-mallow (Sidalcea oregana var. calva) occur based on the...

  11. The national survey of natural radioactivity in concrete produced in Israel.

    Science.gov (United States)

    Kovler, Konstantin

    2017-03-01

    The main goal of the current survey was to collect the results of the natural radiation tests of concrete produced in the country, to analyze the results statistically and make recommendations for further regulation on the national scale. Totally 109 concrete mixes produced commercially during the years 2012-2014 by concrete plants in Israel were analyzed. The average concentrations of NORM did not exceed the values recognized in the EU and were close to the values obtained from the Mediterranean countries such as Greece, Spain and Italy. It was also found that although the average value of the radon emanation coefficient of concrete containing coal fly ash (FA) was lower, than that of concrete mixes without FA, there was no significant difference between the indexes of both total radiation (addressing gamma radiation and radon together), and gamma radiation only, of the averages of the two sub-populations of concrete mixes: with and without FA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Properties of concrete at very low temperatures : A survey of the literature

    NARCIS (Netherlands)

    Van de Veen, V.

    1987-01-01

    This literature survey is focussed on the behaviour of concrete at very low temperatures down to -196°C. To give the reader some theoretical background, first the mechanisms of freezing and frost damage are discussed. Based on these mechanisms, reasonable explanations can be given for the

  13. 75 FR 72781 - Buckhorn Exploration Project 2010, Okanogan-Wenatchee National Forest, Okanogan County, WA

    Science.gov (United States)

    2010-11-26

    ... Forest Service Buckhorn Exploration Project 2010, Okanogan-Wenatchee National Forest, Okanogan County, WA Joint Lead Agencies: Forest Service, Department of Agriculture; and Department of Natural Resources... of Ecology, Washington State. ACTION: Notice of Intent to prepare an Environmental Impact Statement...

  14. Comparison of UPE and GPR systems for the survey of reinforced concrete structures

    Science.gov (United States)

    Derobert, Xavier; Villain, Géraldine; Joubert, Anaelle

    2014-05-01

    The objective of this study is to compare two non-destructive techniques using sonic and radar pulses for the survey of reinforced concre structures. The first studied testing method is a Ultrasonic (US) Pulse-Echo (model M2502, from Acoustic Control Systems manufacturer) composed of an array of 12 S-wave transmitters and 12 receivers in one bloc. Their central frequency is equal to 55 kHz. As the averaged USvelocities in concrete tend to 1800-3000 m/s, the corresponding wavelengths tend to 3-5 cm. The Ground-penetrating radar (GPR) system has been performed with high frequency antennas above 1 GHz (1.5 and 2.6 GHz antennas), which lead to the same range of EM wavelengths than the US ones. Measurements have been performed on some thick reinforced concrete elements of structures, and then are compared in term of resolution, depth penetration and ease to use. One of the studied elements is a concrete beam (dimensions : 16 m long, 0.5 m width and 1 m high) designed in an European Projet (FP7_ISTIMES) and damaged by controled impacts of blocks of several tons dropped from few meters [1]. Therefore, the objective of this studyis to compare the two techniques, and for the last studied element to detect the major cracks and the spallings of the cover concrete which are visible from the opposite side. References: Malhotra V.M., Carino, N.J., CRC Handbook on Nondestructive Testing of Concrete, CRC Press LLC, , 1991, 343p. Taffe A., Wiggenhauser H., Validation for Thickness Measurement in Civil Engineering with Ultrasonic Echo, International Symposium NDT-CE, Saint-Louis, USA, 2006, pp506-512. Géraldine Villain, Anaëlle Luczak, Olivier Durand, Xavier Dérobert, Deepening of the measurement technique by Ultrasonic Pulse Echo UPE, Report, IFSTTAR, January 2011, 22p. Catapano I., Di Napoli R., Soldovieri F., Bavusi M., Loperte A., Dumoulin J. (2012), « Structural monitoring via microwave tomography-enhanced GPR : the Montagnole test site », J. Geophys. Eng., Vol. 9, pp. 100-107.

  15. EBR Strengthening Technique for Concrete, Long-Term Behaviour and Historical Survey

    Directory of Open Access Journals (Sweden)

    Christoph Czaderski

    2018-01-01

    Full Text Available Epoxy bonded steel plates (externally bonded reinforcemen: EBR for the strengthening of concrete structures were introduced to the construction industry in the late 1960s, and the use of fibre reinforced polymers (FRPs was introduced in the 1990s, which means that these techniques have already been used in construction for 50 and 25 years, respectively. In the first part of the paper, a historical survey of the development and introduction of these strengthening techniques into the construction industry are presented. The monitoring of such applications in construction is very important and gives more confidence to this strengthening technique. Therefore, in the second part of the paper, two long-term monitoring campaigns over an extraordinarily long duration will be presented. Firstly, a 47-year monitoring campaign on a concrete beam with an epoxy bonded steel plate and, secondly, a 20-year monitoring campaign on a road bridge with epoxy bonded CFRP (carbon fibre reinforced polymers strips are described. The paper is an expanded version of the paper presented at the SMAR2017 Conference.

  16. 75 FR 42374 - Okanogan-Wenatchee National Forest, Washington, Pack and Saddle Stock Outfitter-Guide Special Use...

    Science.gov (United States)

    2010-07-21

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Okanogan-Wenatchee National Forest, Washington, Pack and Saddle... outfitter-guide campsites more compatible with party size limitations and provide for non- degradation of..., mineral soil) in established campsites. In campsites where the existing amount of barren core exceeds 5...

  17. Innovations in Site Characterization Case Study: Site Cleanup of the Wenatchee Tree Fruit Test Plot Site Using a Dynamic Work Plan

    Science.gov (United States)

    The Wenatchee Tree Fruit Research and Extension Center site contained soils contaminated with organochlorine pesticides, organophosphorus pesticides, and other pesticides due to agriculture-related research activities conducted from 1966 until...

  18. A Survey of a System of Methods for Fire Safety Design of Traditional Concrete Constructions

    DEFF Research Database (Denmark)

    Hertz, Kristian

    2000-01-01

    During the years since 1978 the author has been developing a series of calculation methods and sup-porting test methods for the fire safety design of concrete constructions. The basic methods have been adopted in the fire chapters of the Eurocode ENV1992-1-2 and the Danish code for concrete const...

  19. Light Water Reactor Sustainability Program: Survey of Models for Concrete Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Benjamin W. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation; Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States). Energy and Environment Science and Technology

    2014-08-01

    Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear facilities for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have predictive tools to address concerns related to aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to review and document the main aging mechanisms of concern for concrete structures in nuclear power plants (NPPs) and the models used in simulations of concrete aging and structural response of degraded concrete structures. This is in preparation for future work to develop and apply models for aging processes and response of aged NPP concrete structures in the Grizzly code. To that end, this report also provides recommendations for developing more robust predictive models for aging effects of performance of concrete.

  20. Survey results of corroding problems at biological treatment plants, Stage II Protection of concrete - State of the Art

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Ylva (CBI, Boraas (Sweden)); Henriksson, Gunilla (SP, Boraas (Sweden))

    2011-07-01

    A pilot study on the degradation and corrosion of concrete in biological treatment plants was conducted in 2009/2010 in a Waste Refinery Project WR-27 'Survey results of corroding problems at biological treatment plants'. The results showed that the concrete does not have sufficient resistance in the current aggressive plant environment. Furthermore, it is stated that some form of surface protection system is needed to ensure the good performance of concrete constructions, and that the system must withstand the aggressive environment and the traffic that occurs on site. Consequently, a new study was proposed in order to develop specifications for surface protection of concrete in aggressive food waste environments. Results from that study are presented in this report. The report includes various types of waterproofing/protection coating for concrete in biological treatment plants. A number of proposals from the industry are presented in the light of results from project WR-27, i.e., the materials must, among other things, withstand the aggressive leachate from waste food at temperatures up to 70 deg C, and some degree of wear. Some systems are compared in terms of technical material properties as reported by the manufacturer. It turns out that different testing methods were used, and the test results are thus generally not directly comparable. A proposal for a test program has been developed, focusing on chemical resistance and wear resistance. A test solution corresponding to leachate is specified. Laboratory tests for verification of the proposed methodology and future requirements are proposed, as well as test sites and follow-up in the field

  1. Wildfire may increase habitat quality for spring Chinook salmon in the Wenatchee River subbasin, WA, USA

    Science.gov (United States)

    Flitcroft, Rebecca L; Falke, Jeffrey A.; Reeves, Gordon H.; Hessburg, Paul F.; McNyset, Kris M.; Benda, Lee E.

    2016-01-01

    Pacific Northwest salmonids are adapted to natural disturbance regimes that create dynamic habitat patterns over space and through time. However, human land use, particularly long-term fire suppression, has altered the intensity and frequency of wildfire in forested upland and riparian areas. To examine the potential impacts of wildfire on aquatic systems, we developed stream-reach-scale models of freshwater habitat for three life stages (adult, egg/fry, and juvenile) of spring Chinook salmon (Oncorhynchus tshawytscha) in the Wenatchee River subbasin, Washington. We used variables representing pre- and post-fire habitat conditions and employed novel techniques to capture changes in in-stream fine sediment, wood, and water temperature. Watershed-scale comparisons of high-quality habitat for each life stage of spring Chinook salmon habitat suggested that there are smaller quantities of high-quality juvenile overwinter habitat as compared to habitat for other life stages. We found that wildfire has the potential to increase quality of adult and overwintering juvenile habitat through increased delivery of wood, while decreasing the quality of egg and fry habitat due to the introduction of fine sediments. Model results showed the largest effect of fire on habitat quality associated with the juvenile life stage, resulting in increases in high-quality habitat in all watersheds. Due to the limited availability of pre-fire high-quality juvenile habitat, and increased habitat quality for this life stage post-fire, occurrence of characteristic wildfires would likely create a positive effect on spring Chinook salmon habitat in the Wenatchee River subbasin. We also compared pre- and post-fire model results of freshwater habitat for each life stage, and for the geometric mean of habitat quality across all life stages, using current compared to the historic distribution of spring Chinook salmon. We found that spring Chinook salmon are currently distributed in stream channels in

  2. How Concrete Is Concrete?

    Science.gov (United States)

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  3. TRANSPARENT CONCRETE

    OpenAIRE

    Sandeep Sharma*, Dr. O.P. Reddy

    2017-01-01

    Transparent concrete is the new type of concrete introduced in todays world which carries special property of light transmitting due to presence of light Optical fibres. Which is also known as translucent concrete or light transmitting concrete, it is achieved by replacing coarse aggregates with transparent alternate materials (Optical fibres). The binding material in transparent concrete may be able to transmit light by using clear resins the concrete mix. The concrete used in industry in pr...

  4. Development and construction of low-cracking high-performance concrete (LC-HPC) bridge decks: Free shrinkage tests, restrained ring tests, construction experience, and crack survey results

    Science.gov (United States)

    Yuan, Jiqiu

    2011-12-01

    specimens than those cured for a shorter period. The third portion of the study evaluates the cracking tendency of concrete mixtures using the restrained ring tests. Different concrete ring thicknesses and drying conditions have been tested. The results indicate that specimens with thinner concrete rings crack earlier than those with thicker concrete rings. Exposing specimens to severe drying conditions results in the earlier formation of cracks, although it does not result in increased crack width. Mixtures with a lower water-cement (w/c) ratio crack earlier than mixtures with a higher w/c ratio. Concretes with a higher paste content crack earlier than concretes with a lower paste content. The final portion of the study details the development, construction, and preliminary performance (with most bridges at three years of age) of LC-HPC and control bridge decks in Kansas. The results indicate that the techniques embodied in the LC-HPC bridge deck specifications are easy to learn. Contractor personnel can be trained in a relatively short time. The techniques used for LC-HPC bridge decks are effective in reducing bridge deck cracking. The crack surveys indicate that LC-HPC bridge decks are performing much better than the control decks, with average crack densities reduced by about seventy five percent at three years of age. The factors that may affect bridge deck cracking are analyzed. The analyses indicate that an increase in paste content, slump, compressive strength, maximum daily air temperature, and daily air temperature range causes increased crack densities. Contractor techniques influence cracking. Keywords: bridge construction, bridge deck, contractor, concrete mix design, compressive strength, cracking, curing, evaporable water, fly ash, free shrinkage, high-performance concrete, non-evaporable water, paste content, restrained shrinkage, restrained ring tests, shrinkage reducing admixture, slump

  5. How Concrete is Concrete

    OpenAIRE

    Koeno Gravemeijer

    2010-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two diff...

  6. How Concrete is Concrete

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2010-07-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics

  7. How Concrete is Concrete?

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2011-01-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics.Key words:  Conceret Learning Materials, School Math, Common Sense, Scaffolding, Communication DOI: http://dx.doi.org/10.22342/jme.2.1.780.1-14

  8. Structural Precast Concrete Handbook

    DEFF Research Database (Denmark)

    Kjærbye, Per Oluf H

    Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly.......Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly....

  9. Glazed Concrete

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    Why glazed concrete? Concrete hardens and finds its strength at room temperature whereas clay products must first be fired before they achieve this strength. They are stronger and three times as durable as clay products, which is a weighty reason for choosing concrete.5 Another reason, which....... If this succeeds, it will be possible to manufacture thin, large-scale glazed concrete panels comparable in size to concrete sandwich construction and larger which, with or without back-casting, can work as load-bearing construction elements....

  10. Concrete Hinges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2014-01-01

    . The present paper uses the prior research results to optimize a test-setup for concrete hinge testing by means of a universal method taking into account the application of the hinge in an arch structure. 3D CAD is utilized in all steps of the planning to reduce errors during assembly of the parts in the test......In the first part of the 20th century concrete hinges developed by Freyssinet and Mesnager were widely tested and implemented in concrete structures. The concrete hinges were used a great deal in closed-spandrel arch bridges. Since such a bridge type has not been competitive for the past 40 years......, the research in concrete hinges has not evolved significantly in that period. But introducing a new state-of-the-art concrete arch bridge solution (Pearl-Chain arches invented at the Technical University of Denmark) creates a necessity of a concrete hinge research based on modern standards. Back when research...

  11. Concrete structures

    CERN Document Server

    Setareh, Mehdi

    2017-01-01

    This revised, fully updated second edition covers the analysis, design, and construction of reinforced concrete structures from a real-world perspective. It examines different reinforced concrete elements such as slabs, beams, columns, foundations, basement and retaining walls and pre-stressed concrete incorporating the most up-to-date edition of the American Concrete Institute Code (ACI 318-14) requirements for the design of concrete structures. It includes a chapter on metric system in reinforced concrete design and construction. A new chapter on the design of formworks has been added which is of great value to students in the construction engineering programs along with practicing engineers and architects. This second edition also includes a new appendix with color images illustrating various concrete construction practices, and well-designed buildings. The ACI 318-14 constitutes the most extensive reorganization of the code in the past 40 years. References to the various sections of the ACI 318-14 are pro...

  12. NANOMODIFIED CONCRETE

    Directory of Open Access Journals (Sweden)

    B. M. Khroustalev

    2015-01-01

    Full Text Available One of the main directions in construction material science is the development of  next generation concrete that is ultra-dense, high-strength, ultra-porous, high heat efficient, extra corrosion-resistant. Selection of such direction is caused by extreme operational impacts on the concrete, namely: continuously increasing load on the concrete and various dynamics of such loads; the necessity in operation of concrete products in a wide temperature range and their exposure to various chemical and physical effects.The next generation concrete represents high-tech concrete mixtures with additives that takes on and retain the required properties when hardening and being used under any operational conditions. A differential characteristic of the next generation concrete is its complexity that presumes usage of various mineral dispersed components, two- and three fractional fine and coarse aggregates, complex chemical additives, combinations of polymer and iron reinforcement.Design strength and performance properties level of the next generation concrete is achieved by high-quality selection of the composition, proper selection of manufacturing techniques, concrete curing, bringing the quality of concrete items to the required level of technical condition during the operational phase. However, directed formation of its structure is necessary in order to obtain high-tech concrete.Along with the traditional methods for regulation of the next generation concrete structure, modification of concrete while using silica nanoparticles is also considered as a perspective one because the concrete patterning occurs due to introduction of a binder in a mineral matrix. Due to this it is possible to obtain nano-modified materials with completely new properties.The main problem with the creation of nano-modified concrete is a uniform distribution of nano-materials in the volume of the cement matrix which is particularly important in the cases of adding a modifier in

  13. Genetic and Phenotypic Catalog of Native Resident Trout of the interior Columbia River Basin : FY-2001 Report : Populations in the Wenatchee, Entiat, Lake Chelan and Methow River Drainages.

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, Patrick C.

    2001-10-01

    The 1994 Fish and Wildlife Program of the Northwest Power Planning Council specifies the recovery and preservation of population health of native resident fishes of the Columbia River Basin. Among the native resident species of concern are interior rainbow trout of the Columbia River redband subspecies Oncorhynchus mykiss gairdneri 1 and westslope cutthroat trout O. clarki lewisi. The westslope cutthroat trout has been petitioned for listing under the U. S. Endangered Species Act (American Wildlands et al. 1997). Before at-risk populations can be protected, their presence and status must be established. Where introgression from introduced species is a concern, as in the case of both westslope cutthroat trout and redband rainbow trout, genetic issues must be addressed as well. As is true with native trout elsewhere in the western United States (Behnke 1992), most of the remaining pure populations of these species in the Columbia River Basin are in relatively remote headwater reaches. The objective of this project was to photo-document upper Columbia Basin native resident trout populations in Washington, and to ascertain their species or subspecies identity and relative genetic purity using a nonlethal DNA technique. FY-2001 was year three (and final year) of a project in which we conducted field visits to remote locations to seek out and catalog these populations. In FY-2001 we worked in collaboration with the Wenatchee National Forest to catalog populations in the Wenatchee, Entiat, Lake Chelan, and Methow River drainages of Washington State.

  14. Seismic performance evaluation of an historical concrete deck arch bridge using survey and drawing of the damages, in situ tests, dynamic identification and pushover analysis

    Science.gov (United States)

    Bergamo, Otello; Russo, Eleonora; Lodolo, Fabio

    2017-07-01

    The paper describes the performance evaluation of a retrofit historical multi-span (RC) deck arch bridge analyzed with in situ tests, dynamic identification and FEM analysis. The peculiarity of this case study lies in the structural typology of "San Felice" bridge, an historical concrete arch bridge built in the early 20th century, a quite uncommon feature in Italy. The preservation and retrofit of historic cultural heritage and infrastructures has been carefully analyzed in the international codes governing seismic response. A complete survey of the bridge was carried out prior to sketching a drawing of the existing bridge. Subsequently, the study consists in four steps: material investigation and dynamic vibration tests, FEM analysis and calibration, retrofit assessment, pushover analysis. The aim is to define an innovative approach to calibrate the FEM analysis through modern experimental investigations capable of taking structural deterioration into account, and to offer an appropriate and cost-effective retrofitting strategy.

  15. Water Entrainment in Concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    This report gives a survey of different techniques for incorporation of designed, water-filled cavities in concrete: Water entrainment. Also an estimate of the optimum size of the water inclusions is given. Water entrainment can be used to avoid self-desiccation and self-desiccation shrinkage...... during hydration [1,26]. What is needed is some sort of container which retains the shape of the water when mixed into the concrete. The container may function based on several different physical or chemical principles. Cells and gels are examples of containers found in nature. A cell membrane provides...... a boundary to water, whereas a polymer network incorporates water in its intersticious space with its affinity due to interaction energy and polymer entropy. Such containers allow water to be stored as an entity. In relation to concrete the water encapsulation may be accomplished either before or after start...

  16. A Geospatial Assessment of Mountain Pine Beetle Infestations and Their Effect on Forest Health in Okanogan-Wenatchee National Forest

    Science.gov (United States)

    Allain, M.; Nguyen, A.; Johnson, E.; Williams, E.; Tsai, S.; Prichard, S.; Freed, T.; Skiles, J. W.

    2010-12-01

    Fire-suppression over the past century has resulted in an accumulation of forest litter and increased tree density. As nutrients are sequestered in forest litter and not recycled by forest fires, soil nutrient concentrations have decreased. The forests of Northern Washington are in poor health as a result of these factors coupled with sequential droughts. The mountain pine beetle (MPB) thrives in such conditions, giving rise to an outbreak in Washington’s Okanogan-Wenatchee National Forest. These outbreaks occur in three successive stages— the green, red, and gray stages. Beetles first infest the tree in the green phase, leading to discoloration of needles in the red phase and eventually death in the gray phase. With the use of geospatial technology, these outbreaks can be better mapped and assessed to evaluate forest health. Field work on seventeen randomly selected sites was conducted using the point-centered quarter method. The stratified random sampling technique ensured that the sampled trees were representative of all classifications present. Additional measurements taken were soil nutrient concentrations (sodium [Na+], nitrate [NO3-], and potassium [K+]), soil pH, and tree temperatures. Satellite imagery was used to define infestation levels and geophysical parameters, such as land cover, vegetation classification, and vegetation stress. ASTER images were used with the Ratio Vegetation Index (RVI) to explore the differences in vegetation, while MODIS images were used to analyze the Disturbance Index (DI). Four other vegetation indices from Landsat TM5 were used to distinguish the green, red and gray phases. Selected imagery from the Hyperion sensor was used to run a minimum distance supervised classification in ENVI, thus testing the ability of Hyperion imagery to detect the green phase. The National Agricultural Imagery Program (NAIP) archive was used to generate accurate maps of beetle-infested regions. This algorithm was used to detect bark beetle

  17. Concrete spirituality

    National Research Council Canada - National Science Library

    Kritzinger, Johannes N J

    2014-01-01

    .... The basic contention of the article is that well designed liturgies that facilitate experiences of beauty can nurture a concrete spirituality to mobilise urban church members for a justice-seeking lifestyle...

  18. Photocatalyticpaving concrete

    Directory of Open Access Journals (Sweden)

    Lyapidevskaya Ol'ga Borisovna

    2014-02-01

    Full Text Available Today bituminous concrete is a conventional paving material. Among its advantages one can name dustlessness and noiselessness, fine wear (up to 1 mm a year and fine maintainability. As the main disadvantages of this material one can name high slipperiness under humidification, low durability and weather resistance. Besides that, during placement of the bituminous concrete a lot of different air pollutants are emitted, which are harmful for environment and human’s health (they are listed in the paper according to the US Environmental Protection Agency materials. As an alternative, one can use cement-concrete pavement, which is in many ways more efficient than the bituminous concrete. It is proposed to enhance environmental performance of the cement-concrete pavement via usage of photocatalysis. The mechanism of different photocatalytic reactions is described in the paper, namely heterogeneous and homogeneous photocatalysis, photo-induces, photoactivated catalysis and catalytical photoreactions. It is pro-posed to use heterogeneous photocatalysis with titanium dioxide as a photocatalyst. The mechanism of photo oxidation of air contaminants, with the usage of titanium dioxide is2described. The paper sets problems, connected with the sensibilization of TiOto thevisible light (it is proposed to use titanium dioxide, doped with the atoms of certain elements to increase its sensibility to the visible light and with the development of a new photocatalytic paving concrete, which will meet the requirements, specified for paving in the climatic and traffic conditions of the Russian Federation.

  19. Self-Placing Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Certain concrete pours have areas where the congestion of reinforcing bars make placement of concrete almost impossible. Using conventional placing and vibration techniques, the resulting concrete can have considerable honeycombing due to the development of voids. Self-placing concrete is a possible solution to the problem. Also known as self-compactable concrete, self-consolidating concrete, flowable concrete, and non-vibration concrete. These concretes eliminate the need for vibration in a ...

  20. Geochemical signatures in fin rays provide a nonlethal method to distinguish the natal rearing streams of endangered juvenile Chinook Salmon Oncorhynchus tshawytscha in the Wenatchee River, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Linley, Timothy J.; Krogstad, Eirik J.; Nims, Megan K.; Langshaw, Russell B.

    2016-09-01

    Rebuilding fish populations that have undergone a major decline is a challenging task that can be made more complicated when estimates of abundance obtained from physical tags are biased or imprecise. Abundance estimates based on natural tags where each fish in the population is marked can help address these problems, but generally requires that the samples be obtained in a nonlethal manner. We evaluated the potential of using geochemical signatures in fin rays as a nonlethal method to determine the natal tributaries of endangered juvenile spring Chinook Salmon in the Wenatchee River, Washington. Archived samples of anal fin clips collected from yearling smolt in 2009, 2010 and 2011 were analyzed for Ba/Ca, Mn/Ba, Mg/Ca, Sr/Ca, Zn/Ca and 87Sr/86Sr by inductively coupled plasma mass spectrometry. Water samples collected from these same streams in 2012 were also quantified for geochemical composition. Fin ray and water Ba/Ca, Sr/Ca, and 87Sr/86Sr were highly correlated despite the samples having been collected in different years. Fin ray Ba/Ca, Mg/Ca, Sr/Ca, Zn/Ca and 87Sr/86Sr ratios differed significantly among the natal streams, but also among years within streams. A linear discriminant model that included Ba/Ca, Mg/Ca, Sr/Ca, and 87Sr/86Sr correctly classified 95% of the salmon to their natal stream. Our results suggest that fin ray geochemistry may provide an effective, nonlethal method to identify mixtures of Wenatchee River spring Chinook Salmon for recovery efforts when these involve the capture of juvenile fish to estimate population abundance.

  1. Historic Concrete : From Concrete Repair to Concrete Conservation

    NARCIS (Netherlands)

    Heinemann, H.A.

    2013-01-01

    Concrete like materials were already applied during the Roman Empire. After the decline of the Roman Empire, a wide scale application of concrete only reappeared in the 19th century. Here lies also the origin of modern (reinforced) concrete. Since then, both concrete application and composition have

  2. Quantifying spatial patterns in the Yakama Nation Tribal Forest and Okanogan-Wenatchee National Forest to assess forest health

    Science.gov (United States)

    Wilder, T. F.

    2013-05-01

    Over the past century western United States have experienced drastic anthropogenic land use change from practices such as agriculture, fire exclusion, and timber harvesting. These changes have complex social, cultural, economic, and ecological interactions and consequences. This research studied landscapes patterns of watersheds with similar LANDFIRE potential vegetation in the Southern Washington Cascades physiographic province, within the Yakama Nation Tribal Forest (YTF) and Okanogan-Wenatchee National Forest, Naches Ranger District (NRD). In the selected watersheds, vegetation-mapping units were delineated and populated based on physiognomy of homogeneous areas of vegetative composition and structure using high-resolution aerial photos. Cover types and structural classes were derived from the raw, photo-interpreted vegetation attributes for individual vegetation mapping units and served as individual and composite response variables to quantify and assess spatial patterns and forest health conditions between the two ownerships. Structural classes in both the NRD and YTF were spatially clustered (Z-score 3.1, p-value 0.01; Z-score 2.3, p-value 0.02, respectively), however, ownership and logging type both explained a significant amount of variance in structural class composition. Based on FRAGSTATS landscape metrics, structural classes in the NRD displayed greater clustering and fragmentation with lower interspersion relative to the YTF. The NRD landscape was comprised of 47.4% understory reinitiation structural class type and associated high FRAGASTAT class metrics demonstrated high aggregation with moderate interspersion. Stem exclusion open canopy displayed the greatest dispersal of structural class types throughout the NRD, but adjacencies were correlated to other class types. In the YTF, stem exclusion open canopy comprised 37.7% of the landscape and displayed a high degree of aggregation and interspersion about clusters throughout the YTF. Composite cover

  3. Concrete Memories

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    2015-01-01

    and poetic appropriations and inscriptions of the bunker site are depicted. Ranging between overlooked side presences and an overwhelming visibility, the concrete remains of fascist war architecture are involved in and motivate different sensuous experiences and mnemonic appropriations. The article meets...

  4. High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Traian Oneţ

    2009-01-01

    Full Text Available The paper presents the last studies and researches accomplished in Cluj-Napoca related to high performance concrete, high strength concrete and self compacting concrete. The purpose of this paper is to raid upon the advantages and inconveniences when a particular concrete type is used. Two concrete recipes are presented, namely for the concrete used in rigid pavement for roads and another one for self-compacting concrete.

  5. Dynamic Response of Concrete and Concrete Structures

    Science.gov (United States)

    1984-01-26

    low - . AFOSR-T... 84-0.165 DYNAMIC RESPONSE OF CONCRETE AND CONCRETE STRUCTURES FIRST ANNUAL TECHNICAL REPORT LAWRENCE E. 14ALVERN C. ALLEN ROSS...and Subtitle) S. TYPE OF REPORT I PERIOD COVERED DYNAMIC RESPONSE OF CONCRETE 1 DEC 1982 - 30 NOV 1983 AND CONCRETE STRUCTURES I_____198__-__0_NOV_198...Bar Dynamic Loads Fracture Materials Testing Dynamic Properties Impact Rate Effects Dynamic Testing Hopkinson Bar Reinforced Concrete Structures 20

  6. Hemp concretes

    OpenAIRE

    de Bruijn, Paulien

    2008-01-01

    Hemp (Cannabis sativa) is an agricultural crop that can be used as a building material in combination with lime and cement. A composite building material that combines a cementitious binder (building limes and cement) with hemp shives, the woody core of the hemp stalk is generally referred to as hemp concrete (HC). However, industrial facilities to separate hemp shives and fibres are currently not available in Sweden. HC has many advantages as a building material but it is not load-bearing an...

  7. Concrete evidence

    Energy Technology Data Exchange (ETDEWEB)

    Provis, J.; Duxson, P.; van Deventer, J. [University of Melbourne, Vic. (Australia)

    2008-11-15

    The time is right for a revolution in the cement industry which is responsible for 5-8% of all human-derived carbon dioxide emissions. Zeobond, an Australian company, has developed E-Crete which is a geopolymer concrete using fly ash and blast furnace slags which reduces CO{sub 2} emissions by 80% from the 0.67t of CO{sub 2} per ton of cement emitted by the Australian triple blend of cement, fly ash and slag. The article discusses the products development, standards for cements and challenges to the commercialization of E-Crete. 5 refs., 3 figs.

  8. Concrete construction engineering handbook

    CERN Document Server

    Nawy, Edward G

    2008-01-01

    Provides coverage of concrete construction engineering and technology. This work features discussions focusing on: the advances in engineered concrete materials; reinforced concrete construction; specialized construction techniques; and, design recommendations for high performance.

  9. Recycled concrete aggregate in portland cement concrete.

    Science.gov (United States)

    2013-01-01

    Aggregates can be produced by crushing hydraulic cement concrete and are known as recycled concrete : aggregates (RCA). This report provides results from a New Jersey Department of Transportation study to identify : barriers to the use of RCA in new ...

  10. The Future Concrete: Self-Compacting Concrete

    OpenAIRE

    Liana Iureş; Corneliu Bob

    2010-01-01

    The paper presents the characteristics of the self-compacting concretes, their advantages and disadvantages when they are used in buildings. Due to its properties and composition, the self-compacting concrete is described here as being one of the future friendly enviromental material for buildings. Tests concerning to obtaining a self-compacting concrete, together with the specific fresh concrete properties tests, are described.

  11. The Future Concrete: Self-Compacting Concrete

    Directory of Open Access Journals (Sweden)

    Liana Iureş

    2010-01-01

    Full Text Available The paper presents the characteristics of the self-compacting concretes, their advantages and disadvantages when they are used in buildings. Due to its properties and composition, the self-compacting concrete is described here as being one of the future friendly enviromental material for buildings. Tests concerning to obtaining a self-compacting concrete, together with the specific fresh concrete properties tests, are described.

  12. Concrete durability

    Directory of Open Access Journals (Sweden)

    Gaspar Tébar, Demetrio

    1991-03-01

    Full Text Available The evidence that the concrete is not a material for ever was noticed from the beginning of its industrial use. In the present work, the author describes the studies carried out during the last century and the early ages of the present one, mainly devoted to the study of the durability in sea water. At the present days, and in spite of the numerous papers published from then, the study of the concrete durability continues focusing the research priorities and economical resources of researchers and industries related with this material. Moreover, the new laboratory techniques are allowing to understand old problems and even to open again the discussion on reaction mechanisms which were believed to be completely understood. The article finalizes with a brief description of the numerous studies carried out at the Institute Eduardo Torroja on concrete durability, mainly those related with the resistance against gypsum attack (so abundant in our country land and against sea water attack.

    La realidad de que el hormigón no es un material eterno y es susceptible de sufrir ataques por agentes químicos, fue constatada desde el comienzo mismo de su uso industrial. En el presente trabajo el autor enumera los estudios realizados el siglo pasado y a comienzos del presente sobre la durabilidad del hormigón en agua de mar. En la actualidad y a pesar de los numerosos trabajos desarrollados desde entonces, el estudio de la durabilidad del hormigón sigue centrando la atención prioritaria y los recursos económicos de los investigadores e industrias relacionadas con este material. Además las nuevas técnicas de estudio están permitiendo comprender antiguos problemas e incluso reabrir la discusión sobre mecanismos de reacción que se creían completamente explicados. Finaliza el artículo con una descripción somera de los múltiples trabajos realizados en el Instituto Eduardo Torreja sobre la materia, en especial los estudios realizados sobre

  13. Refractory concretes

    Science.gov (United States)

    Holcombe, Jr., Cressie E.

    1979-01-01

    Novel concrete compositions comprise particles of aggregate material embedded in a cement matrix, said cement matrix produced by contacting an oxide selected from the group of Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Sm.sub.2 O.sub.3, Eu.sub.2 O.sub.3 and Gd.sub.2 O.sub.3 with an aqueous solution of a salt selected from the group of NH.sub.4 NO.sub.3, NH.sub.4 Cl, YCl.sub.3 and Mg(NO.sub.3).sub.2 to form a fluid mixture; and allowing the fluid mixture to harden.

  14. Concrete spirituality

    Directory of Open Access Journals (Sweden)

    Johannes N.J. Kritzinger

    2014-02-01

    Full Text Available This article reflects on a number of liturgical innovations in the worship of Melodi ya Tshwane, an inner-city congregation of the Uniting Reformed Church in Southern Africa (URCSA. The focus of the innovations was to implement the understanding of justice in Article 4 of the Confession of Belhar, a confessional standard of the URCSA. The basic contention of the article is that well designed liturgies that facilitate experiences of beauty can nurture a concrete spirituality to mobilise urban church members for a justice-seeking lifestyle. After exploring the message of Article 4 of Belhar, the article analyses eight liturgical features of Melodi ya Tshwane, showing how beauty and justice interact in those acts of worship.

  15. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  16. Corrosion of steel in concrete in cooling water walls. Report part 1 - Literature survey; Korrosion paa staal i betong i kylvattenvaegar. Delrapport 1 - Litteraturgranskning

    Energy Technology Data Exchange (ETDEWEB)

    Lindmark, Sture; Sederholm, Bror

    2010-09-15

    The aim of the present literature study has been to collect knowledge about reported concentrations of chloride concentrations in concrete exposed to brackish water and also to get an overview of whether a critical threshold chloride concentration for chloride induced corrosion on steel embedded in concrete has been reported and/or accepted. Only five known reports present chloride concentrations in concrete that has been exposed to brackish water. All three refer to the Baltic sea or the Gulf of Bothnia. Reported chloride concentrations in the concrete is considerably higher (more than a factor of ten) than what would have been expected if the chloride had been present in the concrete only as sea water in the pore system. One reason why high chloride concentrations occur in certain zones of the concrete may be that in these zones, evaporation and capillary suction of salt water may occur alternately. Another reason is that chloride ions are physically and/or chemically bound to the cement paste structure. Chloride binding is reported to be dependent on pH value in the pore solution. In line with this, another report suggests that the pH value of the outer chloride solution (the exposure solution) may be affected by the test sample when tests are carried out in small beakers, like in the laboratory. The author of that report says this might be a reason why critical chloride concentrations with respect to steel corrosion measured in the laboratory and in the field will deviate. As for reported threshold levels, many different values have been reported, differing by more than a factor 100, irrespective of the way of reporting (chloride by cement weight, chloride to hydroxide ratio, chloride to pore solution volume, etc). Some authors claim that in fact no one, single critical chloride concentration exists, but that it will depend on several other factors such as humidity, oxygen availability, pH etc. Furthermore, there are different opinions on whether bound

  17. Monitoring the Reproductive Success of Naturally Spawning Hatchery and Natural Spring Chinook Salmon in the Wenatchee River, 2008-2009 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J.; Williamson, Kevin S. [Northwest Fisheries Science Center

    2009-05-28

    male fitness. For both sexes, run time had a smaller but still significant effect on fitness, with earlier returning fish favored. Spawning location within the river had a significant effect on fitness for both males and females, and for females explained most of the reduced fitness observed for hatchery fish in this population. While differences have been reported in the relative reproductive success of hatchery and naturally produced salmonids Oncorhynchus spp., factors explaining the differences are often confounded. We examined the spawning site habitat and redd structure variables of hatchery and naturally produced spring Chinook salmon O. tshawytscha of known size that spawned in two tributaries of the Wenatchee River. We controlled for variability in spawning habitat by limiting our analysis to redds found within four selected reaches. No difference in the instantaneous spawner density or location of the redd in the stream channel was detected between reaches. Within each reach, no difference in the fork length or weight of hatchery and naturally produced fish was detected. While most variables differed between reaches, we found no difference in redd characteristics within a reach between hatchery and naturally produced females. Correlation analysis of fish size and redd characteristics found several weak but significant relationships suggesting larger fish contract larger redds in deeper water. Spawner density was inversely related to several redd structure variables suggesting redd size may decrease as spawner density increases. Results should be considered preliminary until samples size and statistical power goals are reached in future years. Trends in relative reproductive success of hatchery and naturally produced spring Chinook salmon Oncorhynchus tshawytscha in the Wenatchee Basins suggest females that spawn in the upper reaches of the tributaries produced a great number of offspring compared to females that spawn in the lower reaches of the tributaries

  18. Fibre Concrete 2017

    Science.gov (United States)

    2017-09-01

    9th international conference on fibre reinforced concretes (FRC), textile reinforced concretes (TRC) and ultra-high performance concretes (UHPC) Preface The Fibre Concrete Conference series is held biennially to provide a platform to share knowledge on fibre reinforced concretes, textile concretes and ultra-high performance concretes regarding material properties and behaviour, technology procedures, topics of long-term behaviour, creep, durability; sustainable aspects of concrete including utilisation of waste materials in concrete production and recycling of concrete. The tradition of Fibre Concrete Conferences started in eighties of the last century. Nowadays the conference is organized by the Department of Concrete and Masonry Structures of the Czech Technical University in Prague, Faculty of Civil Engineering. The 9th International Conference Fibre Concrete 2017 had 109 participants from 27 countries all over the world. 55 papers were presented including keynote lectures of Professor Bažant, Professor Bartoš and Dr. Broukalová. The conference program covered wide range of topics from scientific research to practical applications. The presented contributions related to performance and behaviour of cement based composites, their long-term behaviour and durability, sustainable aspects, advanced analyses of structures from these composites and successful applications. This conference was organized also to honour Professor Zděnek P. Bažant on the occasion of his jubilee and to appreciate his merits and discoveries in the field of fibre reinforced composites, structural mechanics and engineering.

  19. Microscopic examination of deteriorated concrete

    NARCIS (Netherlands)

    Nijland, T.G.; Larbi, J.A.

    2010-01-01

    Concrete petrography is the integrated microscopic and mesoscale (hand specimen size) investigation of hardened concrete, that can provide information on the composition of concrete, the original relationships between the concrete's various constituents, and any changes therein, whether as a result

  20. Sustainable Concrete Technology

    Directory of Open Access Journals (Sweden)

    Sim J.

    2015-12-01

    Full Text Available The growing concern over global warming and significant ecological changes requires sustainable development in all fields of science and technology. Concrete not only consumes huge amount of energy and natural sources, but also emits large amount of CO2, mainly due to the production of cement. It is evident that such large amount of concrete production has put significant impact on the energy, resource, environment, and ecology of the society. Hence, how to develop the concrete technology in a sustainable way has become a significant issue. In this paper, some of Korean researches for sustainable development of concrete are presented. These are sustainable strengthening for deteriorated concrete structure, sustainable reinforcement of new concrete structure, sustainable concrete using recycled aggregate and supplementary cementing materials and finally application of each technique to precast concrete.

  1. Concrete pavement joint deterioration.

    Science.gov (United States)

    2015-12-01

    Concrete pavements are an important part of our national infrastructure. In recent years the relatively small number of reported joints deteriorating prematurely in concrete pavements around Indiana has increased. Changes over the past 45 years in IN...

  2. Properties of Sulfur Concrete.

    Science.gov (United States)

    1979-07-06

    sulfur 19 11 Effect of H2 S on compressive strength of sulfur concretes 21 12 Modulus of rupture vs. temperature for raw sulfur and a sulfur mortar 22 13...sulfur, Jordaan investigated the effects of hydrogen sulfide on sulfur concrete. Concretes were made with different mixtures of pyrrhotite and flyash ...temperature for raw sulfur and a sulfur mortar (Ref. 19). eabove results were obtained with a sulfur mortar and raw sulfur; however, sulfur concrete could be

  3. Deterioration of Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Chloride ingress is a common cause of deterioration of reinforced concrete bridges. Concrete may be exposed to chloride by seawater or de-icing salts. The chloride initiates corrosion of the reinforcement, which through expansion disrupts the concrete. In addition, the corrosion reduces the cross...

  4. concrete5 for developers

    CERN Document Server

    Uzayr, Sufyan bin

    2014-01-01

    Whether you have had some previous experience with concrete5 or are entirely new to it, this book will help you understand all that you need to know in order to get started with concrete5 development. A background in PHP is required; some knowledge of HTML/CSS is needed in order to fully grasp the concepts underlying concrete5 theme development.

  5. Work Element B: 157. Sampling in Fish-Bearing Reaches [Variation in Productivity in Headwater Reaches of the Wenatchee Subbasin], Final Report for PNW Research Station.

    Energy Technology Data Exchange (ETDEWEB)

    Polivka, Karl; Bennett, Rita L. [USDA Forest Service, Pacific Northwest Research Station, Wenatchee, WA

    2009-03-31

    We studied variation in productivity in headwater reaches of the Wenatchee subbasin for multiple field seasons with the objective that we could develop methods for monitoring headwater stream conditions at the subcatchment and stream levels, assign a landscape-scale context via the effects of geoclimatic parameters on biological productivity (macroinvertebrates and fish) and use this information to identify how variability in productivity measured in fishless headwaters is transmitted to fish communities in downstream habitats. In 2008, we addressed this final objective. In collaboration with the University of Alaska Fairbanks we found some broad differences in the production of aquatic macroinvertebrates and in fish abundance across categories that combine the effects of climate and management intensity within the subbasin (ecoregions). From a monitoring standpoint, production of benthic macroinvertebrates was not a good predictor of drifting macroinvertebrates and therefore might be a poor predictor of food resources available to fish. Indeed, there is occasionally a correlation between drifting macroinvertebrate abundance and fish abundance which suggests that headwater-derived resources are important. However, fish in the headwaters appeared to be strongly food-limited and there was no evidence that fishless headwaters provided a consistent subsidy to fish in reaches downstream. Fish abundance and population dynamics in first order headwaters may be linked with similar metrics further down the watershed. The relative strength of local dynamics and inputs into productivity may be constrained or augmented by large-scale biogeoclimatic control. Headwater streams are nested within watersheds, which are in turn nested within ecological subregions; thus, we hypothesized that local effects would not necessarily be mutually exclusive from large-scale influence. To test this we examined the density of primarily salmonid fishes at several spatial and temporal scales

  6. Recycled Concrete as Aggregate for Structural Concrete Production

    OpenAIRE

    Mirjana Malešev; Vlastimir Radonjanin; Snežana Marinković

    2010-01-01

    A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC) as a control concrete and two types of concrete made with natural fine and recycle...

  7. Autogenous Deformation of Concrete

    DEFF Research Database (Denmark)

    Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased...... focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions...... at the American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate...

  8. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  9. Waterproofing Underground Concrete Structures

    Science.gov (United States)

    1990-01-01

    their explosive potential, were required to be hardened earth covered concrete structures . Because the water table was located only one foot below the... concrete structures such as utility tunnels, communication vaults, I basements, elevator pits, missile silos, and control rooms. *|2 1.2 Reasons for...underground concrete structures which are usually surrounded by moisture the need to keep the water out is critical. Probably the most common example of

  10. POLYMER CONCRETE CREEP

    OpenAIRE

    Yu. М. Borisov; I. S. Surovtsev; Yu. B. Potapov

    2012-01-01

    Problem statement. It is well known that creep is the tendency of a solid material to move slowly or deform permanently under the influence of stresses. The aim of the paper is to study the process of creep in polymer concretes. Results and conclusions. It is shown that creep in polymer concrete occurs according to the same pattern as in many other polymer composites with the elastic core. Equations which indirectly es-tablish the relation between complete deformations of polymer concrete, in...

  11. Evaluation of recycled concrete as aggregate in new concrete pavements.

    Science.gov (United States)

    2014-04-01

    This study evaluated the use of recycled concrete as coarse aggregate in new concrete pavements. : Recycled concrete aggregate (RCA) produced from demolished pavements in three geographically dispersed locations in Washington state were used to perfo...

  12. Concrete portable handbook

    CERN Document Server

    Woodson, R Dodge

    2011-01-01

    Whether or not, you are on the job site or back in the office, this book will help you to avoid mistakes, code violations, and wasted time and money. The book's four part treatment begins with constituent materials followed by self contained parts on Concrete Properties, Processes, and Concrete Repair and Rehabilitation. Designed to be an ""all in one"" reference, the author includes a wealth information for the most popular types of testing. This includes: Analysis of Fresh Concrete; Testing Machines; Accelerated Testing Methods; Analysis of Hardened Concrete and Mortar; Core Sampl

  13. MULTIDISCIPLINARY APPROACH TO STUDY MIGMATITES: ORIGIN AND TECTONIC HISTORY OF THE NASON RIDGE MIGMATITIC GNEISS, WENATCHEE BLOCK, CASCADES CRYSTALLINE CORE, WA, USA

    Directory of Open Access Journals (Sweden)

    Stowell Harold H.

    2008-12-01

    Full Text Available The Nason Ridge Migmatitic Gneiss of the Cascades Core is a migmatitic unit comprising concordant pelitic schist and gneiss, amphibolite, and tonalite gneiss, and cross cutting tonalite, quartz-rich granitoid, and pegmatite. There are several generations of 'igneous' lithologies (leucosomes = tonalite, quartz-rich granitoid, and pegmatite some of which are concordant; others clearly crosscut the strongly deformed host rocks. The host rocks are interpreted to be Chiwaukum Schist with metasedimentary (pelitic schist and some gneiss and metavolcanic(amphibolites origins. Metamorphic fabric in the Nason Ridge Migmatitic Gneiss is characterized by preferred orientation of platy minerals (continuous schistosity, compositional layering, mineral lineations (elongate grains and grain aggregates, and non-coaxial deformational features (asymmetric augen, grain offsets,rotated porphyroblasts, etc.. Compositional layering is characterized by quartz-plagioclase lenses and patches (mm to cm scale and by large variations in biotite content. This composite fabric is faulted and folded by mesoscopic structures. The most strongly foliated leucosomes (gneissic tonalites are generally concordant with the regional trend of foliation, while weakly foliated leucosomes (tonalites and pegmatite veins crosscut host rock and tonalite gneisses. Thin melanosome layers (biotiteand amphibole schist are developed locally around quartz - plagioclase lenses and patches. Metamorphism in the Nason Ridge Migmatitic Gneiss and the nearby Chiwaukum Schist likely peaked after intrusion of the Mt. Stuart Batholith ca. 91-94 Ma. Peak temperatures and pressures for the Nason Ridge Migmatitic Gneiss in the Wenatchee Ridge and Pacific Crest areas were 650 - 720 °C and 6 - 9 kbar with a pressure increase of £ 2.0 kbar during metamorphism. Thermodynamic modeling indicates that hydrous partial melting would begin at ca. 660 °C and is relatively pressure independent. Field

  14. LIGHTWEIGHT CONCRETE BASED GRANSHLAK

    Directory of Open Access Journals (Sweden)

    NETESA M. I.

    2016-02-01

    Full Text Available Raising of problem. Concrete advisable to obtain a low strength with local secondary resources for recycling and reduce the environmental burden on the environment. But it is important to design such concrete compositions with a reduced flow of cement. It is known that the coefficient of efficiency of use of cement in the concrete of the heavy and B10 is less than about 0.5, which is almost two times smaller than in class B15 concrete and above. Even lower coefficient of efficiency in light concrete cement low strength. Therefore, it is important to find patterns determining the composition of lightweight concrete based on local-products industry with more efficient use of cement in them. Purpose.. Based on the analysis of earlier research results, including with the use of methods of mathematical planning of experiments to determine the concrete contents, which can provide the requirements for the underlying layers of the floor, the compressive strength of which should correspond to the class B5. It is important to provide the required strength at minimum flow of the cement, which is the most expensive and energy-intensive part of concrete. Conclusion. Analysis of the test results of control samples of concrete in 28-day-old, the following laws. The required tensile strength of concrete compressive strength of 7.0 MPa can be obtained in the test range when used in formulations as a filler as the Dnieper hydroelectric power station fly ash and tailings Krivoy Rog iron ore YuGOK. To ensure providing the required characteristic strength of the concrete in the underlying layers of the floor is advisable to use a nominal composition per cubic meter of concrete: cement 160 kg granshlaka Plant named after Petrovsky, 675 kg of fly ash Dnieper HPP 390 kg, 400 kg of sand, 230 liters of water. Thus, while ensuring rational grain composition components can obtain the desired strength lightweight concrete based granshlaka plant Petrovsky, using as fillers

  15. Concrete, hardened: Self desiccation

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard; Persson, Bertil

    1999-01-01

    The test method covers the determination of internal relative humidity (RH) in hardened concrete and cement mortar using RH instruments. The determination of RH is done on crushed samples of concrete or cement motar. This test method is only for measuring equipment which gives off or takes up...

  16. Curing of Concrete

    African Journals Online (AJOL)

    use it economically. Curing of concrete involves the retention of sufficient free water in the cement paste so that the process of cement hydration may readily proceed. It also involves favorable temperature, humidity, and wind speed. No part of the process of making good concrete is more important than thorough curing.

  17. Concrete deck material properties.

    Science.gov (United States)

    2009-01-01

    The two-fold focus of this study was (a) to develop an understanding of the mechanisms responsible for causing : cracking in the concrete; and (b) to study the influence of the local materials on the performance of NYSDOTs HP : concrete mixture. R...

  18. Environmental Impact of Concrete

    Directory of Open Access Journals (Sweden)

    Dan Babor

    2009-01-01

    Full Text Available The cement and concrete industries are huge. What does this mean in terms of the environment? Concrete and other cementitious materials have both environmental advantages and disadvantages. This paper takes a look at how these materials are made, then reviews a number of environmental considerations relating to their production and use.

  19. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ...

  20. Concrete-Design

    Directory of Open Access Journals (Sweden)

    Leczovics Péter

    2014-12-01

    Full Text Available Present paper introduces a new interpretation of concrete, demonstrating some extreme possibilities of this rigid material such as a design element. In the first part a brief overview of the previous achievements are shown. The second part of this paper focuses on the relationship between concrete and fashion.

  1. concrete5 Beginner's Guide

    CERN Document Server

    Laubacher, Remo

    2011-01-01

    This book is part of Packt's Beginner's Guide series. You will be guided through the set up of a Concrete5 site with step-by-step practical examples. This book is ideal for developers who would like to build their first site with Concrete5. Some k

  2. Concrete quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Holz, N. [Harza Engineering Company, Chicago, IL (United States)

    2000-08-01

    This short article reports on progress at the world's largest civil construction project, namely China's Three Gorges hydro project. Work goes on around the clock to put in place nearly 28 M m{sup 3} of concrete. At every stage of the work there is strong emphasis on quality assurance (QA) and concrete is no exception. The US company Harza Engineering has been providing QA since the mid-1980s and concrete QA has been based on international standards. Harza personnel work in the field with supervisors developing educational tools for supervising concrete construction and quality, as well as providing training courses in concrete technology. Some details on flood control, capacity, water quality and environmental aspects are given..

  3. Concrete sample point: 304 Concretion Facility

    Energy Technology Data Exchange (ETDEWEB)

    Rollison, M.D.

    1995-03-10

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis.

  4. Performance of Waterless Concrete

    Science.gov (United States)

    Toutanji, Houssam; Evans, Steve; Grugel, Richard N.

    2010-01-01

    The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target a 5-cm cubic sample of sulfur concrete. This item consisted of JSC-1 lunar regolith simulant (65%) and sulfur (35%). The sample was placed in the MSFC Impact Test Facility s Micro Light Gas Gun target chamber, and was struck by a 1-mm diameter (1.4e-03 g) aluminum projectile at 5.85 km/s. In addition, HZTERN code, provided by NASA was used to study the effectiveness of sulfur concrete when subjected to space radiation.

  5. concrete5 cookbook

    CERN Document Server

    Strack, David

    2013-01-01

    The Cookbook-style recipes allow you to go both directly to your topic of interest or follow topics throughout a chapter to gain in-depth knowledge. This practical Cookbook will cater to the needs of both intermediate and advanced concrete5 developers.This book is geared towards intermediate to advanced PHP developers who would like to learn more about the concrete5 content management system. Developers already familiar with concrete5 will learn new time-saving tricks and will find the book to be a great reference tool.

  6. Life Cycle Cost Analysis of Ready Mix Concrete Plant

    Science.gov (United States)

    Topkar, V. M.; Duggar, A. R.; Kumar, A.; Bonde, P. P.; Girwalkar, R. S.; Gade, S. B.

    2013-11-01

    India, being a developing nation is experiencing major growth in its infrastructural sector. Concrete is the major component in construction. The requirement of good quality of concrete in large quantities can be fulfilled by ready mix concrete batching and mixing plants. The paper presents a technique of applying the value engineering tool life cycle cost analysis to a ready mix concrete plant. This will help an investor or an organization to take investment decisions regarding a ready mix concrete facility. No economic alternatives are compared in this study. A cost breakdown structure is prepared for the ready mix concrete plant. A market survey has been conducted to collect realistic costs for the ready mix concrete facility. The study establishes the cash flow for the ready mix concrete facility helpful in investment and capital generation related decisions. Transit mixers form an important component of the facility and are included in the calculations. A fleet size for transit mixers has been assumed for this purpose. The life cycle cost has been calculated for the system of the ready mix concrete plant and transit mixers.

  7. Electrokenitic Corrosion Treatment of Concrete

    Science.gov (United States)

    Cardenas, Henry E (Inventor)

    2015-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  8. Electrokinetic Strength Enhancement of Concrete

    Science.gov (United States)

    Cardenas, Henry E. (Inventor)

    2016-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  9. Anchorage in concrete construction

    CERN Document Server

    Eligehausen, Rolf; Silva, John F

    2013-01-01

    A comprehensive treatment of current fastening technology using inserts (anchor channels, headed stud), anchors (metal expansion anchor, undercut anchor, bonded anchor, concrete screw and plastic anchor) as well as power actuated fasteners in concrete. It describes in detail the fastening elements as well as their effects and load-bearing capacities in cracked and non-cracked concrete. It further focuses on corrosion behaviour, fire resistance and characteristics with earthquakes and shocks. It finishes off with the design of fastenings according to the European Technical Approval Guideline (ETAG 001), the Final Draft of the CEN Technical Specification 'Design of fastenings for use in concrete' and the American Standards ACI 318-05, Appendix D and ACI 349-01, Appendix B.

  10. Prestressed concrete design

    CERN Document Server

    Hurst, MK

    1998-01-01

    This edition provides up-to-date guidance on the detailed design of prestressed concrete structures. All major topics are dealt with, including prestressed flat slabs, an important and growing application in the design of buildings.

  11. INORGANIC CEMENT CONCRETE

    Directory of Open Access Journals (Sweden)

    Alisson Clay Rios Silva

    2014-07-01

    Full Text Available In this work, a Geopolymeric Cement Concrete (GCC was developed through adequate portions of geopolymer components. Its characteristics were compared with Portland Cement Concrete (PCC, through of the establishment of some parameters of design, as consumption of binders, water/aggregates ratio and mortar content. The concrete mechanical performance was evaluated with emphasis to the fatigue behavior. Were tested the effects of different tensile strength maximum (increasing and decreasing. The results of fatigue tests had shown that GCC presents a better performance when compared to PCC. Its fatigue strength was 15% higher than that of PCC, when 70% of rupture tension of the concrete in static bending (SR, was applied. Tensions of about 80% SR resulted in 96% of increase, when compared to GCC. The SEM microstructural analysis showed that the GCC has a matrix/aggregate bonding very strong, when compared to PCC, probably due to the massive nature of the geopolymeric matrix.

  12. Concrete Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This is a 20,000-sq ft laboratory that supports research on all aspects of concrete and materials technology. The staff of this facility offer wide-ranging expertise...

  13. Modeling reinforced concrete durability.

    Science.gov (United States)

    2014-06-01

    This project developed a next-generation modeling approach for projecting the extent of : reinforced concrete corrosion-related damage, customized for new and existing Florida Department of : Transportation bridges and suitable for adapting to broade...

  14. Improving concrete overlay construction.

    Science.gov (United States)

    2010-03-01

    Several road construction projects involving concrete overlays at the state and county levels in Iowa in 2009 were studied for : construction techniques and methods. The projects that were evaluated consisted of sites in four Iowa counties: Osceola, ...

  15. Concrete Block Pavements

    Science.gov (United States)

    1983-03-01

    intersections, bus loading areas, and pedestrian crosswalks. The change in surface texture between conven- tional and block pavements has been successful...blocks polished under traffic within a few weeks, providing a pavement surface with unsatisfactory skid resistance. U. K. Cement and Concrete Association...further problems of this type. Kellersman (1980) reports that although many brick pavements have become polished and slippery under traffic, no concrete

  16. Shear Resistance between Concrete-Concrete Surfaces

    Science.gov (United States)

    Kovačovic, Marek

    2013-12-01

    The application of precast beams and cast-in-situ structural members cast at different times has been typical of bridges and buildings for many years. A load-bearing frame consists of a set of prestressed precast beams supported by columns and diaphragms joined with an additionally cast slab deck. This article is focused on the theoretical and experimental analyses of the shear resistance at an interface. The first part of the paper deals with the state-of-art knowledge of the composite behaviour of concrete-concrete structures and a comparison of the numerical methods introduced in the relevant standards. In the experimental part, a set of specimens with different interface treatments was tested until failure in order to predict the composite behaviour of coupled beams. The experimental part was compared to the numerical analysis performed by means of FEM basis nonlinear software.

  17. Performance of "Waterless Concrete"

    Science.gov (United States)

    Toutanji, H. A.; Grugel, R. N.

    2009-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.

  18. Recycled Concrete as Aggregate for Structural Concrete Production

    Directory of Open Access Journals (Sweden)

    Mirjana Malešev

    2010-04-01

    Full Text Available A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate. Ninety-nine specimens were made for the testing of the basic properties of hardened concrete. Load testing of reinforced concrete beams made of the investigated concrete types is also presented in the paper. Regardless of the replacement ratio, recycled aggregate concrete (RAC had a satisfactory performance, which did not differ significantly from the performance of control concrete in this experimental research. However, for this to be fulfilled, it is necessary to use quality recycled concrete coarse aggregate and to follow the specific rules for design and production of this new concrete type.

  19. New generation concretes including reactive powder concretes

    Directory of Open Access Journals (Sweden)

    Stefania Grzeszczyk

    2015-09-01

    Full Text Available Based on a broad literature review, this paper presents characteristics of new generation composites on the basis of cements which are applied in engineering structures and in rehabilitation of structures. The role of cement, microfillers, superplasticizers and fibers in the above stated composites i.e. factors which allow for the maximum packing of particles in the cement matrix and a minimum pore volume, and the increase in composite bending strength, have been discussed. Special attention was paid to Reactive Powder Concrete in which coarse aggregate was replaced by ground quartz and sand. Such composites contain active microfillers and the applied new-generation superplasticizers allow us to decrease the water-cement ratio in the composite up to 0.2. Whereas, steel fibre additive allows us to significantly improve the bending strength.The paper presents the properties of the excellent Ductal — a composite from Reactive Powder Concrete, which at compressive strength from 180 to 230 MPa achieves the tensile strength of 30 to 50 MPa. Its application allows us to create slim profiles and tall light and slender, and simultaneously durable and corrosion-resistant structural elements of considerable span. This paper gives a few examples of Ductal application in practice.[b]Keywords[/b]: civil engineering, composite materials, reactive powder concrete

  20. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...

  1. Fracture Mechanics of Concrete

    DEFF Research Database (Denmark)

    Ulfkjær, Jens Peder

    Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high-strength......Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high......-strength concrete. Chapter 2 A description of the factors which influence the strength and cracking of concrete and high strength concrete is made. Then basic linear fracture mechanics is outlined followed by a description and evaluation of the models used to describe concrete fracture in tension. The chapter ends...... to describe fracture in concrete are presented. Two of the methods are combined into a power method which is stable for all brittleness numbers and which is able of calculating the entire load-displacement curve even for very ductile beams. This method is used extensively in the rest of the thesis. Chapter 4...

  2. Concrete with onyx waste aggregate as aesthetically valued structural concrete

    Science.gov (United States)

    Setyowati E., W.; Soehardjono, A.; Wisnumurti

    2017-09-01

    The utillization of Tulungagung onyx stone waste as an aggregate of concrete mixture will improve the economic value of the concrete due to the brighter color and high aesthetic level of the products. We conducted the research of 75 samples as a test objects to measure the compression stress, splits tensile stress, flexural tensile stress, elasticity modulus, porosity modulus and also studied 15 test objects to identify the concrete micro structures using XRD test, EDAX test and SEM test. The test objects were made from mix designed concrete, having ratio cement : fine aggregate : coarse aggregate ratio = 1 : 1.5 : 2.1, and W/C ratio = 0.4. The 28 days examination results showed that the micro structure of Tulungagung onyx waste concrete is similar with normal concrete. Moreover, the mechanical test results proved that Tulungagung onyx waste concretes also have a qualified level of strength to be used as a structural concrete with higher aesthetic level.

  3. An Incursion on Punching of Reinforced Concrete Flat Slabs

    Directory of Open Access Journals (Sweden)

    Dan-Vasile Bompa

    2009-01-01

    Full Text Available Starting from the early 60s continuous studies have been made regarding punching of concrete flat slabs. The evolution of technology and calculus systems influenced this engineering branch. Nowadays is possible to account in structural analysis all the non-linear behaviour of reinforced and prestressed concrete and to get the most close structural response in comparison with the real behaviour. As a controversy matter, several tests and theories have been developed. Nowadays researchers try to find the most accurate and economic formula for punching. This paper purpose is to make a survey on punching classical model and related nonlinear concrete behaviour regarded to this issue.

  4. Drying of Concrete

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Geiker, Mette Rica; Nygaard, Peter Vagn

    2002-01-01

    Estimated and measured relative humidity (RH) change during drying are compared for two concretes, 1: w/c=0.46 and 2: w/(c+0.5fa+2sf)=0.50. The estimations were undertaken by means of the Swedish program TorkaS 1.0. Measurements were performed by RH-sensors type Humi-Guard. Drying of 150 mm thick...... samples from sides at 60% RH and 22 °C took place from 4 to 56 days after casting. At the end of the drying period the measured RH was about 4% lower than the estimated RH at 1/5th depth from the exposed surface for both concretes. In the middle of the samples, the measured RH of concretes 1 and 2 were 2...

  5. Use of fiber reinforced concrete for concrete pavement slab replacement.

    Science.gov (United States)

    2014-03-01

    Unlike ordinary concrete pavement, replacement concrete slabs need to be open to traffic within 24 hours (sooner in : some cases). Thus, high early-strength concrete is used; however, it frequently cracks prematurely as a result of high : heat of hyd...

  6. Electrokinetic decontamination of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Lomasney, H. [ISOTRON Corp., New Orleans, LA (United States)

    1995-10-01

    The U.S. Department of Energy has assigned a priority to the advancement of technology for decontaminating concrete surfaces which have become contaminated with radionuclides, heavy metals, and toxic organics. This agency is responsible for decontamination and decommissioning of thousands of buildings. Electrokinetic extraction is one of the several innovative technologies which emerged in response to this initiative. This technique utilizes an electropotential gradient and the subsequent electrical transport mechanism to cause the controlled movement of ionics species, whereby the contaminants exit the recesses deep within the concrete. This report discusses the technology and use at the Oak Ridge k-25 plant.

  7. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...

  8. Cross-cultural comparison of concrete recycling decision-making and implementation in construction industry.

    Science.gov (United States)

    Tam, Vivian W Y; Tam, Leona; Le, Khoa N

    2010-02-01

    Waste management is pressing very hard with alarming signals in construction industry. Concrete waste constituents major proportions of construction and demolition waste of 81% in Australia. To minimize concrete waste generated from construction activities, recycling concrete waste is one of the best methods to conserve the environment. This paper investigates concrete recycling implementation in construction. Japan is a leading country in recycling concrete waste, which has been implementing 98% recycling and using it for structural concrete applications. Hong Kong is developing concrete recycling programs for high-grade applications. Australia is making relatively slow progress in implementing concrete recycling in construction. Therefore, empirical studies in Australia, Hong Kong, and Japan were selected in this paper. A questionnaire survey and structured interviews were conducted. Power spectrum was used for analysis. It was found that "increasing overall business competitiveness and strategic business opportunities" was considered as the major benefit for concrete recycling from Hong Kong and Japanese respondents, while "rising concrete recycling awareness such as selecting suitable resources, techniques and training and compliance with regulations" was considered as the major benefit from Australian respondents. However, "lack of clients' support", "increase in management cost" and "increase in documentation workload, such as working documents, procedures and tools" were the major difficulties encountered from Australian, Hong Kong, and Japanese respondents, respectively. To improve the existing implementation, "inclusion of concrete recycling evaluation in tender appraisal" and "defining clear legal evaluation of concrete recycling" were major recommendations for Australian and Hong Kong, and Japanese respondents, respectively.

  9. Recycled aggregate concrete; an overview

    OpenAIRE

    Sorato, Renan

    2016-01-01

    The aim of this Bachelor’s thesis was to investigate whether recycled materials can be incorporated into the production of concrete without compromising the compressive strength of the concrete produced. In order to shed light on the compressive strength of concrete made from recycled materials, the thesis reviewed studies in which waste materials are utilised as recycled aggregates in the composition of concrete and presented the results of this synthesis and analysis. It was found that som...

  10. Concrete produced with recycled aggregates

    OpenAIRE

    Tenório,J. J. L.; Gomes,P. C. C.; Rodrigues,C. C.; Alencar,T. F. F. de

    2012-01-01

    This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC) for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW), which were d...

  11. Structural Concrete, Science into Practice

    NARCIS (Netherlands)

    Bruggeling, A.S.G.

    1987-01-01

    There is a need for a more rational and unified approach to all types of concrete structure, reinforced of prestressed. The first chapter explains in a historical review why the approach of reinforced concrete and that of prestressed concrete have hitherto been very different. In outlining the

  12. Concrete produced with recycled aggregates

    Directory of Open Access Journals (Sweden)

    J. J. L. Tenório

    Full Text Available This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW, which were divided into recycled sand (fine and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW. The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

  13. From concrete repair to concrete conservation: How to preserve the heritage values of historic concrete

    NARCIS (Netherlands)

    Heinemann, H.A.; Zijlstra, H.; Hees, R.P.J. van; Nijland, T.G.

    2012-01-01

    The conservation of historic concrete is an increasing task, challenging both concrete repair specialists and conservation specialists. In practice, too often repair strategies are followed where conservation strategies would have been necessary. The application of repair techniques poses two

  14. THE STUDY ON THE DURABILITY OF SUBMERGED STRUCTURE DISPLACEMENT DUE TO CONCRETE FAILURE

    Directory of Open Access Journals (Sweden)

    M. Mohd

    2016-09-01

    Full Text Available Concrete structures that exposed to marine environments are subjected to multiple deterioration mechanisms. An overview of the existing technology for submerged concrete, pressure resistant, concrete structures which related such as cracks, debonds, and delamination are discussed. Basic knowledge related to drowning durability such as submerged concrete structures in the maritime environment are the durability of a concrete and the ability to resist to weathering, chemical attack, abrasion or other deterioration processes. The measuring techniques and instrumentation for geometrical monitoring of submerged structural displacements have traditionally been categorized into two groups according to the two main groups, namely as geodetic surveying and geotechnical structural measurements of local displacements. This paper aims to study the durability of submerged concrete displacement and harmful effects of submerged concrete structures.

  15. Danish High Performance Concretes

    DEFF Research Database (Denmark)

    Nielsen, M. P.; Christoffersen, J.; Frederiksen, J.

    1994-01-01

    In this paper the main results obtained in the research program High Performance Concretes in the 90's are presented. This program was financed by the Danish government and was carried out in cooperation between The Technical University of Denmark, several private companies, and Aalborg University...

  16. Teaching concrete structures

    DEFF Research Database (Denmark)

    Goltermann, Per

    2014-01-01

    The teaching of concrete structures has been revised and a number of new approaches have been developed, implemented and evaluated. Inductive teaching, E-learning and “patches” have been found to be improvements and may be an inspiration and help for others development of the teaching and learning...

  17. Polyester polymer concrete overlay.

    Science.gov (United States)

    2013-01-01

    Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

  18. Anisotropic Concrete Compressive Strength

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2017-01-01

    When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...

  19. Forterra Concrete Products, Inc.

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Forterra Concrete Products, Inc., a business located at 511 E. John Carpenter Freeway, Irving, TX, 75062, for alleged violations at its facility located at 23600 W. 40th St

  20. Fracture Mechanics of Concrete

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    there was a workshop on the size effect in concrete structures, organized by H Mihashi,. H Okamura and Z P Ba˘zant, at Sendai, Japan in 1993. Various international committees were formed, the earliest one being the RILEM Committee chaired by F H Wittmann. Several other important meetings took place at different ...

  1. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...

  2. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    TECS

    ting. It is used in industrial floorings, ship decks, railway passenger coach floorings, hospital floors, ammunition factory floors, missile silos and underground armament factories and bunkers. Recently, concrete of high compres- sive and tensile strength prepared with magnesium oxy- chloride cement and recycled rubber ...

  3. Electrical pulses protect concrete

    NARCIS (Netherlands)

    Koleva, D.; Fraaij, A.; Van Kasteren, J.

    2006-01-01

    Even concrete is not as hard as it looks. Sea water, salt on icy roads, and indirectly even carbon dioxide from the air can corrode the steel of the reinforcing bars and so threaten the strength and integrity of a bridge pier, jetty, or viaduct. Dessi Koleva, a chemical engineer from Bulgaria, spent

  4. Shell concrete pavement.

    Science.gov (United States)

    1966-10-01

    This report describes the testing performed with reef shell, clam shell and a combination of reef and clam shell used as coarse aggregate to determine if a low modulus concrete could be developed for use as a base material as an alternate to the pres...

  5. Self-compacting concrete (SCC)

    DEFF Research Database (Denmark)

    Geiker, Mette Rica

    2008-01-01

    In many aspects Self-Compacting Concrete (SCC, “Self-Consolidating Concrete” in North America) can be considered the concrete of the future. SCC is a family of tailored concretes with special engineered properties in the fresh state. SCC flows into the formwork and around even complicated...... reinforcement arrangements under its own weight. Thus, SCC is not vibrated like conventional concrete. This drastically improves the working environment during construction, the productivity, and potentially improves the homogeneity and quality of the concrete. In addition SCC provides larger architectural...

  6. Life Cycle Assessment of Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Sjunnesson, Jeannette

    2005-09-15

    This is an environmental study on concrete that follows the standard protocol of life cycle assessment (LCA). The study is done for two types of concrete, ordinary and frost-resistant concrete, and has an extra focus on the superplasticizers used as admixtures. The utilization phase is not included in this study since the type of construction for which the concrete is used is not defined and the concrete is assumed to be inert during this phase. The results show that it is the production of the raw material and the transports involved in the life cycle of concrete that are the main contributors to the total environmental load. The one single step in the raw material production that has the highest impact is the production of cement. Within the transportation operations the transportation of concrete is the largest contributor, followed by the transportation of the cement. The environmental impact of frost-resistant concrete is between 24-41 % higher than that of ordinary concrete due to its higher content of cement. Superplasticizers contribute with approximately 0.4-10.4 % of the total environmental impact of concrete, the least to the global warming potential (GWP) and the most to the photochemical ozone creation potential (POCP). Also the toxicity of the superplasticizers is investigated and the conclusion is that the low amount of leakage of superplasticizers from concrete leads to a low risk for the environment and for humans.

  7. Online Corrosion and Force Monitoring for Inner Containment Concrete Structures

    Directory of Open Access Journals (Sweden)

    K. Kumar

    2008-05-01

    Full Text Available Corrosion of steel in concrete reduces the service life and durability of concrete structures. It is a worldwide problem, which causes heavy losses to the economy of the country. The durability of concrete structures primarily depends on the condition of the embedded steel in concrete, apart from any deterioration that concrete may undergo. In general potential surveys are carried out on concrete structures to know about the condition of steel. Most of these measurements in the field are carried out manually and the data obtained are analyzed. This offline measurements leads to an error in the data collected, time consuming and involvement of huge man power. Online corrosion monitoring eliminates such errors in the measurements and improves the accuracy of the data collected from humanly inaccessible regions of a structure. To mitigate corrosion prior to significant degradation and optimize the performance of such concrete structures, various sensors have been used to detect the corrosion and to provide early warning. To assess the condition of the embedded steel, the sensors of the probe are connected to a computer through specialized data acquisition hardware. The computer controls the data acquisition using suitable user friendly software that calculates the corrosion rate at prescribed intervals for continuous monitoring. New types of corrosion sensors and its mechanism in real time measurements are described. Online analysis of data for corrosion and force monitoring is described in this paper.

  8. Micro Environmental Concrete

    Science.gov (United States)

    Lanez, M.; Oudjit, M. N.; Zenati, A.; Arroudj, K.; Bali, A.

    Reactive powder concretes (RPC) are characterized by a particle diameter not exceeding 600 μm and having very high compressive and tensile strengths. This paper describes a new generation of micro concrete, which has an initial as well as a final high physicomechanical performance. To achieve this, 15% by weight of the Portland cement have been substituted by materials rich in Silica (Slag and Dune Sand). The results obtained from the tests carried out on the RPC show that compressive and tensile strengths increase when incorporating the addition, thus improving the compactness of mixtures through filler and pozzolanic effects. With a reduction in the aggregate phase in the RPC and the abundance of the dune sand (southern of Algeria) and slag (industrial by-product of the blast furnace), the use of the RPC will allow Algeria to fulfil economical as well as ecological requirements.

  9. Laser ablation of concrete.

    Energy Technology Data Exchange (ETDEWEB)

    Savina, M.

    1998-10-05

    Laser ablation is effective both as an analytical tool and as a means of removing surface coatings. The elemental composition of surfaces can be determined by either mass spectrometry or atomic emission spectroscopy of the atomized effluent. Paint can be removed from aircraft without damage to the underlying aluminum substrate, and environmentally damaged buildings and sculptures can be restored by ablating away deposited grime. A recent application of laser ablation is the removal of radioactive contaminants from the surface and near-surface regions of concrete. We present the results of ablation tests on concrete samples using a high power pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied on various model systems consisting of Type I Portland cement with varying amounts of either fine silica or sand in an effort to understand the effect of substrate composition on ablation rates and mechanisms. A sample of non-contaminated concrete from a nuclear power plant was also studied. In addition, cement and concrete samples were doped with non-radioactive isotopes of elements representative of cooling waterspills, such as cesium and strontium, and analyzed by laser-resorption mass spectrometry to determine the contamination pathways. These samples were also ablated at high power to determine the efficiency with which surface contaminants are removed and captured. The results show that the neat cement matrix melts and vaporizes when little or no sand or aggregate is present. Surface flows of liquid material are readily apparent on the ablated surface and the captured aerosol takes the form of glassy beads up to a few tens of microns in diameter. The presence of sand and aggregate particles causes the material to disaggregate on ablation, with intact particles on the millimeter size scale leaving the surface. Laser resorption mass spectrometric analysis showed that cesium and potassium have similar chemical environments in the

  10. Concrete containment aging study

    Energy Technology Data Exchange (ETDEWEB)

    Pachner, J. [International Atomic Energy Agency, Vienna (Austria); Tai, T.M. [Bechtel National, Inc., Oak Ridge, TN (United States); Naus, D. [Oak Ridge National Lab., TN (United States)

    1994-04-01

    In 1989, IAEA initiated a pilot study on the management of aging of nuclear power plant components. The Phase I and II studies of concrete containment are discussed. With the data base, plant owners will be able to review and enhance their existing programs. IAEA will analyze data provided by participating plants and the report is scheduled to be released by late 1994 (final report release mid-1995).

  11. New era for concrete

    OpenAIRE

    Petra Novotna; Federico Meneghello

    2016-01-01

    The article presentes the Eco-Binder project, the scope of the project is to demonstrate the fasibility of replacing Ordinary Portland Cement (OPC) and OPC based concrete (products) with new products based on the innovative Belite-Ye’elimite-Ferrite (BYF) class of low-CO2 binders. ECO-Binder aims to address the vast market for envelope retrofitting and new construction with a new generation of prefabricated building envelope components with: -30% carbon footprints +20% insulating pr...

  12. Nondestructive Concrete Characterization System

    Science.gov (United States)

    2013-05-20

    blocks to establish the mechanical properties of the concrete material. The destructive tests were undertaken according to the relevant ASTM standards...The large blocks were cast for Non Destructive Testing ( NDT ) along with the cylinders and small beams for destructive testing with the following...NCSU performed the destructive testing in accordance with the following standards: ASTM C39 for compressive strength, ASTM C469 for modulus of

  13. Design of ultra-lightweight concrete: towards monolithic concrete structures

    Directory of Open Access Journals (Sweden)

    Yu Qing Liang

    2014-04-01

    Full Text Available This study addresses the development of ultra-lightweight concrete. A moderate strength and an excellent thermal conductivity of the lightweight concrete are set as the design targets. The designed lightweight aggregates concrete is targeted to be used in monolithic concrete façade structure, performing as both load bearing element and thermal insulator. The developed lightweight concrete shows excellent thermal properties, with a low thermal conductivity of about 0.12 W/(m·K; and moderate mechanical properties, with 28-day compressive strengths of about 10-12 N/mm . This combination of values exceeds, to the researchers’ knowledge, the performance of all other lightweight building materials. Furthermore, the developed lightweight concrete possesses excellent durability properties.

  14. Let’s Get Concrete!

    DEFF Research Database (Denmark)

    Jones, Candace; Boxenbaum, Eva

    Scholars emphasize the cognitive or ideational aspects of institutional logics. Less clear is the role of materiality, which is a key aspect of institutional logics, and aesthetic responses to material objects. This study focuses on the introduction of a new building material—concrete— during 1890...... to 1939 in the architectural profession. Our findings reveal that how professional logics were enacted drove different process for incorporating concrete as a legitimate building material: in France professional and state logics combined to create regulations that governed architects’ use of concrete......-legitimated not only concrete but also stone. Concrete was perceived as merely imitative and thus inauthentic. For concrete to become a legitimate and widely adopted material, architects had to theorize concrete as unique material with distinctive aesthetic possibilities, which led to new kinds of buildings and new...

  15. Spall Damage of Concrete Structures

    Science.gov (United States)

    1988-06-01

    C1 APPENDIX D DATA ON DAMAGE OF REINFORCED CONCRETE STRUCTURES CAUSED BY’ NEARBY BOMB DETONATIONS ..................... D1 LIST OF...27.6799 grams/centimeters 3 xiii SPALL DAMAGE TO CONCRETE STRUCTURES PART I: INTRODUCTION Backaround Spall is defined as the ejection of fragments of a...of the walls. Additional data from other tests with detonations of bombs near concrete structures were also collected in a literature search. The data

  16. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  17. Markets: Ready-Mixed Concrete

    OpenAIRE

    Chad Syverson

    2008-01-01

    Concrete's natural color is gray. Its favored uses are utilitarian. Its very ubiquity causes it to blend into the background. But ready-mix concrete does have one remarkable characteristic: other than manufactured ice, perhaps no other manufacturing industry faces greater transport barriers. The transportation problem arises because ready-mix concrete both has a low value-to-weight ratio and is highly perishable -- it absolutely must be discharged from the truck before it hardens. These trans...

  18. Properties of Low Strength Concrete made with Recycled Concrete ...

    African Journals Online (AJOL)

    Conventional concrete aggregate consists of sand and various sizes of stones. In recent years, there has been a growing interest in substituting conventional aggregates with recycled materials. The present investigation has been carried out to study the effect of fly ash on the mechanical properties of low strength concrete ...

  19. TECHNOLOGICAL PROPERTIES OF CONCRETES AND MORTARS FOR UNDERWATER CONCRETING

    Directory of Open Access Journals (Sweden)

    O. V. Anufrieva

    2009-03-01

    Full Text Available The article is about the results of experimental-and-theoretical research of usefulness of mortar and concrete mixes for underwater repair works. It is shown that the developed compositions of hydraulic engineering concretes are characterized by high effectiveness in the corrosive medium.

  20. Anisotropic Concrete Compressive Strength

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2017-01-01

    When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...... correlation to the curing time. The experiments show no correlation between the anisotropy and the curing time and a small strength difference between the two drilling directions. The literature shows variations on which drilling direction that is strongest. Based on a Monto Carlo simulation of the expected...

  1. Characterisation and management of concrete grinding residuals.

    Science.gov (United States)

    Kluge, Matt; Gupta, Nautasha; Watts, Ben; Chadik, Paul A; Ferraro, Christopher; Townsend, Timothy G

    2018-02-01

    Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

  2. The influence of recycled concrete aggregates in pervious concrete

    Directory of Open Access Journals (Sweden)

    L. M. TAVARES

    Full Text Available The expansion of urban areas under constant changes in the hydrological cycle directly affects the drainage of rainwater. The problems of urban drainage become major engineering problems to be solved in order to avoid negative consequences for local populations. Another urban problem is the excessive production of construction and demolition waste (CDW, in which , even with a increasingly policy of waste management , have been an end up being thrown in inappropriate disposal sites. Alternatively aiming to a minimization of the problems presented, we propose the study of permeable concrete using recycled concrete aggregate. In this study, there were evaluated the performance of concrete by means of permeability, consistency, strength, and interface conditions of the materials . Satisfactory relationships of resistance/permeability of concrete with recycled aggregate in relation to the concrete with natural aggregates was obtained, showing their best potential.

  3. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to

  4. Interface Microstructures in Concrete

    Directory of Open Access Journals (Sweden)

    Puertas, Francisca

    1991-03-01

    Full Text Available This paper constitutes a compilation as well as an interpretation of the present state of knowledge about the different microstructures developed in the interface areas of concrete, that is, the cement paste-aggregates, the cement paste-reinforcement, the cement paste-fiber, etc. The Chemical reactions taking place in interface areas, the development and morphology of such areas and their strength ^since interfaces are taken as the weakest points of concrete are the aspects dealt with in some detail in this work.

    El presente trabajo constituye un resumen y también una interpretación del estado actual del conocimiento respecto de las diferentes microestructuras que se desarrollan en las zonas interfaciales de los hormigones, es decir: pasta de cemento-áridos, pasta de cemento-armaduras, pasta de cemento-fibras, etc. Las reacciones químicas que tienen lugar en la zona interfacial, el desarrollo y morfología de dicha zona y su resistencia (las interfases se consideran como uno de los puntos débiles del hormigón son los aspectos que con cierto detalle se tratan en el trabajo.

  5. of reinforced concrete columns

    Directory of Open Access Journals (Sweden)

    Anna Szcześniak

    2015-09-01

    Full Text Available The paper presents the modification of the dynamic relaxation method in order to increase its effectiveness in the range of the post-critical analysis. For this purpose, the arc-length parameter on the equilibrium path was introduced into the computational procedure. The additional constraints equation that combines increment of load parameter and the vector of displacement increments with the arc-length increment on the solution path was incorporated to analysis of the equations of motion. Solution of nonlinear equilibrium equations is obtained recursively in subsequent pseudo-time instants. The proposed method allows for tracking the global softening phenomenon of the structural element in the post-critical range, which leads to failure. We ran numerical experiments for the reinforced concrete eccentrically loaded column. Our comparative analysis with previously published numerical results demonstrated that the proposed computational method is effective.[b]Keywords[/b]: reinforced concrete columns, dynamic relaxation method, arc-length method, load-carrying capacity

  6. Molded Concrete Center Mine Wall

    Science.gov (United States)

    Lewis, E. V.

    1987-01-01

    Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

  7. Concrete Operations and Attentional Capacity.

    Science.gov (United States)

    Chapman, Michael; Lindenberger, Ulman

    1989-01-01

    To test predictions regarding the attentional capacity requirements of Piaget's stage of concrete operations, a battery of concrete operational tasks and two measures of attentional capacity were administered to 120 first-, second-, and third-graders. Findings concern class inclusion, transitivity of length and weight, and multiplication of…

  8. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  9. Fatigue of Concrete Armour Units

    DEFF Research Database (Denmark)

    Sørensen, N. B.; Burcharth, H. F.; Liu, Z.

    1995-01-01

    In the present article fatigue as a possible reason for failure of Dolosse armour units made of plain concrete is discussed.......In the present article fatigue as a possible reason for failure of Dolosse armour units made of plain concrete is discussed....

  10. Urban heritage, building maintenance : Concrete

    NARCIS (Netherlands)

    Verhoef, L.G.W.

    1999-01-01

    Concrete as a conglomerate of sand, stone and a binder, is a very old material indeed. In the Roman period earth from Puozzoli, together with lime and water could bind the sand and the stones to form a conglomerate that has an affmity to our modem concrete. Later, in the more northem areas of

  11. The steel–concrete interface

    DEFF Research Database (Denmark)

    Angst, Ueli M.; Geiker, Mette Rica; Michel, Alexander

    2017-01-01

    Although the steel–concrete interface (SCI) is widely recognized to influence the durability of reinforced concrete, a systematic overview and detailed documentation of the various aspects of the SCI are lacking. In this paper, we compiled a comprehensive list of possible local characteristics at...

  12. Proportioning of light weight concrete

    DEFF Research Database (Denmark)

    Palmus, Lars

    1996-01-01

    Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory......Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory...

  13. Novel techniques for concrete curing

    DEFF Research Database (Denmark)

    Kovler, Konstantin; Jensen, Ole Mejlhede

    2005-01-01

    It is known that some high-strength/high-performance concretes (HSC/HPC) are prone to cracking at an early age unless special precautions are taken. The paper deals with the methods of curing as one of the main strategies to ensure good performance of concrete. Curing by both external (convention...

  14. The Concrete and Pavement Challenge

    Science.gov (United States)

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  15. Numerical Simulation of GFRP Reinforced Concrete Beams

    National Research Council Canada - National Science Library

    Xia Zhao; Xiong-Jun He; Yong-Chao Yang

    2017-01-01

    .... The finite element numerical simulation of GFRP fiber reinforced concrete beam was carried out, and the load deflection nephogram of fiber reinforced concrete beam, strain nephogram, crack nephogram...

  16. Diffusion of ultrasound in concrete.

    Science.gov (United States)

    Anugonda, P; Wiehn, J S; Turner, J A

    2001-10-01

    The propagation and scattering of ultrasound in concrete is discussed. The heterogeneous composition of concrete causes the ultrasound to scatter considerably. In the limit of many scattering events, the ultrasonic energy density in circular cylinders of concrete is shown to evolve in accordance with a one-dimensional diffusion equation. The ultrasonic diffusivity and dissipation are measured experimentally over the frequency range of 100-900 kHz. Theoretical descriptions of the diffusivity are in accord with the experimental values. Such frequencies are well above typical frequencies used for concrete inspection. Thus, it is anticipated that the use of these higher frequencies will result in new techniques for characterizing material properties and damage in concrete structures.

  17. Basic principles of concrete structures

    CERN Document Server

    Gu, Xianglin; Zhou, Yong

    2016-01-01

    Based on the latest version of designing codes both for buildings and bridges (GB50010-2010 and JTG D62-2004), this book starts from steel and concrete materials, whose properties are very important to the mechanical behavior of concrete structural members. Step by step, analysis of reinforced and prestressed concrete members under basic loading types (tension, compression, flexure, shearing and torsion) and environmental actions are introduced. The characteristic of the book that distinguishes it from other textbooks on concrete structures is that more emphasis has been laid on the basic theories of reinforced concrete and the application of the basic theories in design of new structures and analysis of existing structures. Examples and problems in each chapter are carefully designed to cover every important knowledge point. As a basic course for undergraduates majoring in civil engineering, this course is different from either the previously learnt mechanics courses or the design courses to be learnt. Compa...

  18. From concrete repair to concrete conservation: how to preserve the heritage values of historic concrete

    NARCIS (Netherlands)

    Nijland, T.G.; Hees, R.P.J. van; Heinemann, H.A.; Zijlstra, H.

    2011-01-01

    ABSTRACT: The conservation of historic concrete is an increasing task, challenging both concrete repair specialists and conservation specialists. In practice, too often repair strategies are followed where conserva-tion strategies would have been necessary. The application of repair techniques poses

  19. High performance polymer concrete

    Directory of Open Access Journals (Sweden)

    Frías, M.

    2007-06-01

    Full Text Available This paper studies the performance of concrete whose chief components are natural aggregate and an organic binder —a thermosetting polyester resin— denominated polymer concrete or PC. The material was examined macro- and microscopically and its basic physical and mechanical properties were determined using mercury porosimetry, scanning electron microscopy (SEM-EDAX, X-ray diffraction (XRD and strength tests (modulus of elasticity, stress-strain curves and ultimate strengths. According to the results of these experimental studies, the PC exhibited a low density (4.8%, closed pore system and a concomitantly continuous internal microstructure. This would at least partially explain its mechanical out-performance of traditional concrete, with average compressive and flexural strength values of 100 MPa and over 20 MPa, respectively. In the absence of standard criteria, the bending test was found to be a useful supplement to compressive strength tests for establishing PC strength classes.Este trabajo de investigación aborda el estudio de un hormigón de altas prestaciones, formado por áridos naturales y un aglomerante orgánico constituido por una resina termoestable poliéster, denominado hormigón polimérico HP. Se describe el material a nivel microscópico y macroscópico, presentando sus propiedades físicas y mecánicas fundamentales, mediante diferentes técnicas experimentales, tales como: porosimetría de mercurio, microscopía electrónica (SEM-EDAX, difracción de rayos X (DRX y ensayos mecánicos (módulo de elasticidad, curvas tensión- deformación y resistencias últimas. Como consecuencia del estudio experimental llevado a cabo, se ha podido apreciar cómo el HP está formado por porosidad cerrada del 4,8%, proporcionando una elevada continuidad a su microestructura interna, lo que justifica, en parte, la mejora de propiedades mecánicas respecto al hormigón tradicional, con unos valores medios de resistencia a compresión de 100

  20. Porosity of Concrete - Morphological Study of Model Concrete

    NARCIS (Netherlands)

    Hu, J.

    2004-01-01

    This study has developed a comprehensive methodological framework for characterizing geometrical and morphological aspects of pore space in cementitious materials and explored its application to actual cement pastes and model concretes for the purpose of predicting mechanical and transport

  1. Long-life concrete : how long will my concrete last?

    Science.gov (United States)

    2013-10-01

    There is an ongoing discussion about moving toward performance-based specifications for concrete pavements. This document seeks to : move the discussion forward by outlining the needs and the challenges, and proposing some immediate actions. However,...

  2. PCM Concrete. [Phase Change Materials

    Energy Technology Data Exchange (ETDEWEB)

    Juul Andersen, T. [Danish Technological Institute, Taastrup (Denmark); Poulsen, H.-H. [BASF A/S, Roedekro (Denmark); Passov, F. [Spaencom A/S, Hedehusene (Denmark); Heiselberg, P. [Aalborg Univ..Aalborg (Denmark)

    2013-04-01

    PCM-Concrete was a research and development project launched in 2009 and finished in 2012. The project, which was funded by The Danish National Advanced Technology Foundation, had a total budget of 1.7 million Euros and included 4 partners: Danish Technological Institute (project manager), Aalborg University, BASF A/S and Spaencom A/S. The overall vision of the project was to reduce energy consumption for heating and cooling in buildings by developing high-performance concrete structures microencapsulated Phase Change Materials (PCM). The PCM used in the project was Micronal produced by BASF A/S. Micronal is small capsules with an acrylic shell and inside a wax with a melting point at approx. 23 deg. C equal to a comfortable indoor temperature. During the melting process thermal energy is transferred to chemical reaction (melting/solidification) depending on PCM being heated up or cooled down. Adding Micronal to concrete would theoretically increase the thermal mass of the concrete and improve the diurnal heat capacity which is the amount of energy that can be stored and released during 24 hours. Nevertheless, it is a relatively new technology that has not received much attention, yet. In the PCM-Concrete project 5 main investigations were carried out: 1) Development of concrete mix design with PCM. 2) Investigation of thermal properties of the PCM concrete: thermal conductivity, specific heat capacity, density. 3) Up-scaling the research to industrial production of PCM-concrete structures. 4) Testing energy efficiency in full scale. 5) Confronting aesthetic and acoustic barriers to full exploitation of the potential of PCM-concrete structures. The results from the test program showed: 1) That the diurnal heat storage capacity is higher for all 4 hollow core decks with tiles attached compared to the reference hollow core deck. 2) The hollow core decks with concrete tiles without PCM performs slightly better than the tiles with PCM. 3) That is was impossible to

  3. Characteristics of Concrete with Admixtures

    Directory of Open Access Journals (Sweden)

    Bogdan Roşca

    2008-01-01

    Full Text Available In recent decades, tremendous success has been achieved in the advancement of chemical admixtures for Portland cement concrete. Most efforts have centered on improving the properties of concrete with minimal investments by ready-mix suppliers and contractors in the way of specialized equipment or special skills and education of their labor forces. This approach has resulted in construction cost reductions and universally accepted ready-made remedies for unexpected problems during construction. The behavior of concrete improved with superplasticizers additives is studied.

  4. Mechanical Properties of Polymer Concrete

    Directory of Open Access Journals (Sweden)

    Raman Bedi

    2013-01-01

    Full Text Available Polymer concrete was introduced in the late 1950s and became well known in the 1970s for its use in repair, thin overlays and floors, and precast components. Because of its properties like high compressive strength, fast curing, high specific strength, and resistance to chemical attacks polymer concrete has found application in very specialized domains. Simultaneously these materials have been used in machine construction also where the vibration damping property of polymer concrete has been exploited. This review deals with the efforts of various researchers in selection of ingredients, processing parameters, curing conditions, and their effects on the mechanical properties of the resulting material.

  5. Durability of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard

    1996-01-01

    The planned research will indicate, whether fibre reinforced concrete has better or worse durability than normal concrete. Durability specimens will be measured on cracked as well as uncracked specimens. Also the pore structure in the concrete will be characterized.Keywords: Fibre reinforced...... concrete, durability, pore structure, mechanical load...

  6. Betonreparationers holdbarhed (Durability of Concrete Repairs)

    DEFF Research Database (Denmark)

    Brimnes, Eydbjørn; Dali, Bogi í; Larsen, Erik Stoklund

    1999-01-01

    Concrete repairs on 11 pillars on bridges built in the sixties and repaired 8 to 9 years ago have been examined. Especially the chloride penetration in the repair concrete have been measured. Chloride penetration in the repair concrete is much lower than in the original concrete....

  7. Deliberate deformation of concrete after casting

    NARCIS (Netherlands)

    Grunewald, S.; Janssen, B.; Schipper, H.R.; Vollers, K.J.; Walraven, J.C.

    2012-01-01

    This paper discusses the effect of intentional deformation of a flexible formwork after casting of the concrete and the influence of the characteristics of concrete in the fresh state on the quality of a concrete element. This deformation is intended to bring the concrete element in its desired

  8. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat...

  9. Influence of treated recycled concrete aggregate on concrete properties

    OpenAIRE

    Galindo, Anna; Etxeberria Larrañaga, Miren

    2017-01-01

    The amount and the quality of the old cement mortar attached to the aggregates influence the quality of the recycled concrete aggregate (RCA) produced. The characteristics of RCA adversely affect the physical, mechanical and durability properties of concretes. Due to these adverse effects, it is necessary to improve the RCA properties, not only changing their surface but also their internal microstructure. The main objective of this research work was to analyse the influence of chemically tre...

  10. Review of concrete properties for prestressed concrete pressure vesssels

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, R.K.

    1976-10-01

    The desire for increasing power output along with safety requirements has resulted in consideration of the prestressed concrete pressure vessel (PCPV) for most current nuclear reactor systems, as well as for the very-high-temperature reactor for process heat and as primary pressure vessels for coal conversion systems. Results are presented of a literature review to ascertain current knowledge regarding plain concrete properties under conditions imposed by a mass concrete structure such as PCRV. The effects of high temperature on such properties as strength, elasticity, and creep are discussed, as well as changes in thermal properties, multiaxial behavior, and the mechanisms thought to be responsible for the observed behavior. In addition, the effects of radiation and moisture migration are discussed. It is concluded that testing results found in the technical literature show much disagreement as to the effects of temperature on concrete properties. The variations in concrete mixtures, curing and testing procedures, age at loading, and moisture conditions during exposure and testing are some of the reasons for such disagreement. Test results must be limited, in most cases, to the materials and conditions of a given test rather than applied to such a general class of materials such as concrete. It is also concluded that sustained exposure of normal concretes to current PCRV operating conditions will not result in any significant loss of properties. However, lack of knowledge regarding effects of temperatures exceeding 100/sup 0/C (212/sup 0/F), moisture migration, and multiaxial behavior precludes a statement advocating operation beyond current design limits. The report includes recommendations for future research on concrete for PCPVs.

  11. Concrete density estimation by rebound hammer method

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Mohamad Pauzi bin, E-mail: pauzi@nm.gov.my; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri [NDT Group, Nuclear Malaysia, Bangi, Kajang, Selangor (Malaysia); Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin [Material Technology Program, Faculty of Applied Sciences, UiTM, Shah Alam, Selangor (Malaysia); Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin [Pusat Penyelidikan Mineral, Jabatan Mineral dan Geosains, Ipoh, Perak (Malaysia)

    2016-01-22

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite.

  12. Towards Better Understanding of Concrete Containing Recycled Concrete Aggregate

    Directory of Open Access Journals (Sweden)

    Hisham Qasrawi

    2013-01-01

    Full Text Available The effect of using recycled concrete aggregates (RCA on the basic properties of normal concrete is studied. First, recycled aggregate properties have been determined and compared to those of normal aggregates. Except for absorption, there was not a significant difference between the two. Later, recycled aggregates were introduced in concrete mixes. In these mixes, natural coarse aggregate was partly or totally replaced by recycled aggregates. Results show that the use of recycled aggregates has an adverse effect on the workability and air content of fresh concrete. Depending on the water/cement ratio and on the percent of the normal aggregate replaced by RCA, the concrete strength is reduced by 5% to 25%, while the tensile strength is reduced by 4% to 14%. All results are compared with previous research. As new in this research, the paper introduces a simple formula for the prediction of the modulus of elasticity of RCA concrete. Furthermore, the paper shows the variation of the air content of RAC.

  13. Fiber reinforcement of concrete structures

    Science.gov (United States)

    2002-09-01

    Deterioration of concrete structures due to steel corrosion is a matter of considerable concern since the repairing of these structures proved to be a costly process. Repair and rehabilitation of the civil structures needs an enduring repair material...

  14. Electrically conductive polymer concrete overlays

    Science.gov (United States)

    Fontana, J. J.; Webster, R. P.

    1984-08-01

    The use of cathodic protection to prevent the corrosion of reinforcing steel in concrete structures has been well established. Application of a durable, skid-resistant electrically conductive polymer concrete overlay would advance the use of cathodic protection for the highway industry. Laboratory studies indicate that electrically conductive polymer concrete overlays using conductive fillers, such as calcined coke breeze, in conjunction with polyester or vinyl ester resins have resistivities of 1 to 10 ohm-cm. Both multiple-layer and premixed mortar-type overlays were made. Shear bond strengths of the conductive overlays to concrete substrates vary from 600 to 1300 psi, with the premixed overlays having bond strengths 50 to 100% higher than the multiple-layer overlays.

  15. GFRP reinforced concrete bridge decks.

    Science.gov (United States)

    2000-07-01

    This report investigates the application of glass fiber reinforced polymer (GFRP) rebars in concrete bridge decks as a potential replacement or supplement to conventional steel rebars. Tests were conducted to determine the material properties of the ...

  16. Uncontrolled concrete bridge parapet cracking.

    Science.gov (United States)

    2013-06-01

    The Ohio Department of Transportation has recently identified the problem of wide-spread premature cracking of concrete bridge : parapets throughout its District 12 region (Northeast Ohio). Many of the bridge decks that contain these prematurely crac...

  17. Premature asphalt concrete pavement cracking.

    Science.gov (United States)

    2015-06-01

    Recently, the Oregon Department of Transportation (ODOT) has identified hot mix asphalt concrete : (HMAC) pavements that have displayed top-down cracking within three years of construction. The objective of : the study was to evaluate the top-down cr...

  18. Tests on standard concrete samples

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    Compression and tensile tests on standard concrete samples. The use of centrifugal force in tensile testing has been developed by the SB Division and the instruments were built in the Central workshops.

  19. Self-healing of polymer modified concrete

    OpenAIRE

    Abd_Elmoaty M. Abd_Elmoaty

    2011-01-01

    Self healing phenomenon of concrete has been observed in traditional, fibrous, self compacting concrete. This phenomenon occurred mainly due to the presence of unhydrated cement particles in the presence of water. Mechanism of polymer in concrete depends on creating a layer and net of polymer around cement particles which enhances the properties of polymer modified concrete. This mechanism may affect the self healing of this type of concrete. This work aims to study the presence of the self h...

  20. Monitoring water loss form fresh concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    2006-01-01

    Desiccation of concrete before or during setting may lead to detrimental plastic shrinkage cracking in the concrete surface zone. Cracking due to plastic shrinkage is a major technological problem for any concrete, however, modern high-performance concretes are especially susceptible to this. Thi...... determination of the evaporation loss from hardening concrete and thus better possibility for preventing curing problems, including detrimental crack damage due to plastic shrinkage....

  1. Characteristics of Concrete with Admixtures

    OpenAIRE

    Bogdan Roşca; P. Mihai

    2008-01-01

    In recent decades, tremendous success has been achieved in the advancement of chemical admixtures for Portland cement concrete. Most efforts have centered on improving the properties of concrete with minimal investments by ready-mix suppliers and contractors in the way of specialized equipment or special skills and education of their labor forces. This approach has resulted in construction cost reductions and universally accepted ready-made remedies for unexpected problems during construction...

  2. Electrically conductive polymer concrete coatings

    Science.gov (United States)

    Fontana, Jack J.; Elling, David; Reams, Walter

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  3. Annotated Bibliography: Polymers in Concrete.

    Science.gov (United States)

    1982-10-01

    sulfur within 20 hr. Limonene, myrcene , alloocimene, dicyclopentadiene, cyclododeca- 1,5,9-triene, cycloocta-1,3-diene, styrene, and the polymeric poly...saturated into hardened concrete and subsequently polymerized . Section C covers latex-modified concretes and has 256 abstracts on articles dating back... polymerization led by the associated crystals. A44 Franke, W., "The Employment of Epoxy Resin in the Sanitation of Prefabricated Bridge Members Made of

  4. Concrete waterproofing in nuclear industry.

    Science.gov (United States)

    Scherbyna, Alexander N; Urusov, Sergei V

    2005-01-01

    One of the main points of aggregate safety during the transportation and storage of radioactive materials is to supply waterproofing for all constructions having direct contact with radiating substances and providing strength, seismic shielding etc. This is the problem with all waterside structures in nuclear industry and concrete installations in the treatment and storage of radioactive materials. In this connection, the problem of developing efficient techniques both for the repair of operating constructions and the waterproofing of new objects of the specified assignment is genuine. Various techniques of concrete waterproofing are widely applied in the world today. However, in conditions of radiation many of these techniques can bring not a profit but irreparable damage of durability and reliability of a concrete construction; for instance, when waterproofing materials contain organic constituents, polymers etc. Application of new technology or materials in basic construction elements requires in-depth analysis and thorough testing. The price of an error might be very large. A comparative analysis shows that one of the most promising types of waterproofing materials for radiation loaded concrete constructions is "integral capillary systems" (ICS). The tests on radiation, thermal and strength stability of ICS and ICS-treated concrete samples were initiated and fulfilled in RFNC-VNIITF. The main result is--ICS applying is increasing of waterproofing and strength properties of concrete in conditions of readiation The paper is devoted to describing the research strategy, the tests and their results and also to planning of new tests.

  5. Self Healing in Concrete Materials

    Science.gov (United States)

    Li, Victor C.; Yang, En-Hua

    The phenomenon of self healing in concrete has been known for many years. It has been observed that some cracks in old concrete structures are lined with white crystalline material suggesting the ability of concrete to self-seal the cracks with chemical products by itself, perhaps with the aid of rainwater and carbon dioxide in air. Later, a number of researchers [1, 2] in the study of water flow through cracked concrete under a hydraulic gradient, noted a gradual reduction of permeability over time, again suggesting the ability of the cracked concrete to self-seal itself and slow the rate of water flow. The main cause of self-sealing was attributed to the formation of calcium carbonate, a result of reaction between unhydrated cement and carbon dioxide dissolved in water [1]. Thus, under limited conditions, the phenomenon of self-sealing in concrete is well established. Self-sealing is important to watertight structures and to prolonging service life of infrastructure.

  6. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers

    OpenAIRE

    Francisco Cartuxo; Jorge de Brito; Luis Evangelista; José Ramón Jiménez; Enrique F. Ledesma

    2016-01-01

    This paper evaluates the influence of two superplasticizers (SP) on the durability properties of concrete made with fine recycled concrete aggregate (FRCA). For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All...

  8. Drying of concrete. Part II: The drying time of concrete structures

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Christensen, Søren Lolk

    1998-01-01

    The composition of a concrete mix has a significant influence on the drying time to reach a given relative humidity in the concrete pores. Knowledge of the influence on the drying of a specific component in the concrete makes it possible to design a concrete mix having a predetermined drying time....... In the paper the effects of the air content and the silica fume content on the drying time are investigated on two concrete mixes having different water/cement ratios. One concrete represents a normal concrete and the other represents a selfdesiccation concrete....

  9. Retrofitting of Reinforced Concrete Beams using Reactive Powder Concrete (RPC)

    Science.gov (United States)

    Karthik, S.; Sundaravadivelu, Karthik

    2017-07-01

    Strengthening of existing damaged structures is one of the leading studies in civil engineering. The purpose of retrofitting is to structurally treat the member with an aim to restore the structure to its original strength. The focus of this project is to study the behaviour of damaged Reinforced Concrete beam retrofitted with Reactive Powder Concrete (RPC) Overlay. Reinforced concrete beams of length 1200 mm, width 100 mm and depth 200 mm were casted with M30 grade of concrete in the laboratory and cured for 28 days. One beam is taken as control and are tested under two point loading to find out ultimate load. Remaining beams are subjected to 90 % ultimate load of control beams. The partially damaged beams are retrofitted with Reactive Powder Concrete Overlay at the full tension face of the beam and side overlay depends upon the respectable retrofitting techniques with 10 mm and 20 mm thick layer to find optimum. Materials like steel fibres are added to enhance the ductility by eliminating coarse particle for homogeneity of the structure. Finally, the modes of failure for retrofitted beams are analysed experimentally under two point loading & compared the results with Control beam.

  10. Nanogranular origin of concrete creep

    Science.gov (United States)

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  11. Use of roller-compacted concrete pavement in Stafford, Virginia.

    Science.gov (United States)

    2015-05-01

    Roller-compacted concrete (RCC) is a relatively stiffer hydraulic cement concrete mixture than regular concrete when : fresh. Similar to regular concrete, RCC is a mixture of aggregate, cementitious materials, and water, but it is placed using asphal...

  12. Bending characteristics of resin concretes

    Directory of Open Access Journals (Sweden)

    Ribeiro Maria Cristina Santos

    2003-01-01

    Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.

  13. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold...... is reached causing the formation of anodic and cathodic regions along the reinforcement. Critical chloride thresholds, randomly distributed along the reinforcement sur-face, link the initiation and propagation phase of reinforcement corrosion. To demonstrate the potential use of the developed model......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  14. A Failure Criterion for Concrete

    DEFF Research Database (Denmark)

    Ottosen, N. S.

    1977-01-01

    A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace in the devi......A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace...

  15. Concrete structures under projectile impact

    CERN Document Server

    Fang, Qin

    2017-01-01

    In this book, the authors present their theoretical, experimental and numerical investigations into concrete structures subjected to projectile and aircraft impacts in recent years. Innovative approaches to analyze the rigid, mass abrasive and eroding projectile penetration and perforation are proposed. Damage and failure analyses of nuclear power plant containments impacted by large commercial aircrafts are numerically and experimentally analyzed. Ultra-high performance concrete materials and structures against the projectile impact are developed and their capacities of resisting projectile impact are evaluated. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.

  16. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  17. Topology optimization of reinforced concrete structures

    DEFF Research Database (Denmark)

    Amir, Oded

    Recent advances regarding topology optimization procedures of reinforced concrete structures are presented. We discuss several approaches to the challenging problem of optimizing the distribution of concrete and steel reinforcement. In particular, the consideration of complex nonlinear constitutive...

  18. Development of concrete shrinkage performance specifications.

    Science.gov (United States)

    2003-01-01

    During its service life, concrete undergoes volume changes. One of the types of deformation is shrinkage. The four main types of shrinkage associated with concrete are plastic, autogenous, carbonation, and drying shrinkage. The volume changes in conc...

  19. Long-life slab replacement concrete.

    Science.gov (United States)

    2015-03-01

    This research was initiated following reports of high incidence of cracking on FDOT concrete pavement replacement : slab projects. Field slabs were instrumented for data acquisition from high-early-strength concrete pavement : replacement slabs place...

  20. Recycled materials in Portland cement concrete

    Science.gov (United States)

    2000-06-01

    This report pertains to a comprehensive study involving the use of recycled materials in Portland cement concrete. Three different materials were studied including crushed glass (CG), street sweepings (SS), and recycled concrete (RC). Blast furnace s...

  1. Concrete pavement construction basics : tech notes.

    Science.gov (United States)

    2006-08-01

    This tech note has been produced for developers, consultants, and engineers planning concrete pavement construction projects, superintendents and supervisors who want a basic training aid and reference, and crew members new to the concrete paving ind...

  2. Joint sealant materials for concrete pavement repairs.

    Science.gov (United States)

    1991-01-01

    This report on joint sealant materials for concrete pavement repairs is based on conversations with specialists from several states, the Federal Highway Administration, the Portland Cement Association, and the American Concrete Pavement Association, ...

  3. crushed concrete as a source of aggregate for new concrete

    African Journals Online (AJOL)

    Engr. Dr. F.O. Okafor

    KEYWORDS: Waste Concrete; Recycled Aggregate; Workability, Compressive Strength. ... better methods of solid waste disposal and probably energy ... Specific gravity. Water absorption, (%). Aggregate crushing value, (%). 2.65. 0.21. 22.52. 2.49. 3.67. 29.86. Grading (% by weight passing sieve size stated). 25.4 mm.

  4. Evaluation of concrete inlay for continuously reinforced concrete pavement rehabilitation.

    Science.gov (United States)

    2010-06-01

    In 1996, WisDOT constructed a concrete inlay test section on I43 in Manitowoc County. The existing pavement was CRCP constructed in 1978 and was badly deteriorated with punchouts. In the area of the 2777foot test section, the existing paveme...

  5. Study of technological features of tubular compressed concrete members in concreting

    Directory of Open Access Journals (Sweden)

    Voskobiinyk Olena

    2017-01-01

    Full Text Available The technological features of core concreting were analyzed as the main factor in ensuring of strength and reliability of compressed concrete-filled steel tubular (CFST members. We have conducted the analysis of existing concreting methods of CFST members. In this respect, the most dangerous types of possible technological defects of concrete core of CFST members are inhomogeneity along the height, voids, caverns, and concrete “weak spots”. The authors considered the influence of such technological factors of concreting: placeability, time, concrete mixture compaction method, concreting height on the concrete core strength of CFST members. Based on the experimental studies conducted we suggested the regression correlations for determining the concrete strength of CFST members of different length depending on the movability of concrete mixture and a time for its compaction. The authors performed the correlation analysis of technological factors of concreting on the strength of the concrete core. We carried out the comparison of data on the concrete core strength of CFST members, that were determined by non-destructive methods (sclerometer test results, ultrasonic method and direct compression strength tests. We experimentally proved that using movable mixtures with the slump of about 4 – 9 cm the overall variation coefficient of concrete core strength of CFST members along the height reaches nearly 13%. Based on the experimental studies conducted we suggested the guidelines on optimal regimes of concrete compaction during manufacturing CFST members at a construction site environment.

  6. Modelling the Loss of Steel-Concrete Bonds in Corroded Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2007-01-01

    The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete.......The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete....

  7. ConcreteWorks v3 training/user manual (P1) : ConcreteWorks software (P2).

    Science.gov (United States)

    2017-04-01

    ConcreteWorks is designed to be a user-friendly software package that can help concrete : professionals optimize concrete mixture proportioning, perform a concrete thermal analysis, and : increase the chloride diffusion service life. The software pac...

  8. Durability of concrete structures incorporating recycled aggregates

    OpenAIRE

    SCHMITT, Lucie; MAI-NHU, Jonathan; DJERBI TEGGUER, Assia; ROUGEAU, Patrick; SAILLIO, Mickael

    2016-01-01

    Nowadays sustainable development holds a more and more important rank in our society. As concrete is the second material the most consumed in the world after water, thinking about a way to reuse the construction wastes is completely justified in this context. The French national project RECYBETON and ANR ECOREB works aim to answer some questions dealing with the use of recycled concrete aggregates into new concrete. One of the goal of ANR ECOREB is to study the influence of recycled concrete ...

  9. Probabilistic design of fibre concrete structures

    Science.gov (United States)

    Pukl, R.; Novák, D.; Sajdlová, T.; Lehký, D.; Červenka, J.; Červenka, V.

    2017-09-01

    Advanced computer simulation is recently well-established methodology for evaluation of resistance of concrete engineering structures. The nonlinear finite element analysis enables to realistically predict structural damage, peak load, failure, post-peak response, development of cracks in concrete, yielding of reinforcement, concrete crushing or shear failure. The nonlinear material models can cover various types of concrete and reinforced concrete: ordinary concrete, plain or reinforced, without or with prestressing, fibre concrete, (ultra) high performance concrete, lightweight concrete, etc. Advanced material models taking into account fibre concrete properties such as shape of tensile softening branch, high toughness and ductility are described in the paper. Since the variability of the fibre concrete material properties is rather high, the probabilistic analysis seems to be the most appropriate format for structural design and evaluation of structural performance, reliability and safety. The presented combination of the nonlinear analysis with advanced probabilistic methods allows evaluation of structural safety characterized by failure probability or by reliability index respectively. Authors offer a methodology and computer tools for realistic safety assessment of concrete structures; the utilized approach is based on randomization of the nonlinear finite element analysis of the structural model. Uncertainty of the material properties or their randomness obtained from material tests are accounted in the random distribution. Furthermore, degradation of the reinforced concrete materials such as carbonation of concrete, corrosion of reinforcement, etc. can be accounted in order to analyze life-cycle structural performance and to enable prediction of the structural reliability and safety in time development. The results can serve as a rational basis for design of fibre concrete engineering structures based on advanced nonlinear computer analysis. The presented

  10. Summary of Self-compacting Concrete Workability

    OpenAIRE

    GUO Gui-xiang; Duan Hong-jun

    2015-01-01

    On the basis of a large number of domestic and foreign literature, situation and development of self-compacting concrete is introduced. Summary of the compacting theory of self-compacting concrete. And some of the factors affecting the workability of self-compacting concrete were discussed and summarized to a certain extent. Aims to further promote the application and research of self-compacting concrete

  11. Cement and Concrete Nanoscience and Nanotechnology

    OpenAIRE

    Taijiro Sato; Jon Makar; Rouhollah Alizadeh; James Beaudoin; Laila Raki

    2010-01-01

    Concrete science is a multidisciplinary area of research where nanotechnology potentially offers the opportunity to enhance the understanding of concrete behavior, to engineer its properties and to lower production and ecological cost of construction materials. Recent work at the National Research Council Canada in the area of concrete materials research has shown the potential of improving concrete properties by modifying the structure of cement hydrates, addition of nanoparticles and nanotu...

  12. Nanoparticles for high performance concrete (HPC)

    OpenAIRE

    Torgal, Fernando Pacheco; Miraldo, Sérgio; Ding, Yining; J.A. Labrincha

    2013-01-01

    According to the 2011 ERMCO statistics, only 11% of the production of ready-mixed concrete relates to the high performance concrete (HPC) target. This percentage has remained unchanged since at least 2001 and appears a strange choice on the part of the construction industry, as HPC offers several advantages over normal-strength concrete, specifically those of high strength and durability. It allows for concrete structures requiring less steel reinforcement and offers a longer serviceable life...

  13. High Performance Concrete Pavement in Indiana

    OpenAIRE

    Nantung, Tommy E

    2011-01-01

    Until the early 1990s, curling and warping of Portland cement concrete pavement did not concern pavement engineers in many transportation agencies. Since beginning construction of the interstate system in the United States in the late 1950s through the late 1980s, the performance of Portland cement concrete pavement has been associated with properties of concrete as a pavement material. In those years developed standards and design guidelines emphasized better concrete materials and construct...

  14. Mechanical properties of concrete containing recycled concrete aggregate (RCA) and ceramic waste as coarse aggregate replacement

    Science.gov (United States)

    Khalid, Faisal Sheikh; Azmi, Nurul Bazilah; Sumandi, Khairul Azwa Syafiq Mohd; Mazenan, Puteri Natasya

    2017-10-01

    Many construction and development activities today consume large amounts of concrete. The amount of construction waste is also increasing because of the demolition process. Much of this waste can be recycled to produce new products and increase the sustainability of construction projects. As recyclable construction wastes, concrete and ceramic can replace the natural aggregate in concrete because of their hard and strong physical properties. This research used 25%, 35%, and 45% recycled concrete aggregate (RCA) and ceramic waste as coarse aggregate in producing concrete. Several tests, such as concrete cube compression and splitting tensile tests, were also performed to determine and compare the mechanical properties of the recycled concrete with those of the normal concrete that contains 100% natural aggregate. The concrete containing 35% RCA and 35% ceramic waste showed the best properties compared with the normal concrete.

  15. Significance of tests and properties of concrete and concrete-making materials

    CERN Document Server

    Pielert, James H

    2006-01-01

    Reflects a decade of technological changes in concrete industry! The newest edition of this popular ASTM publication reflects the latest technology in concrete and concrete-making materials. Six sections cover: (1) General information on the nature of concrete, sampling, variability, and testing laboratories. A new chapter deals with modeling cement and concrete properties. (2) Properties of freshly mixed concrete. (3) Properties of hardened concrete. (4) Concrete aggregates—this section has been revised and the chapters are presented in the order that most concerns concrete users: grading, density, soundness, degradation resistance, petrographic examination, reactivity, and thermal properties. (5) Materials other than aggregates—the chapter on curing materials now reflects the current technology of materials applied to new concrete surfaces. The chapter on mineral admixtures has been separated into two chapters: supplementary cementitious materials and ground slag. (6) Specialized concretes—contains a ...

  16. Limits of Spalling of Fire Exposed Concrete

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    1998-01-01

    The supporting document describes the present knowledge about explosive spalling of traditional concrete and dense concrete based on 36 references and the authors own tests and observations.The document concludes that the risk of spalling is limited for traditional concretes within 3-4 percent...

  17. Prediction of Deterioration of Concrete Bridges

    NARCIS (Netherlands)

    Gaal, G.C.M.

    2004-01-01

    In the early 20th century, the general idea was that concrete structures would never show deterioration. However, in the 1990s concrete structures showed an increase in number of cracks and area of spalling. Especially spalling of the concrete cover could create a harmful situation to the users.

  18. Field validation of recycled concrete fines usage.

    Science.gov (United States)

    2015-03-01

    The amount of recycled concrete fines permitted in concrete mixing water is limited by ASTM C 1602 to 5.0 percent of the mixing : water, by mass, in order to avoid detrimental effects on concrete properties. Depending upon the exact nature of the rec...

  19. 9 CFR 91.26 - Concrete flooring.

    Science.gov (United States)

    2010-01-01

    ... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000 psi... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Concrete flooring. 91.26 Section 91.26...

  20. Concrete bridge deck early problem detection and mitigation using robotics

    Science.gov (United States)

    Gucunski, Nenad; Yi, Jingang; Basily, Basily; Duong, Trung; Kim, Jinyoung; Balaguru, Perumalsamy; Parvardeh, Hooman; Maher, Ali; Najm, Husam

    2015-04-01

    More economical management of bridges can be achieved through early problem detection and mitigation. The paper describes development and implementation of two fully automated (robotic) systems for nondestructive evaluation (NDE) and minimally invasive rehabilitation of concrete bridge decks. The NDE system named RABIT was developed with the support from Federal Highway Administration (FHWA). It implements multiple NDE technologies, namely: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW). In addition, the system utilizes advanced vision to substitute traditional visual inspection. The RABIT system collects data at significantly higher speeds than it is done using traditional NDE equipment. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. The interpretation and visualization platform specifically addresses data integration and fusion from the four NDE technologies. The data visualization platform facilitates an intuitive presentation of the main deterioration due to: corrosion, delamination, and concrete degradation, by integrating NDE survey results and high resolution deck surface imaging. The rehabilitation robotic system was developed with the support from National Institute of Standards and Technology-Technology Innovation Program (NIST-TIP). The system utilizes advanced robotics and novel materials to repair problems in concrete decks, primarily early stage delamination and internal cracking, using a minimally invasive approach. Since both systems use global positioning systems for navigation, some of the current efforts concentrate on their coordination for the most effective joint evaluation and rehabilitation.

  1. Shape characterization of concrete aggregate

    NARCIS (Netherlands)

    Stroeven, P.; Hu, J.

    2006-01-01

    As a composite material, the performance of concrete materials can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The microstructure at the interfacial transition zone (ITZ) is assumed to be different from the bulk material. In

  2. Crablock Concrete Breakwater Armour Unit

    CSIR Research Space (South Africa)

    Phelp, D

    2012-02-01

    Full Text Available concrete armour units. This paper describes the development and use of CRABLOCK, which is similar to the Hexapod in shape (SPM, 2006). The results of physical model tests carried out at CSIR, in South Africa, are also presented and discussed....

  3. (Oil Palm Shell) Lightweight Concrete

    African Journals Online (AJOL)

    The compressive strength as destructive test and, ultrasonic pulse velocity (UPV) and dynamic modulus of elasticity (Ed) as non-destructive tests have been carried out on a new lightweight concrete produced using oil palm shell (OPS) as coarse aggregate, as a way to establish the usefulness of these tests to determine the ...

  4. Roller-compacted concrete pavements.

    Science.gov (United States)

    2010-09-01

    Roller-compacted concrete (RCC) gets its name from the heavy vibratory steel drum and rubber-tired rollers used to help compact it into its final form. RCC has similar strength properties and consists of the same basic ingredients as conventional con...

  5. Timber-concrete composite beams

    NARCIS (Netherlands)

    Van der Linden, M.L.R.

    1999-01-01

    In this paper an easy-to-use design model for timber-concrete composite beams is discussed. The model is applicable for computer simulations as well as for hand calculations. A research programme was started in 1992 in co-operation with the University of Karlsruhe, to study the loadbearing

  6. Large Scale Glazed Concrete Panels

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    and finally Lene Tranberg and Bøje Lungård’s Elsinore water purification plant. These buildings have qualities that I would like applied, perhaps transformed or most preferably, if possible, interpreted anew, for the large glazed concrete panels I shall develop. The article is ended and concluded...

  7. Timber floors strengthened with concrete

    NARCIS (Netherlands)

    Blass, H.J.; Linden, M.L.R. van der; Schlager, M.

    1998-01-01

    Timber-concrete composite (tcc) beams may be used for the renovation of old timber floors. Although these systems are not new (Pokulka, 1997) and form a simple and practical solution, they are not widely adopted. One of the reasons for this is the Jack of uniform design rules. In this research

  8. Computer models of concrete structures

    OpenAIRE

    Cervenka, Vladimir; Eligehausen, Rolf; Pukl, Radomir

    1991-01-01

    The application of the nonlinear finite element analysis of concrete structures as a design tool is discussed. A computer program for structures in plane stress state is described and examples of its application in the research of fastening technique and in engineering practice are shown.

  9. Early Property Development in Concrete

    DEFF Research Database (Denmark)

    Normann, Gitte; Munch-Petersen, Christian

    The Freiesleben Maturity function is widely used for planning of execution. We tested if for concrete with and without fly ash. The test showed surprisingly that the maturity function in general is not valid. We found that curing at high temperature gave a significant decrease in strength. Fly as...

  10. A review on the suitability of rubberized concrete for concrete bridge decks

    Science.gov (United States)

    Syamir Senin, Mohamad; Shahidan, Shahiron; Radziah Abdullah, Siti; Anting Guntor, Nickholas; Syazani Leman, Alif

    2017-11-01

    Road authorities manage a large population of ageing bridges, a substantial number of which fail to meet the current requirements either due to deterioration and other structural deficiencies or as a result of the escalating demands imposed by increased traffic. This problem is related to the dynamic load from vehicles. This problem can be solved by producing a type of concrete that can reduce the amplitude of oscillation or vibration such as rubberized concrete. Green construction has been a very important aspect in concrete production field in the last decade. One of the most problematic waste materials is scrap tires. The use of scrap tires in civil engineering is increasing by producing rubberized concrete. Rubberized concrete is a type of concrete that is mixed with rubber. The purpose of this review is to justify the suitability of rubberized concrete for concrete bridge decks. Several parameters named physical, chemical and mechanical properties were measured to ensure the suitability of rubberized concrete for concrete bridge decks. Rubberized concrete has similar workability to normal concrete. The rubber reduced the density and compressive strength of the concrete while increased the flexural strength, water absorption and damping ratio. The used of rubber in concrete beyond 20% is not recommended due to decreasing in compressive strength. Rubberized concrete recommended to be used in circumstances where vibration damping was required such as in bridge construction as shock-wave absorber.

  11. Research on 3D reconstruction of concrete

    Directory of Open Access Journals (Sweden)

    Shi Pan-fei

    2015-01-01

    Full Text Available In order to associate with using acoustic emission, ultrasonic or other means to locate damage of concrete, based on the concrete CT image information, the research of 3D reconstruction of concrete crack structure was completed by using Amira 5.2.1 3D reconstruction software. Experiments showed that: three dimensional reconstruction of concrete can reflect the real crack structure, and distribution of aggregate concrete of three dimensional model established was basically in accordance with the original CT image, which laid the good foundation to simulate and analysis by using ANSYS finite element software in the future.

  12. Concrete structures protection, repair and rehabilitation

    CERN Document Server

    Woodson, R Dodge

    2009-01-01

    The success of a repair or rehabilitation project depends on the specific plans designed for it. Concrete Structures: Protection, Repair and Rehabilitation provides guidance on evaluating the condition of the concrete in a structure, relating the condition of the concrete to the underlying cause or causes of that condition, selecting an appropriate repair material and method for any deficiency found, and using the selected materials and methods to repair or rehabilitate the structure. Guidance is also provided for engineers focused on maintaining concrete and preparing concrete investigation r

  13. Mechanical characterization of fiber reinforced Polymer Concrete

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2005-09-01

    Full Text Available A comparative study between epoxy Polymer Concrete plain, reinforced with carbon and glass fibers and commercial concrete mixes was made. The fibers are 6 mm long and the fiber content was 2% and 1%, respectively, in mass. Compressive tests were performed at room temperature and load vs. displacement curves were plotted up to failure. The carbon and glass fibers reinforcement were randomly dispersed into the matrix of polymer concrete. An increase in compressive properties was observed as function of reinforcement. The comparison also showed that Polymer Concrete, plain and reinforced, has a better performance than regular market concrete, suggesting that PC is a reliable alternative for construction industry.

  14. Metrology Needs for Predicting Concrete Pumpability

    Directory of Open Access Journals (Sweden)

    Myoungsung Choi

    2015-01-01

    Full Text Available With the increasing use of pumping to place concrete, the development and refinement of the industry practice to ensure successful concrete pumping are becoming important needs for the concrete construction industry. To date, research on concrete pumping has been largely limited to a few theses and research papers. The major obstacle to conduct research on concrete pumping is that it requires heavy equipment and large amounts of materials. Thus, developing realistic and simple measurement techniques and prediction tools is a financial and logistical challenge that is out of reach for small research labs and many private companies in the concrete construction industry. Moreover, because concrete pumping involves the flow of a complex fluid under pressure in a pipe, predicting its flow necessitates detailed knowledge of the rheological properties of concrete, which requires new measurement science. This paper summarizes the technical challenges associated with concrete pumping and the development in concrete pumping that have been published in the technical literature and identifies future research needed for the industry to develop best practices for ensuring successful concrete pumping in the field.

  15. NEW TECHNOLOGY OF ASH AND SLAG CONCRETES

    Directory of Open Access Journals (Sweden)

    PAVLENKO T. M.

    2017-03-01

    Full Text Available Summary. Purpose. Development of scientific-technical bases of manufacture and application of concrete on the basis of ash and slag mixes of thermal power plants. Methods. It is proposed a new technology of preparation of ash and slag concrete mixes. First the ash and slag mix is dispersed through the sieve with meshes 5 mm in a fine-grained fraction and slag. Then, in accordance with the composition of the concrete, obtained fine-grained fraction, slag, cement and tempering water are separately dosed into the mixer. Results. It is proven the high efficiency of the proposed technology of manufacture of ash and slag concretes. It is established that this technological solution allows to increase the strength of concrete by 20...30%, and in the preparation of full-strength concrete to reduce the cement consumption by 15...20%. Scientific novelty. It is developed the new technology of ash and slag mixes application. The concrete mix on the basis of ash and slag mix has an optimal particle size distribution, which ensures the best compaction and, accordingly, the greatest strength of ash and slag concrete with the given cement consumption. Practical significance. The research results promote the mass application of ash and slag mixes of thermal power plants in construction, obtaining of products from the proposed concretes of low cost with high physical-mechanical properties. Conclusion. It is proven the high efficiency of the proposed technology of production of ash and slag concretes. It is established that this technological solution allows increasing concrete strength, and obtaining full-strength concrete to reduce cement consumption. The extensive application of such concrete in construction makes it possible to solve the problem of aggregates for concrete, promotes recycling of TPP waste and consequently the protection of the environment.

  16. Control of Early Age Concrete. Phase 3: Creep in Concrete

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, Anders Boe; Damkilde, Lars; Hansen, Per Freiesleben

    1997-01-01

    The mechanical properties of the "Road Directorate Concrete" at early ages are studied. Creep in tension at 24 and 72 maturity hours are measured on dogbone shaped specimens. The development of tensile modulus of elasticity and strength are measured with a method developed here. The results...... are compared to compression values and splitting strengths. It is found that the properties of creep in tension are similar to the properties in compression. Further the influence form temperature on creep is found to be significant....

  17. Reactions of sodium with various concretes and concrete materials

    Energy Technology Data Exchange (ETDEWEB)

    Hassberger, J.A.; Barton, G.B.; Witkowski, R.E.; Charles, R.G.

    1976-01-01

    This paper presents a summary of the work performed to date on the investigation of sodium-concrete reactions. Principal results to date have been achieved in laboratory-scale investigations using differential thermal analysis (DTA), thermo-magnetic analysis (TMA), and other techniques. The results of these tests are described. Comparisons with the laboratory-scale tests and available bench- and large-scale tests are made. In view of these data, future work requirements and plans are discussed.

  18. Concrete Shield Performance of the VSC-17 Spent Nuclear Fuel Cask

    Energy Technology Data Exchange (ETDEWEB)

    Sheryl L. Morton; Philip L. Winston; Toshiari Saegusa; Koji Shirai; Akihiro Sasahara; Takatoshi Hattori

    2006-04-01

    In 2003, representatives from the Central Research Institute of Electric Power Industry (CRIEPI) requested development of a project with the objective of determining the performance of a concrete spent nuclear fuel storage cask. Radiation and environmental effects may cause chemical alteration of the concrete that could result in excessive cracking, spalling, and loss of compressive strength. The Idaho National Laboratory (INL) project team and CRIEPI representatives identified the Ventilated Storage Cask (VSC-17) spent nuclear fuel storage cask as a candidate to study cask performance, because it had been used to store fuel as part of a dry cask storage demonstration project for more than 15 years. The project involved investigating the properties of the concrete shield. INL performed a survey of the cask in the summers of 2003 and 2004. Preliminary cask evaluations performed in 2003 indicated that the cask has no visual degradation. However, a 4-5 mrem/hr step-change in the radiation levels about halfway up the cask and a localized hot spot beneath an upper air vent indicate that there may be variability in the density of the concrete or localized cracking. In 2005, INL and CRIEPI scientists performed additional surveys on the VSC-17 cask. This document summarizes the methods used on the VSC-17 to evaluate the cask for compressive strength, concrete cracking, concrete thickness, and temperature distribution.

  19. Self-consolidating concrete homogeneity

    Directory of Open Access Journals (Sweden)

    Jarque, J. C.

    2007-08-01

    Full Text Available Concrete instability may lead to the non-uniform distribution of its properties. The homogeneity of self-consolidating concrete in vertically cast members was therefore explored in this study, analyzing both resistance to segregation and pore structure uniformity. To this end, two series of concretes were prepared, self-consolidating and traditional vibrated materials, with different w/c ratios and types of cement. The results showed that selfconsolidating concretes exhibit high resistance to segregation, albeit slightly lower than found in the traditional mixtures. The pore structure in the former, however, tended to be slightly more uniform, probably as a result of less intense bleeding. Such concretes are also characterized by greater bulk density, lower porosity and smaller mean pore size, which translates into a higher resistance to pressurized water. For pore diameters of over about 0.5 μm, however, the pore size distribution was found to be similar to the distribution in traditional concretes, with similar absorption rates.En este trabajo se estudia la homogeneidad de los hormigones autocompactantes en piezas hormigonadas verticalmente, determinando su resistencia a la segregación y la uniformidad de su estructura porosa, dado que la pérdida de estabilidad de una mezcla puede conducir a una distribución no uniforme de sus propiedades. Para ello se han fabricado dos tipos de hormigones, uno autocompactante y otro tradicional vibrado, con diferentes relaciones a/c y distintos tipos de cemento. Los resultados ponen de manifiesto que los hormigones autocompactantes presentan una buena resistencia a la segregación, aunque algo menor que la registrada en los hormigones tradicionales. A pesar de ello, su estructura porosa tiende a ser ligeramente más uniforme, debido probablemente a un menor sangrado. Asimismo, presentan una mayor densidad aparente, una menor porosidad y un menor tamaño medio de poro, lo que les confiere mejores

  20. Research on Deterioration Mechanism of Concrete Materials in an Actual Structure

    Directory of Open Access Journals (Sweden)

    Shiping Zhang

    2014-01-01

    Full Text Available The cause for deterioration of the concrete structure located in severe environment has been explored both in field and in laboratory. Serious cracking and spalling appeared upon surface of the concrete structure soon after the structure was put into service. Both alkali-aggregate reaction and freeze-thaw cycles may result in similar macro visible cracking and spalling. The possibility of alkali-aggregate reaction was excluded by both field survey and lab examination such as chemical analysis, petrographic analysis, and determination of alkali reactivity of aggregates. According to results of freeze-thaw cycles, impermeability testing, and microstructure analysis, it is deduced that the severe environmental conditions plus the relatively inferior frost resistance cause the deterioration of concrete. Usage of air entraining admixture can improve frost resistance and impermeability. Furthermore, new approaches to mitigate the deterioration of concrete used in severe environmental condition are discussed.

  1. SHAPE CHARACTERIZATION OF CONCRETE AGGREGATE

    Directory of Open Access Journals (Sweden)

    Jing Hu

    2011-05-01

    Full Text Available As a composite material, the performance of concrete materials can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The microstructure at the interfacial transition zone (ITZ is assumed to be different from the bulk material. In general, properties of conventional concrete have been found favoured by optimum packing density of the aggregate. Particle size is a common denominator in such studies. Size segregation in the ITZ among the binder particles in the fresh state, observed in simulation studies by concurrent algorithm-based SPACE system, additionally governs density as well as physical bonding capacity inside these shell-like zones around aggregate particles. These characteristics have been demonstrated qualitatively pertaining also after maturation of the concrete. Such properties of the ITZs have direct impact on composite properties. Despite experimental approaches revealed effects of aggregate grain shape on different features of material structure (among which density, and as a consequence on mechanical properties, it is still an underrated factor in laboratory studies, probably due to the general feeling that a suitable methodology for shape characterization is not available. A scientific argument hindering progress is the interconnected nature of size and shape. Presently, a practical problem preventing shape effects to be emphasized is the limitation of most computer simulation systems in concrete technology to spherical particles. New developments at Delft University of Technology will make it possible in the near future to generate jammed states, or other high-density fresh particle mixtures of non-spherical particles, which thereupon can be subjected to hydration algorithms. This paper will sketch the outlines of a methodological approach for shape assessment of loose (non-embedded aggregate grains, and demonstrate its use for two types of aggregate, allowing

  2. Severe ASR damaged concrete bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren

    2015-01-01

    Technical University of Denmark (DTU) and University of Southern Denmark (SDU) have conducted several full-scale experiments with severe ASR deteriorated bridges. This paper presents few and preliminary results from both the shear tests and the measuring of the material properties. The shear test...... show that the shear capacity is almost unaffected of ASR despite significant reduction in compressive concrete strength. Furthermore, measurements show a significant tensile reinforcement strain developed due to ASR expansion....

  3. Numerical Characterization of Concrete Heterogeneity

    OpenAIRE

    Pitangueira, Roque Luiz; Silva, Raul Rosas e

    2002-01-01

    In this paper, a finite element model including both material heterogeneity and size effects is presented. The concrete is considered as a statistical combination of constituent phase with different properties (aggregate, mortar and interface material). The material point response is based on a combination of the random occurrence of the solid phases in the structural volume as well as on the differences of structural response due to the size effect. Such combination allows for higher or lowe...

  4. Self-healing of polymer modified concrete

    Directory of Open Access Journals (Sweden)

    Abd_Elmoaty M. Abd_Elmoaty

    2011-06-01

    Full Text Available Self healing phenomenon of concrete has been observed in traditional, fibrous, self compacting concrete. This phenomenon occurred mainly due to the presence of unhydrated cement particles in the presence of water. Mechanism of polymer in concrete depends on creating a layer and net of polymer around cement particles which enhances the properties of polymer modified concrete. This mechanism may affect the self healing of this type of concrete. This work aims to study the presence of the self healing phenomenon in polymer modified concrete and the related parameters. An experimental investigation on self healing of polymer modified concrete was undertaken. In this research work, effect of polymer type, polymer dose, cement content, cement type, w/cm ratio and age of damage were studied. The healing process extended up to 60 days. Ultrasonic pulse velocity measurements were used to evaluate the healing process. Results indicated that, the self healing phenomenon existed in polymer modified concrete as in traditional concrete. The increase of polymer dose increases the healing degree at the same healing time. This increase depends on polymer type. Also, the decrease of w/cm ratio reduces the self healing degree while the use of Type V Portland cement improves the self healing process compared with Type I Portland cement. Cement content has an insignificant effect on healing process for both concrete with and without polymer. In addition, the increase of damage age decreases the efficiency of self healing process.

  5. The effect of Nano-liquid on the properties of hardened concrete

    Directory of Open Access Journals (Sweden)

    Kamal Gad Sharobim

    2013-12-01

    Full Text Available Nanotechnology is one of the most active research areas that encompasses a number of disciplines including civil engineering and it may have a great impact on the field of construction materials. The literature survey shows that little is reported to evaluate the mechanical properties of concrete incorporating nano particles. This paper deals with studying the effect of Nano-liquid on the mechanical and physical properties of hardened concrete such as water permeability, absorption, abrasion resistance, compressive strength, indirect tensile strength and flexural strength. An experimental study was carried out on two types of concrete with cement content 350 and 450 kg/m3 with water/cement ratio of 0.50 and 0.40 respectively to have a slump of 100 ± 20 mm. Concrete specimens were cured in molds for 24 h, then in water for 28 days. All specimens were subjected to drying in room temperature for 7 days before applying Nano-liquid. The used Nano-liquid was sprayed on the dry surface of hardened concrete specimens two days before testing. Hardened concrete specimens were tested according to the Egyptian standard specifications to determine the effect of Nano-liquid on mechanical and physical properties such as water permeability, absorption, abrasion resistance, compressive strength, indirect tensile and flexural strength. The experiment results show that, Nano-liquid can reduce the water absorption and coefficient of permeability. Also, it can improve the abrasion resistance of concrete, but it has no effect on concrete strength. The effect of Nano-liquid depends on concrete quality (i.e W/C ratio and the surface condition received the Nano-liquid.

  6. Numerical Limit Analysis of Precast Concrete Structures

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen

    . The strength and efficiency of the presented framework are demonstrated by two real size examples, a two-dimensional precast shear wall and a three-dimensional precast concrete stairwell. The analysis shows that the framework is capable of modelling complex precast concrete structures efficiently. Moreover......Precast concrete elements are widely used in the construction industry as they provide a number of advantages over the conventional in-situ cast concrete structures. Joints cast on the construction site are needed to connect the precast elements, which poses several challenges. Moreover....... The scope is to be able to model entire precast concrete structures while accounting for the local behaviour of the joints. The in-situ cast joints are crucial to the capacity of precast concrete structures, however, the behaviour of joints is in practice assessed by simple, empirical design formulas...

  7. Properties of Concrete Mixes with Carwash Wastewater

    Directory of Open Access Journals (Sweden)

    Shahidan Shahiron

    2017-01-01

    Full Text Available The rapid growth of the car wash industry today results in the need for wastewater reclamation. Thus, this paper aims to investigate the effect of using car wash wastewater on concrete properties in terms of mechanical properties. The basic characteristics of wastewater were investigated according to USEPA (Method 150.1 & 3 00.0 while the mechanical properties of concrete with car wash wastewater were compared according to ASTM C1602 and BS EN 1008 standards. In this research, the compressive strength, modulus of elasticity and tensile strength were studied. The percentages of wastewater replaced in the concrete mix ranged from 0% up to 40%. In addition, the results also suggest that the concrete with 20% car wash wastewater achieved the highest compressive strength and modulus of elasticity compared to other compositions of wastewater. Moreover, the results also recommended that concrete mixed with car wash wastewater has better compressive strength compared to conventional concrete.

  8. Transitional Thermal Creep of Early Age Concrete

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, Anders Boe; Damkilde, Lars; Freiesleben Hansen, Per

    1999-01-01

    Couplings between creep of hardened concrete and temperature/water effects are well-known. Both the level and the gradients in time of temperature or water content influence the creep properties. In early age concrete the internal drying and the heat development due to hydration increase the effect...... of these couplings. The purpose of this work is to set up a mathematical model for creep of concrete which includes the transitional thermal effect. The model govern both early age concrete and hardened concrete. The development of the material properties in the model are assumed to depend on the hydration process...... termed the microprestresses, which reduces the stiffness of the concrete and increase the creep rate. The aging material is modelled in an incremental way reflecting the hydration process in which new layers of cement gel solidifies in a stress free state and add stiffness to the material. Analysis...

  9. Transitional Thermal Creep of Early Age Concrete

    DEFF Research Database (Denmark)

    Hauggaard, A. B.; Damkilde, L.; Hansen, Per Freiesleben

    1999-01-01

    Couplings between creep of hardened concrete and temperature/water effects are well-known. Both the level and the gradients in time of temperature or water content influence the creep properties. In early age concrete the internal drying and the heat development due to hydration increase the effect...... of these couplings. The purpose of this work is to set up a mathematical model for creep of concrete that includes the transitional thermal effect. The model governs both early age concrete and hardened concrete. The development of the material properties in the model is assumed to depend on the hydration process...... termed the microprestresses, which reduce the stiffness of the concrete and increase the creep rate. The aging material is modeled in an incremental way reflecting the hydration process in which new layers of cement gel solidify in a stress free state and add stiffness to the material. Analysis...

  10. Clogging in permeable concrete: A review.

    Science.gov (United States)

    Kia, Alalea; Wong, Hong S; Cheeseman, Christopher R

    2017-05-15

    Permeable concrete (or "pervious concrete" in North America) is used to reduce local flooding in urban areas and is an important sustainable urban drainage system. However, permeable concrete exhibits reduction in permeability due to clogging by particulates, which severely limits service life. This paper reviews the clogging mechanism and current mitigating strategies in order to inform future research needs. The pore structure of permeable concrete and characteristics of flowing particulates influence clogging, which occurs when particles build-up and block connected porosity. Permeable concrete requires regular maintenance by vacuum sweeping and pressure washing, but the effectiveness and viability of these methods is questionable. The potential for clogging is related to the tortuosity of the connected porosity, with greater tortuosity resulting in increased potential for clogging. Research is required to develop permeable concrete that can be poured on-site, which produces a pore structure with significantly reduced tortuosity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Rotational Capacity of Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Ulfkjær, J. P.; Henriksen, M. S.; Brincker, Rune

    1995-01-01

    The European Structural Integrity Society-Technical Committee 9, has initiated a Round Robin on 'Scale Effects and Transitional Failure Phenomena of Reinforced Concrete Beams in Flexure'. In Denmark, Aalborg University is participating. The programme for Aalborg University involves an experimental...... programme where 120 reinforced concrete beams, 54 plain concrete beams and 324 concrete cylinders are tested. For the reinforced concrete beams four different parar meters are varied. The slenderness is 6, 12 and 18, the beam depth is 100 mm, 200 mm and 400 mm giving nine different geometries, five...... reinforcement ratios between 0.14% and 1.57%, and the concrete has a compressive strength of approximately 60 MPa or 90 MPa. The beams are tested in threepoint bending in a servo controlled materials testing system specially designed for the wide range of geometries The casting of the beams is finished...

  12. Reviewing the Carbonation Resistance of Concrete

    Directory of Open Access Journals (Sweden)

    S P Singh

    2016-07-01

    Full Text Available The paper reviews the studies on one of the important durability properties of concrete i.e. Carbonation. One of the main causes of deterioration of concrete is carbonation, which occurs when carbon dioxide (CO2 penetrates the concrete’s porous system to create an environment with lower pH around the reinforcement in which corrosion can proceed. Carbonation is a major cause of degradation of concrete structures leading to expensive maintenance and conservation operations. Herein, the importance, process and effect of various parameters such as water/cement ratio, water/binder ratio, curing conditions, concrete cover, super plasticizers, type of aggregates, grade of concrete, porosity, contaminants, compaction, gas permeability, supplementary cementitious materials (SCMs/ admixtures on the carbonation of concrete has been reviewed. Various methods for estimating the carbonation depth are also reported briefly

  13. Prediction of Chloride Penetration into Hardening Concrete

    Directory of Open Access Journals (Sweden)

    Wei-Jie Fan

    2015-01-01

    Full Text Available In marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. Currently, most of experimental investigations about submerged penetration of chloride ions are started after the four-week standard curing of concrete. The further hydration of cement and reduction of chloride diffusivity during submerged penetration period are ignored. To overcome this weak point, this paper presents a numerical procedure to analyze simultaneously cement hydration reaction and chloride ion penetration process. First, using a cement hydration model, degree of hydration and phase volume fractions of hardening concrete are determined. Second, the dependences of chloride diffusivity and chloride binding capacity on age of concrete are clarified. Third, chloride profiles in hardening concrete are calculated. The proposed numerical procedure is verified by using chloride submerged penetration test results of concrete with different mixing proportions.

  14. Handbook for Design of Undersea, Pressure-Resistant Concrete Structures

    Science.gov (United States)

    1986-10-01

    design guidelines. The guidelines are based primarily on test results from laboratory and ocean investigations of model concrete structures conducted at...NCEL over the past two decades; the guides are principally for designing cylindrical and spherical plain (unreinforced) concrete structures to resist...strength increase factors. Keywords: Pressure-resistant structures, concrete spheres, concrete cylinders, submerged concrete structures , undersea

  15. Study on strength, elastic modulus of artifical lightweight aggregate concrete

    Science.gov (United States)

    Kakizaki, M.

    1982-04-01

    Aggregate strength of artificial lightweight concrete and concrete used with this artificial lightweight aggregate can be expected to have nearly the same strength as normal weight concrete. An experimental study of properties of concrete strength and correlation between compressive and tensile and flexural strengths and elastic modulus of its concrete was made.

  16. Effect of Penetron Admix on the Properties of Concrete

    African Journals Online (AJOL)

    2012r

    2014-07-02

    Jul 2, 2014 ... Admix on the fresh and hardened properties of structural concrete and assesses whether the product is suitable for ... Keywords: waterproofing admixture, structural concrete, effects on concrete properties. *For correspondences ...... Use of Recycled Concrete Aggregate in. Structural Concrete Production ...

  17. Open to a Changing World: Concrete Poetry in Denmark

    DEFF Research Database (Denmark)

    Ørum, Tania

    2010-01-01

    The essay describes the rise of concrete poetry in Denmark in the 1960s, the intermedial roots of concrete poetry, concrete poetry as open work (in Eco's sense), the main Danish poets, the development of concrete poetry into systemic writing and the longer cultural perspectives of concrete poetry...

  18. corIncorporating cracking of concrete on chloride ingress and service life modeling of concrete structures

    NARCIS (Netherlands)

    Pacheco, Jose; Polder, R.B.

    2016-01-01

    Chloride induced reinforcement corrosion is the most common degradation mechanisms for reinforced concrete structures. The service life of concrete structures is normally predicted by estimating the rate of chloride ingress and the necessary time to initiate reinforcement corrosion. Normally,

  19. Cracking in concrete-debonding length at the concrete/steel interface

    OpenAIRE

    Kjeldby, Liv Brox

    2016-01-01

    Investigation of the debonding length at the concrete/steel interface have been investigated based on different types of cracks in concrete. Different methods for investigation have been used in the laboratory.

  20. Investigation of concrete produced using recycled aluminium dross for hot weather concreting conditions

    Directory of Open Access Journals (Sweden)

    Gireesh Mailar

    2016-06-01

    Full Text Available Aluminium dross is a by-product obtained from the aluminium smelting process. Currently, this dross is processed in rotary kilns to recover the residual aluminium, and the resultant salt cake is sent to landfills. The present study investigates the utilization of recycled aluminium dross in producing concrete, which is suitable for hot weather concreting condition. The primary objectives of the experimental study are to examine the feasibility of using concrete blended with recycled aluminium dross under hot weather concreting situations and then to evaluate the strength and durability aspects of the produced concrete. From the experimental results it is observed that the initial setting time of the recycled aluminium dross concrete extended by about 30 minutes at 20% replacement level. This property of recycled aluminium dross concrete renders it to be suitable for hot weather concreting conditions. Based on the results obtained, the replacement of cement with 20% of Al dross yields superior mechanical and durability characteristics.

  1. Influence of Concrete Properties on Molten Core-Concrete Interaction: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Jin-yang Jiang

    2016-01-01

    Full Text Available In a severe nuclear power plant accident, the molten core can be released into the reactor pit and interact with sacrificial concrete. In this paper, a simulation study is presented that aims to address the influence of sacrificial concrete properties on molten core-concrete interaction (MCCI. In particular, based on the MELCOR Code, the ferrosiliceous concrete used in European Pressurized Water Reactor (EPR is taken into account with respect to the different ablation enthalpy and Fe2O3 and H2O contents. Results indicate that the concrete ablation rate as well as the hydrogen generation rate depends much on the concrete ablation enthalpy and Fe2O3 and H2O contents. In practice, the ablation enthalpy of sacrificial concrete is the higher the better, while the Fe2O3 and H2O content of sacrificial concrete is the lower the better.

  2. Durability assessment of recycled concrete aggregates for use in new concrete.

    Science.gov (United States)

    2012-06-01

    The primary goal of this research project was to investigate the long-term durability of concrete incorporating : recycled concrete aggregate (RCA) through accelerated laboratory testing. Overall it was found that modifications to : standard aggregat...

  3. Using recycled concrete as aggregate in concrete pavements to reduce materials cost.

    Science.gov (United States)

    2013-08-01

    The main objective of this project was to evaluate the effects of using aggregate produced from crushed concrete pavement as a replacement for natural (virgin) coarse aggregate in pavement mixtures. A total of ten different concrete mixtures containi...

  4. Laboratory evaluation of recycled concrete as aggregate in new concrete pavements.

    Science.gov (United States)

    2014-09-01

    The Washington State Department of Transportation (WSDOT) has initiated a research project to investigate the use of recycled concrete as : aggregates (RCA) in Portland (hydraulic) cement concrete pavements (PCCP). The planned source for the RCA in t...

  5. Concrete pavement mixture design and analysis (MDA) : assessment of air void system requirements for durable concrete.

    Science.gov (United States)

    2012-06-01

    Concrete will suffer frost damage when saturated and subjected to freezing temperatures. Frost-durable concrete can be produced if a : specialized surfactant, also known as an air-entraining admixture (AEA), is added during mixing to stabilize micros...

  6. Composite Grids for Reinforcement of Concrete Structures.

    Science.gov (United States)

    1998-06-01

    ADVANCEMENT RESEARCH (CPAR) PROGRAM Composite Grids for Reinforcement of Concrete Structures by Piyush K. Dutta, David M. Bailey, Stephen W. Tsai...AGENCY USE ONLY (Leave Blank) 2. REPORT DATE June 1998 4. TITLE AND SUBTITLE Composite Grids for Reinforcement of Concrete Structures 3. REPORT...CPAR) Work Unit LX4, "Composite Grid/Frame Reinforcement for Concrete Structures ." The U.S. Army Construction Engineering Research Laboratories

  7. Radiation shielding concrete made of Basalt aggregates.

    Science.gov (United States)

    Alhajali, S; Yousef, S; Kanbour, M; Naoum, B

    2013-04-01

    In spite of the fact that Basalt is a widespread type of rock, there is very little available information on using it as aggregates for concrete radiation shielding. This paper investigates the possibility of using Basalt for the aforementioned purpose. The results have shown that Basalt could be used successfully for preparing radiation shielding concrete, but some attention should be paid to the choice of the suitable types of Basalt and for the neutron activation problem that could arise in the concrete shield.

  8. Mechanical characterization of fiber reinforced Polymer Concrete

    OpenAIRE

    Reis,João Marciano Laredo dos

    2005-01-01

    A comparative study between epoxy Polymer Concrete plain, reinforced with carbon and glass fibers and commercial concrete mixes was made. The fibers are 6 mm long and the fiber content was 2% and 1%, respectively, in mass. Compressive tests were performed at room temperature and load vs. displacement curves were plotted up to failure. The carbon and glass fibers reinforcement were randomly dispersed into the matrix of polymer concrete. An increase in compressive properties was observed as fun...

  9. DECISION MAKING MODELING OF CONCRETE REQUIREMENTS

    Directory of Open Access Journals (Sweden)

    Suhartono Irawan

    2001-01-01

    Full Text Available This paper presents the results of an experimental evaluation between predicted and practice concrete strength. The scope of the evaluation is the optimisation of the cement content for different concrete grades as a result of bringing the target mean value of tests cubes closer to the required characteristic strength value by reducing the standard deviation. Abstract in Bahasa Indonesia : concrete+mix+design%2C+acceptance+control%2C+optimisation%2C+cement+content.

  10. Structural Repair Of Prestressed Concrete Bridge Beams

    OpenAIRE

    Pekyer, Bülent

    2010-01-01

    Each year a lot of prestressed concrete beams are damaged by overwheight vehicles and environmental effects. There are numerous repair techniques proposed by entrepreneurial and academic institutions which restore prestressed concrete girder flexural strength and save both material and economic resources. This document focuses on the practical application of prestressed concrete bridge girder repair methods. In this document, repair methods are presented for three prototype prestressed concre...

  11. Microstructural Properties of the Interfacial Transition Zone and Strength Development of Concrete Incorporating Recycled Concrete Aggregate

    OpenAIRE

    S. Boudali; A. M. Soliman; B. Abdulsalam; K. Ayed; D. E. Kerdal; S. Poncet

    2017-01-01

    This study investigates the potential of using crushed concrete as aggregates to produce green and sustainable concrete. Crushed concrete was sieved to powder fine recycled aggregate (PFRA) less than 80 µm and coarse recycled aggregates (CRA). Physical, mechanical, and microstructural properties for PFRA and CRA were evaluated. The effect of the additional rates of PFRA and CRA on strength development of recycled aggregate concrete (RAC) was investigated. Additionally, the characteristics of ...

  12. Fibre reinforced concrete exposed to elevated temperature

    Science.gov (United States)

    Novák, J.; Kohoutková, A.

    2017-09-01

    Although concrete when subject to fire performs very well, its behaviour and properties change dramatically under high temperature due to damaged microstructure and mesostructure. As fibre reinforced concrete (FRC) represents a complex material composed of various components with different response to high temperature, to determine its behaviour and mechanical properties in fire is a demanding task. The presented paper provides a summary of findings on the fire response of fibre FRC. Namely, the information on steel fibre reinforced concrete (SFRC), synthetic fibre reinforced concrete and hybrid (steel + synthetic) fibre reinforced concrete have been gathered from various contributions published up to date. The mechanical properties including the melting point and ignition point of fibres affect significantly the properties of concrete composites with addition of fibres. The combination of steel and synthetic fibres represents a promising alternative how to ensure good toughness of a concrete composite before heating and improve its residual mechanical behaviour and spalling resistance as well as the ductility after heating. While synthetic fibres increase concrete spalling resistance, steel fibres in a concrete mix leads to an improvement in both mechanical properties and resistance to heating effects.

  13. STRUCTURAL AND THERMOPHYSICAL PROPERTIES OF HARDENING CONCRETE

    Directory of Open Access Journals (Sweden)

    L. Krasulina

    2012-01-01

    Full Text Available Structural and thermophysical properties of thermally treated concrete have been studied in the paper. The paper demonstrates regularities of changes in structural and thermophysical properties of concrete during heat treatment process. It is established that stabilization of coefficient values for heat- and temperature conductivity of concrete corresponds to completion of the process pertaining to intensive formation of the material pore structure and indicates the possibility of transition from the stage of isothermal extraction to the stage of temperature decrease. The obtained results are confirmed by studies of strength growth kinetics of concrete samples.

  14. EXPERIMENTAL INVESTIGATION OF LIGHTWEIGHT CONCRETE WITH STEELFIBER

    Directory of Open Access Journals (Sweden)

    Fatih ALTUN

    2006-03-01

    Full Text Available In this study, Dramix RC-80/60-BN steel fiber was added into lightweight concrete of 400 cement dosage in the amounts of 10, 20, 30, 40, 50 and 60. The specimens were tested 28 days later to find the measured apparent specific gravity, concrete strength, modulus of elasticity and toughness value experimentally. Our study concluded that the addition of steel fiber has not changed the concrete strength and modulus of elasticity while it has increased the toughness of lightweight concrete of fixed cement dosage.

  15. Economic analysis of recycling contaminated concrete

    Energy Technology Data Exchange (ETDEWEB)

    Stephen, A.; Ayers, K.W.; Boren, J.K.; Parker, F.L. [Vanderbilt Univ., Nashville, TN (United States)

    1997-02-01

    Decontamination and Decommissioning activities in the DOE complex generate large volumes of radioactively contaminated and uncontaminated concrete. Currently, this concrete is usually decontaminated, the contaminated waste is disposed of in a LLW facility and the decontaminated concrete is placed in C&D landfills. A number of alternatives to this practice are available including recycling of the concrete. Cost estimates for six alternatives were developed using a spreadsheet model. The results of this analysis show that recycling alternatives are at least as economical as current practice.

  16. Cement and Concrete Nanoscience and Nanotechnology

    Directory of Open Access Journals (Sweden)

    Taijiro Sato

    2010-02-01

    Full Text Available Concrete science is a multidisciplinary area of research where nanotechnology potentially offers the opportunity to enhance the understanding of concrete behavior, to engineer its properties and to lower production and ecological cost of construction materials. Recent work at the National Research Council Canada in the area of concrete materials research has shown the potential of improving concrete properties by modifying the structure of cement hydrates, addition of nanoparticles and nanotubes and controlling the delivery of admixtures. This article will focus on a review of these innovative achievements.

  17. Proceedings of the concrete decontamination workshop

    Energy Technology Data Exchange (ETDEWEB)

    Halter, J.M.; Sullivan, R.G.; Currier, A.J.

    1980-05-28

    Fourteen papers were presented. These papers describe concrete surface removal methods and equipment, as well as experiences in decontaminating and removing both power and experimental nuclear reactors.

  18. Properties of Fiber Reinforced Polymer Concrete

    Directory of Open Access Journals (Sweden)

    Marinela Bărbuţă

    2008-01-01

    Full Text Available Polymer concrete is a composite material realized with resin and aggregates. In the present study the epoxy resin was used for binding the aggregates. In the composition were introduced near the fly ash, used as filler, the cellulose fibers. The mechanical characteristics such as compressive strength, flexural strength and split tensile strength of polymer concrete with fibers were investigated. The fiber percentage was constant, the epoxy resin and the filler dosages were varied. The cellulose fiber had not improved the mechanical characteristics of the polymer concrete in comparison to that of polymer concrete without cellulose fibers.

  19. Recycled construction and demolition concrete waste as aggregate for structural concrete

    Directory of Open Access Journals (Sweden)

    Ashraf M. Wagih

    2013-12-01

    Full Text Available In major Egyptian cities there is a surge in construction and demolition waste (CDW quantities causing an adverse effect on the environment. The use of such waste as recycled aggregate in concrete can be useful for both environmental and economical aspects in the construction industry. This study discusses the possibility to replace natural coarse aggregate (NA with recycled concrete aggregate (RCA in structural concrete. An investigation into the properties of RCA is made using crushing and grading of concrete rubble collected from different demolition sites and landfill locations around Cairo. Aggregates used in the study were: natural sand, dolomite and crushed concretes obtained from different sources. A total of 50 concrete mixes forming eight groups were cast. Groups were designed to study the effect of recycled coarse aggregates quality/content, cement dosage, use of superplasticizer and silica fume. Tests were carried out for: compressive strength, splitting strength and elastic modulus. The results showed that the concrete rubble could be transformed into useful recycled aggregate and used in concrete production with properties suitable for most structural concrete applications in Egypt. A significant reduction in the properties of recycled aggregate concrete (RAC made of 100% RCA was seen when compared to natural aggregate concrete (NAC, while the properties of RAC made of a blend of 75% NA and 25% RCA showed no significant change in concrete properties.

  20. Novel approach to make concrete structures self-healing using porous network concrete

    NARCIS (Netherlands)

    Sangadji, S.; Schlangen, E.

    2012-01-01

    Many researchers proposed self healing mechanism using hollow fibres and or microcapsule containing a modifying agent dispersed in the concrete to prolong its service life and make it more durable. A novel self healing concrete concept is proposed in this paper by using porous network concrete

  1. Mimicking Bone Healing Process to Self Repair Concrete Structure Novel Approach Using Porous Network Concrete

    NARCIS (Netherlands)

    Sangadji, S.; Schlangen, H.E.J.G.

    2013-01-01

    To repair concrete cracks in difficult or dangerous conditions such as underground structures or hazardous liquid containers, self healing mechanism is a promising alternative method. This research aims to imitate the bone self healing process by putting porous concrete internally in the concrete

  2. Fatigue of concrete under compression : Database and proposal for high strength concrete

    NARCIS (Netherlands)

    Lantsoght, E.O.L.

    2014-01-01

    The compressive strength of concrete decreases as an element is subjected to cycles of loading. In a typical fatigue test for the concrete compressive strength, a concrete specimen (typically a cylinder) is loaded between a lower and upper stress limit. These limits are expressed as a fraction of

  3. Thermal treatment of recycled concrete aggegate for general use in concrete. A preliminary study

    NARCIS (Netherlands)

    Larbi, J.A.; Heijnen, W.M.M.; Brouwer, J.P.; Mulder, E.

    2000-01-01

    In this paper, the results of a preliminary laboratory study to assess the effectiveness of thermally treating recycled concrete aggregate for genera) use in concrete are presented. The samples used for the study consisted of sieved fractions of crushed concrete that were subjected to various

  4. Waste Concrete as a Source of Aggregate for New Concrete | Okafor ...

    African Journals Online (AJOL)

    Three concrete mixes of widely differing water cement ratios were made using crushed waste concrete as coarse aggregate. The properties investigated include the physical properties of the recycled aggregate, the compressive and flexural strengths of the concrete. These properties were compared with those of similar ...

  5. Monolithic Concrete vs Precast Concrete for the Construction of Bridge by Th Cantilever Method

    Directory of Open Access Journals (Sweden)

    Morlova Dumitru Daniel

    2015-07-01

    Full Text Available In the article "Monolithic Concrete vs Precast Concrete for the Construction of Bridges by the Cantilever Method", there are approached a number of issues that come out in the design and execution of prestressed concrete bridge structures using the cantilever method.

  6. THE INFLUENCE OF SUPERPLASTICIZER C-3 BASED ON THE PROPERTIES OF CONCRETE MIXES AND CONCRETE

    Directory of Open Access Journals (Sweden)

    O. M. Pshinko

    2008-11-01

    Full Text Available On the example of fine-grained concrete with addition of superplasticizer C-3 and constituents of its factions of different molecular weight the influence of molecular weight and dosage of additions on the mobility of concrete mixture and the hardening of concrete is studied.

  7. Glassfibre Reinforced Concrete: a Review

    Science.gov (United States)

    Bartos, P. J. M.

    2017-09-01

    Introduced to construction about 40 years ago, GRC has come of age. It is now widely used all over the world and in quantities very likely greater than most of the other types of fibre reinforced concrete, although it remains less known. A brief history of GRC is followed by review of the basic make-up of this complex composite. Methods of production are identified, properties reviewed and modes of fracture which are unique to GRC are explained. Benefits which are already available and exploited by its users are summarised and the wide spectrum of current applications of GRC is outlined.

  8. Experimental and Theoretical Research on Reinforced Lightweight Concrete Flexural Elements

    National Research Council Canada - National Science Library

    Deividas Rumšys; Darius Bačinskas; Edmundas Spudulis; Eugenijus Gudonis; Aleksandr Sokolov

    2014-01-01

    The paper deals with analysis of structural lightweight concrete. New lightweight concrete mixture made with expanded clay aggregate has been proposed and applied for experimental rein-forced concrete beams...

  9. Application of ultra-high performance concrete to bridge girders.

    Science.gov (United States)

    2009-02-01

    "Ultra-High Performance Concrete (UHPC) is a new class of concrete that has superior performance characteristics : compared to conventional concrete. The enhanced strength and durability properties of UHPC are mainly due to optimized : particle grada...

  10. Internal curing of high-performance concrete for bridge decks.

    Science.gov (United States)

    2013-03-01

    High performance concrete (HPC) provides a long lasting, durable concrete that is typically used in bridge decks due to its low permeability, high abrasion resistance, freeze-thaw resistance and strength. However, this type of concrete is highly susc...

  11. Impact of biofouling on corrosion resistance of reinforced concrete

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, B.T.; Gajendragad, M.R.; Ranganna, G.; Wagh, A.B.; Sudhakaran, T.

    The settlement of marine organisms on reinforced concrete surfaces can affect the durability of concrete structures due to the initiation of corrosion processes. A uniform settlement of biofoulers covering an entire concrete surface can protect...

  12. Improving Fatigue Strength of polymer concrete using nanomaterials.

    Science.gov (United States)

    2016-11-30

    Polymer concrete (PC) is that type of concrete where the cement binder is replaced with polymer. PC is often used to improve friction and protect structural substrates in reinforced concrete and orthotropic steel bridges. However, its low fatigue per...

  13. Recycled tires as coarse aggregate in concrete pavement mixtures.

    Science.gov (United States)

    2013-07-01

    The reuse potential of tire chips as coarse aggregates in pavement concrete was examined in this research by : investigating the effects of low- and high-volume tire chips on fresh and hardened concrete properties. One concrete : control mixture was ...

  14. Acoustic emission techniques applied to conventionally reinforced concrete bridge girders.

    Science.gov (United States)

    2008-09-01

    Reinforced concrete (RC) bridges generally operate at service-level loads except during discrete overload events that can reduce the integrity of the structure by initiating concrete cracks, widening or extending of existing concrete cracks, as well ...

  15. Modeling and characterization of strengthened concrete tension members

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Stang, Henrik

    2011-01-01

    The structural potential for cracking of externally strengthened concrete tension members, can be predicted with three parameters, describing the structural cracking potential based on fracture mechanical properties of the of concrete and interface between concrete and strengthening medium...

  16. Self-Consolidating Concrete for Prestressed Bridge Girders : Research Brief

    Science.gov (United States)

    2017-08-01

    Self-consolidating concrete (SCC) is commonly used as an alternative to conventional concrete (CC) in precast, prestressed concrete (PSC) bridge girders. The high strength, highly workable mixture can flow through dense reinforcement to fill formwork...

  17. Testing of plain and fibrous concrete single cavity prestressed concrete reactor vessel models

    Energy Technology Data Exchange (ETDEWEB)

    Oland, C.B.

    1985-01-01

    Two single-cavity prestressed concrete reactor vessel (PCRV) models were fabricated and tested to failure to demonstrate the structural response and ultimate pressure capacity of models cast from high-strength concretes. Concretes with design compressive strengths in excess of 70 MPa (10,000 psi) were developed for this investigation. One model was cast from plain concrete and failed in shear at the head region. The second model was cast from fiber reinforced concrete and failed by rupturing the circumferential prestressing at the sidewall of the structure. The tests also demonstrated the capabilities of the liner system to maintain a leak-tight pressure boundary. 3 refs., 4 figs.

  18. Accelerated slab replacement using temporary precast panels and self-consolidating concrete.

    Science.gov (United States)

    2016-06-06

    Slab replacement is the main activity in any concrete pavement rehabilitation project. According to a survey of industry and FDOT, contractor productivity in slab replacements has been very low, ranging between 25 to 50 cu. yds. The low number of sla...

  19. Ground tire rubber (GTR) as a component material in concrete mixtures for paving concrete, phase 2 : [summary].

    Science.gov (United States)

    2015-02-01

    Using ground tire rubber (GTR) in : concrete mixtures is a possible solution : to mitigating flexibility and thermal : expansion issues with high-strength : concrete pavements. Florida State : University researchers designed concrete : mixtures using...

  20. Radionuclide Retention in Concrete Wasteforms

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  1. Fly ash reactions in concrete

    Science.gov (United States)

    Diamond, S.

    1981-12-01

    A suite of flyashes was assembled including representatives of ASTM Class F (low CaO) and Class C (high CaO) categories. These were chemically analyzed, particle size distributions were obtained, and X-ray diffraction studies carried out. The Class C flyashes had CaO contents of over 30% and subtantial Na2O and SO3 contents. In contrast the Class F flyashes had less than 4% CaO and low Na2O contents. X-ray diffraction disclosed substantial differences between the nature of the glass present in the two kinds of flyash, and in the suites of crystalline components present. The Class C flyashes contained cementitious compounds and alkali sulfates as well as more inert crystalline components. Compressive strengths of both mortars and concretes with 30% replacement of flyash for cement were equal to those of reference mortars or concretes in a few months with Class C flyashes, but strength development with Class F flyashes was much slower.

  2. Going green with geopolymer concrete

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-05-15

    Getting a low CO{sub 2} concrete from the lab to streets and buildings around Australia was quite challenging, but the increased emphasis on climate change and environmentally friendly solutions helped achieve this outcome by University of Melbourne researchers John Provis, Peter Duxson and Jannie van Deventer from the Department of Chemical and Biomolecular Engineering. The use of fly ash in geopolymers does not give raw materials- derived CO{sub 2} emissions. The ash cools rapidly as it leaves the furnace, so contains reactive glassy phases without the need for energy-intensive treatment in a cement kiln. These glasses are generally not quite as reactive as Portland cement, so 'activation' is needed to make them react quickly enough to give acceptable strength development in a concrete. In the geopolymer process, an alkaline activating solution - usually an alkali metal hydroxide or silicate - is mixed with the ash to initiate and accelerate formation of a hardened binder phase. The commercial development of geopolymers in Australia is being led by Melbourne-based company Zeobond Pty Ltd, who are marketing fly ash-based geopolymer technology under the trade name 'E-Crete'. In addition to large slabs, ready-mix E-Crete has been used to construct footpaths in the northern suburbs of Melbourne, and also in precasting of large panels. 5 refs., 5 figs.

  3. Bond strength between stell-concrete and between concretes with different ages in structural rehabilitation

    Directory of Open Access Journals (Sweden)

    M. R. DORIA

    Full Text Available ABSTRACTIn inspections of buildings, it is common to find structures that, well before reaching its useful life longer require repairs and reinforcements. This study examined the bond strength between concrete of different ages and between steel and concrete, focusing on the recovery of reinforced concrete structures. To analyze the bond between concrete of different ages, trials with specimens receiving three different types of treatments at the interface between the concrete were performed: brushing; brushing and mortar equal to concrete of substrate and brushing and epoxy layer. Indirect tensile tests and oblique and vertical shear tests at the interface were made . The bond stress between steel and concrete was evaluated by pull out test under the conditions of the bar inserted in the still fresh concrete and when inserted in the hardened concrete with epoxy. Results showed increased bond strength by indirect tensile stress of 15% and 37%; 4% and 12% for the adherence test by oblique shear, and 108% and 178%, for the testing of vertical shear, respectively, for the specimens whose interfaces have received, in addition to brushing, layer of mortar and epoxy bridge, compared to those who received only brushing. Insignificant loss (about 0.52% of bond stress was noticed for pull out test of steel bar when compared with test results of the specimens that had steel bar inserted in the concrete in the hardened state with epoxy adhesion bridge, with those who had inserted steel bar in fresh concrete.

  4. The Influence of Crushed Concrete Demolition Waste Aggregates on the Hardening Process of Concrete Mixtures

    Directory of Open Access Journals (Sweden)

    Olga FINOŽENOK

    2013-03-01

    Full Text Available Concrete – complex structure composite material consisting of the components with various structure and size. Not only coarse and fine aggregates are used in concrete production, but also filler aggregates. Aggregates of natural, man-made origin or aggregates, produced from recycled materials, can be utilised in concrete production. Aggregates can be produced from recycled materials by reprocessing of concrete and reinforced concrete waste. The influence of the filler aggregates produced from the crushed concrete waste on the characteristics of binder’s paste, when part of the binder (5; 10; 15; 20; 25; 30 % is replaced by such filler aggregate, is analysed in the research. Concrete mixtures with natural aggregates and crushed concrete waste were selected and concrete mixtures of required consistence were produced during the research. Exothermic reactions take place during the hardening of concrete mixture, at that time the heat is dissipated, which increases the temperature of the concrete sample. Thus the exothermic processes were investigated during the concrete’s mixture hardening period and the temperatures of exothermic reactions were determined.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3833

  5. Characterization of Sisal Fibre Reinforced Concrete | Elinwa ...

    African Journals Online (AJOL)

    Experimental characterization of sisal fibre reinforced concrete showed that incorporating fibre into the concrete mixture is beneficial. Optimum performance for a matrix having sisal fibre as reinforcement is at 3% fibre volume fraction (Vff), with 70mm fibre length (Lf) and at a water-cement ratio of 0.6. There is a load increase ...

  6. Self-compacting fibre-reinforced concrete

    NARCIS (Netherlands)

    Grunewald, S.; Walraven, J.C.

    2001-01-01

    The project 'self-compacting fibre-reinforced concrete (SCFRC)' is part of the Dutch STW/PPM program - 'cement-bonded materials' - DCT.4010. Subproject III to which the project ,SCFRC' belongs deals with the development of new high performance concretes. The project 'SCFRC' aims at investigating the

  7. Evaluation of Sustainable Concrete Production and Construction ...

    African Journals Online (AJOL)

    Hence, this paper evaluates the production of sustainable concrete and its cost implication in Nigeria. Experimental design of high strength concrete made with steel fibre and bamboo fibre as reinforcement having a targeted compressive strength of 50 Mpa was considered. The steel and bamboo fibres were proportioned at ...

  8. FLEXURAL IMPROVEMENT OF PLAIN CONCRETE BEAMS ...

    African Journals Online (AJOL)

    As a result, this study carryout experimental, numerical and analytical investigation to study the behaviour of plain concrete (PC) beams strengthened with High Performance Fibre Reinforced Concrete (HPFRC) layer using three different jacketing configurations and tested in flexure. Results show significant improvement in ...

  9. Computational Modelling of Particle Packing in Concrete

    NARCIS (Netherlands)

    He, H.

    2010-01-01

    Physical particle packing is becoming a hot topic in concrete technology as more and more types of granular materials are used in concrete either for ecological or for engineering purposes. Although various analytical methods have been developed for optimum mixture design, comprehensive information

  10. flexural improvement of plain concrete beams strengthened

    African Journals Online (AJOL)

    Muhammad Nura Isa

    carryout experimental, numerical and analytical investigation to study the behaviour of plain concrete (PC) beams strengthened with High Performance Fibre ... behaviour of full-scale RC beam strengthened with a jacket of Fibre Reinforced Concrete ... test on UHPFRC dog-bone specimens. 3.2 Strengthening schemes.

  11. Autogenous Deformation and Internal Curing of Concrete

    NARCIS (Netherlands)

    Lura, P.

    2003-01-01

    High-performance concrete (HPC) is generally characterized by a low water/binder ratio and by silica-fume addition, which guarantee a low porosity and a discontinuous capillary pore structure of the cement paste. Modern concretes possess some highly advantageous properties compared to traditional

  12. Limit analysis of solid reinforced concrete structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    2009-01-01

    element for lower bound analysis of reinforced concrete structures is presented. The method defines the stress state at a point within the solid as a combination of concrete- and reinforcement stresses and yield criterions are applied to the stress components separately. This method allows for orthotropic...

  13. Air void analyzer for plastic concrete.

    Science.gov (United States)

    2008-10-01

    The two main test methods that measure the air content in plastic concrete are the pressure method and the volumetric : or roll-a-meter method. Although these methods report the total air in the concrete, they do not distinguish between : entrained a...

  14. Recent advances on self healing of concrete

    NARCIS (Netherlands)

    Schlangen, H.E.J.G.; Jonkers, H.M.; Qian, S.; Garcia, A.

    2010-01-01

    In this paper an overview is given of new developments obtained in research on self healing of cracks in cement based materials and asphalt concrete. At Delft University various projects are running to study self healing mechanisms. The first project that is discussed is Bacterial Concrete, in which

  15. Recent advances on self healing of concrete

    NARCIS (Netherlands)

    Schlangen, H.E.J.G.; Jonkers, H.M.; Qian, S.; Garcia, A.

    In this paper an overview is given of new developments obtained in research on self healing of cracks in cement based materials and asphalt concrete. At Delft University various projects are running to study self healing mechanisms. The first project that is discussed is Bacterial Concrete, in which

  16. Durability of hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J. de; Polder, R.B.; Borsje, H.

    1998-01-01

    The subject of this study was the performance of hydrophobic treatment to protect concrete against chloride penetration from de-icing salts. Hydrophobic treatment makes a concrete surface absorb less water and less chloride. Several types of tests were carried out to study the performance of

  17. Durability of hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J. de; Polder, R.B.; Borsje, H.

    1998-01-01

    The subject of this study was the performance of hydrophobic treatment to protect concrete against chloride penetration from de-icing salts. Hydrophobic treatment makes a concrete surface absorb less water and less chloride. Test methods and requirements for commercial products were established. In

  18. Using Concrete Manipulatives in Mathematical Instruction

    Science.gov (United States)

    Jones, Julie P.; Tiller, Margaret

    2017-01-01

    Concrete, Representational, Abstract (CRA) instruction is a process for teaching and learning mathematical concepts. Starting with manipulation of concrete materials (counters, beans, Unifix cubes), the process moves students to the representational level (tallies, dots, stamps), and peaks at the abstract level, at which numbers and symbols are…

  19. Topics in cement and concrete research

    NARCIS (Netherlands)

    Brouwers, Jos; Russel, M.I.; Basheer, P.A.M.

    2007-01-01

    The present paper addresses several topics in regard to the sustainable design and use of concrete. First, major features concerning the sustainable aspects of the material concrete are summarised. Then the major constituent, from an environmental point of view, cement is discussed in detail,

  20. Precast concrete barrier crash testing : final report.

    Science.gov (United States)

    2001-12-01

    The objectives of this project were to crash test the Oregon Standard (32-inch) F-shape precast concrete barrier and the Oregon Tall (42-inch) F-shape precast concrete barrier against the new NCHRP Report 350 standards, to ensure compliance of these ...

  1. Concrete in dynamic tension: The fracture process

    NARCIS (Netherlands)

    Vegt, I.

    2016-01-01

    Concrete is commonly used in protective and civil structures, like tunnels and storage buildings. For the design and reliable safety assessment of such structures it is very important to know the behaviour of concrete under static loading conditions as well as under impulsive loading. To understand

  2. The spalling mechanism of fire exposed concrete

    NARCIS (Netherlands)

    Lottman, B.B.G.

    2017-01-01

    --- ENGLISH VERSION --- The spalling damage observed to concrete structures after severe fire exposure has been the topic of scientific research for the past decades. This phenomenon is commonly characterised by the sudden and in some cases violent breaking off of concrete pieces from the

  3. Form Filling with Self-Compacting Concrete

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm

    2002-01-01

    This paper describes a newly started Ph.D. project with the aim of simulating the form filling ability of Self-Compacting Concrete (SCC) taking into account the form geometry, reinforcement configuration, casting technique, and the rheological properties of the concrete. Comparative studies...

  4. Re-Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

  5. Strength of Cracked Reinforced Concrete Disks

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1999-01-01

    The paper deals with models, based on the theory of plasticity, to be used in strength assessments of reinforced concrete disks suffering from different kinds of cracking. Based on the assumption that the sliding strength of concrete is reduced in sections where cracks are located, solutions...

  6. FATIGUE LIMIT OF AXIALLY COMPRESSED CONCRETE

    African Journals Online (AJOL)

    ES Obe

    1981-03-01

    Mar 1, 1981 ... kept the same (adequate) for all samples. All 80 test and control specimens were cast from one batch of concrete at the same time. Since the properties of concrete change with age (especially just after hardening period) in order to have more uniform influence of this factor on the strength creep, shrinkage.

  7. Optimizing Conventional Design Methods for Reinforced Concrete ...

    African Journals Online (AJOL)

    The results obtained suggest that a suitable percentage of the concrete cross section area of raft slab foundations should be used as compression reinforcement in order to prevent differential settlements. The required nominal area of compression reinforcement is 0.9% of the cross section area of the concrete section.

  8. Unexpectedly low tensile strength in concrete structures

    NARCIS (Netherlands)

    Siemes, A.J.M.; Han, N.; Visser, J.H.M.

    2002-01-01

    During an extensive investigation of some 25 concrete bridges and other structures suffering from alkali-silica reaction it has been found that the uniaxial tensile strength of the concrete was extremely low in relation to both the compressive strength and the splitting tensile strength. It is known

  9. DETERMINATION OF FIELD STRENGTH OF CONCRETE FROM ...

    African Journals Online (AJOL)

    conforms to ASTM Standard Cl09(6). Moreover the preparation, storage and testing of the samples were carried out according to the same standard. The most important factors on which the strength development of concrete depends are the cement type, concrete mix design, water cement ratio, a

  10. Concreteness effects revisited: the influence of dynamic visual noise on memory for concrete and abstract words.

    Science.gov (United States)

    Parker, Andrew; Dagnall, Neil

    2009-05-01

    Two experiments are presented that investigate the effects of dynamic visual noise (DVN) on memory for concrete and abstract words. Memory for concrete words is typically superior to that of abstract words and is referred to as the concreteness effect. DVN is a procedure that has been demonstrated to interfere selectively with visual working memory and the generation of images from long-term memory. It was reasoned that if concreteness effects arise because of the ability of the latter to activate visual representations, then DVN should selectively impair memory for concrete words. Experiment 1 found DVN to selectively reduce free recall of concrete words. Experiment 2 investigated recognition memory and found DVN to reduce memory accuracy and remember responses, while increasing know responses to concrete words.

  11. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    Durability studies are carried out at BKM as part of the research project "Design Methods for Fibre Reinforced Concrete" (FRC) involving BKM, The Concrete Research Center at DTI, Building Technology at Aalborg University, Rambøll, 4K-Beton and Rasmussen & Schiøtz. Concrete beams with or without...... fibre reinforcement are exposed to a combination of mechanical and environmental load to indicate whether fibre reinforcement will improve the durability of cracked concrete structures. Secondly, it is the aim to identify important mechanisms for the effect of the fibre reinforcement on the durability......) and polypropylene fibres (PP) are used in the concrete beams as well as main reinforcement. Results of the durability tests on cracked FRC-beams are compared with results for uncracked FRC-beams and beams without fibres....

  12. XFEM for Thermal Crack of Massive Concrete

    Directory of Open Access Journals (Sweden)

    Guowei Liu

    2013-01-01

    Full Text Available Thermal cracking of massive concrete structures occurs as a result of stresses caused by hydration in real environment conditions. The extended finite element method that combines thermal fields and creep is used in this study to analyze the thermal cracking of massive concrete structures. The temperature field is accurately simulated through an equivalent equation of heat conduction that considers the effect of a cooling pipe system. The time-dependent creep behavior of massive concrete is determined by the viscoelastic constitutive model with Prony series. Based on the degree of hydration, we consider the main properties related to cracking evolving with time. Numerical simulations of a real massive concrete structure are conducted. Results show that the developed method is efficient for numerical calculations of thermal cracks on massive concrete. Further analyses indicate that a cooling system and appropriate heat preservation measures can efficiently prevent the occurrence of thermal cracks.

  13. Conductive concrete wins Popular Science prize

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1997-06-01

    A conductive concrete developed by a research team at IRC (Institute for Research in Construction, National Research Council of Canada) has won a prize in the home technology category because of its possible use in heating homes. Following the award, there have been a number of inquiries regarding possible applications for the concrete. Greatest interests in the concrete have been in its potential to heat buildings by using it as flooring. Other possible applications included de-icing pavements to building warming pads for parking aircraft. Essentially, carbon fibres and conductive particles are added to a concrete mix in such a quantity that they form a network within the mix, ensuring high electrical conductivity. A demonstration project is underway to build a 20 by 80 foot conductive concrete pad to test the material`s capability as a snow removal and de-icing tool.

  14. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

    Energy Technology Data Exchange (ETDEWEB)

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-03-22

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.

  15. Electrical Resistance Tomography imaging of concrete

    KAUST Repository

    Karhunen, Kimmo

    2010-01-01

    We apply Electrical Resistance Tomography (ERT) for three dimensional imaging of concrete. In ERT, alternating currents are injected into the target using an array of electrodes attached to the target surface, and the resulting voltages are measured using the same electrodes. These boundary measurements are used for reconstructing the internal (3D) conductivity distribution of the target. In reinforced concrete, the metallic phases (reinforcing bars and fibers), cracks and air voids, moisture gradients, and the chloride distribution in the matrix carry contrast with respect to conductivity. While electrical measurements have been widely used to characterize the properties of concrete, only preliminary results of applying ERT to concrete imaging have been published so far. The aim of this paper is to carry out a feasibility evaluation with specifically cast samples. The results indicate that ERT may be a feasible modality for non-destructive evaluation of concrete. © 2009 Elsevier Ltd. All rights reserved.

  16. Experimental Study on Permeability of Concrete

    Science.gov (United States)

    Yang, Honglu; Liu, Rentai; Zheng, Zhuo; Liu, Haojie; Gao, Yan; Liu, Yankai

    2018-01-01

    To study the influencing factors on permeability of pervious concrete, by adding inorganic organic composite materials obtained experimental results show that different aggregate size, aggregate cement ratio of different, different water cement ratio on the permeability performance. The permeability of the concrete was tested by using the self - made permeable device. The experimental results showed that the permeation coefficient of the experiment was obtained and the factors influencing the permeability of the concrete were compared and analyzed. At the same time, the porosity of pervious concrete was measured, the influence of various variables on porosity was studied, and the influence of various factors on the permeability of voids was found. Finally, through comprehensive analysis of a variety of factors, the optimal water cement ratio is 0.28. At this time, the pervious performance of concrete is optimal.

  17. Properties of sulfur-extended asphalt concrete

    Directory of Open Access Journals (Sweden)

    Gladkikh Vitaliy

    2016-01-01

    Full Text Available Currently, increased functional reliability of asphalt concrete coatings associated with various modifying additives that improve the durability of pavements. Promising builder is a technical sulfur. Asphalt concrete, made using a complex binder consisting of petroleum bitumen and technical sulfur, were calledsSulfur-Extended Asphalt Concrete. Such asphalt concrete, due to changes in the chemical composition of particulate and bitumen, changes the intensity of the interaction at the interface have increased rates of physical and mechanical properties. There was a lack of essential knowledge concerning mechanical properties of the sulfur-bituminous concrete with such an admixture; therefore, we had carried out the necessary examination. It is revealed that a new material satisfies local regulations in terms of compressive and tensile strength, shear resistance, and internal friction.

  18. Studies on recycled aggregates-based concrete.

    Science.gov (United States)

    Rakshvir, Major; Barai, Sudhirkumar V

    2006-06-01

    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design.

  19. Research of polymer concrete fracture parameters

    Science.gov (United States)

    Vorontsova, N.; Makarevich, A.; Stoyushko, N.; Zinchenko, O.

    2017-10-01

    The present article reviews the problem of polymer concrete fracture mechanics. These construction materials can be effectively used in industrial building structures. They combine strength and chemical resistance and unlike ordinary concrete don’t require protection from aggressive environment. We have studied samples of polymer concrete with different composition; have determined the parameters of cracking resistance. In our studies we have used the photoelastic coating method, which keeps the advantages of photoelastic methods and at the same time eliminates the difficulties of mock-ups building. We have also conducted experiments on dynamic distribution of cracks in polymer concrete. We have received the numerical value of crack rate at its flooding development, which may permit to solve a problem of crack stopping in polymer concrete structures.

  20. ABRASION RESISTANCE ESTIMATION OF HIGH STRENGTH CONCRETE

    Directory of Open Access Journals (Sweden)

    Şemsi YAZICI

    2007-01-01

    Full Text Available This study gives the results of a laboratory investigation undertaken to determine the relationship between mechanical properties (compressive and flexural strengths and abrasion resistance of 65-85 MPa high strength concretes incorporating silica fume, fly ash and silica fume-fly ash mixtures as supplementary cementing materials. A series of six different concrete mixtures including a control high strength concrete mixture (C1, and five high strength concrete mixtures (C2, C3, C4, C5, C6 incorporating supplementary cementing materials, were manufactured. The compressive strength, flexural strength, and abrasion resistance were determined for each mixture at 28-days. Mathematical expressions were suggested to estimate the abrasion resistance of concrete regarding their compressive strength and flexural strength.

  1. Radiation Damage In Reactor Cavity Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G [ORNL; Le Pape, Yann [ORNL; Naus, Dan J [ORNL; Remec, Igor [ORNL; Busby, Jeremy T [ORNL; Rosseel, Thomas M [ORNL; Wall, Dr. James Joseph [Electric Power Research Institute (EPRI)

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  2. Design of concrete for high flowability : Progress report of fib task group 4.3

    NARCIS (Netherlands)

    Schmidt, W.; Grunewald, S.; Ferrara, L.; Dehn, F.

    2015-01-01

    Flowable concretes can differ significantly from traditional vibrated concrete. Concrete types like selfcompacting concrete (SCC), ultra-high performance concrete (UHPC) and high performance fibre reinforced cementitious composites (HPFRCCs) require novel mix design approaches. This has consequences

  3. Research on Durability of Recycled Ceramic Powder Concrete

    Science.gov (United States)

    Chen, M. C.; Fang, W.; Xu, K. C.; Xie, L.

    2017-06-01

    Ceramic was ground into powder with 325 mesh and used to prepare for concrete. Basic mechanical properties, carbonation and chloride ion penetration of the concrete tests were conducted. In addition, 6-hour electric fluxes of recycled ceramic powder concrete were measured under loading. The results showed that the age strength of ceramics powder concrete is higher than that of the ordinary concrete and the fly ash concrete. The ceramic powder used as admixture would reduce the strength of concrete under no consideration of its impact factor; under consideration of the impact factor for ceramic powder as admixture, the carbonation resistance of ceramic powder concrete was significantly improved, and the 28 day carbonation depth of the ceramic powder concrete was only 31.5% of ordinary concrete. The anti-chloride-permeability of recycled ceramic powder concrete was excellent.

  4. Vanderbilt University Gamma Irradiation of Nano-modified Concrete (2017 Milestone Report)

    Energy Technology Data Exchange (ETDEWEB)

    Deichert, Geoffrey G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Selby, Aaron P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Reches, Yonathan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This document outlines the irradiation of concrete specimens in the Gamma Irradiation Facility in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Two gamma irradiation runs were performed in July of 2017 on 18 reference mortar bar specimens, 26 reference cement paste bar specimens, and 28 reference cement paste tab specimens to determine the dose and temperature response of the specimens in the gamma irradiation environment. Specimens from the first two gamma irradiations were surveyed and released to Vanderbilt University. The temperature and dose information obtained informs the test parameters of the final two gamma irradiations of nano-modified concrete planned for FY 2018.

  5. The influence of concrete mixture’s rheological properties on the quality of formed concrete surfaces

    Science.gov (United States)

    Daukšys, M.; Klovas, A.; Venčkauskas, L.

    2017-09-01

    This study mainly lays emphasis on examining the influence of concrete mixture rheological properties on the quality of formed concrete surfaces. Mixture’s fine aggregate change was taken into the consideration. Over the course of concrete mixture preparation the inner ratio of fine aggregate (sand: fraction of 0/1 and 0/4) was changed. The idea was to increase the quantity of fine particles in the total aggregate’s volume therefore quantity of sand (fraction 0/1) was increased. Six different concrete mixture’s compositions were designed as well as three specimens (concrete piles of 1m2 surface area) were casted. Rheological properties of concrete mixtures were analytically obtained and the quality of formed concrete surfaces was evaluated using image analysis method “BetonGUY 2.0”. As can be obtained from the dependence between concrete mixture rheological properties and its formed surface quality, the increase of concrete mixture’s yield stress and plastic viscosity reduces the quantity of air pores on formed concrete surfaces.

  6. The Fire Resistance Performance of Recycled Aggregate Concrete Columns with Different Concrete Compressive Strengths.

    Science.gov (United States)

    Dong, Hongying; Cao, Wanlin; Bian, Jianhui; Zhang, Jianwei

    2014-12-08

    In order to ascertain the fire resistance performance of recycled aggregate concrete (RAC) components with different concrete compressive strengths, four full-scaled concrete columns were designed and tested under high temperature. Two of the four specimens were constructed by normal concrete with compressive strength ratings of C20 and C30, respectively, while the others were made from recycled coarse aggregate (RCA) concrete of C30 and C40, respectively. Identical constant axial forces were applied to specimens while being subjected to simulated building fire conditions in a laboratory furnace. Several parameters from the experimental results were comparatively analyzed, including the temperature change, vertical displacement, lateral deflection, fire endurance, and failure characteristics of specimens. The temperature field of specimens was simulated with ABAQUS Software (ABAQUS Inc., Provindence, RI, USA) and the results agreed quite well with those from the experiments. Results show that the rate of heat transfer from the surface to the interior of the column increases with the increase of the concrete's compressive strength for both RAC columns and normal concrete columns. Under the same initial axial force ratio, for columns with the same cross section, those with lower concrete compressive strengths demonstrate better fire resistance performance. The fire resistance performance of RAC columns is better than that of normal concrete columns, with the same concrete compressive strength.

  7. Numerical Characterization of Concrete Heterogeneity

    Directory of Open Access Journals (Sweden)

    Roque Luiz Pitangueira

    2002-09-01

    Full Text Available In this paper, a finite element model including both material heterogeneity and size effects is presented. The concrete is considered as a statistical combination of constituent phase with different properties (aggregate, mortar and interface material. The material point response is based on a combination of the random occurrence of the solid phases in the structural volume as well as on the differences of structural response due to the size effect. Such combination allows for higher or lower heterogeneity corresponding to smaller or larger structural size. Simulations of the material heterogeneity and associated size effect in a computationally efficient and simple manner show good qualitative agreement with available experimental results for the three-point bending and Brazilian split tests.

  8. Immobilization of iodine in concrete

    Science.gov (United States)

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  9. A survey of waterproofing membrane systems for bridge decks.

    Science.gov (United States)

    1972-01-01

    This survey was concerned with only a few of the many waterproof systems available for sealing concrete bridge decks, and made use of personal contacts with engineers of other highway agencies. The information gathered indicated that there were sever...

  10. Unbonded capping for concrete masonry units

    Energy Technology Data Exchange (ETDEWEB)

    Crouch, L.K.; Knight, M.L.; Henderson, R.C.; Sneed, W.A. Jr.

    1999-07-01

    Due to the manufacturing process, the bearing surfaces of concrete masonry units are often somewhat rough and uneven. Therefore, concrete masonry units must be capped when tested in compression according to ASTM C 140-96, Standard Test Methods of Sampling and Testing Concrete Masonry Units. Capping of concrete masonry units is time consuming and expensive. Several studies of compression tests on concrete cylinders indicate that use of elastic pads in rigid retaining caps give similar compressive strength results to approved capping methods.An unbonded capping system for concrete masonry units similar to that described in ASTM C 1231-93, Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders, was developed. The average compressive strength results obtained when using the unbonded capping system ranged from 92--94% of the average compressive strength results obtained when using ASTM C 140-96 approved methods. Further, use of the unbonded capping system was found to increase productivity and substantially reduce testing cost.

  11. Nondestructive evaluation of thick concrete structures

    Science.gov (United States)

    Clayton, Dwight A.

    2015-03-01

    Concrete has been used in the construction of nuclear power plants (NPPs) due to three primary properties: its low cost, structural strength, and ability to shield radiation. Examples of concrete structures important to the safety of Light Water Reactor (LWR) plants include the containment building, spent fuel pool, and cooling towers. Use in these structures has made concrete's long-term performance crucial for the safe operation of commercial NPPs. Extending LWR operating period to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. New mechanisms of materials degradation are also possible. This creates the need to be able to nondestructively evaluate the current subsurface concrete condition of aging concrete material in NPP structures. The size and complexity of NPP containment structures and heterogeneity of Portland cement concrete make characterization of the degradation extent a difficult task. Specially designed and fabricated test specimens can provide realistic flaws that are similar to actual flaws in terms of how they interact with a particular nondestructive evaluation (NDE) technique. Artificial test blocks allow the isolation of certain testing problems as well as the variation of certain parameters. Representative large heavily reinforced concrete specimens would allow for comparative testing to evaluate the state-of-the-art NDE in this area and to identify additional developments necessary to address the challenges potentially found in NPPs.

  12. Life Cycle Assessment of Completely Recyclable Concrete.

    Science.gov (United States)

    De Schepper, Mieke; Van den Heede, Philip; Van Driessche, Isabel; De Belie, Nele

    2014-08-21

    Since the construction sector uses 50% of the Earth's raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW) is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC) is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C) principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA) needs to be performed, of which the results are presented in a this paper. It was observed that CRC could significantly reduce the global warming potential of concrete.

  13. Engineering Behavior of Concrete with Recycled Aggregate

    Directory of Open Access Journals (Sweden)

    Ayob Afizah

    2017-01-01

    Full Text Available Concrete is extensively used as construction materials in Malaysia. Concrete contributes suitable feature for construction industry for instance durability, adequate compressive strength, fire resistance, availability and is economic as compared to other construction materials. Depletion of natural resources and disposal of construction and demolition waste remarkably claim environmental threat. In this paper, the engineering behavior, durability, and concrete microstructure of recycled concrete aggregates (RCA on short-term concrete properties were investigated. The studied concrete at design mix proportion of 1:0.55:2.14:2.61 (weight of cement :coarse aggregates :sand :water used to obtain medium-high compressive strength with 20%, 50%, and 100% of RCA. Results show that for the same water/cement ratio, RCA replacement up to 50% still achieved the targeted compressive strength of 25 MPa at 28 curing days. Addition, at similar RCA replacement, the highest carbonation depth value was found at 1.03 mm which could be attributed to the pozzolanic reaction, thus led to lower carbonation resistance. Scanning electron microscopy microstructure shows that the RCA surface was porous and covered with loose particles. Moreover, the interfacial transition zone was composed of numerous small pores, micro cracks, and fissures that surround the mortar matrix. On the basis of the obtained results, recommendable mineral admixtures of RCA are necessary to enhance the quality of concrete construction.

  14. Self-cleaning geopolymer concrete - A review

    Science.gov (United States)

    Norsaffirah Zailan, Siti; Mahmed, Norsuria; Bakri Abdullah, Mohd Mustafa Al; Sandu, Andrei Victor

    2016-06-01

    Concrete is the most widely used construction materials for building technology. However, cement production releases high amounts of carbon dioxide (CO2) to the atmosphere that leads to increasing the global warming. Thus, an alternative, environmental friendly construction material such as geopolymer concrete has been developed. Geopolymer concrete applies greener alternative binder, which is an innovative construction material that replaces the Portland cement. This technology introduced nano-particles such as nanoclay into the cement paste in order to improve their mechanical properties. The concrete materials also have been developed to be functioned as self-cleaning construction materials. The self-cleaning properties of the concrete are induced by introducing the photocatalytic materials such as titania (TiO2) and zinc oxide (ZnO). Self-cleaning concrete that contains those photocatalysts will be energized by ultraviolet (UV) radiation and accelerates the decomposition of organic particulates. Thus, the cleanliness of the building surfaces can be maintained and the air surrounding air pollution can be reduced. This paper briefly reviews about self-cleaning concrete.

  15. Behaviour of concrete structures in fire

    Directory of Open Access Journals (Sweden)

    Fletcher Ian A.

    2007-01-01

    Full Text Available This paper provides a "state-of-the-art" review of research into the effects of high temperature on concrete and concrete structures, extending to a range of forms of construction, including novel developments. The nature of concrete-based structures means that they generally perform very well in fire. However, concrete is fundamentally a complex material and its properties can change dramatically when exposed to high temperatures. The principal effects of fire on concrete are loss of compressive strength, and spalling - the forcible ejection of material from the surface of a member. Though a lot of information has been gathered on both phenomena, there remains a need for more systematic studies of the effects of thermal exposures. The response to realistic fires of whole concrete structures presents yet greater challenges due to the interactions of structural elements, the impact of complex small-scale phenomena at full scale, and the spatial and temporal variations in exposures, including the cooling phase of the fire. Progress has been made on modeling the thermomechanical behavior but the treatment of detailed behaviors, including hygral effects and spalling, remains a challenge. Furthermore, there is still a severe lack of data from real structures for validation, though some valuable insights may also be gained from study of the performance of concrete structures in real fires. .

  16. Life Cycle Assessment of Completely Recyclable Concrete

    Directory of Open Access Journals (Sweden)

    Mieke De Schepper

    2014-08-01

    Full Text Available Since the construction sector uses 50% of the Earth’s raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA needs to be performed, of which the results are presented in a this paper. It was observed that CRC could significantly reduce the global warming potential of concrete.

  17. CONCRETE BASED ON MODIFIED DISPERSE CEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    D. V. Rudenko

    2016-08-01

    Full Text Available Purpose. The article considers definition of the bond types occurring in a modified cement concrete matrix, and the evaluation of the quality of these links in a non-uniform material to determine the geometrical and physical relationships between the structure and the cement matrix modifiers. Methodology. To achieve this purpose the studies covered the microstructure of dispersed modified concrete cement matrix, the structure formation mechanism of the modified cement concrete system of natural hardening; as well as identification of the methods of sound concrete strength assessment. Findings. The author proposed a model of the spatial structure of the concrete cement matrix, modified by particulate reinforcement crystal hydrates. The initial object of study is a set of volume elements (cells of the cement matrix and the system of the spatial distribution of reinforcing crystallohydrates in these volume elements. It is found that the most dangerous defects such as cracks in the concrete volume during hardening are formed as a result of internal stresses, mainly in the zone of cement matrix-filler contact or in the area bordering with the largest pores of the concrete. Originality. The result of the study is the defined mechanism of the process of formation of the initial strength and stiffness of the modified cement matrix due to the rapid growth of crystallohydrates in the space among the dispersed reinforcing modifier particles. Since the lack of space prevents from the free growth of crystals, the latter cross-penetrate, forming a dense structure, which contributes to the growth of strength. Practical value. Dispersed modifying cement matrix provides a durable concrete for special purposes with the design performance characteristics. The developed technology of dispersed cement system modification, the defined features of its structure formation mechanism and the use of congruence principle for the complex of technological impacts of physical

  18. Survey of Experience Using Reinforced Concrete in Floating Marine Structures.

    Science.gov (United States)

    1983-01-01

    boats. For the underdeveloped countries in this region, the low-technology, labor -intensive techniques of ferrocement construction are very... Labor costs ran higher than anticipated. The oil barges had to be relined with expensive protective coating in order to make them suitable for...34SHELL STRUCTURES AND CLIMA - TIC INFLUENCES," lIASS CALGARY SYMPOSIUM PROC., UNIVERSITY OF CALGARY, ALTA., JULY 3-6, 1972. 200. GOLUVCHENOKO, A

  19. Fatigue in Breakwater Concrete Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    1985-01-01

    made of unreinforced and steel fibre reinforced flyash concrete are presented. Moreover universal graphs for fatigue in armour units made of conventional unreinforced concrete exposed to impact load and pulsating load are presented. The effect of fibre reinforcement and the implementation of fatigue......The reliability of rubble mound breakwaters depends on the hydraulic stability and the mechanical strength of the armour units. The paper deals with the important aspect of fatigue related to the strength of concrete armour units. Results showing significant fatigue from impact tests with Dolosse...

  20. Fatigue Performance of Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Jun, Zhang; Stang, Henrik

    1996-01-01

    The objective of the present study is to obtain basic data of fibre reinforced concrete under fatigue load and to set up a theoretical model based on micromechanics. In this study, the bridging stress in fiber reinforced concrete under cyclic tensile load was investigted in details. The damage...... mechanism of the interface between fiber and matrix was proposed and a rational model given. Finally, the response of a steel fiber reinforced concrete beam under fatigue loading was predicted based on this model and compared with experimental results....

  1. Influence of Additives on Reinforced Concrete Durability

    Directory of Open Access Journals (Sweden)

    Neverkovica Darja

    2014-12-01

    Full Text Available The article presents the results of the research on carbonation and chloride induced corrosion mechanisms in reinforced concrete structures, based on three commercially available concrete admixtures: Xypex Admix C-1000, Penetron Admix and Elkem Microsilica. Carbonation takes place due to carbon dioxide diffusion, which in the required amount is present in the air. Chlorides penetrate concrete in case of the use of deicing salt or structure exploitation in marine atmosphere. Based on the implemented research, Elkem Microsilica is the recommended additive for the use in aggressive environmental conditions. Use of Xypex Admix C-1000 and Penetron Admix have only average resistance to the aggressive environmental impact.

  2. Method for Bubbledeck Concrete Slab with Gaps

    Directory of Open Access Journals (Sweden)

    Sergiu Călin

    2009-01-01

    Full Text Available The composite slabs are made of BubbleDeck type slab elements with spherical gaps, poured in place on transversal and longitudinal directions. By introducing the gaps leads to a 30...50\\% lighter slab which reduces the loads on the columns, walls and foundations, and of course of the entire building. BubbleDeck slab elements are plates with ribs on two directions made of reinforced concrete or precast concrete with spherical shaped bubbles. These slab elements have a bottom and an upper concrete part connected with vertical ribs that go around the gaps.

  3. MECHANICAL CHARACTERIZATION OF RECYCLED TIRES IN CONCRETE

    OpenAIRE

    KÖROĞLU, MEHMET ALPASLAN

    2016-01-01

    Waste tires have been an increasing problem every year due to the increase of vehicle sales. The disposal of waste tires has presented very serious problems to the human community in the world. Currently, some research has been studied on not only waste tire chips (WTC) but also   recycled steel tire fibres (RSF) in concrete. Recent study is focusing on the usage of WTC and RSF in concrete mixture. The different weight of WTC and RSF is mixed in concrete in order to investigate the effect on ...

  4. Flexural Behavior of Textile-Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Volkova Anna

    2016-01-01

    Full Text Available This paper deals with the flexural behaviour of textile-reinforced concrete (TRC. Two samples of TRC made of high strength reinforcing fabrics made of glass and carbon rovings were produced. Three-point bending test was carried out to examine the flexural performance of the developed samples. The maximum flexural strength and reinforcement efficiency were calculated. Experimental results showed that that all types of applied fabric reinforcement contributed to increases strength as compared to nonreinforced concrete. Furthermore, the deformation behavior of reinforced concrete was analyzed. The advantage is in higher residual load-bearing capacity, which allows maintaining the integrity of the structure.

  5. A Comparison of Bond Performance of Concrete Reinforced with ...

    African Journals Online (AJOL)

    The transfer of stress from a deformed bar to the concrete is achieved by mechanical locking of the steel into the surrounding concrete. This interfacial bond strength between steel and the surrounding concrete is an important factor influencing the strength and durability of reinforced concrete structure. This paper presents ...

  6. Performance of Engineered Cementitious Composites for Concrete Repairs

    NARCIS (Netherlands)

    Zhou, J.

    2011-01-01

    Background and goals of this thesis The concrete repair, rehabilitation and retrofitting industry grows rapidly, driven by deterioration of, damage to and defects in concrete structures. However, it is well known that to achieve durable concrete repairs is very difficult. The failure of concrete

  7. Design of ecological concrete by particle packing optimization

    NARCIS (Netherlands)

    Fennis, S.A.A.M.

    2011-01-01

    The goal of this research project on Ecological Concrete was to reduce the CO2-emission of concrete and to reuse secondary materials form concrete production and other industries simultaneously. This also minimizes the use of natural resources and the production costs. To replace cement in concrete

  8. 29 CFR 1926.704 - Requirements for precast concrete.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural framing...

  9. 76 FR 34890 - Track Safety Standards; Concrete Crossties

    Science.gov (United States)

    2011-06-15

    ... Federal Railroad Administration 49 CFR Part 213 RIN 2130-AC01 Track Safety Standards; Concrete Crossties... mandates specific requirements for effective concrete crossties, for rail fastening systems connected to concrete crossties, and for automated inspections of track constructed with concrete crossties. The Track...

  10. 76 FR 55819 - Track Safety Standards; Concrete Crossties

    Science.gov (United States)

    2011-09-09

    ... Federal Railroad Administration 49 CFR Part 213 RIN 2130-AC35 Track Safety Standards; Concrete Crossties... concrete crossties, for rail fastening systems connected to concrete crossties, and for automated inspections of track constructed with concrete crossties. This document amends and clarifies the final rule...

  11. Potential of waste tires as aggregates in concrete | Mutuku | Journal ...

    African Journals Online (AJOL)

    Potential use of this kind of concrete includes nonstructural purposes such as lightweight concrete walls and blocks, building facades and crash barriers. Keywords: concrete aggregates, rubber chips, rubberized concrete, used tires, waste recycling. Journal of Civil Engineering Research and Practice Vol. 3(1) 2006: 75-84 ...

  12. Surface treatment systems for concrete in marine environment: Effect of concrete cover thickness

    Directory of Open Access Journals (Sweden)

    Marcelo Henrique Farias de Medeiros

    Full Text Available Abstract There are some ways to extend the service life of a reinforced concrete structure. This paper focuses on the extension of the service life by treating the surface of reinforced concrete, specifically on the effect of the concrete cover thickness on the surface treatment system efficacy. Thus, chloride migration tests were performed and diffusion chloride coefficients were calculated. The service life of each case (treated or non-treated concrete was estimated using these data and Fick's second law of diffusion. Results indicated that the thicker the concrete cover is, the greater the efficacy of the concrete surface treatment system will be. The dissemination of this information is important, since it is almost intuitive to think that the effect of a surface treatment system depends only on itself and this study shows the opposite.

  13. Mechanical and Physical Properties of Polyester Polymer Concrete Using Recycled Aggregates from Concrete Sleepers

    Directory of Open Access Journals (Sweden)

    Francisco Carrión

    2014-01-01

    Full Text Available Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate, and waste aggregates (basalt and limestone coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%, and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

  14. Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.

    Science.gov (United States)

    Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

    2014-01-01

    Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

  15. Concrete mixtures with high-workability for ballastless slab tracks

    Directory of Open Access Journals (Sweden)

    Olga Smirnova

    2017-10-01

    Full Text Available The concrete track-supporting layer and the monolithic concrete slab of ballastless track systems are made in-situ. For this reason the concrete mixtures of high workability should be used. Influence of the sand kind, the quartz microfiller fineness and quantity as well as quantity of superplasticizer on workability of fresh concrete and durability of hardened concrete is shown. The compositions of the high-workability concrete mixtures with lower consumption of superplasticizer are developed. The results of the research can be recommended for high performance concrete of ballastless slab track.

  16. Recycled construction and demolition concrete waste as aggregate for structural concrete

    OpenAIRE

    Ashraf M. Wagih; Hossam Z. El-Karmoty; Magda Ebid; Samir H. Okba

    2013-01-01

    In major Egyptian cities there is a surge in construction and demolition waste (CDW) quantities causing an adverse effect on the environment. The use of such waste as recycled aggregate in concrete can be useful for both environmental and economical aspects in the construction industry. This study discusses the possibility to replace natural coarse aggregate (NA) with recycled concrete aggregate (RCA) in structural concrete. An investigation into the properties of RCA is made using crushing a...

  17. Investigation of concrete produced using recycled aluminium dross for hot weather concreting conditions

    OpenAIRE

    Mailar, Gireesh; N, Sujay Raghavendra; B.M, Sreedhara; D.S, Manu; Hiremath, Parameshwar; K., Jayakesh

    2016-01-01

    Aluminium dross is a by-product obtained from the aluminium smelting process. Currently, this dross is processed in rotary kilns to recover the residual aluminium, and the resultant salt cake is sent to landfills. The present study investigates the utilization of recycled aluminium dross in producing concrete, which is suitable for hot weather concreting condition. The primary objectives of the experimental study are to examine the feasibility of using concrete blended with recycled aluminium...

  18. DEFLECTION CALCULATION OF REINFORCED CONCRETE FLEXURAL ELEMENTS WITH THE TOP LAYER MADE OF HIGH QUALITY CONCRETE

    Directory of Open Access Journals (Sweden)

    Potapov Yuriy Borisovich

    2016-03-01

    Full Text Available One of the main requirements to the operational integrity of reinforced concrete flexural elements is nonexeedance of the deflection limits at the assumed load. It is possible to provide the given requirement using different methods, one of which is the production of a sandwich construction of the concretes with different strength. The article presents the results of theoretical and experimental investigations of the deflection of reinforced concrete beams with the top layer made of high-quality concrete, with different percentage and strength of longitudinal tensile reinforcement without prestressing. The study of different methods of calculating the curvature of reinforced concrete beams is carried out and the recommendations on calculating the deflections of such elements are made. The use of high quality concrete in the compression area of flexural elements allows reducing the deflections. The theoretical deflections of beams produced of the B60 class concrete are 15…20 % more than the deflections of the proposed composite sections in case of equal bearing capacity. The authors proposed a formula to calculate the bending of reinforced concrete flexural members with the top layer made of high-quality concrete in the compressed area.

  19. The Fire Resistance Performance of Recycled Aggregate Concrete Columns with Different Concrete Compressive Strengths

    Directory of Open Access Journals (Sweden)

    Hongying Dong

    2014-12-01

    Full Text Available In order to ascertain the fire resistance performance of recycled aggregate concrete (RAC components with different concrete compressive strengths, four full-scaled concrete columns were designed and tested under high temperature. Two of the four specimens were constructed by normal concrete with compressive strength ratings of C20 and C30, respectively, while the others were made from recycled coarse aggregate (RCA concrete of C30 and C40, respectively. Identical constant axial forces were applied to specimens while being subjected to simulated building fire conditions in a laboratory furnace. Several parameters from the experimental results were comparatively analyzed, including the temperature change, vertical displacement, lateral deflection, fire endurance, and failure characteristics of specimens. The temperature field of specimens was simulated with ABAQUS Software (ABAQUS Inc., Provindence, RI, USA and the results agreed quite well with those from the experiments. Results show that the rate of heat transfer from the surface to the interior of the column increases with the increase of the concrete’s compressive strength for both RAC columns and normal concrete columns. Under the same initial axial force ratio, for columns with the same cross section, those with lower concrete compressive strengths demonstrate better fire resistance performance. The fire resistance performance of RAC columns is better than that of normal concrete columns, with the same concrete compressive strength.

  20. The use of a concrete additive to eliminate returned concrete waste volumes

    Directory of Open Access Journals (Sweden)

    Bester Johannes

    2017-01-01

    Full Text Available This paper investigates the effects of the use of a recently developed two-component powdered product made from polymers and inorganic compounds that can be mechanically mixed into returned fresh ready-mix concrete to allow for the separation of the concrete into fine and coarse aggregates. This allows for the re-use of the returned concrete as aggregates in the manufacturing of new concrete. The returned concrete waste can therefore be eliminated, thus reducing virgin aggregate usage, as well as reducing the environmental impact of returned concrete. In this study, the treated recycled fresh concrete was separated into fine and coarse aggregates, and then used at replacement levels of 0%, 25%, 50%, 75% and 100%. The effect of the product on the material classification, and on important fresh and hardened properties of the concrete for the above-mentioned replacement values was tested. For the fine aggregate, the results indicate minimal changes in both the fresh and hardened properties. For the coarse aggregate, the results show a marked improvement of flexural strength with an increase in replacement value when coarse aggregates are used. Very high replacement levels may be used with very little effect on the quality of the new concrete.

  1. Effect of concrete strength gradation to the compressive strength of graded concrete, a numerical approach

    Science.gov (United States)

    Pratama, M. Mirza Abdillah; Aylie, Han; Gan, Buntara Sthenly; Umniati, B. Sri; Risdanareni, Puput; Fauziyah, Shifa

    2017-09-01

    Concrete casting, compacting method, and characteristic of the concrete material determine the performance of concrete as building element due to the material uniformity issue. Previous studies show that gradation in strength exists on building member by nature and negatively influence the load carrying capacity of the member. A pilot research had modeled the concrete gradation in strength with controllable variable and observed that the weakest material determines the strength of graded concrete through uniaxial compressive loading test. This research intends to confirm the recent finding by a numerical approach with extensive variables of strength disparity. The finite element analysis was conducted using the Strand7 nonlinear program. The results displayed that the increase of strength disparity in graded concrete models leads to the slight reduction of models strength. A substantial difference in displacement response is encountered on the models for the small disparity of concrete strength. However, the higher strength of concrete mix in the graded concrete models contributes to the rise of material stiffness that provides a beneficial purpose for serviceability of building members.

  2. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...

  3. Development of a Failure Theory for Concrete

    Science.gov (United States)

    2012-07-31

    The failure behavior of concrete materials is not completely understood because conventional test methods fail to assess the : material response independent of the sample size and shape. : To study the influence of strength affecting test conditions,...

  4. Concrete slurry, wash and loss water mitigation.

    Science.gov (United States)

    2012-08-01

    This report presents an evaluation of wastewaters derived from concrete placement and maintenance and the : preparation of best management practices (BMPs). Investigation and documentation of existing practices was done : to ensure application to rea...

  5. Doubling the Life of Concrete Structures

    Energy Technology Data Exchange (ETDEWEB)

    Pesic, Batric [Univ. of Idaho, Moscow, ID (United States); Raja, Krishnan [Univ. of Idaho, Moscow, ID (United States); Xi, Yumping [Univ. of Colorado, Boulder, CO (United States); Jun, Jiheon [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-07-24

    Overall objective of the project was to study the fundamental properties of concrete (with and without steel reinforcement) with respect to chemical and physical parameters that can influence its structural integrity.

  6. Gates Precast Concrete User Project Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Post, Brian K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roschli, Alex C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chesser, Phillip C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    The primary objective of the project was to demonstrate the viability of using carbon fiber reinforced ABS plastic and the Big Area Additive Manufacturing (BAAM) technology to rapidly manufacture molds for the precast concrete industry.

  7. Corrosion of steel in locally deficient concrete.

    Science.gov (United States)

    2009-02-28

    This investigation confirmed prior noted trends of extensive preferential chloride intrusion at preexisitng cracks in a majority of cases of substructure members in Florida bridges built with low permeability conventional concrete.

  8. Corrosion resistant alloys for reinforced concrete [2009

    Science.gov (United States)

    2009-04-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for four-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focus...

  9. Multimedia package for LRFD concrete bridge design.

    Science.gov (United States)

    2009-02-01

    This Project developed a Load and Resistance Factor Design (LRFD) multimedia package to provide a practical introduction and an in-depth understanding of the technological advances in the design of concrete bridges. This package can be used to train ...

  10. Modeling of Corrosion-induced Concrete Damage

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie A.; Michel, Alexander; Stang, Henrik

    2013-01-01

    In the present paper a finite element model is introduced to simulate corrosion-induced damage in concrete. The model takes into account the penetration of corrosion products into the concrete as well as non-uniform formation of corrosion products around the reinforcement. To ac-count for the non......-uniform formation of corrosion products at the concrete/reinforcement interface, a deterministic approach is used. The model gives good estimates of both deformations in the con-crete/reinforcement interface and crack width when compared to experimental data. Further, it is shown that non-uniform deposition...... of corrosion products affects both the time-to cover cracking and the crack width at the concrete surface....

  11. Use of metallic fibers in concretes

    Directory of Open Access Journals (Sweden)

    Kherbache Souad

    2014-04-01

    Full Text Available The addition of a waste (fibers in construction materials, particularly, the concretes is a technique increasingly used, for several reasons, either ecological, or economic, or to improve some properties in a fresh or hardened state. In our work we studied the behavior of the concrete and the mortar containing metallic fibers resulting from the unit BCR which is in Bordj-Menaiel in Algeria (metallic fibers resulting from the rejection at the end of the domestic operation of silvering of the tools and which is stored in plastic bags which are preserved in metal containers. Our work consists to study the behavior of the concretes and the mortars containing these fibers of cement substitution. We noted that the use of these fibers in the concretes in substitution of cement decreases its of compressive strength and flexural strength but to 10% of waste these strength remain acceptable.

  12. Preventive maintenance of asphalt concrete pavements

    Science.gov (United States)

    1988-01-01

    Preventive maintenance of asphalt concrete can often extend the pavement life for a number of years at relatively low costs. The types of preventive maintenance that are discussed in this report include rejuvenators, slurry seals, surface treatments,...

  13. Degradation and Decontamination of VX in Concrete

    National Research Council Canada - National Science Library

    Wagner, G. W; O'Connor, Richard J; Edwards, Jennifer L; Brevett, Carol A

    2004-01-01

    .... Water added to concrete samples containing sorbed VX to mimic precipitation and/or a potential decontamination strategy resulted in the desorption of copious amounts of VX into the water along...

  14. Degradation And Decontamination of VX in Concrete

    National Research Council Canada - National Science Library

    Wagner, George W; O'Connor, Richard J; Edwards, Jennifer L; Brevett, Carol A

    2004-01-01

    ... than 0.2 L drops. Water added to concrete samples containing sorbed VX to mimic precipitation and/or a potential decontamination strategy resulted in the desorption of copious amounts of VX into the water along...

  15. Long-life slab replacement concrete : [summary].

    Science.gov (United States)

    2015-04-01

    Concrete slab replacement projects in Florida have demonstrated a high incidence of : replacement slab cracking. Causes of cracking have not been reliably determined. University of South Florida researchers : sought to identify the factors or : param...

  16. Properties of Fiber Reinforced Polymer Concrete

    National Research Council Canada - National Science Library

    Marinela Bărbuţă; Maria Harja

    2008-01-01

    .... In the composition were introduced near the fly ash, used as filler, the cellulose fibers. The mechanical characteristics such as compressive strength, flexural strength and split tensile strength of polymer concrete with fibers were investigated...

  17. Chloride migration in concrete with superabsorbent polymers

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    2015-01-01

    Superabsorbent polymers (SAP) can be used as a means for internal curing of concrete. In the present study, the development of transport properties of concrete with SAP is investigated. The chloride migration coefficient according to NT BUILD 492 is used as a measure of this. Twenty concrete...... mixtures are tested 7, 14, and 28 days after casting. The development of degree of hydration is followed for 20 corresponding paste mixtures. Both when SAP is added with extra water to compensate the SAP water absorption in fresh concrete and without extra water, the internal curing water held by SAP may...... contribute to increase the degree of hydration. No matter if SAP is added with or without extra water, it appears that the so-called gel space ratio can be used as a key parameter to link age and mixture proportions (water-to-cement ratio and SAP dosage) to the resulting chloride migration coefficient...

  18. Performance of I-57 recycled concrete pavements.

    Science.gov (United States)

    2009-01-01

    In 1986-1987 the Illinois Department of Transportation (IDOT) constructed a demonstration project on I-57 near Effingham, Illinois to evaluate the viability : of recycling an existing jointed reinforced concrete pavement for use as its primary aggreg...

  19. Pentek concrete scabbling system: Baseline report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-31

    The Pentek scabbling technology was tested at Florida International University (FIU) and is being evaluated as a baseline technology. This report evaluates it for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek concrete scabbling system consisted of the MOOSE{reg_sign}, SQUIRREL{reg_sign}-I, and SQUIRREL{reg_sign}-III scabblers. The scabblers are designed to scarify concrete floors and slabs using cross-section, tungsten carbide tipped bits. The bits are designed to remove concrete in 318 inch increments. The bits are either 9-tooth or demolition type. The scabblers are used with a vacuum system designed to collect and filter the concrete dust and contamination that is removed from the surface. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  20. Controlling conductivity of asphalt concrete with graphite.

    Science.gov (United States)

    2014-08-01

    Electrically conductive asphalt concrete has a huge potential for various multifunctional applications such as : self-healing, self-sensing, and deicing. In order to utilize the full spectrum of applications of electrically conductive : asphalt compo...

  1. REINFORCED CONCRETE SILO DEMOLITION BY BLASTING

    Directory of Open Access Journals (Sweden)

    Josip Krsnik

    1993-12-01

    Full Text Available This paper represents the demolition of reinforced concrete silo by blasting. The loadbearing structure was blasted so that the weight of the silo itself done most of the felling (the paper is published in Croatian.

  2. High performance concrete pavement in Indiana.

    Science.gov (United States)

    2011-01-01

    Until the early 1990s, curling and warping of Portland cement concrete pavement did not concern : pavement engineers in many transportation agencies. Since beginning construction of the interstate system in the : United States in the late 1950s throu...

  3. Evaluation of concrete pavement patching techniques.

    Science.gov (United States)

    1989-01-01

    This final report presents the results of a study undertaken to improve in concrete pavement patching techniques. Activities included an evaluation of the suitability of the impact hammer and maturity calculations for determining when a patch is read...

  4. Performance evaluation of precast prestressed concrete pavement.

    Science.gov (United States)

    2007-11-01

    This report describes in detail an experimental investigation of an innovative precast prestressed concrete pavement (PPCP) system used to rehabilitate a 1,000 ft. section of interstate highway located on the northbound lanes of I-57 near Charleston,...

  5. Rectal impaction following enema with concrete mix.

    Science.gov (United States)

    Stephens, P J; Taff, M L

    1987-06-01

    This article describes an unusual rectal foreign body resulting from homosexual anal erotic activities. The patient had used an enema containing a concrete mix which became impacted and required surgical removal. The use, abuse, and complications of enemas are reviewed.

  6. Content Differences for Abstract and Concrete Concepts

    National Research Council Canada - National Science Library

    Katja Wiemer‐Hastings, Katja; Xu, Xu

    2005-01-01

    ... number. Abstract concepts were predominantly related to social aspects of situations. Properties were significantly less specific for abstract than for concrete concepts. Thus, abstractness emerged as a function of several, both qualitative and quantitative, factors.

  7. DESIGN OF COMPOSITION OF CONCRETE USING POLYPROPYLENE FIBRE REINFORCEMENT

    OpenAIRE

    Dang Van Thanh1,*, Vu Hoang Hiep2, Nguyen Van Bac1, Hoang Gia Duong1

    2016-01-01

    Fibre-reinforced concrete is an emerging trend that delivers new materials with high quality for construction. Polyporpylene fibre, an organic textile, has high potential to be used for reinforcing concrete, but there has been little research conducted into using this fibre for concrete reinforcement worldwide and no research work on this fibre reinforced concrete has been published in Vietnam. Thereofore, researchinginto Polyporylene fibre reinforced concrete to establish fundamental underst...

  8. Recycled aggregates in concrete production: engineering properties and environmental impact

    OpenAIRE

    Seddik Meddah Mohammed

    2017-01-01

    Recycled concrete aggregate is considered as the most abundant and used secondary aggregate in concrete production, other types of solid waste are also being used in concrete for specific purposes and to achieve some desired properties. Recycled aggregates and particularly, recycled concrete aggregate substantially affect the properties and mix design of concrete both at fresh and hardened states since it is known by high porosity due to the adhered layer of old mortar on the aggregate which ...

  9. Experimental analysis of properties of high performance recycled aggregate concrete

    OpenAIRE

    Gonzàlez Corominas, Andreu; Etxeberria Larrañaga, Miren

    2014-01-01

    Due to the increase in the demolition of high strength concrete structures and the interest of precast concrete companies in being more competitive, it is necessary to analyse the use of recycled concrete aggregates (RCA) in high performance concrete (HPC). In this study, HPC were produced using 20%, 50% and 100% of RCA on substitution of natural coarse aggregates. Three types of RCA were used, they were produced crushing original concrete of 100, 60 and 40 MPa of compressive strength. The ph...

  10. Strength Characteristics of Groundnut Leaf/Stem Ash (GLSA) Concrete

    OpenAIRE

    Oseni O. W.; Audu M. T.

    2016-01-01

    The compressive strength properties of concrete are substantial factors in the design and construction of concrete structures. Compressive strength directly affects the degree to which the concrete can be able to carry a load over time. These changes are complemented by deflections, cracks etc., in the structural elements of concrete. This research investigated the effect of groundnut leaf/stem ash (GLSA) on the compressive strength of concrete at 0%, 5 %, 10 % and 15 % replacements of cement...

  11. Concrete Cover Influence on Inelastic Buckling of Longitudinal Reinforcing Bars

    Science.gov (United States)

    Korentz, Jacek; Kucharczyk, Anna

    2017-10-01

    The paper presents the results of numerical analyses of post yielding behaviour of compressed reinforcing bars, taking into account the impact of concrete cover on static equilibrium path. Concrete cover was modelled as a transverse ties with characteristics like for the tensioned concrete. The calculations were performed for various parameters of concrete cover and bar slenderness, with the use commercial system Abaqus/CAE. The results of analysis showed that the concrete cover has a significant impact on inelastic buckling of reinforcing bars.

  12. Design Methods for Fibre Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil.......The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil....

  13. Tensile properties of structural fibre reinforced concrete

    Science.gov (United States)

    Tipka, M.; Vašková, J.

    2017-09-01

    The paper deals with the comparison of several loading tests, which are using for determination of tensile strength of cementitious composites. The paper describes several test methods, their advantages, disadvantages and possible outputs. In the experimental program several recipes of concrete and fibre reinforced concrete were tested in splitting test, 3-point and 4-point bending tests and in 2 variants of axial tension test. Tension strength ratios and conversion factors between loading tests were determined for each recipe, based on test results.

  14. Strain rate effects for spallation of concrete

    Directory of Open Access Journals (Sweden)

    Häussler-Combe Ulrich

    2015-01-01

    Full Text Available Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property – which can be covered by rate dependent stress strain relations – or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  15. Waste steel wires modified structural lightweight concrete

    OpenAIRE

    Aghaee, Kamran; Yazdi,Mohammad Ali

    2014-01-01

    Nowadays, the use of different waste fibers in concrete has started to increase rapidly due to some reasons such as economic savings and positive effects on the environment. In this study, waste steel wires taken from reinforcement and formwork which were previously utilized in construction projects, were employed in structural lightweight concrete (SLWC). The objective was to investigate the possibility of using this type of fiber as reinforcement in the SLWC. Compressive, tensile, flexural ...

  16. concrete waterproofing by crystallization - xXYPEX

    OpenAIRE

    Jovanović, Rajko

    2011-01-01

    The Diploma thesis deals with a variety of waterproofing systems, focusing on the XYPEX waterproofing system. The XYPEX system can be used either as additive to fresh concrete or can be applied after hardening of concrete as a waterproof coating. I have chosen few building assemblies - some classic and others using XYPEX and described their features and advantages. I compared chosen systems from technological point of view and compared time consumption and costs for construction of each ...

  17. Detection of corrosion in submerged reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Carney, R.F.A.; Lawrence, P.F.; Wilkins, N.J.M. [UKAEA Harwell Lab. (United Kingdom). Materials Development Div.

    1990-12-31

    Steel reinforcement in concrete is not usually subject to corrosion when it is under water and not exposed to air. However, research carried out within the Concrete in the Oceans Programme has produced evidence that localised corrosion can occur at cracks which intersect the reinforcing bars even though the concrete is fully immersed in seawater. The problem with underwater corrosion is that, although the corrosion products migrate out of the crack and slight rust staining appears, these are not easy to see. In contrast, when reinforced concrete is exposed to air, then corrosion is marked by expansive rust deposits and spalling concrete. The principal objective of this report was to define the conditions of crack geometry, electrochemical potential and rate of seawater flow, under which there would be no external visible signs of corrosion. A further objective was to define, on a concrete offshore platform, where this type of unseen corrosion is most likely to occur. At seawater flowrates of 0.25 metres per second or less, localised corrosion occurring at cracks in the concrete which intersected the reinforcing bars was only visible as rust staining or deposits near the crack. At higher flowrates there was no clear visual evidence of corrosion. Visual inspection is therefore not a reliable method of checking on the presence of corrosion in underwater concrete structures. It is also concluded than an overall underwater potential of -700 mV Ag/AgCl or more negative is required in order to dismiss the possibility of localized corrosion occurring at cracks. (author)

  18. Properties of Concrete Mixes with Carwash Wastewater

    OpenAIRE

    Shahidan Shahiron; Senin Mohamad Syamir; Abdul Kadir Aeslina Binti; Yee Lau Hai; Ali Noorwirdawati

    2017-01-01

    The rapid growth of the car wash industry today results in the need for wastewater reclamation. Thus, this paper aims to investigate the effect of using car wash wastewater on concrete properties in terms of mechanical properties. The basic characteristics of wastewater were investigated according to USEPA (Method 150.1 & 3 00.0) while the mechanical properties of concrete with car wash wastewater were compared according to ASTM C1602 and BS EN 1008 standards. In this research, the compressiv...

  19. Topics in cement and concrete research

    OpenAIRE

    Brouwers, Jos; Russel, M.I.; Basheer, P.A.M.

    2007-01-01

    The present paper addresses several topics in regard to the sustainable design and use of concrete. First, major features concerning the sustainable aspects of the material concrete are summarised. Then the major constituent, from an environmental point of view, cement is discussed in detail, particularly the hydration and application of slag cement. The intelligent combining of mineral oxides, which are found in clinker, slag, fly ashes etc., is designated as mineral oxide engineering. It re...

  20. An Investigation on Properties of Transparent Concretes

    OpenAIRE

    Topçu, İlker Bekir; Tayfun UYGUNOĞLU

    2016-01-01

    Transparentconcrete is a cement-based building material which has optical properties dueto the embedded light transmitting elements within the composite. In thisstudy, the design of transparent concrete, its mechanical properties, lighttransmission properties of optical fibers and the use of optic fibers werediscussed. The study was performed as a literature review, and it was focusedon the light absorption of translucent concrete, transmission, the mechanismand losses in the transmission. In...

  1. The Recent Research on Bamboo Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Dewi Sri Murni

    2017-01-01

    Full Text Available The paper presents the last research on bamboo reinforced concrete in Brawijaya University Indonesia. Three kinds of structures studied in recent year, the mounting of pegs on reinforcement, the use of lightweight brick to reduce the weight of the beams, and the use the light weight aggregate for bamboo concrete composite frame. All that experiments overcome some problems exist in using bamboo as environmental acceptance structures.

  2. Prediction of Chloride Penetration into Hardening Concrete

    OpenAIRE

    Wei-Jie Fan; Xiao-Yong Wang

    2015-01-01

    In marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. Currently, most of experimental investigations about submerged penetration of chloride ions are started after the four-week standard curing of concrete. The further hydration of cement and reduction of chloride diffusivity during submerged penetration period are ignored. To overcome this weak point, this paper presents a numerical procedure to analyze simult...

  3. Making Metamodels Aware of Concrete Syntax

    OpenAIRE

    Fondement, Frédéric; Baar, Thomas

    2005-01-01

    Language-centric methodologies, triggered by the success of Domain Specific Languages, rely on precise specifications of modeling languages. While the definition of the abstract syntax is standardized by the 4-layer metamodel architecture of the OMG, most language specifications are held informally for the description of the semantics and the (graphical) concrete syntax. This paper is tackling the problem of specifying the concrete syntax of a language in a formal and non-ambiguous way. We pr...

  4. Pedogenic Carbonate Concretions in the Russian Chernozem

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailova, E. A.; Post, C. J.; Magrini-Bair, K.; Castle, J. W.

    2006-12-01

    Pedogenic carbonate concretions are commonly found in grassland soils, but their origin is not fully understood. This study was conducted to determine the radiocarbon age, the stable isotope geochemistry, and chemical composition of carbonate concretions in the Russian Chernozem, one of the typical soils in grasslands. Three sites were sampled: a native grassland field (not cultivated for at least 300 years), an adjacent 50-year continuous fallow field in the V. V. Alekhin Central-Chernozem Biosphere State Reserve in the Kursk region of Russia, and a continuously cropped field in the Experimental Station of the Kursk Institute of Agronomy and Soil Erosion Control. All sampled soils were classified as fine-silty, mixed, frigid Pachic Hapludolls. The mineralogical composition of concretions varies from low-magnesium calcite to pure calcite. The concretion contains 0.05% N, 6.4% C, and has [delta]13C and [delta]18O values of -10.9[per mille sign] (the per mill symbol, parts per thousand) and -7.8[per mille sign], respectively. The outside part of the carbonate concretion is 1909 +/- 40 14C age Before Present (B.P.) compared with 1693 +/- 40 14C age B.P. for the inside part of the same concretion, even though the concretion is found in the C horizon of much older age (10,902 +/- 63 14C age B.P.). Remnants of soil organic matter in concretions are closely associated with the cropped and fallow/plowed soils by pyrolysis molecular beam mass spectrometry.

  5. Concrete Durability: A Multibillion-Dollar Opportunity

    Science.gov (United States)

    1987-01-01

    results in cracking of the affected concrete. In the alkali-carbonate reactions, specific kinds of dolomitic rock, usually containing the clay mineral...illite, have been found to be alkali-reactive. The mechanism involves conversion of magnesium from dolomite to magnesium hydroxide, which again...greater degree of reactivity in the concrete. ASTM C 618-85, "Standard Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as a

  6. Quality control chart for crushed granite concrete

    Directory of Open Access Journals (Sweden)

    Ewa E. DESMOND

    2016-07-01

    Full Text Available A chart for assessing in-situ grade (strength of concrete, has been developed in this study. Four grades of concrete after the Nigerian General Specification for Roads and bridges (NGSRB-C20, C25, C30 and C35, is studied at different water-cement ratios for medium and high slump range. The concrete mixes are made from crushed granite rock as coarse aggregate with river sand as fine aggregate. Compression test on specimens are conducted at curing age of 1, 3, 7, 14, 21, 28 and 56 days. Results on concrete workability from slump values, and water-cement ratios revealed that specimens with lower water-cement ratio were less workable but had higher strength, compared to mixes with higher water cement ratio. A simple algorithm using nonlinear regression analysis performed on each experimental data set produced Strength-Age (S-A curves which were used to establish a quality control chart. The accuracy of these curves were evaluated by computing average absolute error (AAS, the error of estimate (EoE and the average absolute error of estimate (Abs EoE for each concrete mix. These were done based on the actual average experimental strengths to measure how close the predicted values are to the experimental data set. The absolute average error of estimate (Abs. EoE recorded was less than ±10% tolerance zone for concrete works.

  7. Concrete Nanoscience and Nanotechnology: Definitions and Applications

    Science.gov (United States)

    Garboczi, E. J.

    There are many improvements needed in concrete, especially for use in renewal and expansion of the world’s infrastructure. Nanomodification can help solve many of these problems. However, concrete has been slow to catch on to the nanotechnology revolution. There are several reasons for this lag in the nanoscience and nanotechnology of concrete (NNC). First is the lack of a complete basic understanding of chemical and physical mechanisms and structure at the nanometer length scale. Another reason is the lack of a broad understanding of what nanomodification means to concrete, which is a liquid-solid composite. NNC ideas need to profit from, but not be bound by, experience with other materials. As an illustration of these ideas, a specific application will be given of using nano-size molecules in solution to affect the viscosity of the concrete pore solution so that ionic diffusion is slowed. A molecular-based understanding would help move this project towards true nanotechnology. A final section of this paper lists some possibly fruitful focus areas for the nanoscience and nanotechnology of concrete.

  8. Organic compounds in concrete from demolition works.

    Science.gov (United States)

    Van Praagh, M; Modin, H; Trygg, J

    2015-11-01

    This study aims to verify the effect of physically removing the outer surface of contaminated concrete on total contents and on potential mobility of pollutants by means of leaching tests. Reclaimed concrete from 3 industrial sites in Sweden were included: A tar impregnated military storage, a military tar track-depot, as well as concrete constructions used for disposing of pesticide production surplus and residues. Solid materials and leachates from batch and column leaching tests were analysed for metals, Cl, F, SO4, DOC and contents of suspected organic compounds (polycyclic aromatic hydrocarbons, PAH, and pesticides/substances for pesticide production such as phenoxy acids, chlorophenols and chlorocresols, respectively). In case of PAH contaminated concrete, results indicate that removing 1 or 5 mm of the surface lead to total concentrations below the Swedish guidelines for recycling of aggregates and soil in groundwork constructions. 3 out of 4 concrete samples contaminated with pesticides fulfilled Swedish guidelines for contaminated soil. Results from batch and column leaching tests indicated, however, that concentrations above environmental quality standards for certain PAH and phenoxy acids, respectively, might occur at site when the crushed concrete is recycled in groundwork constructions. As leaching tests engaged in the study deviated from leaching test standards with a limited number of samples, the potential impact of the leaching tests' equipment on measured PAH and pesticide leachate concentrations has to be evaluated in future work. Copyright © 2015. Published by Elsevier Ltd.

  9. Repairing design and construction of wastewater storage tank, which is exposed to high temperature, with self-compacting concrete; Koon ni sarasareru haisui choso no koryudo concrete ni yoru hoshu sekkei / seko

    Energy Technology Data Exchange (ETDEWEB)

    Maruya, T.; Sakamoto, J.; Shimada, M. [Taisei Construction Co. Ltd., Tokyo (Japan)

    1998-09-01

    The Anesaki Thermal power Plant of Tokyo Electric Power Co., Inc. at Ichihara, Chiba Prefecture is installed with an outside blow tank, a reinforced concrete structure as a facility to store temporarily surplus high temperature water at starting and suspension of the boiler. This tank is applied with a lining material of acid-resisting epoxy resin on the ceiling, walls and bottom in order to prevent deterioration of reinforced concrete, however, it requires repair due to exfoliation of bonded surface and deterioration of the lining material after a long period exposure to high temperature. The condition of the deterioration was surveyed and the repairing method and the cost were examined. The repair works were conducted with additional concrete casting using self-compacting concrete. This paper describes the survey of the deterioration, the examination of the repair works and the outline of the execution of the works. The features of this works include the use of a Vickers hardness meter for the determination of the deterioration near the surface of the body in addition to the conventional survey and the application self-compacting concrete. 3 refs., 4 figs., 3 tabs.

  10. Modelling heterogeneity of concrete using 2D lattice network for concrete fracture and comparison with AE study

    OpenAIRE

    Sagar, Vidya R; Prasad, Raghu BK

    2009-01-01

    In this paper, numerical modelling of fracture in concrete using two-dimensional lattice model is presented and also a few issues related to lattice modelling technique applicable to concrete fracture are reviewed. A comparison is made with acoustic emission (AE) events with the number of fractured elements. To implement the heterogeneity of the plain concrete, two methods namely, by generating grain structure of the concrete using Fuller's distribution and the concrete material properties ar...

  11. Deflections Results for Beams of Self Compacted Concrete (SCC) and Normal Concrete for Period t = 400 Days

    OpenAIRE

    , RM Hadri; , HE Sadiku; , DR Kryeziu

    2016-01-01

    Concrete is a material which has wide usage in engineering especially in construction engineering and road infrastructure facilities. Development trends indicate for high rise constructions, modern skyscrapers that building of such constructions with normal concretes and low consistency is impossible, therefore there is a need for concrete with high processes because of great amount of steel in cross section of concrete elements. The solution for such construction is the selfcompacted concret...

  12. Elastic Characterization of Concrete Materials

    Science.gov (United States)

    Guerra-Vela, Claudio; Ruiz, Abraham; Zypman, Fredy R.

    2001-03-01

    Many geographical locations share a common problem of high environmental humidity. It is thus desirable to build houses that can withstand strong water loading. In this work we study the evolution of High Performance Concrete as a function of hardening stage. The technique that we use is based on the propagation of resonant audio frequency modes of oscillation along the long axis of homemade HPC cylindrical samples. An audio generator fed piezoelectric (at one end of the rod) excites vibrations in the sample. Off resonance these vibrations do not propagate away from the piezoelectric site. On the other hand, when a resonance is reached the vibration extends all over the bar. A second piezoelectric is placed at the other extreme of the cylinder. We measure three parameters: the resonant frequency, speed of sound, and loss factor. To measure the resonant frequency we connect the two piezos to an oscilloscope in the x-y mode. At resonance the oscilloscope displays an ellipse and the audio generator reports the frequency. To measure the speed of sound, we excite the firs piezo with a pulse and measure the delay time in the second piezo. The loss factor can be extracted from the ratio of the exciting pulse and the measured one. From these parameters we calculate the Young modulus, the area moment of inertia and the effective density of the HPC. These quantities are measured twice a day during the 28-day hardening time.

  13. Moisture Transport Through Sprayed Concrete Tunnel Linings

    Science.gov (United States)

    Holter, Karl Gunnar; Geving, Stig

    2016-01-01

    Waterproofing of permanent sprayed concrete tunnel linings with sprayed membranes in a continuous sandwich structure has been attempted since 2000 and has seen increased use in some countries. The main function of a sprayed membrane from a waterproofing perspective is to provide crack bridging and hence prevent flow of liquid water into the tunnel through cracks and imperfections in the concrete material. However, moisture can migrate through the concrete and EVA-based membrane materials by capillary and vapor diffusion mechanisms. These moisture transport mechanisms can have an influence on the degree of saturation, and may influence the pore pressures in the concrete material as well as risk of freeze-thaw damage of the concrete and membrane. The paper describes a detailed study of moisture transport material parameters, moisture condition in tunnel linings and climatic conditions tunnels in hard rock in Norway. These data have been included in a hygrothermal simulation model in the software WUFI for moisture transport to substantiate moisture transport and long-term effects on saturation of the concrete and membrane material. The findings suggest that EVA-based membranes exhibit significant water absorption and vapor transport properties although they are impermeable to liquid water flow. State-of-the-art sprayed concrete material applied with the wet mix method exhibits very low hydraulic conductivities, lower than 10-14 m/s, thus saturated conductive water flow is a very unlikely dominant transport mechanism. Moisture transport through the lining structure by capillary flow and vapor diffusion are calculated to approximately 3 cm3/m2 per day for lining thicknesses in the range of 25-35 cm and seasonal Nordic climate variations. The calculated moisture contents in the tunnel linings from the hygrothermal simulations are largely in agreement with the measured moisture contents in the tunnel linings. The findings also indicate that the concrete material exhibits

  14. MULTI-WAVE ULTRASONIC CONTROL OF CONCRETE

    Directory of Open Access Journals (Sweden)

    D. Yu. Snezgkov

    2017-01-01

    Full Text Available The existing non-destructive testing system of structure concrete is actually orientated on the usage of longitudinal acoustical waves. This is due to simplicity of technical realization for measuring velocity (time of acoustical pulse propagation in bulk concrete. But a reverse side of simple measuring procedure is a loss of additional information on concrete which is contained in the accepted acoustical signal. Therefore usage of an ultrasonic concrete testing method is limited by assessment of its strength. Joint usage of several wave types, so-called multi-wave testing, allows to refine metrology parameters of the ultrasonic method and to gain more information while determining physical and mechanical properties of concrete in laboratory and in situ conditions. The paper considers testing of elongated concrete elements and structures by an ultrasonic pulsing method on the basis of longitudinal subsurface and Rayleigh waves. It has been proposed to use methodology for time selection of wave components according to amplitude parameter and it has been applied for standard acoustical transformers with considerable reverberation time and not possessing spatial selectivity Basic principle of the proposed methodology is visual (according to oscillogram of the received signal determination of characteristic time moments which are used for calculation of differential value of a propagation velocity in the Rayleigh wave impulse. The paper presents results pertaining to simulation of acoustical pulse propagation on the basis of 0.15 m and data of concrete ultrasonic in situ testing on measuring bases from 0.25 to 1.75 m. Advantage of large baseline for sonic test is a possibility for execution of a hundred percent inspection for surface of large-sized elements and structures, and so there is no need to make a selective inspection in some control areas as it is stipulated by provided by existing regulations. Responsivity of the Rayleigh wave parameters

  15. Exploitation of Ultrahigh-Performance Fibre-Reinforced Concrete for the Strengthening of Concrete Structural Members

    Directory of Open Access Journals (Sweden)

    Mohammed A. Al-Osta

    2018-01-01

    Full Text Available The repair and strengthening of reinforced concrete members are very important due to several factors, including unexpected increases in load levels and/or the damaging impact of aggressive environmental conditions on structural concrete members. Many researchers have turned to using materials for the repair and strengthening of damaged structures or the construction of new concrete structural members. Ultrahigh-performance fibre-reinforced concrete (UHPFRC, characterized by superior structural and durability performance in aggressive environmental conditions, is one of the materials that have been considered for the repair and strengthening of concrete structural members. The repair or strengthening of concrete structures using UHPFRC needs a thorough knowledge of the behaviour of both the strengthening material and the strengthened concrete structure at service load conditions, in addition to an understanding of the design guidelines governing the use of such materials for effective repair and strengthening. In this study, the recent issues and findings regarding the use of UHPFRC as a repair or strengthening material for concrete structural members are reviewed, analysed, and discussed. In addition, recommendations were made concerning areas where future attention and research on the use of UHPFRC as a strengthening material needs to be focused if the material is to be applied in practice.

  16. Effect of Aggregate Mineralogy and Concrete Microstructure on Thermal Expansion and Strength Properties of Concrete

    Directory of Open Access Journals (Sweden)

    Jinwoo An

    2017-12-01

    Full Text Available Aggregate type and mineralogy are critical factors that influence the engineering properties of concrete. Temperature variations result in internal volume changes could potentially cause a network of micro-cracks leading to a reduction in the concrete’s compressive strength. The study specifically studied the effect of the type and mineralogy of fine and coarse aggregates in the normal strength concrete properties. As performance measures, the coefficient of thermal expansion (CTE and compressive strength were tested with concrete specimens containing different types of fine aggregates (manufactured and natural sands and coarse aggregates (dolomite and granite. Petrographic examinations were then performed to determine the mineralogical characteristics of the aggregate and to examine the aggregate and concrete microstructure. The test results indicate the concrete CTE increases with the silicon (Si volume content in the aggregate. For the concrete specimens with higher CTE, the micro-crack density in the interfacial transition zone (ITZ tended to be higher. The width of ITZ in one of the concrete specimens with a high CTE displayed the widest core ITZ (approx. 11 µm while the concrete specimens with a low CTE showed the narrowest core ITZ (approx. 3.5 µm. This was attributed to early-age thermal cracking. Specimens with higher CTE are more susceptible to thermal stress.

  17. Experimental Study of Beam-Column Joints Reinforced Concrete with Fiber Concrete and Fly-Ash

    Directory of Open Access Journals (Sweden)

    Purwanto Edy

    2017-01-01

    Full Text Available Reinforced concrete elements in the beam - column joint (HBK plays a very important role for maintaining the structure when subjected to the lateral load, despite the presence of many bars in the area often results in imperfections implementation. The use of fly-ash and fiber in the area of HBK can be one of available solutions; both can increase the strength of concrete and reduce the reinforcement. This study discusses the usage of fly-ash in concrete with proportion of 25% by weight of cement and dramix steel fibers and 10 kg for one m3 of concrete. This study uses the specimens of HBK with a variation of the concrete at age of 28 and 90 days. The analysis of 28 days HBK results: specimen with normal and with fly ash have average load of 10.53 kN and 6.97 kN where specimen with Fly-ash + additive has 12.65 kN (20.13% higher than normal specimen. At the age of 90 days, HBK with normal concrete, fly ash and fiber concrete can withstand load at 12.73 kN, 10.87 kN, and 13.15 kN respectively, where HBK with fiber + fly-ash reaches at 13.38 kN or has 5.00% more than HBK with normal concrete.

  18. Ultrasonic measurements of undamaged concrete layer thickness in a deteriorated concrete structure

    NARCIS (Netherlands)

    Demcenko, A.; Visser, Roy; Akkerman, Remko

    2016-01-01

    Ultrasonic wave propagation in deteriorated concrete structures was studied numerically and experimentally. Ultrasonic single-side access immersion pulse-echo and diffuse field measurements were performed in deteriorated concrete structures at 0.5 MHz center frequency. Numerically and experimentally

  19. Porous Network Concrete : A bio-inspired building component to make concrete structures self-healing

    NARCIS (Netherlands)

    Sangadji, S.

    2015-01-01

    The high energy consumption, its corresponding emission of CO2 and financial losses due to premature failure are the pressing sustainability issues which must be tackled by the concrete infrastructure industry. Enhancement of concrete materials and durability of structures (designing new

  20. Use of fiber reinforced concrete for concrete pavement slab replacement : [summary].

    Science.gov (United States)

    2014-03-01

    Replacing cracked concrete in roadways requires : lanes to be closed and traff c disrupted. One way : to reduce road closure time is to reduce concrete : curing time. To accelerate curing time, pavement : engineers mix a very low water-cement ratio w...

  1. Preliminary laboratory investigation of thermally treated recycled concrete aggregate for general use in concrete

    NARCIS (Netherlands)

    Larbi, J.A.; Heijnen, W.M.M.; Brouwer, J.P.; Mulder, E.

    2000-01-01

    This paper deals with a preliminary laboratory study to assess the effectiveness of thermal treatment methods to improve the quality of recycled concrete aggregate. The samples used for the study consisted of sieved fractions of crushed concrete that were subjected to various thermal treatments at

  2. Concrete pavement mixture design and analysis (MDA) : effect of aggregate systems on concrete mixture properties.

    Science.gov (United States)

    2012-07-01

    For years, specifications have focused on the water to cement ratio (w/cm) and strength of concrete, despite the majority of the volume : of a concrete mixture consisting of aggregate. An aggregate distribution of roughly 60% coarse aggregate and 40%...

  3. Penetration analysis of projectile with inclined concrete target

    Directory of Open Access Journals (Sweden)

    Kim S.B.

    2015-01-01

    Full Text Available This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction and CONCRETE_DAMAGE (K&C concrete models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

  4. Bond characteristics of reinforcing steel embedded in geopolymer concrete

    Science.gov (United States)

    Kathirvel, Parthiban; Thangavelu, Manju; Gopalan, Rashmi; Raja Mohan Kaliyaperumal, Saravana

    2017-07-01

    The force transferring between reinforcing steel and the surrounding concrete in reinforced concrete is influenced by several factors. Whereas, the study on bond behaviour of geopolymer concrete (GPC) is lagging. In this paper, an experimental attempt has been made to evaluate the geopolymer concrete bond with reinforcing steel of different diameter and embedded length using standard pull out test. The geopolymer concrete is made of ground granulated blast furnace slag (GGBFS) as geopolymer source material (GSM). The tests were conducted to evaluate the development of bond between steel and concrete of grade M40 and M50 with 12 and 16 mm diameter reinforcing steel for geopolymer and cement concrete mixes and to develop a relation between bond strength and compressive strength. From the experimental results, it has been observed that the bond strength of the geopolymer concrete mixes was more compared to the cement concrete mixes and increases with the reduction in the diameter of the bar.

  5. Placement of mass concrete for cast-in-place concrete piling : the effects of heat of hydration of mass concrete for cast-in-place piles.

    Science.gov (United States)

    2008-12-01

    This report describes models, ABAQUS and Schmidt, to predict the peak temperature in the center of cast-in-place concrete piling. Five concrete piles with varying diameters and made up of concrete mixes with different percentage of fly ash are used. ...

  6. Abstract and concrete sentences, embodiment and languages

    Directory of Open Access Journals (Sweden)

    Claudia eScorolli

    2011-09-01

    Full Text Available One of the main challenges of embodied theories is accounting for meanings of abstract words. The most common explanation is that abstract words, like concrete ones, are grounded in perception and action systems. According to other explanations, abstract words, differently from concrete ones, would activate situations and introspection; alternatively, they would be represented through metaphoric mapping. However, evidence provided so far pertains to specific domains. To be able to account for abstract words in their variety we argue it is necessary to take into account not only the fact that language is grounded in the sensorimotor system, but also that language represents a linguistic-social experience. To study abstractness as a continuum we combined a concrete (C verb with both a concrete and an abstract (A noun; and an abstract verb with the same nouns previously used (grasp vs. describe a flower vs. a concept. To disambiguate between the semantic meaning and the grammatical class of the words, we focused on two syntactically different languages: German and Italian. Compatible combinations (CC, AA were processed faster than mixed ones (CA, AC. This is in line with the idea that abstract and concrete words are processed preferentially in parallel systems - abstract in the language system and concrete more in the motor system, thus costs of processing within one system are the lowest. This parallel processing takes place most probably within different anatomically predefined routes. With mixed combinations, when the concrete word preceded the abstract one (CA, participants were faster, regardless of the grammatical class and the spoken language. This is probably due to the peculiar mode of acquisition of abstract words, as they are acquired more linguistically than perceptually. Results confirm embodied theories which assign a crucial role to both perception-action and linguistic experience for abstract words.

  7. The carbonaceous concrete based on sawdust

    Directory of Open Access Journals (Sweden)

    BELOUSOVA Elena Sergeevna

    2015-06-01

    Full Text Available Today there are many requirements for strength, ecology and economy of produced concretes. The authors of the paper study attenuation of electromagnetic radiation of carbonaceous powders in the concrete composition. Carbon black was selected as a carbon powder for addition in concrete composition. Carbon black is a nanomaterial with disoriented structure of particles (average size is about 50 nm. The composition of the carbon black contains at least 90 wt.% amorphous carbon, more than 5 wt. % chemisorbed oxygen and about 4 wt.% of impurities. Materials with the addition of carbon black have electrical conductivity due to the high content of carbon. These materials are able to absorb electromagnetic radiation. For cement composition with addition of carbon black (more than 30 wt. % and water transmission coefficient of electromagnetic radiation is about –10 dB, for cement composition with 20 wt. % of carbon black the reflection coefficient is –8 dB in the frequency range 8–12 GHz. The concretes with a saturated aqueous solution of calcium chloride and 10% of carbon black possess minimal reflection coefficient (–14... –8 dB. Electromagnetic radiation shielding of concrete with the addition of sawdust was investigated. The concrete with sawdust (40 wt. % impregnated with an aqueous solution with carbon black has the reflection coefficient less than –8 dB and transmission coefficient –40 dB in the frequency range 8–12 GHz. These concretes can be used for creation of a shielded room with the technical equipment for information processing to prevent data leakage through the compromising emanations and crosstalk.

  8. Void structure of concrete with superabsorbent polymers and its relation to frost resistance of concrete

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede; Laustsen, Sara

    2013-01-01

    surfactant prior to concrete mixing. The method comprises rinsing of the SAP with ethanol. This effectively removes the surfactant. Freeze-thaw testing of concrete with rinsed and non-rinsed SAP shows that for equal dosages of SAP, the extra air entrained due to surfactant is considerable and can make......Superabsorbent polymers (SAP) can be used to control air void formation in concrete. However, due to surfactant left on suspension polymerized SAP particles during production, they may not only create SAP voids but also entrain extra air. In the present investigation, a method is tested to remove...... the difference between poor and satisfactory frost-resistance. Furthermore, the results indicate that voids created directly by SAP protect concrete against frost deterioration just like other air voids; if the concrete contains enough SAP voids, these alone can provide sufficient frost resistance. © 2013 RILEM....

  9. 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

  10. Self-compacting fine-grained concretes with compensated shrinkage

    Directory of Open Access Journals (Sweden)

    Alimov Lev

    2017-01-01

    Full Text Available This paper substantiates the efficiency of application of fine-grained concrete for erection of cast-in-place concrete and reinforced concrete structures of different purpose. On the basis of analysis of experimental research results it was established that the introduction of microfillers with expansion effect to composite binder allows not only improving the rheological properties of fine-grained concrete, but also decreasing of value of shrinkage strain and improving of concrete crack resistance and durability. The analysis of the results of industrial use of fine-grained concretes with compensated shrinkage is given.

  11. Numerical simulation of steel-concrete composite Virender beam

    Science.gov (United States)

    Wu, Qinggui; Cao, Xinming; Luo, Quanrui

    2017-08-01

    In this paper, a new type of steel-concrete composite Vierendeel beam is proposed. The finite element analysis of the new type of steel-concrete composite Vierendeel beam is carried out by using ABAQUS. To compare the mechanical properties with traditional beam, the normal reinforced concrete beam with the same section size is also analyzed by using ABAQUS. The simulation results show that the material strength of the new type steel-concrete composite Vierendeel beam is fully utilized, and the flexural capacity and deformation performance of the new type of steel-concrete composite Vierendeel beam are greatly improved compared with normal reinforced concrete beam.

  12. Review on supplymentary cementitious materials used in inorganic polymer concrete

    Science.gov (United States)

    Srinivasreddy, K.; Srinivasan, K.

    2017-11-01

    This paper presents a review on various supplementary cementitious materials generated from industries are used in concrete, which one is considered a waste material. These materials are rich in aluminosilicates and are activated by sodium/potassium based alkaline solution to form geopolymer concrete. When these geopolymer concrete is used in civil engineering applications has showed better or similar mechanical properties and durability properties than ordinary Portland cement concrete. This paper also given the overview on sodium hydroxide (NaOH) & sodium silicate solution (Na2SiO3) ratios, curing adopted for different geopolymer concretes and the effect of adding fibres in geopolymer concretes.

  13. Review on Potential of Geopolymer for Concrete Repair and Rehabilitation

    Directory of Open Access Journals (Sweden)

    Warid Wazien A.Z.

    2016-01-01

    Full Text Available Cracking, spalling, surface deterioration, seepage and other concrete damage of the existing infrastructure have raised concern among residents, local authorities and developers. Dealing with concrete infrastructure rehabilitation is an important issue due to most of infrastructures today are concrete based. To simply patch up the spalling concrete as temporary solution and sooner or later, the cracks will return to haunt. This paper reviewed the current research and studies on concrete repair materials, highlighting the properties of geopolymer. It covers geopolymer repair materials which addressed in the field of concrete infrastructure rehabilitation. Geopolymer had good repair characteristics and displays the potential as an excellent repair material.

  14. Nanomechanics and Multiscale Modeling of Sustainable Concretes

    Science.gov (United States)

    Zanjani Zadeh, Vahid

    The work presented in this dissertation is aimed to implement and further develop the recent advances in material characterization for porous and heterogeneous materials and apply these advances to sustainable concretes. The studied sustainable concretes were concrete containing fly ash and slag, Kenaf fiber reinforced concrete, and lightweight aggregate concrete. All these cement-based materials can be categorized as sustainable concrete, by achieving concrete with high strength while reducing cement consumption. The nanoindentation technique was used to infer the nanomechanical properties of the active hydration phases in bulk cement paste. Moreover, the interfacial transition zone (ITZ) of lightweight aggregate, normal aggregate, and Kenaf fibers were investigated using nanoindentation and imagine techniques, despite difficulties regarding characterizing this region. Samples were also tested after exposure to high temperature to evaluate the damage mechanics of sustainable concretes. It has been shown that there is a direct correlation between the nature of the nanoscale structure of a cement-based material with its macroscopic properties. This was addressed in two steps in this dissertation: (i) Nanoscale characterization of sustainable cementitious materials to understand the different role of fly ash, slag, lightweight aggregate, and Kenaf fibers on nanoscale (ii) Link the nanoscale mechanical properties to macroscale ones with multiscale modeling. The grid indentation technique originally developed for normal concrete was extended to sustainable concretes with more complex microstructure. The relation between morphology of cement paste materials and submicron mechanical properties, indentation modulus, hardness, and dissipated energy is explained in detail. Extensive experimental and analytical approaches were focused on description of the materials' heterogeneous microstructure as function of their composition and physical phenomenon. Quantitative

  15. Application of self compacting concrete for steel-concrete-steel sandwich structure; Hagane concrete full sandwich kozo eno koryudo concrete no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, M.; Kawamura, R. [Ministry of Transport, Tokyo (Japan); Yuguchi, Y.; Yamamoto, A.

    1998-04-01

    This construction refers to a construction to fabricate a submerged box constituting a submerged tunnel. Since the construction shape thereof is of a steel-concrete-steel sandwich structure (full-sandwich structure), it is indispensable to use self compacting concrete having excellent fillability and very little volumetric change after placement. Therefore, a test construction was performed before the actual construction to select correct mixing of self compacting concrete having good quality and conduct smooth construction. The test provided a very good result presenting no unfilled portions in the actual concrete construction. This paper reports the construction result thereof. This submerged box forms a part of the submerged tunnel linking the urban area of the Kobe city and an artificial island as one of the traffic networks in the port of Kobe. Its construction shape employs the full sandwich structure. The structure is such that sheet steels in place of reinforcing bars and unreinforced concrete filled inside a steel shell enclosed by sheared reinforcing sheet steels are integrated to resist external force. 1 ref., 9 figs., 4 tabs.

  16. Predicting the remaining service life of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, J.F.

    1991-11-01

    Nuclear power plants are providing, currently, about 17 percent of the U.S. electricity and many of these plants are approaching their licensed life of 40 years. The U.S. Nuclear Regulatory Commission and the Department of Energy`s Oak Ridge National Laboratory are carrying out a program to develop a methodology for assessing the remaining safe-life of the concrete components and structures in nuclear power plants. This program has the overall objective of identifying potential structural safety issues, as well as acceptance criteria, for use in evaluations of nuclear power plants for continued service. The National Institute of Standards and Technology (NIST) is contributing to this program by identifying and analyzing methods for predicting the remaining life of in-service concrete materials. This report examines the basis for predicting the remaining service lives of concrete materials of nuclear power facilities. Methods for predicting the service life of new and in-service concrete materials are analyzed. These methods include (1) estimates based on experience, (2) comparison of performance, (3) accelerated testing, (4) stochastic methods, and (5) mathematical modeling. New approaches for predicting the remaining service lives of concrete materials are proposed and recommendations for their further development given. Degradation processes are discussed based on considerations of their mechanisms, likelihood of occurrence, manifestations, and detection. They include corrosion, sulfate attack, alkali-aggregate reactions, frost attack, leaching, radiation, salt crystallization, and microbiological attack.

  17. Enhanced radiation shielding with galena concrete

    Directory of Open Access Journals (Sweden)

    Hadad Kamal

    2015-01-01

    Full Text Available A new concrete, containing galena mineral, with enhanced shielding properties for gamma sources is developed. To achieve optimized shielding properties, ten types of galena concrete containing different mixing ratios and a reference normal concrete of 2300 kg/m3 density are studied experimentally and numerically using Monte Carlo and XCOM codes. For building galena concrete, in addition to the main composition, micro-silica and water, galena mineral (containing lead were used. The built samples have high density of 4470 kg/m3 to 5623 kg/m3 and compressive strength of 628 kg/m2 to 685 kg/m2. The half and tenth value layers (half value layer and tenth value layers for the galena concrete, when irradiated with 137Cs gamma source, were found to be 1.45 cm and 4.94 cm, respectively. When irradiated with 60Co gamma source, half value layer was measured to be 2.42 cm. The computation modeling by FLUKA and XCOM shows a good agreement between experimental and computational results.

  18. Initial rheological description of high performance concretes

    Directory of Open Access Journals (Sweden)

    Alessandra Lorenzetti de Castro

    2006-12-01

    Full Text Available Concrete is defined as a composite material and, in rheological terms, it can be understood as a concentrated suspension of solid particles (aggregates in a viscous liquid (cement paste. On a macroscopic scale, concrete flows as a liquid. It is known that the rheological behavior of the concrete is close to that of a Bingham fluid and two rheological parameters regarding its description are needed: yield stress and plastic viscosity. The aim of this paper is to present the initial rheological description of high performance concretes using the modified slump test. According to the results, an increase of yield stress was observed over time, while a slight variation in plastic viscosity was noticed. The incorporation of silica fume showed changes in the rheological properties of fresh concrete. The behavior of these materials also varied with the mixing procedure employed in their production. The addition of superplasticizer meant that there was a large reduction in the mixture's yield stress, while plastic viscosity remained practically constant.

  19. FLEXURAL TOUGHNESS OF STEEL FIBER REINFORCED CONCRETE

    Directory of Open Access Journals (Sweden)

    Fehmi ÇİVİCİ

    2006-02-01

    Full Text Available Fiber concrete is a composite material which has mechanical and physical characteristics unlike plain concrete. One of the important mechanical characteristics of fiber concrete is its energy absorbing capability. This characteristics which is also called toughness, is defined as the total area under the load-deflection curve. A number of composite characteristics such as crack resistance, ductility and impact resistance are related to the energy absorbtion capacity. According to ASTM C 1018 and JSCE SF-4 the calculation of toughness is determined by uniaxial flexural testing. Fiber concrete is often used in plates such as bridge decks, airport pavements, parking areas, subjected to cavitation and erosion. In this paper, toughness has been determined according to ASTM C 1018 and JSCE SF-4 methods by testing beam specimens. Energy absorbing capacities of plain and steel fiber reinforced concrete has been compared by evaluating the results of two methods. Also plain and steel fiber reinforced plate specimens behaviors subjected to biaxial flexure are compared by the loaddeflection curves of each specimen.

  20. Feasibility study of a concrete plug made of low pH concrete

    Energy Technology Data Exchange (ETDEWEB)

    Dahlstroem, Lars-Olof; Magnusson, Jonas (NCC Engineering (Sweden)); Gueorguiev, Ginko; Johansson, Morgan (Reinertsen Sverige AB, Goeteborg (Sweden))

    2009-09-15

    In this report a concrete plug, used as a barrier between the deposition tunnels and the access tunnel, is investigated. The objectives of the work is to see whether it is possible to use low pH concrete for the plug and whether it can be designed without using reinforcement. The requirements set on the plug are that the water leakage through it should be small enough and that the concrete stresses are limited to a value valid for the concrete used. A modified geometry of the plug is proposed, which makes it possible to use it as a general solution in all deposition tunnels. Material properties of a low pH concrete (B200) determined by CBI have been used. Loads considered in the study is the pressure from water and swelling, the temperature change in the rock and plug due to heat development from nuclear fuel stored in nearby copper canisters, pre-stressing in the plug due to cooling during construction and the shrinkage of concrete in the plug. Two-dimensional, axis-symmetric finite element analyses, assuming linear elastic material behaviour in rock and concrete where contact friction between concrete and rock is taken into consideration, have been used to study the structural response of the plug. A total of 48 main load combinations, consisting of 8 different load scenarios and 6 material combinations, have been used. It is found that the concrete plug will not remain uncracked when subjected to the loads studied but that it, nevertheless, is possible to achieve an unreinforced concrete plug that satisfies the requirements set up. The minimum size of the concrete compressed zone will be 0.5 m, resulting in a water leakage through the plug determined to be lower than the requirement of 0.01 l/min set up in this study. Further, the maximum compressive stresses of interest are 33 MPa and the maximum displacement in the plug is about 3 mm, which are deemed to be satisfactorily. Consequently, it is concluded that it seems possible to use low pH concrete for the plug

  1. Online Monitoring of Concrete Structures in Nuclear Power Plants: Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    The existing fleet of nuclear power plants in the United States have initial operating licenses of 40 years, and many of these plants have applied for and received license extensions. As plant structures, systems, and components age, their useful life—considering both structural integrity and performance—is reduced as a result of deterioration of the materials. Assessment and management of aging concrete structures in nuclear plants require a more systematic approach than simple reliance on existing code-based design margins of safety. Structural health monitoring is required to produce actionable information regarding structural integrity that supports operational and maintenance decisions. The online monitoring of concrete structures project conducted under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability program at Idaho National Laboratory is seeking to develop and demonstrate capabilities for concrete structures health monitoring. Through this research project, several national laboratories and Vanderbilt University propose to develop a framework of research activities for the health monitoring of nuclear power plant concrete structures that includes the integration of four elements—damage modeling, monitoring, data analytics, and uncertainty quantification. This report briefly discusses activities in this project during October-December, 2014. The most significant activity during this period was the organizing of a two-day workshop on research needs in online monitoring of concrete structures, hosted by Vanderbilt University in November 2014. Thirty invitees from academia, industry and government participated in the workshop. The presentations and discussions at the workshop surveyed current activities related to concrete structures deterioration modeling and monitoring, and identified the challenges, knowledge gaps, and opportunities for advancing the state of the art; these

  2. Electrical and mechanical properties of asphalt concrete containing conductive fibers and fillers

    NARCIS (Netherlands)

    Wang, H.; Yang, Jun; Liao, Hui; Chen, Xianhua

    2016-01-01

    Electrically conductive asphalt concrete has the potential to satisfy multifunctional applications. Designing such asphalt concrete needs to balance the electrical and mechanical performance of asphalt concrete. The objective of this study is to design electrically conductive asphalt concrete

  3. Ultra-high performance concrete for Michigan bridges, material performance : phase I.

    Science.gov (United States)

    2008-10-13

    One of the latest advancements in concrete technology is Ultra-High Performance Concrete (UHPC). UHPC is : defined as concretes attaining compressive strengths exceeding 25 ksi (175 MPa). It is a fiber-reinforced, denselypacked : concrete material wh...

  4. Report E : self-consolidating concrete (SCC) for infrastructure elements - hardened mechanical properties and durability performance.

    Science.gov (United States)

    2012-08-01

    Concrete is one of the most produced and utilized materials in the world. Due to : the labor intensive and time consuming nature of concrete construction, new and : innovative concrete mixes are being explored. Self-consolidating concrete (SCC) is on...

  5. Report of concrete pavement evaluation : project 105 C-4181-01 Donahoo Road, Wyandotte County.

    Science.gov (United States)

    2013-12-01

    The physical properties of hardened concrete cores and fresh concrete test results were compared with aggregate : gradation workability differences. The concrete cores were taken from a rural two-lane concrete road in northeastern Kansas : constructe...

  6. Nuclear Concrete Materials Database Phase I Development

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Naus, Dan J [ORNL

    2012-05-01

    The FY 2011 accomplishments in Phase I development of the Nuclear Concrete Materials Database to support the Light Water Reactor Sustainability Program are summarized. The database has been developed using the ORNL materials database infrastructure established for the Gen IV Materials Handbook to achieve cost reduction and development efficiency. In this Phase I development, the database has been successfully designed and constructed to manage documents in the Portable Document Format generated from the Structural Materials Handbook that contains nuclear concrete materials data and related information. The completion of the Phase I database has established a solid foundation for Phase II development, in which a digital database will be designed and constructed to manage nuclear concrete materials data in various digitized formats to facilitate electronic and mathematical processing for analysis, modeling, and design applications.

  7. Compressive strength models of repaired concrete structures

    Science.gov (United States)

    Apandi, Nazirah Mohd; Ma, Chau-Khun; Awang, Abdullah Zawawi; Omar, Wahid

    2017-11-01

    Application of confinement as repairing technique can improve the strength and ductility of concrete significantly. This paper compares the existing models of repaired concrete, and describes the differences between these models. Over recent years, a great number of studies have been done to develop the models to define the stress-strain behaviour of repaired structures. The considered variables are the cross-sectional area, types of confinement, types of materials used and type of the strength models. Subsequently, the limitations were discussed and significant conclusions on the strength and weakness of each existing models were highlighted. This paper presented the state of the art design strength models available for repaired concrete structures and indicated a direction for future development.

  8. Concrete decontamination by electro-hydraulic scabbling

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, V.; Gannon, R. [Textron Defense System, Everett, MA (United States)

    1995-10-01

    Textron Defense Systems (TDS) is developing an electro-hydraulic device that has the potential for faster, safer, and less expensive scabbling of contaminated concrete surfaces. In the device, shock waves and cavitating bubbles are produced in water by the electric pulses, and the direct and reflected shock waves impinging on the concrete surface result in the crushing and cracking of the concrete. Pulse energy, frequency, and traverse speed control the depth of the scabbling action. Performance thus far has demonstrated the capability of a prototype unit to process a swath 24 inches wide, up to 3/4 inch deep at a linear velocity of up to 6 feet per hour, i.e., at a scabbling rate of 12 sq. ft. per hour.

  9. CT measurements of SAP voids in concrete

    DEFF Research Database (Denmark)

    Laustsen, Sara; Bentz, Dale P.; Hasholt, Marianne Tange

    2010-01-01

    X-ray computed tomography (CT) scanning is used to determine the SAP void distribution in hardened concrete. Three different approaches are used to analyse a binary data set created from CT measurement. One approach classifies a cluster of connected, empty voxels (volumetric pixel of a 3D image......) as one void, whereas the other two approaches are able to classify a cluster of connected, empty voxels as a number of individual voids. Superabsorbent polymers (SAP) have been used to incorporate air into concrete. An advantage of using SAP is that it enables control of the amount and size...... to calculate the liquid absorption of the SAP within the fresh concrete. This estimated liquid absorption is in reasonable agreement with previous studies....

  10. Nonlinear fracture of concrete and ceramics

    Science.gov (United States)

    Kobayashi, Albert S.; Du, Jia-Ji; Hawkins, Niel M.; Bradt, Richard C.

    1989-01-01

    The nonlinear fracture process zones in an impacted unnotched concrete bend specimen, a prenotched ceramic bend specimen, and an unnotched ceramic/ceramic composite bend specimen were estimated through hybrid experimental numerical analysis. Aggregate bridging in concrete, particulate bridging in ceramics, and fiber bridging in ceramic/ceramic composite are modeled by Barenblatt-type cohesive zones which are incorporated into the finite-element models of the bend specimens. Both generation and propagation analyses are used to estimate the distribution of crack closure stresses in the nonlinear fracture process zones. The finite-element models are then used to simulate fracture tests consisting of rapid crack propagation in an impacted concrete bend specimen, and stable crack growth and strain softening in a ceramic and ceramic/ceramic composite bend specimens.

  11. Concretes with red mud coarse aggregates

    Directory of Open Access Journals (Sweden)

    Dênio Ramam Carvalho de Oliveira

    2012-06-01

    Full Text Available Red mud (RM is a mineral waste, residue of the Bayer process used to obtain alumina from bauxite. While the exploration of rolled pebble damages the environment and is much more controlled by the government, the huge RM disposal areas do not stop increasing and polluting soil, rivers and groundwater sources in Amazon. In this work, the material mixtures used to produce coarse aggregates presented up to 80% of RM, 30% of metakaolin and 30% of active silica as recycled waste. Several tests were carried out to determine the aggregates physical properties and to evaluate the mechanical performance of the concretes with the new aggregates, including hydraulic abrasion strength, and the results were compared to the reference ones, i.e. rolled pebble concretes. Additionally, the sintering process neutralizes any toxic substance as occur in some RM products like tiles and bricks, and these results have encouraged an industrial or semi-industrial production of RM aggregates for concretes.

  12. Concentration profiles of tritium penetrated into concrete

    Energy Technology Data Exchange (ETDEWEB)

    Takata, H.; Furuichi, K.; Nishikawa, M.; Fukada, S.; Katayama, K.; Takeishi, T. [Interdisciplinary Graduate School of Engineering Science, Kyushu Univ., Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Kobayashi, K.; Hayashi, T. [Japan Atomic Energy Agency, Tokai-mura 319-11, Ibaraki 319-1195 (Japan); Namba, H. [Shimizu Corporation, No.2-3, Shibaural-chome, Minato-ku, Tokyo 105-8007 (Japan)

    2008-07-15

    Concentration profiles of tritium in cement paste, mortar and concrete were measured after exposure to tritiated water vapor for a given time. Tritium penetrated a distance of about 5 cm from the exposed surface during an exposure of 6 months. The model of tritium behavior in concrete materials reported by the present authors was developed in this study with the consideration of the effects of sand and aggregate on both the diffusion coefficient of tritiated water vapor and the isotope exchange capacity. Predictive calculations based on the tritium transport model were also carried out in some situations of tritium leakage. The results of the calculations show that a large amount of tritium will be trapped in the concrete walls, and the trapped tritium will be gradually released back to the tritium handling room over the time of months to years even after the decontamination of the room is completed. (authors)

  13. Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers

    Directory of Open Access Journals (Sweden)

    Francisco Cartuxo

    2016-02-01

    Full Text Available This paper evaluates the influence of two superplasticizers (SP on the durability properties of concrete made with fine recycled concrete aggregate (FRCA. For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All mixes had the same particle size distribution, cement content and amount of superplasticizer. The w/c ratio was calibrated to obtain similar slump. The results showed that the incorporation of FRCA increased the water absorption by immersion, the water absorption by capillary action, the carbonation depth and the chloride migration coefficient, while the use of superplasticizers highly improved these properties. The incorporation of FRCA jeopardized the SP’s effectiveness. This research demonstrated that, from a durability point of view, the simultaneous incorporation of FRCA and high-performance SP is a viable sustainable solution for structural concrete production.

  14. Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers.

    Science.gov (United States)

    Cartuxo, Francisco; de Brito, Jorge; Evangelista, Luis; Jiménez, José Ramón; Ledesma, Enrique F

    2016-02-08

    This paper evaluates the influence of two superplasticizers (SP) on the durability properties of concrete made with fine recycled concrete aggregate (FRCA). For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All mixes had the same particle size distribution, cement content and amount of superplasticizer. The w/c ratio was calibrated to obtain similar slump. The results showed that the incorporation of FRCA increased the water absorption by immersion, the water absorption by capillary action, the carbonation depth and the chloride migration coefficient, while the use of superplasticizers highly improved these properties. The incorporation of FRCA jeopardized the SP's effectiveness. This research demonstrated that, from a durability point of view, the simultaneous incorporation of FRCA and high-performance SP is a viable sustainable solution for structural concrete production.

  15. Bond characteristics of reinforced TMT bars in Self Compacting Concrete and Normal Cement Concrete

    Directory of Open Access Journals (Sweden)

    Nipun Verma

    2015-12-01

    Full Text Available In its simplest form, it can be said that the resistance to separation of mortar and concrete from reinforcing steel (or other materials with which it is in contact is called bond strength. These days different kinds of concrete are manufactured, all with different properties. But bond strength is something which is essentially a well sort after quality for any RCC structure or element. Bond strength can be easily found out by standard pull-out test machine. But in this work, the bond strength was measured using Universal testing machine (UTM with some modified arrangements. The bond between the concrete and steel reinforcement was investigated for two different kinds of concretes. Using reinforcing bars bond strengths were measured using Self Compacting Concrete (SCC specimen and Normal Cement Concrete (NCC specimen. Castings of SCC specimens were carried out without compaction, while the normal concrete specimens were casted with substantial compaction and vibration. The study revealed that SCC specimens generated higher bond to reinforcing bars in comparison with NCC specimens. Secondly, the correlation between bond strength and compressive strength of NCC is more consistent. Thirdly, the results obtained with UTM were compared with the results obtained with standard pull-out test machine and they were found in permissible limits.

  16. Reinforced concrete bridges: effects due to corrosion and concrete young modulus variation

    Directory of Open Access Journals (Sweden)

    P. T. C. Mendes

    Full Text Available Most of the Brazilian bridges of federal road network are made of reinforced concrete and are more than 30 years old, with little information about the mechanical properties of their constitutive materials. Along the service life of these bridges much modification occurred on vehicles load and geometry and in design standard. Many of them show signs of concrete and steel deterioration and their stability conditions are unknown. With the aim of contributing to the structural evaluation of reinforced concrete bridges it was decided to analyze the stresses in reinforced concrete bridge sections to verify the effects due to reinforcement corrosion and variation of the concrete Young modulus on the stress distribution regarding several load patterns and cracking effects in a representative bridge of the Brazilian road network with different longitudinal reinforcement taxes and two concrete Young modulus, Ec and 0.5Ec, and with different percentage of reinforcement corrosion. The analysis considered two finite element models: frame and shell elements as well as solid elements. The results indicate that these variation effects are more significant in reinforcement bars than in concrete.

  17. TRANSPORT THROUGH CRACKED CONCRETE: LITERATURE REVIEW

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.

    2012-05-11

    Concrete containment structures and cement-based fills and waste forms are used at the Savannah River Site to enhance the performance of shallow land disposal systems designed for containment of low-level radioactive waste. Understanding and measuring transport through cracked concrete is important for describing the initial condition of radioactive waste containment structures at the Savannah River Site (SRS) and for predicting performance of these structures over time. This report transmits the results of a literature review on transport through cracked concrete which was performed by Professor Jason Weiss, Purdue University per SRR0000678 (RFP-RQ00001029-WY). This review complements the NRC-sponsored literature review and assessment of factors relevant to performance of grouted systems for radioactive waste disposal. This review was performed by The Center for Nuclear Waste Regulatory Analyses, San Antonio, TX, and The University of Aberdeen, Aberdeen Scotland and was focused on tank closure. The objective of the literature review on transport through cracked concrete was to identify information in the open literature which can be applied to SRS transport models for cementitious containment structures, fills, and waste forms. In addition, the literature review was intended to: (1) Provide a framework for describing and classifying cracks in containment structures and cementitious materials used in radioactive waste disposal, (2) Document the state of knowledge and research related to transport through cracks in concrete for various exposure conditions, (3) Provide information or methodology for answering several specific questions related to cracking and transport in concrete, and (4) Provide information that can be used to design experiments on transport through cracked samples and actual structures.

  18. Gas and Water Permeability of Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M. V.; Martin, P. L.; Romero, F. J.; Gutierrez-Rodirgo, V.; Barcala, J. M.

    2012-11-01

    The gas pressure of concrete samples was measured in an unsteady-state equipment working under low injection pressures and in a newly fine tuned steady-state setup working under different pressures. These measurements allowed the estimation of the intrinsic and relative gas permeability of the concrete and of the effect of boundary conditions on them. Permeability decreased with water content, but it was also greatly affected by the hydraulic history of concrete, i.e. if it had been previously dried or wetted. In particular, and for a given degree of saturation, the gas permeability of concrete previously saturated was lower than if the concrete had been just air dried or saturated after air drying. In any case, the gas permeability was about two orders of magnitude higher than the liquid water permeability (10-16 vs. 10-18 m2), probably due to the chemical reactions taking place during saturation (carbonation). The relative gas permeability of concrete increased sharply for water degrees of saturation smaller than 50%. The boundary conditions also affected the gas permeability, which seemed to be mostly conditioned by the back pressure and the confining pressure, increasing as the former increased and decreasing as the latter increased, i.e. decreasing as the effective pressure increased. Overall the increase of pressure head or injection pressure implied a decrease in gas permeability. External,microcracking during air-drying could not be ruled out as responsible for the decrease of permeability with confining pressure. The apparent permeability obtained applying the Klinkenberg method for a given effective pressure was only slightly smaller than the average of all the values measured for the same confining pressure range. For this reason it is considered that the Klinkenberg effect was not relevant in the range of pressures applied. (Author) 37 refs.

  19. Evaluation of concrete recycling system efficiency for ready-mix concrete plants.

    Science.gov (United States)

    Vieira, Luiz de Brito Prado; Figueiredo, Antonio Domingues de

    2016-10-01

    The volume of waste generated annually in concrete plants is quite large and has important environmental and economic consequences. The use of fresh concrete recyclers is an interesting way for the reuse of aggregates and water in new concrete production. This paper presents a study carried out for over one year by one of the largest ready-mix concrete producers in Brazil. This study focused on the evaluation of two recyclers with distinct material separation systems, herein referred to as drum-type and rotary sieve-type equipment. They were evaluated through characterization and monitoring test programs to verify the behaviour of recovered materials (aggregates, water, and slurry). The applicability of the recovered materials (water and aggregates) was also evaluated in the laboratory and at an industrial scale. The results obtained with the two types of recyclers used were equivalent and showed no significant differences. The only exception was in terms of workability. The drum-type recycler generated fewer cases that required increased pumping pressure. The analysis concluded that the use of untreated slurry is unfeasible because of its intense negative effects on the strength and workability of concrete. The reclaimed water, pre-treated to ensure that its density is less than 1.03g/cm(3), can be used on an industrial scale without causing any harm to the concrete. The use of recovered aggregates consequently induces an increase in water demand and cement consumption to ensure the workability conditions of concrete that is proportional to the concrete strength level. Therefore, the viability of their use is restricted to concretes with characteristic strengths lower than 25MPa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Advanced Numerical Model for Irradiated Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Giorla, Alain B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-03-01

    In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or back-calculated from mechanical tests on concrete. If some

  1. Analyses of Concrete Structures Exposed to Fire

    DEFF Research Database (Denmark)

    Hertz, Kristian

    The text book contains the data and methods necessary for fire safety design of concrete constructions. The methods relate to standard fire as well as to any time of any other fire course.Material data are presented for concretes exposed to fire, and calculation methods are given for the ultimate...... bending capacity of beams and slabs, the ultimate shear capacity of beams, for the instability of columns and walls and for the deflection of prestressed and non-prestressed beams, slabs, walls and columns.All methods have been derived and compared to tests by Kristian Hertz....

  2. Smart and multifunctional concrete toward sustainable infrastructures

    CERN Document Server

    Han, Baoguo; Ou, Jinping

    2017-01-01

    This book presents the latest research advances and findings in the field of smart/multifunctional concretes, focusing on the principles, design and fabrication, test and characterization, performance and mechanism, and their applications in infrastructures. It also discusses future challenges in the development and application of smart/multifunctional concretes, providing useful theory, ideas and principles, as well as insights and practical guidance for developing sustainable infrastructures. It is a valuable resource for researchers, scientists and engineers in the field of civil-engineering materials and infrastructures.

  3. Method for Bubbledeck Concrete Slab with Gaps

    OpenAIRE

    Sergiu Călin; Ciprian Asăvoaie

    2009-01-01

    The composite slabs are made of BubbleDeck type slab elements with spherical gaps, poured in place on transversal and longitudinal directions. By introducing the gaps leads to a 30...50\\% lighter slab which reduces the loads on the columns, walls and foundations, and of course of the entire building. BubbleDeck slab elements are plates with ribs on two directions made of reinforced concrete or precast concrete with spherical shaped bubbles. These slab elements have a bottom and an upper concr...

  4. Fine-Grained Concrete of Composite Binder

    Science.gov (United States)

    Fediuk, R.; Pak, A.; Kuzmin, D.

    2017-11-01

    The article is devoted to the application of industrial wastes for the production of high-quality concretes with specified characteristics. The composite binders with low water demand (BLW) have been developed. Their strength is approximately twice the strength of the initial cement, and dilute BLW with 50 - 70% of the ground slag or quartz sand in their composition provide the same strength as the original Portland cement. It was proved that the quartzite sand screening can be used as a filler in the preparation of fine-grained concretes.

  5. Evaluation of Concrete Cores Caruthersville Floodwall.

    Science.gov (United States)

    1983-09-01

    tended to be light gray (N7) to medium gray (N6). 10 23. In the new concrete, cracking normal to the formed concrete surface was minor. Usually, this...t S., ..~II j ~ , I s k* . - . .1~. * . *. . sii -~ * 4., ~ ~~ 4 * ~.9~ 9 I A W.#e~r fv . D Moor MAtdr& .Wi# Ř /9~ 4 YPd i4 Ot c...Some small pieces of coal 0 Siliceous natural sand 0. 2.0 0 Finished surface (river side) Paste was medium gray (N6) to light gray (N7). 3.0 PLATE 12 MEM

  6. Concrete Cutting Refinement for Crater Repair

    Science.gov (United States)

    2015-08-01

    ER D C/ G SL T R- 15 -2 9 Concrete Cutting Refinement for Crater Repair G eo te ch ni ca l a nd S tr uc tu re s La bo ra to ry...by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default. ERDC/GSL TR-15-29 August 2015 Concrete Cutting Refinement...conducted at the U.S. Army Engineer Research and Development Center in Vicksburg, MS, to evaluate saw- cutting equipment for use by crater repair

  7. Spalling of concrete subjected to blast loading

    Directory of Open Access Journals (Sweden)

    Foglar M.

    2013-09-01

    Full Text Available This paper presents outcomes of the blast field tests of FRC and reinforced concrete specimens, which were performed in cooperation with the Czech Army corps and Police of the Czech Republic in the military training area Boletice. The numerical evaluation of the experiments focused on the spalling of concrete subjected to blast loading started after the first set of the tests, took almost 3 years and required further small-scale experiments performed in the labs of the Czech Technical University.

  8. Ultra thin continuously reinforced concrete pavement research in south Africa

    CSIR Research Space (South Africa)

    Perrie, BD

    2007-08-01

    Full Text Available Ultra thin continuously reinforced concrete pavements (UTCRCP), in literature also referred to as Ultra Thin Reinforced High Performance Concrete (UTHRHPC), have been used in Europe successfully as a rehabilitation measure on steel bridge decks...

  9. Simplified equation for Young's modulus of CNT reinforced concrete

    Science.gov (United States)

    Chandran, RameshBabu; Gifty Honeyta A, Maria

    2017-12-01

    This research investigation focuses on finite element modeling of carbon nanotube (CNT) reinforced concrete matrix for three grades of concrete namely M40, M60 and M120. Representative volume element (RVE) was adopted and one-eighth model depicting the CNT reinforced concrete matrix was simulated using FEA software ANSYS17.2. Adopting random orientation of CNTs, with nine fibre volume fractions from 0.1% to 0.9%, finite element modeling simulations replicated exactly the CNT reinforced concrete matrix. Upon evaluations of the model, the longitudinal and transverse Young's modulus of elasticity of the CNT reinforced concrete was arrived. The graphical plots between various fibre volume fractions and the concrete grade revealed simplified equation for estimating the young's modulus. It also exploited the fact that the concrete grade does not have significant impact in CNT reinforced concrete matrix.

  10. Sustainability and durability analysis of reinforced concrete structures

    Science.gov (United States)

    Horáková, A.; Broukalová, I.; Kohoutková, A.; Vašková, J.

    2017-09-01

    The article describes an assessment of reinforced concrete structures in terms of durability and sustainable development. There is a short summary of findings from the literature on evaluation methods for environmental impacts and also about corrosive influences acting on the reinforced concrete structure, about factors influencing the durability of these structures and mathematical models describing the corrosion impacts. Variant design of reinforced concrete structure and assessment of these variants in terms of durability and sustainability was performed. The analysed structure was a concrete ceiling structure of a parking house for cars. The variants differ in strength class of concrete and thickness of concrete slab. It was found that in terms of durability and sustainable development it is significantly preferable to use higher class of concrete. There are significant differences in results of concrete structures durability for different mathematical models of corrosive influences.

  11. Development of an embeddable reference electrode for reinforced concrete structures.

    Science.gov (United States)

    1998-01-01

    There is a concern that none of the existing concrete-embeddable reference electrodes that are being used as a convenient means for monitoring the condition of the reinforcing steel in concrete bridges or the operation of cathodic protection systems ...

  12. Effect of Soorh Metakaolin on Concrete Compressive Strength and Durability

    Directory of Open Access Journals (Sweden)

    A. Saand

    2017-12-01

    Full Text Available Concrete durability is a key aspect for forecasting the expected life time of concrete structures. In this paper, the effect of compressive strength and durability of concrete containing metakaolin developed from a local natural material (Soorh of Thatta Distict of Sindh, Pakistan is investigated. Soorh is calcined by an electric furnace at 8000C for 2 hours to produce metakaolin. One mix of ordinary concrete and five mixes of metakaolin concrete were prepared, where cement is replaced by developed metakaolin from 5% to 25% by weight, with 5% increment step. The concrete durability was tested for water penetration, carbonation depth and corrosion resistance. The obtained outcomes demonstrated that, 15% replacement level of local developed metakaolin presents considerable improvements in concrete properties. Moreover, a considerable linear relationship was established between compressive strength and concrete durability indicators like water penetration, carbonation depth and corrosion resistance.

  13. Durability performance of submerged concrete structures - phase 2 : [summary].

    Science.gov (United States)

    2015-10-01

    Thousands of Florida bridges have steel-reinforced concrete piling foundations standing : in salt water. Over time, chloride ions in the water can migrate through the concrete to : attack the steel inside. The Florida Department of Transportation (FD...

  14. Fracture in high performance fibre reinforced concrete pavement materials

    CSIR Research Space (South Africa)

    Denneman, E

    2011-05-01

    Full Text Available high performance fibre reinforced concrete pavement slab with a nominal thickness of approximately 50 mm. The material has a significant post crack stress capacity compared to plain concrete. Current design methods for UTCRCP are based on conventional...

  15. High Performance Concrete (HPC) bridge project for SR 43.

    Science.gov (United States)

    2012-10-01

    The objective of this research was to develop and test high performance concrete mixtures, made of locally available materials, having : durability characteristics that far exceed those of conventional concrete mixtures. Based on the results from the...

  16. Computerised analysis of sulphate action on model concrete piles

    Digital Repository Service at National Institute of Oceanography (India)

    Deshmukh, A.M.; Balasubramanian, S.; Venugopal, C.

    the influence of magnesium sulphate on model reinforced concrete piles. The sulphate action on the corrosion rate of rebar in concrete has been distinctly studied through sophisticated computerised potentiodynamic technique. The corrosion of rebar has been...

  17. Testing guide for implementing concrete paving quality control procedures.

    Science.gov (United States)

    2008-03-01

    Construction of portland cement concrete pavements is a complex process. A small fraction of the concrete pavements constructed in the : United States over the last few decades have either failed prematurely or exhibited moderate to severe distress. ...

  18. Impact of aggregate gradation on properties of portland cement concrete.

    Science.gov (United States)

    2013-10-01

    Increasingly, aggregates in South Carolina are failing to meet the standard requirements for gradation for use in portland cement concrete. The effect of such failed aggregate gradations on concrete properties and the consequent effect on short- and ...

  19. Waste polyethylene terephthalate as an aggregate in concrete

    Directory of Open Access Journals (Sweden)

    Nabajyoti Saikia

    2013-04-01

    Full Text Available This paper reports the strength behaviour of concrete containing three types of recycled polyethylene terephthalate (PET aggregate. Results are also analysed to determine the PET-aggregate's effect on the relationship between the flexural and splitting tensile strengths and compressive strength and to know whether the relationships between compressive strength and other strength characteristics given in European design codes are applicable to concrete made with PET-aggregates. The compressive strength development of concrete containing all types of PET-aggregate behaves like in conventional concrete, though the incorporation of any type of PET-aggregate significantly lowers the compressive strength of the resulting concrete. The PET-aggregate incorporation improves the toughness behaviour of the resulting concrete. This behaviour is dependent on PET-aggregate's shape and is maximised for concrete containing coarse, flaky PET-aggregate. The splitting tensile and flexural strength characteristics are proportional to the loss in compressive strength of concrete containing plastic aggregates.

  20. A corrosion monitoring system for existing reinforced concrete structures.

    Science.gov (United States)

    2015-05-01

    This study evaluated a multi-parameter corrosion monitoring system for existing reinforced concrete structures in chloride-laden service environments. The system was fabricated based on a prototype concrete corrosion measurement system that : had bee...