Fracture Failure of Reinforced Concrete Slabs Subjected to Blast Loading Using the Combined Finite-Discrete Element Method

Directory of Open Access Journals (Sweden)

Z. M. Jaini

Full Text Available Abstract Numerical modeling of fracture failure is challenging due to various issues in the constitutive law and the transition of continuum to discrete bodies. Therefore, this study presents the application of the combined finite-discrete element method to investigate the fracture failure of reinforced concrete slabs subjected to blast loading. In numerical modeling, the interaction of non-uniform blast loading on the concrete slab was modeled using the incorporation of the finite element method with a crack rotating approach and the discrete element method to model crack, fracture onset and its post-failures. A time varying pressure-time history based on the mapping method was adopted to define blast loading. The Mohr-Coulomb with Rankine cut-off and von-Mises criteria were applied for concrete and steel reinforcement respectively. The results of scabbing, spalling and fracture show a reliable prediction of damage and fracture.

Towards Early Age Characterisation of Eco-Concrete Containing Blast-Furnace Slag and Limestone Filler

OpenAIRE

Carette, Jerome

2015-01-01

It is estimated that concrete represents 5% of the anthropogenic CO2 emissions, mainly originating from the production of cement, the most essential component of concrete. The recent awareness to the environmental challenges facing our civilization has led the cement industry to consider substituting cement by mineral additions, by-products of existing industries. In this work, a combination of limestone filler and blast furnace slag is used to design an “eco-concrete”, defined as a concrete ...

Modeling of Combined Impact and Blast Loading on Reinforced Concrete Slabs

Directory of Open Access Journals (Sweden)

P. Del Linz

Full Text Available Abstract Explosive devices represent a significant threat to military and civilian structures. Specific design procedures have to be followed to account for this and ensure buildings will have the capacity to resist the imposed pressures. Shrapnel can also be produced during explosions and the resulting impacts can weaken the structure, reducing its capacity to resist the blast pressure wave and potentially causing failures to occur. Experiments were performed by the Defence Science and Technology Agency (DSTA of Singapore to study this combined loading phenomenon. Slabs were placed on the ground and loaded with approximately 9 kg TNT charges at a standoff distance of 2.1 m. Spherical steel ball bearings were used to reproduce the shrapnel loading. Loading and damage characteristics were recorded from the experiments. A finite element analysis (FEA model was then created which could simulate the effect of combined shrapnel impacts and blast pressure waves in reinforced concrete slabs, so that its results could be compared to experimental data from the blast tests. Quarter models of the experimental concrete slabs were built using LS-Dyna. Material models available in the software were employed to represent all the main components, taking into account projectile deformations. The penetration depth and damage areas measured were then compared to the experimental data and an analytical solution to validate the models.

Greener durable concretes through geopolymerisation of blast furnace slag

International Nuclear Information System (INIS)

Rajamane, N P; Nataraja, M C; Jeyalakshmi, R; Nithiyanantham, S

2015-01-01

The eco-friendliness of concrete is quantified by parameters such as ‘embodied energy’ (EE) and ‘embodied CO 2 emission’ (ECO 2 e), besides duration of designed ‘service life’. It may be noted that ECO 2 e is also referred as carbon footprint (CF) in the literature. Geopolymer (GP) is an inorganic polymeric gel, a type of amorphous alumino-silicate product, which can be synthesised by polycondensation reactions. The concrete reported in this paper was prepared using industrial wastes in the form of blast furnace slag, fly ash as geopolymeric source materials and sodium silicate and sodium hydroxide as activators. Many mechanical properties such as compressive strength, chloride diffusion, steel corrosion, rapid chloride permeability test and rapid migration test are compared with Portland cement. (paper)

Anchorage of TiO2-blasted, HA-coated, and machined implants: an experimental study with rabbits

DEFF Research Database (Denmark)

Gotfredsen, K; Wennerberg, A; Johansson, C

1995-01-01

The purpose of this study was to evaluate the histometrical and biomechanical anchorage of TiO2-blasted implants and TiO2-blasted implants coated with hydroxyapatite. The control implants were machined. Twenty-six rabbits had a total of 156 implants placed in the proximal part of the tibia. Each...... rabbit had a machined, a TiO2-blasted, and a TiO2-blasted, HA-coated implant placed in each tibia. After a healing period of 3 and 12 weeks, respectively, the implants placed in the right tibia were used for removal torque test, and the implants placed in the left tibia were used for histomorphometrical...

Ground granulated blast furnace slag efficiency coefficient (k value) in concrete. Applications and limits

International Nuclear Information System (INIS)

Sanjuan, M. A.; Pineiro, A.; Rodriguez, O.

2011-01-01

Recently, a k-value for ground granulated blast-furnace slag or k-value has been added to the revision of the European standard EN 206-1:2000. The proposed values during the discussions in the working groups were very different because in most of cases the compressive strength was the only characteristic considered; while only in few cases the concrete durability was taken into account when ground granulated blast-furnace slag is added directly to the mix. Advantages and disadvantages of the k-values found in the literature are discussed in this paper. The final conclusion may be summarised suggesting a logical proposal of addressing to each country the choice of the k-value in function of the concrete application, environment and placing conditions selected according to their own experience. (Author) 15 refs.

Ground granulated blast furnace slag efficiency coefficient (k value) in concrete. Applications and limits

Energy Technology Data Exchange (ETDEWEB)

Sanjuan, M. A.; Pineiro, A.; Rodriguez, O.

2011-07-01

Recently, a k-value for ground granulated blast-furnace slag or k-value has been added to the revision of the European standard EN 206-1:2000. The proposed values during the discussions in the working groups were very different because in most of cases the compressive strength was the only characteristic considered; while only in few cases the concrete durability was taken into account when ground granulated blast-furnace slag is added directly to the mix. Advantages and disadvantages of the k-values found in the literature are discussed in this paper. The final conclusion may be summarised suggesting a logical proposal of addressing to each country the choice of the k-value in function of the concrete application, environment and placing conditions selected according to their own experience. (Author) 15 refs.

AN EXPERIMENTAL STUDY ON BEHAVIOUR OF RECYCLED AGGREGATE CONCRETE WITH GROUND GRANULATED BLAST FURNACE SLAG FLYASH

OpenAIRE

B.Sasikala*, K.Shanthi, B.Jose RavindraRaj

2017-01-01

Concrete is the single largest manufactured material in the world . The use of recycled materials in construction is an issue of great importance. Utilization of Recycled Aggregates (RA), Ground Granulated Blast Furnace Slag (GGBFS) and fly ash in concrete addresses this issue. In this project, strength, durability of Recycled Aggregate Concrete (RAC) with GGBFS was studied. M-50 grade concrete with 0.30 w/c ratio and maximum size of 16mm course aggregate was used for this study. Totally 16 m...

The role of SiO2 nanoparticles and ground granulated blast furnace slag admixtures on physical, thermal and mechanical properties of self compacting concrete

International Nuclear Information System (INIS)

Nazari, Ali; Riahi, Shadi

2011-01-01

Research highlights: → Nanoparticles in concrete. → Ground granulated blast furnace slag as concrete's binder. → Mechanical properties of concrete specimens by non-traditional admixtures. - Abstract: In this work, strength assessments and percentage of water absorption of self compacting concrete containing ground granulated blast furnace slag and SiO 2 nanoparticles as binder have been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impacts the physical and mechanical properties of concrete at early ages of curing, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt% at later ages. SiO 2 nanoparticles with the average particle size of 15 nm were added partially to concrete with the optimum content of ground granulated blast furnace slag and physical and mechanical properties of the specimens were measured. SiO 2 nanoparticle as a partial replacement of cement up to 3.0 wt% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH) 2 amount at the early ages and hence increase strength and improve the resistance to water permeability of concrete specimens. The increased SiO 2 nanoparticles' content by more than 3.0 wt%, causes the reduced strength because of the decreased crystalline Ca(OH) 2 content required for C-S-H gel formation. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that SiO 2 nanoparticles could improve mechanical and physical properties of the concrete

Magnetic gauge for free surface velocities in reinforced concrete blasted by explosives

International Nuclear Information System (INIS)

Ashuach, Y; Gissis, I; Avinadav, C

2014-01-01

We developed a simple magnetic gauge for measuring free surface velocities of rock materials in the range of 0.1-20 m/s. The gauge consists of two elements: a NdFeB magnet and a pick-up coil. The coil is attached to the free surface at the point of interest. The magnet is placed a few centimeters away from the coil and the rock. The motion of the rock surface, due to blast loading, induces current in the coil due to the changes in the magnetic flux. The coil velocity is deduced from the measured current using a computational code. The gauge was tested and validated in a set of free-falling experiments. We present velocity measurements from various blast experiments in limestone and reinforced concrete, using both the magnetic gauge and a Doppler interferometer. The results obtained from the two measurement techniques are in good agreement. Since the magnetic gauge is cheap and very simple to operate, it is well-suited for mapping the velocity distribution at multiple points of interest on the concrete surface.

The influence of blast furnace slag, fly ash and silica fume on corrosion of reinforced concrete in marine environment

NARCIS (Netherlands)

Polder, R.B.

1996-01-01

Chloride penetration from sea water may cause corrosion of reinforcement in concrete structures. Adding reactive inorganic materials such as blast furnace slag, fly ash or silica fume to the cement matrix improves the resistance against chloride penetration as compared to Portland cement concrete. A

Damage Detection of a Concrete Column Subject to Blast Loads Using Embedded Piezoceramic Transducers.

Science.gov (United States)

Xu, Kai; Deng, Qingshan; Cai, Lujun; Ho, Siuchun; Song, Gangbing

2018-04-28

Some of the most severe structural loadings come in the form of blast loads, which may be caused by severe accidents or even terrorist activities. Most commonly after exposure to explosive forces, a structure will suffer from different degrees of damage, and even progress towards a state of collapse. Therefore, damage detection of a structure subject to explosive loads is of importance. This paper proposes a new approach to damage detection of a concrete column structure subjected to blast loads using embedded piezoceramic smart aggregates (SAs). Since the sensors are embedded in the structure, the proposed active-sensing based approach is more sensitive to internal or through cracks than surface damage. In the active sensing approach, the embedded SAs act as actuators and sensors, that can respectively generate and detect stress waves. If the stress wave propagates across a crack, the energy of the wave attenuates, and the reduction of the energy compared to the healthy baseline is indicative of a damage. With a damage index matrix constructed by signals obtained from an array of SAs, cracks caused by blast loads can be detected throughout the structure. Conventional sensing methods such as the measurement of dynamic strain and acceleration were included in the experiment. Since columns are critical elements needed to prevent structural collapse, knowledge of their integrity and damage conditions is essential for safety after exposure to blast loads. In this research, a concrete column with embedded SAs was chosen as the specimen, and a series of explosive tests were conducted on the column. Experimental results reveal that surface damages, though appear severe, cause minor changes in the damage index, and through cracks result in significant increase of the damage index, demonstrating the effectiveness of the active sensing, enabled by embedded SAs, in damage monitoring of the column under blast loads, and thus providing a reliable indication of structural

The role of SiO{sub 2} nanoparticles and ground granulated blast furnace slag admixtures on physical, thermal and mechanical properties of self compacting concrete

Energy Technology Data Exchange (ETDEWEB)

Nazari, Ali, E-mail: alinazari84@aut.ac.ir [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Felestin Sq., Saveh (Iran, Islamic Republic of); Riahi, Shadi [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Felestin Sq., Saveh (Iran, Islamic Republic of)

2011-02-25

Research highlights: {yields} Nanoparticles in concrete. {yields} Ground granulated blast furnace slag as concrete's binder. {yields} Mechanical properties of concrete specimens by non-traditional admixtures. - Abstract: In this work, strength assessments and percentage of water absorption of self compacting concrete containing ground granulated blast furnace slag and SiO{sub 2} nanoparticles as binder have been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impacts the physical and mechanical properties of concrete at early ages of curing, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt% at later ages. SiO{sub 2} nanoparticles with the average particle size of 15 nm were added partially to concrete with the optimum content of ground granulated blast furnace slag and physical and mechanical properties of the specimens were measured. SiO{sub 2} nanoparticle as a partial replacement of cement up to 3.0 wt% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH){sub 2} amount at the early ages and hence increase strength and improve the resistance to water permeability of concrete specimens. The increased SiO{sub 2} nanoparticles' content by more than 3.0 wt%, causes the reduced strength because of the decreased crystalline Ca(OH){sub 2} content required for C-S-H gel formation. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that SiO{sub 2} nanoparticles could

Estimation of minimum detectable concentration of chlorine in the blast furnace slag cement concrete

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.s [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Garwan, M.A.; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khateeb-ur-Rehman,; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2011-01-01

The Prompt Gamma Neutron Activation Analysis technique was used to measure the concentration of chloride in the blast furnace slag (BFS) cement concrete to assess the possibility of reinforcement corrosion. The experimental setup was optimized using Monte Carlo calculations. The BFS concrete specimens containing 0.8-3.5 wt.% chloride were prepared and the concentration of chlorine was evaluated by determining the yield of 6.11, 6.62, 7.41, 7.79 and 8.58 MeV gamma-rays. The Minimum Detectable Concentration (MDC) of chlorine in the BFS cement concrete was estimated. The best value of MDC limit of chlorine in the BFS cement concrete was found to be 0.034 {+-} 0.011 and 0.038 {+-} 0.012 wt.% for 6.11 and 6.62 MeV prompt gamma-rays. Within the statistical uncertainty the lower bound of the measured MDC of chlorine in the BFS cement concrete meets the maximum permissible limit of 0.03 wt.% of chloride set by the American Concrete Institute.

Properties and Behavior of Geopolymer Concrete Subjected to Explosive Air Blast Loading: A Review

Directory of Open Access Journals (Sweden)

Mohd Mortar Nurul Aida

2017-01-01

Full Text Available The severe damage to civilian buildings, public area, jet aircraft impact and defense target under explosive blast loading can cause a huge property loss. Most of researcher discusses the topics on design the concrete material model to sustain againts the explosive detonation. The implementation of modern reinforcement steels and fibres in ordinary Portland cement (OPC concrete matrix can reduce the extreme loading effects. However, most researchers have proved that geopolymer concrete (GPC has better mechanical properties towards high performance concrete, compared to OPC. GPC has the high early compressive strength and high ability to resist the thermal energy from explosive detonation. In addition, OPC production is less environmental friendly than geopolymer cement. Geopolymer used can lead to environmental protection besides being improved in mechanical properties. Thus, this paper highlighted on an experimental, numerical and the analytical studies cause of the explosive detonation impact to concrete structures.

Innovation based on tradition : Blast furnace slag cement for durable concrete structures in Norway?

NARCIS (Netherlands)

Polder, R.B.; Nijland, T.; De Rooij, M.; Larsen, C.K.; Pedersen, B.

2014-01-01

Blast furnace slag cement (BFSC) has been used to build reinforced concrete structures in marine and road environment in The Netherlands for nearly a century. The experience is good and structures with long service lives can be obtained, as has been shown by several field studies. This is caused by

Full scale numerical analysis of high performance concrete columns designed to withstand severe blast impact

DEFF Research Database (Denmark)

Riisgaard, Benjamin; Georgakis, Christos; Stang, Henrik

2007-01-01

Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Particle system, FDSP, combined with a high strength longitudinal flexural rebar arrangement laced together with polymer lacing to avoid shock initiated disintegration of the structural element under blast...... of PETN (85/15) High Explosives at stand off 1600 mm. Additionally, a LS-DYNA material model suitable for predicting the response of Polymer reinforced Compact Reinforced Concrete improved for close-in detonation and a description of the LS-DYNA multi-material Eulerian method for modeling the blast event...

Evaluation of Blast Resistance of Fiber Reinforced Composite Specimens under Contact Blast Load

Science.gov (United States)

Janota, O.; Foglar, M.

2017-09-01

This paper presents results of experimental programme which took place in 2014, 2015 and 2016. Experiments were focused on the resistance of full scale concrete panels subjected to contact blast loading. Specimens were loaded by contact blast by plastic explosive. All specimens were reinforced concrete slabs made of fiber concrete. Basalt mesh and textile sheets were added to some of the experiments for creating more heterogeneous material to achieve better resistance of the specimens. Evaluation of experiments was mainly focused on the damaged area on the contact side and soffit of the specimens. Dependency of the final damage of concrete panels on the weight of explosive and concrete strength was assessed.

FINITE ELEMENT ANALYSIS OF CONCRETE FILLER INFLUENCE ON DYNAMIC RIGIDITY OF HEAVY MACHINE TOOL PORTAL

Directory of Open Access Journals (Sweden)

Yu. V. Vasilevich

2016-01-01

Full Text Available Virtual testing of portal machine tool has been carried out with the help of finite elements method (FEM. Static, modal and harmonic analyses have been made for a heavy planer. The paper reveals influence of concrete filler on machine tool dynamic flexibility. A peculiar feature of the simulation is concrete filling of a high-level transverse beam. Such approach oes look a typical one for machine-tool industry. Concrete has been considered as generalized material in two variants. It has been established that concrete application provides approximately 3-fold increase in machine tool rigidity per each coordinate. In this regard it is necessary to arrange closure of rigidity contour by filling all the cavities inside of the portal. Modal FEA makes it possible to determine that concrete increases comparatively weakly (1.3–1.4-fold frequencies of resonance modes. Frequency of the lowest mode rises only from 30.25 to 42.86 Hz. The following most active whole-machine eigenmodes have been revealed in the paper: “Portal pecking”, “Parallelogram” and “Traverse pecking”. In order to restrain the last mode it is necessary to carry out concrete filling of the traverse, in particular. Frequency-response characteristics and curves of dynamic rigidity for a spindle have been plotted for 0–150 Hz interval while using harmonic FEM. It has been determined that concrete increases dynamic machine tool rigidity by 2.5–3.5-fold. The effect is obtained even in the case when weakly damping concrete (2 % is used. This is due to distribution of vibrational energy flow along concrete and along cast iron as well. Thus energy density and vibration amplitudes must decrease. The paper shows acceptability for internal reinforcement of high-level machine tool parts (for example, portal traverses and fillers are applied for this purpose. Traverse weighting is compensated by additional torsional, shear and bending rigidity. The machine tool obtains the

Development Of Very-High-Strength and High-Performance Concrete Materials for Improvement of Barriers Against Blast and Projectile Penetration

National Research Council Canada - National Science Library

O'Neill, E. F., III; Cummins, T. K; Durst, B. P; Kinnebrew, P. G; Boone, R. N; Torres, R. X

2004-01-01

.... S. Army Engineer Research and Development Center (ERDC) is developing several high-performance concretes to mitigate the effects of blast and ballistic threats from conventional and asymmetric weapons...

Study of mass attenuation coefficients and effective atomic numbers of bismuth-ground granulated blast furnace slag concretes

International Nuclear Information System (INIS)

Kumar, Sandeep; Singh, Sukhpal

2016-01-01

Five samples of Bismuth-Ground granulated blast furnace slag (Bi-GGBFS) concretes were prepared using composition (0.6 cement + x Bi_2O_3 + (0.4-x) GGBFS, x = 0.05, 0.10, 0.15, 0.20 and 0.25) by keeping constant water (W) cement (C) ratio. Mass attenuation coefficients (μ_m) of these prepared samples were calculated using a computer program winXCOM at different gamma ray energies, whereas effective atomic numbers (Z_e_f_f) is calculated using mathematical formulas. The radiation shielding properties of Bi-GGBFS concrete has been compared with standard radiation shielding concretes.

The use of blast furnace slag

Directory of Open Access Journals (Sweden)

V. Václavík

2012-10-01

Full Text Available The paper presents the results of experimental research that dealt with the substitution of finely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on finely ground blast furnace slag were observed.

Development of a new concrete pipe molding machine using topology optimization

International Nuclear Information System (INIS)

Park, Hong Seok; Dahal, Prakash; Nguyen, Trung Thanh

2016-01-01

Sulfur polymer concrete (SPC) is a relatively new material used to replace Portland cement for manufacturing sewer pipes. The objective of this work is to develop an efficient molding machine with an inner rotating die to mix, compress and shape the SPC pipe. First, the alternative concepts were generated based on the TRIZ principles to overcome the drawbacks of existing machines. Then, the concept scoring technique was used to identify the best design in terms of machine structure and product quality. Finally, topology optimization was applied with the support of the density method to reduce mass and to displace the inner die. Results showed that the die volume can be reduced by approximately 9% and the displacement can be decreased by approximately 3% when compared with the initial design. This work is expected to improve the manufacturing efficiency of the concrete pipe molding machine

Development of a new concrete pipe molding machine using topology optimization

Energy Technology Data Exchange (ETDEWEB)

Park, Hong Seok; Dahal, Prakash [School of Mechanical and Automotive Engineering, University of Ulsan, Ulsan (Korea, Republic of); Nguyen, Trung Thanh [Faculty of Mechanical Engineering, Le Quy Don Technical University, Hanoi (Viet Nam)

2016-08-15

Sulfur polymer concrete (SPC) is a relatively new material used to replace Portland cement for manufacturing sewer pipes. The objective of this work is to develop an efficient molding machine with an inner rotating die to mix, compress and shape the SPC pipe. First, the alternative concepts were generated based on the TRIZ principles to overcome the drawbacks of existing machines. Then, the concept scoring technique was used to identify the best design in terms of machine structure and product quality. Finally, topology optimization was applied with the support of the density method to reduce mass and to displace the inner die. Results showed that the die volume can be reduced by approximately 9% and the displacement can be decreased by approximately 3% when compared with the initial design. This work is expected to improve the manufacturing efficiency of the concrete pipe molding machine.

Numerical Derivation of Iso-Damaged Curve for a Reinforced Concrete Beam Subjected to Blast Loading

Directory of Open Access Journals (Sweden)

Temsah Yehya

2018-01-01

Full Text Available Many engineering facilities are severely damaged by blast loading. Therefore, many manufacturers of sensitive, breakable, and deformed structures (such as facades of glass buildings carry out studies and set standards for these installations to withstand shock waves caused by explosions. Structural engineers also use these standards in their designs for various structural elements by following the ISO Damage Carve, which links pressure and Impulse. As all the points below this curve means that the structure is safe and will not exceed the degree of damage based on the various assumptions made. This research aims to derive the Iso-Damage curve of a reinforced concrete beam exposed to blast wave. An advanced volumetric finite element program (ABAQUS will be used to perform the derivation.

Discrimination of Rock Fracture and Blast Events Based on Signal Complexity and Machine Learning

Directory of Open Access Journals (Sweden)

Zilong Zhou

2018-01-01

Full Text Available The automatic discrimination of rock fracture and blast events is complex and challenging due to the similar waveform characteristics. To solve this problem, a new method based on the signal complexity analysis and machine learning has been proposed in this paper. First, the permutation entropy values of signals at different scale factors are calculated to reflect complexity of signals and constructed into a feature vector set. Secondly, based on the feature vector set, back-propagation neural network (BPNN as a means of machine learning is applied to establish a discriminator for rock fracture and blast events. Then to evaluate the classification performances of the new method, the classifying accuracies of support vector machine (SVM, naive Bayes classifier, and the new method are compared, and the receiver operating characteristic (ROC curves are also analyzed. The results show the new method obtains the best classification performances. In addition, the influence of different scale factor q and number of training samples n on discrimination results is discussed. It is found that the classifying accuracy of the new method reaches the highest value when q = 8–15 or 8–20 and n=140.

Effects of air blast on power plant structures and components

International Nuclear Information System (INIS)

Kot, C.A.; Valentin, R.A.; McLennan, D.A.; Turula, P.

1978-10-01

The effects of air blast from high explosives detonation on selected power plant structures and components are investigated analytically. Relying on a synthesis of state of the art methods estimates of structural response are obtained. Similarly blast loadings are determined from compilations of experimental data reported in the literature. Plastic-yield line analysis is employed to determine the response of both concrete and steel flat walls (plates) under impulsive loading. Linear elastic theory is used to investigate the spalling of concrete walls and mode analysis methods predict the deflection of piping. The specific problems considered are: the gross deformation of reinforced concrete shield and containment structures due to blast impulse, the spalling of concrete walls, the interaction or impact of concrete debris with steel containments and liners, and the response of exposed piping to blast impulse. It is found that for sufficiently close-in detonations and/or large explosive charge weights severe damage or destruction will result. This is particularly true for structures or components directly exposed to blast impulse

Elastomeric Polymers for Retrofitting of Reinforced Concrete Structures against the Explosive Effects of Blast

Directory of Open Access Journals (Sweden)

S. N. Raman

2012-01-01

Full Text Available The main distinction of blast load from other types of dynamic loadings is its impulsive nature, where the loads usually act for a very short duration but transmit very high impulsive pressures. This paper presents an overview of the present retrofitting techniques in use to enhance the capacity of structural elements to withstand the effects of blast loads, and introduces an alternative retrofitting approach by utilizing polymer coatings. The authors have demonstrated the positive effects of this approach by conducting a numerical investigation on the behavior of an unretrofitted reinforced concrete panel subjected to the blast load from a 2 kg charge at 1.6 m stand-off distance, and subsequently comparing its performance with several polymer coated panels. The analysis was performed by using an explicit nonlinear finite element (FE code. The results demonstrate the contributions of this technique in terms of panel displacement control and energy dissipation. Considering that the polymer coating can also act as a protective layer in improving the durability of structural materials, this technique can also be optimized favorably to enhance the overall sustainability of structures.

Prediction of Backbreak in Open-Pit Blasting Operations Using the Machine Learning Method

Science.gov (United States)

Khandelwal, Manoj; Monjezi, M.

2013-03-01

Backbreak is an undesirable phenomenon in blasting operations. It can cause instability of mine walls, falling down of machinery, improper fragmentation, reduced efficiency of drilling, etc. The existence of various effective parameters and their unknown relationships are the main reasons for inaccuracy of the empirical models. Presently, the application of new approaches such as artificial intelligence is highly recommended. In this paper, an attempt has been made to predict backbreak in blasting operations of Soungun iron mine, Iran, incorporating rock properties and blast design parameters using the support vector machine (SVM) method. To investigate the suitability of this approach, the predictions by SVM have been compared with multivariate regression analysis (MVRA). The coefficient of determination (CoD) and the mean absolute error (MAE) were taken as performance measures. It was found that the CoD between measured and predicted backbreak was 0.987 and 0.89 by SVM and MVRA, respectively, whereas the MAE was 0.29 and 1.07 by SVM and MVRA, respectively.

The Mechanical Properties of Foamed Concrete containing Un-processed Blast Furnace Slag

Directory of Open Access Journals (Sweden)

Awang H.

2014-01-01

Full Text Available For many years, supplementary cementation materials have been utilized as cement or filler replacements to heighten the properties of concrete. The objective of this paper is to demonstrate the effects of un-processed blast furnace slag (RS on the compressive, splitting tensile and flexural strengths of foam concrete over periods of 7, 14 and 28 days. The introduction of slag to the cement begins at 30% and rises to 70% of the total content. Six mixes, which include the control mix with a similar mix ratio (1:2:0.45 and a dry density of 1300 kg/m3 is generated. Taking into consideration, from the total weight of the cementation material, 1% of super- plasticizer (PS-1 is added to the mixes with slag content. Test results revealed that the most favourable (optimum replacement level of un-processed slag in foam concrete is 30%. This represents a commercial advantage as the cement requirement is reduced from 414 Kg/m3 to 290 Kg/m3. On the 28th day, the optimum mix showed higher values than the control mix by 32% for compressive strength, 46.5% for splitting tensile strength and 61% for flexural strength.

Studies on the corrosion resistance of reinforced steel in concrete with ground granulated blast-furnace slag--An overview.

Science.gov (United States)

Song, Ha-Won; Saraswathy, Velu

2006-11-16

The partial replacement of clinker, the main constituent of ordinary Portland cement by pozzolanic or latent hydraulic industrial by-products such as ground granulated blast furnace slag (GGBFS), effectively lowers the cost of cement by saving energy in the production process. It also reduces CO2 emissions from the cement plant and offers a low priced solution to the environmental problem of depositing industrial wastes. The utilization of GGBFS as partial replacement of Portland cement takes advantage of economic, technical and environmental benefits of this material. Recently offshore, coastal and marine concrete structures were constructed using GGBFS concrete because high volume of GGBFS can contribute to the reduction of chloride ingress. In this paper, the influence of using GGBFS in reinforced concrete structures from the durability aspects such as chloride ingress and corrosion resistance, long term durability, microstructure and porosity of GGBFS concrete has been reviewed and discussed.

Abrasive blasting, a technique for the industrial decontamination of metal components and concrete blocks from decommissioning to unconditional release levels

International Nuclear Information System (INIS)

Gills, R.; Lewandowski, P.; Ooms, B.; Reusen, N.; Van Laer, W.; Walthery, R.

2007-01-01

When decommissioning nuclear installations, large quantities of metal components are produced as well as significant amounts of other radioactive materials, which mostly show low surface contamination. Having been used or having been brought for a while in a controlled area marks them as 'suspected material'. In view of the very high costs for radioactive waste processing and disposal, alternatives have been considered, and much effort has gone to recycling through decontamination, melting and unconditional release of metals. In a broader context, recycling of materials can considered to be a first order ecological priority in order to limit the quantities of radioactive wastes for final disposal and to reduce the technical and economic problems involved with the management of radioactive wastes. It will help as well to make economic use of primary material and to conserve natural resources of basic material for future generations. In a demonstration programme, Belgoprocess has shown that it is economically interesting to decontaminate metal components to unconditional release levels using dry abrasive blasting techniques, the unit cost for decontamination being only 30 % of the global cost for radioactive waste treatment, conditioning, storage and disposal. As a result, an industrial dry abrasive blasting unit was installed in the Belgoprocess central decontamination infrastructure. At the end of December 2006, more than 1,128 Mg of contaminated metal has been treated as well as 313 Mg of concrete blocks. The paper gives an overview of the experience relating to the decontamination of metal material and concrete blocks at the decommissioning of the Eurochemic reprocessing plant in Dessel, Belgium as well from the decontamination of concrete containers by abrasive blasting. (authors)

Assessment of dynamic mechanical behaviour of reinforced concrete beams using a blast simulator

Directory of Open Access Journals (Sweden)

Peroni Marco

2015-01-01

Full Text Available Critical infrastructures may become the target of terrorist bombing attacks or may have to withstand explosive loads due to accidents. The impulsive load connected to explosions is delivered to the structure in a few milliseconds forcing it to respond or fail in a peculiar mode. With reference to the above scientific framework this work presents an innovative apparatus designed and developed at the European Laboratory for Structural Assessment to reproduce a blast pressure history without using explosives. This apparatus is practically a hybrid nitrogen-spring-driven actuator that accelerates masses of up to 100 kg to a maximum velocity of about 25 m/s that impact against the tested structure. The pressure-load history applied to the structure is modulated and reshaped using appropriate layers of elastic soft materials (such as polymeric foams placed between the specimen and the impacting masses. Specific instrumentation has extensively been utilised to investigate the blast simulator performance and to precisely measure the pressure loads applied to the specimen. A series of tests on real scale reinforced concrete beams/columns (250 × 250 × 2200 mm has been performed to efficiently assess the performance and potentiality of the new blast simulator. Results are under evaluation. In addition to the experimental work, a series of numerical simulations by means of the explicit FEM code EUROPLEXUS have been carried out to support and improve the equipment design.

Drilling-and-blasting method of demolition

Directory of Open Access Journals (Sweden)

Sinitsyn Denis

2018-01-01

Full Text Available This article analyzes the experience and gives the examples of dismantling and demolition of the construction structures of the buildings and facilities using the drilling-and-blasting method. The drilling-and-blasting method is widely used in construction and reconstruction. The demolition means may be classified according to impact on a material of structures to be demolished and to forces application, where, by virtue of an impact energy type, we choose the blasting method. This method is used during the complete demolition or fragmentation of concrete, reinforced concrete, masonry structures, of old buildings and facilities demolition to their base or in the intended direction. Blasting method may be used as well during the steel and reinforced concrete structures demolition to the smaller easy-to-move parts. Reviewed are the organizational-process activities, which are performed during the various structures dismantling. Given are the areas of application for the various methods of structures demolition. Given is the example of demolition of “Sevemaya” boiler house brick chimney at the territory of Murmansk DSK using the blast in confined spaces of the operating company. Subject of research: methods of construction structures demolition in alarm situations and acts of God. Objects: determination of the most efficient demolition methods in the present conditions of construction operations development. Materials and methods: the developed activities on the construction structures dismantling are given. Results: the most efficient methods and ways of construction structures demolition are defined. Conclusions: it is required for improvement of methods and ways of the structures drilling-and-blasting demolition.

Application of micro blasting technique to demolition of biological shield wall of reactor building

International Nuclear Information System (INIS)

Kontani, Osamu

2016-01-01

Although heavily reinforced concrete structures in nuclear facilities could be dismantled effectively with the controlled blasting technique, the noises and vibrations caused by blasting were matters of concern. Recently, in the building replacement at urban areas, there are increasing cases of demolition of large reinforced concrete members below ground. Instead of applying heavy weight breakers, the micro blasting technique that enables to lower noises and vibrations has developed and applied to demolition work of large reinforced concrete members in urban areas. In this report, the features of the micro blasting technique is reviewed by comparing with existing controlled blasting technique and its applicability to demolition work of nuclear facilities is investigated. The results of those study find that it is confirmed that the micro blasting technique could be applicable to large reinforced concrete structures in nuclear facilities because of the low levels of noises and vibrations. However, it is recommended to perform mock-up tests to confirm the demolition efficiency and levels of the noises and vibrations since the rebar used in nuclear facilities is larger in diameters and in rebar ratio compared with ordinary reinforced concrete structures. (author)

Chloride transport testing of blast furnace slag cement for durable concrete structures in Norway : From 2 days to one year age

NARCIS (Netherlands)

Polder, R.B.; de Rooij, M.R.; Larsen, CK; Pedersen, B; Beushausen, H.

2016-01-01

Blast furnace slag cement (BFSC) has been used in reinforced concrete structures in marine and road environment in The Netherlands for nearly a century. Experience is good and long service lives can be obtained. In Norway experience with BFSC is scarce. In The Netherlands, a high resistance against

Chloride transport testing of blast furnace slag cement for durable concrete structires in Norway: From 2 days to one year age

NARCIS (Netherlands)

Polder, R.B.; Rooij, M.R. de; Larsen, C.K.; Pedersen, B.

2016-01-01

Blast furnace slag cement (BFSC) has been used in reinforced concrete structures in marine and road environment in The Netherlands for nearly a century. Experience is good and long service lives can be obtained. In Norway experience with BFSC is scarce. In The Netherlands, a high resistance against

Effects on the Physical and Mechanical Properties of Porous Concrete for Plant Growth of Blast Furnace Slag, Natural Jute Fiber, and Styrene Butadiene Latex Using a Dry Mixing Manufacturing Process.

Science.gov (United States)

Kim, Hwang-Hee; Kim, Chun-Soo; Jeon, Ji-Hong; Park, Chan-Gi

2016-01-29

To evaluate the effects of industrial by-products materials on the performance of porous concrete for plant growth, this study investigated the physical, strength, and freeze/thaw resistances of porous concrete for plant growth, prepared by replacing cement with blast furnace slag powder at 60% by weight, and replacing natural stone aggregates with coarse blast furnace slag aggregates at rates of 0%, 20%, 40%, 60% and 100% by weight. In addition, the effects of adding natural jute fiber and styrene butadiene ( SB) latex to these concrete mixtures were evaluated. The void ratio, compressive strength, and freeze/thaw resistance of the samples were measured. With increasing replacement rate of blast furnace aggregates, addition of latex, and mixing of natural jute fiber the void ratio of the concrete was increased. Compressive strength decreased as the replacement rate of blast-furnace slag aggregates increased. The compressive strength decreased after 100 freeze/thaw cycles, regardless of the replacement rate of blast furnace slag aggregates or of the addition of natural jute fiber and latex. The addition of natural jute fiber and latex decreased the compressive strength after 100 freeze/thaw cycles. The test results indicate that the control mixture satisfied the target compressive strength of 10 MPa and the target void ratio of 25% at replacement rates of 0% and 20% for blast furnace aggregates, and that the mixtures containing latex satisfied the criteria up to an aggregate replacement rate of 60%. However, the mixtures containing natural jute fiber did not satisfy these criteria. The relationship between void ratio and residual compressive strength after 100 freeze/thaw cycles indicates that the control mixture and the mixtures containing jute fiber at aggregate replacement rates of 20% and 40% satisfied the target void ratio of 25% and the target residual compressive strength of over 80% after 100 freeze/thaw cycles. The mixtures containing latex and aggregate

Effects on the Physical and Mechanical Properties of Porous Concrete for Plant Growth of Blast Furnace Slag, Natural Jute Fiber, and Styrene Butadiene Latex Using a Dry Mixing Manufacturing Process

Directory of Open Access Journals (Sweden)

Hwang-Hee Kim

2016-01-01

Full Text Available To evaluate the effects of industrial by-products materials on the performance of porous concrete for plant growth, this study investigated the physical, strength, and freeze/thaw resistances of porous concrete for plant growth, prepared by replacing cement with blast furnace slag powder at 60% by weight, and replacing natural stone aggregates with coarse blast furnace slag aggregates at rates of 0%, 20%, 40%, 60% and 100% by weight. In addition, the effects of adding natural jute fiber and styrene butadiene (SB latex to these concrete mixtures were evaluated. The void ratio, compressive strength, and freeze/thaw resistance of the samples were measured. With increasing replacement rate of blast furnace aggregates, addition of latex, and mixing of natural jute fiber the void ratio of the concrete was increased. Compressive strength decreased as the replacement rate of blast-furnace slag aggregates increased. The compressive strength decreased after 100 freeze/thaw cycles, regardless of the replacement rate of blast furnace slag aggregates or of the addition of natural jute fiber and latex. The addition of natural jute fiber and latex decreased the compressive strength after 100 freeze/thaw cycles. The test results indicate that the control mixture satisfied the target compressive strength of 10 MPa and the target void ratio of 25% at replacement rates of 0% and 20% for blast furnace aggregates, and that the mixtures containing latex satisfied the criteria up to an aggregate replacement rate of 60%. However, the mixtures containing natural jute fiber did not satisfy these criteria. The relationship between void ratio and residual compressive strength after 100 freeze/thaw cycles indicates that the control mixture and the mixtures containing jute fiber at aggregate replacement rates of 20% and 40% satisfied the target void ratio of 25% and the target residual compressive strength of over 80% after 100 freeze/thaw cycles. The mixtures containing

Recycling ground granulated blast furnace slag as cold bonded artificial aggregate partially used in self-compacting concrete.

Science.gov (United States)

Gesoğlu, Mehmet; Güneyisi, Erhan; Mahmood, Swara Fuad; Öz, Hatice Öznur; Mermerdaş, Kasım

2012-10-15

Ground granulated blast furnace slag (GGBFS), a by-product from iron industry, was recycled as artificial coarse aggregate through cold bonding pelletization process. The artificial slag aggregates (ASA) replaced partially the natural coarse aggregates in production of self-compacting concrete (SCC). Moreover, as being one of the most widely used mineral admixtures in concrete industry, fly ash (FA) was incorporated as a part of total binder content to impart desired fluidity to SCCs. A total of six concrete mixtures having various ASA replacement levels (0%, 20%, 40%, 60%, and 100%) were designed with a water-to-binder (w/b) ratio of 0.32. Fresh properties of self-compacting concretes (SCC) were observed through slump flow time, flow diameter, V-funnel flow time, and L-box filling height ratio. Compressive strength of hardened SCCs was also determined at 28 days of curing. It was observed that increasing the replacement level of ASA resulted in decrease in the amount of superplasticizer to achieve a constant slump flow diameter. Moreover, passing ability and viscosity of SCC's enhanced with increasing the amount of ASA in the concrete. The maximum compressive strength was achieved for the SCC having 60% ASA replacement. Copyright © 2012 Elsevier B.V. All rights reserved.

CrocoBLAST: Running BLAST efficiently in the age of next-generation sequencing.

Science.gov (United States)

Tristão Ramos, Ravi José; de Azevedo Martins, Allan Cézar; da Silva Delgado, Gabrielle; Ionescu, Crina-Maria; Ürményi, Turán Peter; Silva, Rosane; Koca, Jaroslav

2017-11-15

CrocoBLAST is a tool for dramatically speeding up BLAST+ execution on any computer. Alignments that would take days or weeks with NCBI BLAST+ can be run overnight with CrocoBLAST. Additionally, CrocoBLAST provides features critical for NGS data analysis, including: results identical to those of BLAST+; compatibility with any BLAST+ version; real-time information regarding calculation progress and remaining run time; access to partial alignment results; queueing, pausing, and resuming BLAST+ calculations without information loss. CrocoBLAST is freely available online, with ample documentation (webchem.ncbr.muni.cz/Platform/App/CrocoBLAST). No installation or user registration is required. CrocoBLAST is implemented in C, while the graphical user interface is implemented in Java. CrocoBLAST is supported under Linux and Windows, and can be run under Mac OS X in a Linux virtual machine. jkoca@ceitec.cz. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Effect of incorporation of fly ash and granulated blast furnace in the electrochemical behavior of concretes of commercial cement

International Nuclear Information System (INIS)

Gutierrez-Junco, O. J.; Pineda-Triana, Y.; Vera-Lopez, E.

2015-01-01

This paper presents the findings of the research properties evaluation pastes of commercial cement (CPC), mixed with fly ash (FA) and granulated blast furnace slag (GBFS). Initially, the sample of 30 combinations were evaluated in terms of compressive strength to establish the optimal proportions from raw material. After that, four optimized blends were characterized during the setting and hardening process. Electrochemical tests were performed on concrete cylinders samples prepared with cementitious materials and a structural steel rod placed in the center of the specimen. With the objective to evaluate the performance before corrosion, thermodynamic and kinetic aspects were taken into consideration. The findings showed that commercial cements blended with fly ash and blast furnace slag as the ones used in this research presents a decreased behavior in mechanical and corrosion strength regarding to CPC. (Author)

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...

Physical, chemical, and mineralogical characteristics of blast furnace slag on durability of concrete

Directory of Open Access Journals (Sweden)

Yogarajah Elakneswaran

2018-01-01

Full Text Available A partial replacement of Portland cement (PC by ground granulated blast furnace slag (GGBFS is an effective method to improve the durability of concrete due to its lower diffusivity and higher chemical resistance compared to PC. Further, the microstructure of GGBFS blended cementitious materials controls the physicochemical properties and performance of the materials in concrete. Therefore, understanding of cement hydration and cementing behavior of GGBFS is essential to establish microstructure property relationship for predicting performance. In this study, hydration, microstructure development, and chloride ingress into GGBFS-blended cement have been investigated. Solid-phase assemblage and pore solution chemistry of hydrating PC and cement blended with GGBFS were predicted using thermodynamic model and compared with experimental data. A mathematical model integrating PC hydration, GGBFS reaction, thermodynamic equilibrium between hydration products and pore solution, ionic adsorption on C-S-H, multi-component diffusion, and microstructural changes was developed to predict chloride ingress into GGBFS blended cementitious materials. The simulation results on chloride profiles for hydrated slag cement paste, which was prepared with 50% of replacement of PC with GGBFS, were compared with experimental results. The model quantitively predicts the states of chloride such as free, adsorbed on C-S-H, and chemically bound as Friedel’s salt.

Estimation of Corrosion-Free Life for Concrete Containing Ground Granulated Blast-Furnace Slag under a Chloride-Bearing Environment

Directory of Open Access Journals (Sweden)

Sung In Hong

2017-01-01

Full Text Available The rate of chloride transport by diffusion in concrete containing ground granulated blast-furnace slag (GGBS was mathematically estimated to predict the corrosion-free service life of concrete structures exposed to seawater environment. As a factor to corrosiveness of steel embedment, replacement ratio of GGBS was selected, accounting for 25 and 50% to total binder. As a result, it was found that an increase in the GGBS content resulted in an increase in the chloride binding capacity, which would give rise to a lower chloride diffusion rate, thereby reducing the risk of chloride-induced corrosion. When it comes to the sensitivity of parameters to service life, the effective diffusivity showed a marginal influence on serviceability, irrespective of GGBS contents while surface chloride content and critical threshold concentration revealed more crucial factors to long term chloride diffusion. As the GGBS replacement increased, the variation in service life has become less influential with changing parameters. Substantially, GGBS concrete at high replacement ratio enhanced the service life due to a combination of dense pore structure and enhanced chloride binding capacity.

29 CFR 1926.906 - Initiation of explosive charges-electric blasting.

Science.gov (United States)

2010-07-01

...) After firing an electric blast from a blasting machine, the leading wires shall be immediately... 29 Labor 8 2010-07-01 2010-07-01 false Initiation of explosive charges-electric blasting. 1926.906... Use of Explosives § 1926.906 Initiation of explosive charges—electric blasting. (a) Electric blasting...

Windows .NET Network Distributed Basic Local Alignment Search Toolkit (W.ND-BLAST

Directory of Open Access Journals (Sweden)

Oliver Melvin J

2005-04-01

Full Text Available Abstract Background BLAST is one of the most common and useful tools for Genetic Research. This paper describes a software application we have termed Windows .NET Distributed Basic Local Alignment Search Toolkit (W.ND-BLAST, which enhances the BLAST utility by improving usability, fault recovery, and scalability in a Windows desktop environment. Our goal was to develop an easy to use, fault tolerant, high-throughput BLAST solution that incorporates a comprehensive BLAST result viewer with curation and annotation functionality. Results W.ND-BLAST is a comprehensive Windows-based software toolkit that targets researchers, including those with minimal computer skills, and provides the ability increase the performance of BLAST by distributing BLAST queries to any number of Windows based machines across local area networks (LAN. W.ND-BLAST provides intuitive Graphic User Interfaces (GUI for BLAST database creation, BLAST execution, BLAST output evaluation and BLAST result exportation. This software also provides several layers of fault tolerance and fault recovery to prevent loss of data if nodes or master machines fail. This paper lays out the functionality of W.ND-BLAST. W.ND-BLAST displays close to 100% performance efficiency when distributing tasks to 12 remote computers of the same performance class. A high throughput BLAST job which took 662.68 minutes (11 hours on one average machine was completed in 44.97 minutes when distributed to 17 nodes, which included lower performance class machines. Finally, there is a comprehensive high-throughput BLAST Output Viewer (BOV and Annotation Engine components, which provides comprehensive exportation of BLAST hits to text files, annotated fasta files, tables, or association files. Conclusion W.ND-BLAST provides an interactive tool that allows scientists to easily utilizing their available computing resources for high throughput and comprehensive sequence analyses. The install package for W.ND-BLAST is

Plant Growth and Water Purification of Porous Vegetation Concrete Formed of Blast Furnace Slag, Natural Jute Fiber and Styrene Butadiene Latex

Directory of Open Access Journals (Sweden)

Hwang-Hee Kim

2016-04-01

Full Text Available The purpose of this study is to investigate porous vegetation concrete formed using the industrial by-products blast furnace slag powder and blast furnace slag aggregates. We investigated the void ratio, compressive strength, freeze–thaw resistance, plant growth and water purification properties using concretes containing these by-products, natural jute fiber and latex. The target performance was a compressive strength of ≥12 MPa, a void ratio of ≥25% and a residual compressive strength of ≥80% following 100 freeze–thaw cycles. Using these target performance metrics and test results for plant growth and water purification, an optimal mixing ratio was identified. The study characterized the physical and mechanical properties of the optimal mix, and found that the compressive strength decreased compared with the default mix, but that the void ratio and the freeze–thaw resistance increased. When latex was used, the compressive strength, void ratio and freeze–thaw resistance all improved, satisfying the target performance metrics. Vegetation growth tests showed that plant growth was more active when the blast furnace slag aggregate was used. Furthermore, the use of latex was also found to promote vegetation growth, which is attributed to the latex forming a film coating that suppresses leaching of toxic components from the cement. Water purification tests showed no so significant differences between different mixing ratios; however, a comparison of mixes with and without vegetation indicated improved water purification in terms of the total phosphorus content when vegetation had been allowed to grow.

A prospective 5-year study of fixed partial prostheses supported by implants with machined and TiO2-blasted surface

DEFF Research Database (Denmark)

Gotfredsen, K; Karlsson, U

2001-01-01

PURPOSE: The aim of the present study was to evaluate whether there was a difference between machined and TiO(2)-blasted implants regarding survival rate and marginal bone loss during a 5-year observation period. MATERIALS AND METHODS: A total of 133 implants (Astra Tech Dental Implants; Astra Tech...... AB, Mölndal, Sweden) were placed in 50 patients at 6 centers in 4 Scandinavian countries. Forty-eight implants were installed in the maxilla and 85 implants in the mandible. A randomization and a stratification were done, so that each fixed partial prosthesis was supported by at least 1 machined...... and 1 TiO(2)-blasted implant. The implant-supported fixed partial prostheses (ISFPP) were fabricated within 2 months after postoperative healing. A total of 52 ISFPP (17 maxillary, 35 mandibular) were inserted. The patients were clinically examined once a year for 5 years. At the annual follow...

High-speed photography of dynamic photoelastic experiment with a highly accurate blasting machine

Science.gov (United States)

Katsuyama, Kunihisa; Ogata, Yuji; Wada, Yuji; Hashizume, K.

1995-05-01

A high accurate blasting machine which could control 1 microsecond(s) was developed. At first, explosion of a bridge wire in an electric detonator was observed and next the detonations of caps were observed with a high speed camera. It is well known that a compressed stress wave reflects at the free face, it propagates to the backward as a tensile stress wave, and cracks grow when the tensile stress becomes the dynamic tensile strength. The behavior of these cracks has been discussed through the observation of the dynamic photoelastic high speed photography and the three dimensional dynamic stress analysis.

Carbon Dioxide Emission Evaluation of Porous Vegetation Concrete Blocks for Ecological Restoration Projects

Directory of Open Access Journals (Sweden)

Hwang-Hee Kim

2017-02-01

Full Text Available The purpose of this study is to determine the mix proportions that can minimize CO2 emissions while satisfying the target performance of porous vegetation concrete. The target performance of porous vegetation concrete was selected as compressive strength (>15 MPa and void ratio (>25%. This study considered the use of reinforcing fiber and styrene butadiene (SB latex to improve the strength of porous vegetation concrete, as well as the use of blast furnace slag aggregate to improve the CO2 emissions-reducing effect, and analyzed and evaluated the influence of fiber reinforcing, SB latex, and blast furnace slag aggregate on the compressive strength and CO2 emissions of porous vegetation concrete. The CO2 emissions of the raw materials were highest for cement, followed by aggregate, SB latex, and fiber. Blast furnace slag aggregate showed a 30% or more CO2 emissions-reducing effect versus crushed aggregate, and blast furnace slag cement showed a 78% CO2 emissions-reducing effect versus Portland cement. The CO2 emissions analyses for each raw material showed that the CO2 emissions during transportation were highest for the aggregate. Regarding CO2 emissions in each production stage, the materials stage produced the highest CO2 emissions, while the proportion of CO2 emissions in the transportation stage for each raw material, excluding fiber, were below 3% of total emissions. Use of blast furnace slag aggregate in porous vegetation concrete produced CO2 emissions-reducing effects, but decreased its compressive strength. Use of latex in porous vegetation concrete improved its compressive strength, but also increased CO2 emissions. Thus, it is appropriate to use latex in porous vegetation concrete to improve its strength and void ratio, and to use a blast furnace slag aggregate replacement ratio of 40% or less.

Control of blast overpressure and vibrations at the Underground Research Laboratory

International Nuclear Information System (INIS)

Kuzyk, G.W.; Onagi, D.P.; Mohanty, B.

1991-01-01

AECL Research (AECL) has constructed an Underground Research Laboratory (URL) as a facility for research and development in the Canadian Nuclear Fuel Waste Management Program. The objectives of the program are to develop and evaluate the technology to ensure safe, permanent disposal of Canada's nuclear fuel waste. Several multidisciplinary experiments and engineering demonstrations are planned for the URL over the next ten years. In 1989, AECL excavated a test room for the Buffer/Container Experiment at the 240 Level. The blasts were designed to limit vibration and overpressure damage because the excavation was located close to existing furnishings and services that were very susceptible to blast-induced vibration and overpressure. An experimental room, which contained sensitive instrumentation, was located within 30 m of the initial blasts. A concrete floor slab, timber curtains and a bulkhead were installed to protect furnishings and services from fly-rock and overpressure. Five of the initial blasts were monitored. This paper describes the results of the monitoring program and the effectiveness of the blast design, floor slab and timber curtains and bulkhead in reducing blast overpressure and vibrations at the blast site. It is shown that greater than a 20-fold reduction in both blast vibrations and air overpressures can be achieved with specific combinations of blast design, installation of timber curtains and construction of a concrete floor slab

Self-compacting concrete with sugarcane bagasse ash – ground blast furnace slag blended cement: fresh properties

Science.gov (United States)

Le, Duc-Hien; Sheen, Yeong-Nain; Ngoc-Tra Lam, My

2018-04-01

In this investigation, major properties in fresh state of self-compacting concrete (SCC) developed from sugarcane bagasse ash and granulated blast furnace slag as supplementary cementitious materials were examined through an experimental work. There were four mix groups (S0, BA10, BA20, and BA30) containing different cement replacing levels; and totally, 12 SCC mixtures and one control mixture were provided for the test. Fresh properties of the proposed SCC were evaluated through measurement of the density, slump, slump-flow, V-funnel test, T500 slump, Box-test, and setting time. The testing results indicated that replacing either SBA and/or BFS to OPC in SCC mixtures led to lower density, lesser flowability, and longer hardening times.

Effect of High-Temperature Curing Methods on the Compressive Strength Development of Concrete Containing High Volumes of Ground Granulated Blast-Furnace Slag

Directory of Open Access Journals (Sweden)

Wonsuk Jung

2017-01-01

Full Text Available This paper investigates the effect of the high-temperature curing methods on the compressive strength of concrete containing high volumes of ground granulated blast-furnace slag (GGBS. GGBS was used to replace Portland cement at a replacement ratio of 60% by binder mass. The high-temperature curing parameters used in this study were the delay period, temperature rise, peak temperature (PT, peak period, and temperature down. Test results demonstrate that the compressive strength of the samples with PTs of 65°C and 75°C was about 88% higher than that of the samples with a PT of 55°C after 1 day. According to this investigation, there might be optimum high-temperature curing conditions for preparing a concrete containing high volumes of GGBS, and incorporating GGBS into precast concrete mixes can be a very effective tool in increasing the applicability of this by-product.

Control buildings for blast resistance

Energy Technology Data Exchange (ETDEWEB)

Brown, G.A.

1982-08-01

Offers advice on interior design for blast-resistant control buildings. Suggests that for the comfort and safety of occupants, special attention must be paid to internal finishes and color schemes. Considers external treatment (e.g. panels, cladding fixings, thermal insulation), air intakes and exhausts, internal finishes (e.g. stud lining method), and internal walls and partitions. Presents diagrams showing construction method for a control building; elimination of ''cold bridge'' at eaves level; staggering door openings to minimize blast effects; and flexure of concrete walls without affecting the inner lining.

Shaft Boring Machine: A method of mechanized vertical shaft excavation

International Nuclear Information System (INIS)

Goodell, T.M.

1991-01-01

The Shaft Boring Machine (SBM) is a vertical application of proven rock boring technology. The machine applies a rotating cutter wheel with disk cutters for shaft excavation. The wheel is thrust against the rock by hydraulic cylinders and slews about the shaft bottom as it rotates. Cuttings are removed by a clam shell device similar to conventional shaft mucking and the muck is hoisted by buckets. The entire machine moves down (and up) the shaft through the use of a system of grippers thrust against the shaft wall. These grippers and their associated cylinders also provide the means to maintain verticality and stability of the machine. The machine applies the same principles as tunnel boring machines but in a vertical mode. Other shaft construction activities such as rock bolting, utility installation and shaft concrete lining can be accomplished concurrent with shaft boring. The method is comparable in cost to conventional sinking to a depth of about 460 meters (1500 feet) beyond which the SBM has a clear host advantage. The SBM has a greater advantage in productivity in that it can excavate significantly faster than drill and blast methods

Verification of wet blasting decontamination technology

International Nuclear Information System (INIS)

Matsubara, Sachito; Murayama, Kazunari; Yoshida, Hirohisa; Igei, Shigemitsu; Izumida, Tatsuo

2013-01-01

Macoho Co., Ltd. participated in the projects of 'Decontamination Verification Test FY 2011 by the Ministry of the Environment' and 'Decontamination Verification Test FY 2011 by the Cabinet Office.' And we tested verification to use a wet blasting technology for decontamination of rubble and roads contaminated by the accident of Fukushima Daiichi Nuclear Power Plant of the Tokyo Electric Power Company. As a results of the verification test, the wet blasting decontamination technology showed that a decontamination rate became 60-80% for concrete paving, interlocking, dense-grated asphalt pavement when applied to the decontamination of the road. When it was applied to rubble decontamination, a decontamination rate was 50-60% for gravel and approximately 90% for concrete and wood. It was thought that Cs-134 and Cs-137 attached to the fine sludge scraped off from a decontamination object and the sludge was found to be separated from abrasives by wet cyclene classification: the activity concentration of the abrasives is 1/30 or less than the sludge. The result shows that the abrasives can be reused without problems when the wet blasting decontamination technology is used. (author)

Development of a Continuous Drill and Blast Tunneling Concept, Phase II

Science.gov (United States)

1974-05-01

A spiral drilling pattern is described which offers high efficiency drill and blast tunnelling via frequent small blasts rather than occasional large blasts. Design work is presented for a machine which would stay at the face to provide essentially c...

Equipment and Protocols for Quasi-Static and Dynamic Tests of Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC)

Science.gov (United States)

2016-08-01

Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) En gi ne er R es ea rc h an d D ev el op m en t Ce nt er Brett A...Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) Brett A. Williams, Robert D. Moser, William F. Heard, Carol F...equipment and protocols for tests of both very-high-strength concrete (VHSC) and high- strength high-ductility concrete (HSHDC) to predict blast

Centrifugal shot blast system

International Nuclear Information System (INIS)

1998-02-01

This report describes a demonstration of Concrete cleaning, Inc., modified centrifugal shot blast technology to remove the paint coating from concrete flooring. This demonstration is part of the Chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), office of Science and Technology (OST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) CP-5 Research Reactor. The purpose of the LSDP is to demonstrate that using innovative and improved decontamination and decommissioning (D and D) technologies from various sources can result in significant benefits, such as decreased cost and increased health and safety, as compared with baseline D and D technologies. Potential markets exist for the innovative centrifugal shot blast system at the following sites: Fernald Environmental Management Project, Los Alamos, Nevada, Oak Ridge Y-12 and K-25, Paducah, Portsmouth Gaseous Diffusion site, and the Savannah River Site. This information is based on a revision to the OST Linkage Tables dated August 4, 1997

Evaluation of mechanical properties of construction joint between new and old concrete under combined tensile and shear stresses; Shinkyu concrete no uchitsugime no incho sendan oryokuka no kyodo tokusei no hyoka

Energy Technology Data Exchange (ETDEWEB)

Ujiike, I. [Ehime University, Ehime (Japan). Faculty of Engineering; Yoshida, N. [Shikoku Railway Company, Kagawa (Japan); Morishita, S. [Oriental Construction Co. Ltd., Tokyo (Japan)

1998-01-15

The objective of this study is to examine the mechanical properties of construction joints between existing and newly placed concrete under combined tensile and shear stresses. Loading tests are conducted by using push off type specimens. The joint surface of existing concrete is roughened by shot blast and a half of the specimen is reconstructed by new concrete using ultra rapid hardening cement. The insufficient treatment of joint surface of the old concrete causes the lowering of tensile rigidity, while shearing rigidity is almost the same as that of the other specimen. The shearing and tensile rigidities of non jointed concrete and concrete shot blasted properly are not dependent on the combination of shearing and tensile forces. For the jointed concrete shot blasted insufficiently, the shearing rigidity decreases with the increase of tensile force and the tensile digidity also becomes lower by the action of shearing force. Both the tensile strength and shearing strength of jointed concrete become small compared to those of non jointed concrete. The ratio of reduction in tensile strength is larger than that in shearing strength. The strength of jointed concrete under combined tensile and shear stresses can be evaluated by Mohr`s failure envelope expressed by parabola tangent to both tensile strength circle and compressive strength circle. 7 refs., 12 figs., 2 tabs.

Prediction of the Chloride Resistance of Concrete Modified with High Calcium Fly Ash Using Machine Learning.

Science.gov (United States)

Marks, Michał; Glinicki, Michał A; Gibas, Karolina

2015-12-11

The aim of the study was to generate rules for the prediction of the chloride resistance of concrete modified with high calcium fly ash using machine learning methods. The rapid chloride permeability test, according to the Nordtest Method Build 492, was used for determining the chloride ions' penetration in concrete containing high calcium fly ash (HCFA) for partial replacement of Portland cement. The results of the performed tests were used as the training set to generate rules describing the relation between material composition and the chloride resistance. Multiple methods for rule generation were applied and compared. The rules generated by algorithm J48 from the Weka workbench provided the means for adequate classification of plain concretes and concretes modified with high calcium fly ash as materials of good, acceptable or unacceptable resistance to chloride penetration.

Capability of GGBS concrete exposed to sea water

International Nuclear Information System (INIS)

Salihuddin Radin Sumadi; Rosli Hamir; Abu Bakar Mohamad Diah

1999-01-01

This paper reported studies the penetration of chloride into ground granulated blast furnace slag (GGBS) concrete with exposure on marine environment. Test were conducted on ordinary portland cement (OPC) concrete and 60% (by weight) of OPC replaced GGBS (S-60). The specimens immersed in sea water were tested for chloride penetration. The results show that higher replacement level of GGBS in concrete significantly reduce the chloride content in concrete. The results also show that chloride concentration decreases with increasing depth into concrete. (author)

Comparison of Machine Learning Techniques for the Prediction of Compressive Strength of Concrete

Directory of Open Access Journals (Sweden)

Palika Chopra

2018-01-01

Full Text Available A comparative analysis for the prediction of compressive strength of concrete at the ages of 28, 56, and 91 days has been carried out using machine learning techniques via “R” software environment. R is digging out a strong foothold in the statistical realm and is becoming an indispensable tool for researchers. The dataset has been generated under controlled laboratory conditions. Using R miner, the most widely used data mining techniques decision tree (DT model, random forest (RF model, and neural network (NN model have been used and compared with the help of coefficient of determination (R2 and root-mean-square error (RMSE, and it is inferred that the NN model predicts with high accuracy for compressive strength of concrete.

Performance and Behaviour of Ground Granulated Blast Furnace Slag Imparted to Geopolymer Concrete Structural Elements and Analyzed with ANSYS

Directory of Open Access Journals (Sweden)

Maria Rajesh Antonyamaladhas

2016-01-01

Full Text Available This paper deals with the behaviour of geopolymer concrete using ground granulated blast furnace slag and steel fibre to compare with M40 grade cement concrete. The cast GPC specimens were placed in a hot curing chamber at 60∘C temperature for 24 hours and tested after 1, 7, 14, and 28 days of ambient curing to find the strength and durability of hardened concrete. The optimum value of compressive strength was attained at 12 Molarities. Fly ash was replaced by GGBS in GPC with different proportions such as 0% to 60% at 5% interval; the optimum strength value was obtained on 40% replacement. From the test results, the compressive, split-tensile, and flexural strength of GPC specimens were 20%, 43%, and 53% higher than those of the control specimens. Based on the optimum strength mix proportion, the structural elements were cast to investigate the stress-strain relations. The GPC beam and L-section showed 33% and 16% higher value. From the results of acid and sulphate resistance tests, it was found that the strength and weight ratio of GPC were higher than the control specimens. From the simulations, it was found that the experimental test results were approximately equal to the ANSYS.

Remote operated vehicle with carbon dioxide blasting (ROVCO2)

International Nuclear Information System (INIS)

Resnick, A.M.

1995-01-01

The Remote Operated Vehicle with Carbon Dioxide Blasting (ROVCO 2 ), as shown in a front view, is a six-wheeled remote land vehicle used to decontaminate concrete floors. The remote vehicle has a high pressure Cryogenesis blasting subsystem, Oceaneering Technologies (OTECH) developed a CO 2 xY Orthogonal Translational End Effector (COYOTEE) subsystem, and a vacuum/filtration and containment subsystem. Figure 2 shows a block diagram with the various subsystems labeled

Centrifugal shot blasting. Innovative technology summary report

International Nuclear Information System (INIS)

1999-07-01

At the US Department of Energy (DOE) Fernald Environmental Management Project (FEMP), the Facilities Closure and Demolition Projects Integrated Remedial Design/Remedial Action (RD/RA) work plan calls for the removal of one inch (1 in) depth of concrete surface in areas where contamination with technetium-99 has been identified. This report describes a comparative demonstration between two concrete removal technologies: an innovative system using Centrifugal Shot Blasting (CSB) and a modified baseline technology called a rotary drum planer

Effect of mineral admixtures on kinetic property and compressive strength of self Compacting Concrete

Science.gov (United States)

Jagalur Mahalingasharma, Srishaila; Prakash, Parasivamurthy; Vishwanath, K. N.; Jawali, Veena

2017-06-01

This paper presents experimental investigations made on the influence of chemical, physical, morphological and mineralogical properties of mineral admixtures such as fly ash, ground granulate blast furnace slag, metakaoline and micro silica used as a replacement of cement in self compacting concrete on workability and compressive strength. Nineteen concrete mixes were cast by replacing with cement by fly ash or ground granulated blast furnace slag as binary blend at 30%, 40%, 50% and with addition of micro silica and metakaoline at 10% as a ternary blend with fly ash, ground granulated blast furnace slag and obtained results were compare with control mix. Water powder ratio 0.3 and super plasticizer dosage 1% of cementitious material was kept constant for all the mixes. The self compacting concrete tested for slump flow, V-funnel, L-Box, J-Ring, T50, and compressive strength on concrete cube were determined at age of 3, 7, 28, 56, 90 days.

Effect of blasting on output increase of bucket wheel excavators

Energy Technology Data Exchange (ETDEWEB)

Musil, P.

1987-12-01

In brown coal surface mines, consolidated sediments become a problem as mining operations advance into greater depth below the original terrain. Owing to higher digging resistance, the output of bucket wheel excavators drops. This problem may be solved by blasting technology and using drilling machines with higher digging force. This paper describes the blasting operations at the Nastup Mines in Tusmice, Czechoslovakia. About 60% of blasting explosives used is a simple mixture of ammonium nitrate and fuel (ANFO), the rest falls on classic blasting gelatines and blasting explosives plasticized by slurry. It is found that blasting improves output by 30% while electric energy consumption is reduced.

Rock fragmentation control in opencast blasting

Directory of Open Access Journals (Sweden)

P.K. Singh

2016-04-01

Full Text Available The blasting operation plays a pivotal role in the overall economics of opencast mines. The blasting sub-system affects all the other associated sub-systems, i.e. loading, transport, crushing and milling operations. Fragmentation control through effective blast design and its effect on productivity are the challenging tasks for practicing blasting engineer due to inadequate knowledge of actual explosive energy released in the borehole, varying initiation practice in blast design and its effect on explosive energy release characteristic. This paper describes the result of a systematic study on the impact of blast design parameters on rock fragmentation at three mines in India. The mines use draglines and shovel–dumper combination for removal of overburden. Despite its pivotal role in controlling the overall economics of a mining operation, the expected blasting performance is often judged almost exclusively on the basis of poorly defined parameters such as powder factor and is often qualitative which results in very subjective assessment of blasting performance. Such an approach is very poor substitutes for accurate assessment of explosive and blasting performance. Ninety one blasts were conducted with varying blast designs and charging patterns, and their impacts on the rock fragmentation were documented. A high-speed camera was deployed to record the detonation sequences of the blasts. The efficiency of the loading machines was also correlated with the mean fragment size obtained from the fragmentation analyses.

Development of engineered cementitious composites with limestone powder and blast furnace slag

NARCIS (Netherlands)

Zhou, J.; Qian, S.; Sierra Beltran, M.G.; Ye, G.; Van Breugel, K.; Li, V.C.

2009-01-01

Nowadays limestone powder and blast furnace slag (BFS) are widely used in concrete as blended materials in cement. The replacement of Portland cement by limestone powder and BFS can lower the cost and enhance the greenness of concrete, since the production of these two materials needs less energy

Close in blasting and rock support at the Bhumibol Powerhouse, Thailand

International Nuclear Information System (INIS)

Murray, L.

1997-01-01

Blasting-related aspects of constructing a pump turbine unit addition to the Bhumibol hydroelectric power plant in Northwest Thailand as part of a retrofit pump storage scheme was described. The work was of particular interest because blasting frequently had to be carried out within one metre of the operating powerhouse for excavation and demolition of 50,000 cubic metre of rock and 5,000 cubic metre of reinforced concrete. Site conditions, work methods, and results of blast vibration monitoring and blast designs were summarized. Although there were severe constraints on the allowable peak particle velocities at the powerhouse electrical equipment, modern time delay blasting techniques were safely used to produce excellent results in a tightly controlled environment. The powerhouse was fully operational during the entire entire blasting phase of the construction project. 5 refs., 4 tabs., 8 figs

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

International Nuclear Information System (INIS)

McPhee, William S.

2001-01-01

The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites

Normal Strength Steel Fiber Reinforced Concrete Subjected to Explosive Loading

OpenAIRE

Mohammed Alias Yusof; Norazman Norazman; Ariffin Ariffin; Fauzi Mohd Zain; Risby Risby; CP Ng

2011-01-01

This paper presents the results of an experimental investigation on the behavior of plain reinforced concrete and Normal strength steel fiber reinforced concrete panels (SFRC) subjected to explosive loading. The experiment were performed by the Blast Research Unit Faculty of Engineering, University Pertahanan Nasional Malaysia A total of 8 reinforced concrete panels of 600mm x 600mm x 100mm were tested. The steel fiber reinforced concrete panels incorporated three different volume fraction, 0...

Evaluation of Grade 120 Granulated Ground blast Furnace Slag.

Science.gov (United States)

1999-06-01

This study evaluates Grade 120 Granulated Ground Blast Furnace Slag (GGBFS) and its effect on the properties of hydraulic cement concretes used in structural and pavement construction. Several mix designs, structural and pavement, were used for this ...

Control technology for crystalline silica exposures in construction: wet abrasive blasting.

Science.gov (United States)

Golla, Vijay; Heitbrink, William

2004-03-01

This study was designed to document the effect that wet abrasive blasting has on reducing worker exposure to crystalline silica, which has been associated with silicosis and premature death. In this study, worker exposure to respirable crystalline silica was monitored during wet abrasive blasting on the exterior walls of a parking garage to remove surface concrete and expose the underlying aggregate. In this process a wet sand mix comprised of 80% dry sand and 20% water was used. Sampling and analysis revealed that the geometric mean respirable quartz concentration was 0.2 mg/m(3) for workers conducting abrasive blasting and 0.06 mg/m(3) for helpers. When abrasive blasting was conducted in areas that apparently had reduced natural ventilation, dust exposures appeared to increase. When compared with other published data, this case study suggests that wet abrasive blasting causes less exposure to crystalline silica than dry abrasive blasting.

The effects of CuO nanoparticles on properties of self compacting concrete with GGBFS as binder

Directory of Open Access Journals (Sweden)

Ali Nazari

2011-09-01

Full Text Available In this work, strength assessments and percentage of water absorption of high performance self compacting concrete containing different amounts of ground granulated blast furnace slag and CuO nanoparticles as binder have been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impacts the physical and mechanical properties of concrete at early age of curing, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt. (% at later ages. CuO nanoparticles with the average particle size of 15 nm were partially added to concrete with the optimum content of ground granulated blast furnace slag and physical and mechanical properties of the specimens were measured. CuO nanoparticle as a partial replacement of cement up to 3.0 wt. (% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH2 amount at the early age of hydration and hence increase strength and improve the resistance to water permeability of concrete specimens. The increased the CuO nanoparticles' content more than 3.0 wt. (%, causes the reduced the split tensile strength because of the decreased crystalline Ca(OH2 content required for C-S-H gel formation. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. More rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that CuO nanoparticles could improve mechanical and physical properties of the concrete specimens.

Comparison on Heat of Hydration between Current Concrete for NPP and High Fluidity Concrete including Pozzolan Powders

International Nuclear Information System (INIS)

Noh, Jea Myoung; Cho, Myung Sug

2010-01-01

Nuclear power plant (NPP) concrete structures are exposed to many construction factors that lower the quality of concrete due to densely packed reinforcements and heat of hydration since they are mostly constructed with mass concrete. The concrete currently being used in Korean NPPs is mixed with Type I cement and fly ash. However, there is a demand to improve the performance of concrete with reduced heat of hydration and superior constructability. Many advantages such as improving workability and durability of concrete and decreasing heat of hydration are introduced by replacing cement with pozzolan binders. Therefore, the manufacturing possibility of high fluidity concrete should be investigated through applying multi-component powders blended with pozzolan binders to the concrete structure of NPPs, while the researches on properties, characteristic of hydration, durability and long-term behavior of high fluidity concrete using multi-component cement should be carried out. High fluidity concrete which is made using portland cement and pozzlonan powders such as fly ash and blast furnace slag has better properties on heat of hydration than the concrete currently in use for NPPs

Mixed materials for concrete. Concrete yo konwazai ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kono, K [Tokushima Univ., Tokushima (Japan). Faculty of Engineering

1994-07-05

The materials except cement, water and aggregate added into the cement paste, mortar or concrete before the execution of smashing are called mixed materials. The mixed materials are indispensable to the concrete for improving the quality of the fresh concrete as well as the hardened concrete; providing the characteristics suitable for the operation; and increasing the economy. In this paper, the main mixed materials including fly ash, which is the by-product in coal thermoelectric power station; silica fume; micropowder of slag in blast furnace; expansive materials and so on are described summarily. Especially, silica fume is the by-product, which are the super micro-powders with the average size around 0.1 micrometer, collected by the dust-collector from the waste gas generated during the manufacture in the electric furnace of ferrosilicon, which is an alloy iron, or silicon metal used as the deacidificating and desulfurizing agents in the steel production. But the most part thereof is depended on the import since the domestic output is low. 38 refs., 19 figs., 6 tabs.

Blast noise classification with common sound level meter metrics.

Science.gov (United States)

Cvengros, Robert M; Valente, Dan; Nykaza, Edward T; Vipperman, Jeffrey S

2012-08-01

A common set of signal features measurable by a basic sound level meter are analyzed, and the quality of information carried in subsets of these features are examined for their ability to discriminate military blast and non-blast sounds. The analysis is based on over 120 000 human classified signals compiled from seven different datasets. The study implements linear and Gaussian radial basis function (RBF) support vector machines (SVM) to classify blast sounds. Using the orthogonal centroid dimension reduction technique, intuition is developed about the distribution of blast and non-blast feature vectors in high dimensional space. Recursive feature elimination (SVM-RFE) is then used to eliminate features containing redundant information and rank features according to their ability to separate blasts from non-blasts. Finally, the accuracy of the linear and RBF SVM classifiers is listed for each of the experiments in the dataset, and the weights are given for the linear SVM classifier.

A review on carbonation study in concrete

Science.gov (United States)

Venkat Rao, N.; Meena, T.

2017-11-01

In this paper the authors have reviewed the carbonation studies which are a vital durability property of concrete. One of the major causes for deterioration and destruction of concrete is carbonation. The mechanism of carbonation involves the penetration carbon dioxide (CO2) into the concrete porous system to form an environment by reducing the pH around the reinforcement and initiation of the corrosion process. The paper also endeavours to focus and elucidate the gravity of importance, the process and chemistry of carbonate and how the various parameters like water/cement ratio, curing, depth of concrete cones, admixtures, grade of concrete, strength of concrete, porosity and permeability effect carbonation in concrete. The role of Supplementary Cementitious Materials (SCMs) like Ground granulated Blast Furnace Slag (GGBS) and Silica Fume (SF) has also been reviewed along with the influence of depth of carbonation.

A Concrete Framework for Environment Machines

DEFF Research Database (Denmark)

Biernacka, Malgorzata; Danvy, Olivier

2007-01-01

calculus with explicit substitutions), we extend it minimally so that it can also express one-step reduction strategies, and we methodically derive a series of environment machines from the specification of two one-step reduction strategies for the lambda-calculus: normal order and applicative order....... The derivation extends Danvy and Nielsen’s refocusing-based construction of abstract machines with two new steps: one for coalescing two successive transitions into one, and the other for unfolding a closure into a term and an environment in the resulting abstract machine. The resulting environment machines...... include both the Krivine machine and the original version of Krivine’s machine, Felleisen et al.’s CEK machine, and Leroy’s Zinc abstract machine....

Remote operated vehicle with carbon dioxide blasting (ROVCO{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Resnick, A.M. [Oceaneering International, Inc., Upper Marlboro, MD (United States)

1995-10-01

The Remote Operated Vehicle with Carbon Dioxide Blasting (ROVCO{sub 2}), as shown in a front view is a six-wheeled remote land vehicle used to decontaminate concrete floors. The remote vehicle has a high pressure Cryogenesis blasting subsystem, Oceaneering Technologies (OTECH) developed a CO{sub 2} xY Orthogonal Translational End Effector (COYOTEE) subsystem, and a vacuum/filtration and containment subsystem. The cryogenesis subsystem performs the actual decontamination work and consists of the dry ice supply unit, the blasting nozzle, the remotely controlled electric and pneumatic valves, and the vacuum work-head. The COYOTEE subsystem positions the blasting work-head within a planar work space and the vacuum subsystem provides filtration and containment of the debris generated by the CO{sub 2} blasting. It employs a High Efficiency Particulate Air (HEPA) filtration unit to separate contaminants for disposal. All of the above systems are attached to the vehicle subsystem via the support structure.

Risk-targeted safety distance of reinforced concrete buildings from natural-gas transmission pipelines

International Nuclear Information System (INIS)

Russo, Paola; Parisi, Fulvio

2016-01-01

Natural-gas pipeline accidents mostly result in major damage even to buildings located far away. Therefore, proper safety distances should be observed in land use planning to ensure target safety levels for both existing and new buildings. In this paper, a quantitative risk assessment procedure is presented for the estimation of the annual probability of direct structural damage to reinforced concrete buildings associated with high-pressure natural-gas pipeline explosions. The procedure is based on Monte Carlo simulation and takes into account physical features of blast generation and propagation, as well as damage to reinforced concrete columns. The natural-gas jet release process and the flammable cloud size are estimated through SLAB one-dimensional integral model incorporating a release rate model. The explosion effects are evaluated by a Multi-Energy Method. Damage to reinforced concrete columns is predicted by means of pressure–impulse diagrams. The conditional probability of damage was estimated at multiple pressure–impulse levels, allowing blast fragility surfaces to be derived at different performance limit states. Finally, blast risk was evaluated and allowed the estimation of minimum pipeline-to-building safety distances for risk-informed urban planning. The probabilistic procedure presented herein may be used for performance-based design/assessment of buildings and to define the path of new natural-gas pipeline networks. - Highlights: • The safety of buildings against blast loads due to pipeline accidents is assessed. • A probabilistic risk assessment procedure is presented for natural-gas pipelines. • The annual risk of collapse of reinforced concrete building columns is evaluated. • Monte Carlo simulation was carried out considering both pipeline and column features. • A risk-targeted safety distance is proposed for blast strength class 9.

Concrete

DEFF Research Database (Denmark)

2015-01-01

Concrete is a component of coherent transition between a concrete base and a wooden construction. The structure is based on a quantity of investigations of the design possibilities that arise when combining digital fabrication tools and material capacities. Through tangible experiments the project...... specific for this to happen. And the knowledge and intention behind the drawing becomes specialised through the understanding of the fabrication processes and their affect on the materials.The structure Concrete is a result of a multi-angled kerf series in ash wood and a concrete base. The ash wood is cut...... using a 5-axis CNC router with a thin saw blade attached. The programming of the machining results in variations of kerfs that lets the ash wood twist into unique shapes.The shapes of the revolving ash ribbons continue into the concrete creating a cohesive shape. The form for the concrete itself is made...

SUSTAINABLE CONCRETE FOR WIND TURBINE FOUNDATIONS.

Energy Technology Data Exchange (ETDEWEB)

BERNDT,M.L.

2004-06-01

The use of wind power to generate electricity continues to grow, especially given commitments by various countries throughout the world to ensure that a significant percentage of energy comes from renewable sources. In order to meet such objectives, increasingly larger turbines with higher capacity are being developed. The engineering aspects of larger turbine development tend to focus on design and materials for blades and towers. However, foundations are also a critical component of large wind turbines and represent a significant cost of wind energy projects. Ongoing wind research at BNL is examining two areas: (a) structural response analysis of wind turbine-tower-foundation systems and (b) materials engineering of foundations. This work is investigating the dynamic interactions in wind turbine systems, which in turn assists the wind industry in achieving improved reliability and more cost efficient foundation designs. The results reported herein cover initial studies of concrete mix designs for large wind turbine foundations and how these may be tailored to reduce cost and incorporate sustainability and life cycle concepts. The approach taken was to investigate material substitutions so that the environmental, energy and CO{sub 2}-impact of concrete could be reduced. The use of high volumes of ''waste'' materials in concrete was examined. These materials included fly ash, blast furnace slag and recycled concrete aggregate. In addition, the use of steel fiber reinforcement as a means to improve mechanical properties and potentially reduce the amount of bar reinforcement in concrete foundations was studied. Four basic mixes were considered. These were: (1) conventional mix with no material substitutions, (2) 50% replacement of cement with fly ash, (3) 50% replacement of cement with blast furnace slag and (4) 25% replacement of cement with fly ash and 25% replacement with blast furnace slag. Variations on these mixes included the addition of 1

PERFORMANCE OF RC AND FRC WALL PANELS REINFORCED WITH MILD STEEL AND GFRP COMPOSITES IN BLAST EVENTS

Energy Technology Data Exchange (ETDEWEB)

Timothy Garfield; William D. Richins; Thomas K. Larson; Chris P. Pantelides; James E. Blakeley

2011-06-01

The structural integrity of reinforced concrete structures in blast events is important for critical facilities. This paper presents experimental data generated for calibrating detailed finite element models that predict the performance of reinforced concrete wall panels with a wide range of construction details under blast loading. The test specimens were 1.2 m square wall panels constructed using Normal Weight Concrete (NWC) or Fiber Reinforced Concrete (FRC). FRC consists of macro-synthetic fibers dispersed in NWC. Five types of panels were tested: NWC panels with steel bar reinforcement (Type A); FRC panels without additional reinforcement (Type B); FRC panels with steel bar reinforcement (Type C); NWC panels with glass fiber reinforced polymer (GFRP) bar reinforcement (Type D); and NWC panels reinforced with steel bar reinforcement and external bidirectional GFRP overlays on both faces (Type E). An additional three Type C panels were used as control specimens (CON). Each panel type was constructed with three thicknesses: 152 mm, 254 mm, and 356 mm. The panels were instrumented with strain gauges, and accelerometers; in addition, pressure sensors and high speed videos were employed during the blast events. Panel types C and E had the best performance, whereas panel type B did not perform well. Preliminary dynamic simulations show crack patterns similar to the experimental results.

Technology Demonstration of Wet Abrasive Blasting for Removal of Lead- and Asbestos-Containing Paint

National Research Council Canada - National Science Library

Race, Timothy

2003-01-01

...). This technology demonstration showed that wet blasting using an engineered abrasive can safely and effectively remove lead- and asbestos-containing paint from exterior concrete masonry unit walls...

Effects of temperature on concrete cask in a dry storage facility for spent nuclear fuels

International Nuclear Information System (INIS)

Huang Weiqing; Wu Ruixian; Zheng Yukuan

2011-01-01

In the dry storage of spent nuclear fuels,concrete cask serves both as a shielding and a structural containment. The concrete in the storage facility is expected to endure the decay heat of the spent nuclear fuel during its service life. Thus, effects of the sustaining high temperature on concrete material need be evaluated for safety of the dry storage facility. In this paper, we report an experimental program aimed at investigating possible high temperature effects on properties of concrete, with emphasis on the mechanical stability, porosity,and crack-resisting ability of concrete mixes prepared using various amounts of Portland cement, fly ash, and blast furnace slag. The experimental results obtained from concrete specimens exposed to a temperature of 94 degree C for 90 days indicate that: (1) compressive strength of the concrete remains practically unchanged; (2) the ultrasonic pulse velocity, and dynamic modulus of elasticity of the concrete decrease in early stage of the high-temperature exposure,and gradually become stable with continuing exposure; (3) shrinkage of concrete mixes exhibits an increase in early stage of the exposure and does not decrease further with time; (4) concrete mixes containing pozzolanic materials,including fly ash and blast furnace slag, show better temperature-resisting characteristics than those using only Portland cement. (authors)

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

Progress of admixtures and quality of concrete. 2. ; Approaches to ultra-high-strength concrete. Konwa zairyo no shinpo to concrete no hinshitsu. 2. ; Chokokyodo concrete eno approach

Energy Technology Data Exchange (ETDEWEB)

Kawai, T. (Shimizu Construction Co. Ltd., Tokyo (Japan)); Abe, M. (Building Research Institute, Tsukuba (Japan))

1994-02-15

Ultra-high-strength concrete of 600 kgf/cm[sup 2] or more is reviewed. MDF (macro defect free) cement, spheroidal cement and mechanically stabilized cement have been developed for ultra-high-strength concrete, however, in general, DSP (densified system containing homogeneously arranged ultra-fine particles) technique is now usual in which a water-cement ratio is reduced by use of advanced air entraining and water reducing agents and cured concrete is densified by use of ultra-fine particles as admixture. Four kinds of substances such as naphthalene system and polycarboxylic acid system are used as air entraining and water reducing agents, and silica fume is used as ultra-fine particle admixture which can be effectively replaced with blast furnace slag or fly ash. Various use examples of ultra-high-strength concrete such as an ocean platform are found in the world, however, only some examples such as a PC truss bridge and the main tower of a PC cable stayed bridge in Japan. 22 refs., 10 figs., 2 tabs.

Implementations of BLAST for parallel computers.

Science.gov (United States)

Jülich, A

1995-02-01

The BLAST sequence comparison programs have been ported to a variety of parallel computers-the shared memory machine Cray Y-MP 8/864 and the distributed memory architectures Intel iPSC/860 and nCUBE. Additionally, the programs were ported to run on workstation clusters. We explain the parallelization techniques and consider the pros and cons of these methods. The BLAST programs are very well suited for parallelization for a moderate number of processors. We illustrate our results using the program blastp as an example. As input data for blastp, a 799 residue protein query sequence and the protein database PIR were used.

Prompt gamma analysis of fly ash, silica fume and Superpozz blended cement concrete specimen

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: aanaqvi@kfupm.edu.sa; Garwan, M.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khateeb-ur-Rehman; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2009-09-15

Preventive measures against corrosion of reinforcing steel require making the concrete dense by adding pozzolanic materials, such as fly ash, silica fume, Superpozz, blast furnace slag, etc. to Portland cement. In order to obtain the desired strength and durability of concrete, it is desirable to monitor the concentration of the pozzolan in the blended cement concrete. Addition of pozzolan to blended cement changes the overall concentration of calcium and silicon in the blended cement concrete. The resulting variation in calcium and silicon gamma-ray yield ratio from blended cement concrete has found to have an inverse correlation with concentration of fly ash, silica fume, Superpozz, blast furnace slag in the blended cement concrete. For experimental verification of the correlation, intensities of calcium and silicon prompt gamma-ray due to capture of thermal neutrons in blended cement concrete samples containing 5-80% (by weight of cement) silica fume, fly ash and Superpozz were measured. The gamma-ray intensity ratio was measured from 6.42 MeV gamma-rays from calcium and 4.94 MeV gamma-ray from silicon. The experimentally measured values of calcium to silicon gamma-ray yield ratio in the fly ash, silica fume and Superpozz cement concrete specimens agree very well with the results of the Monte Carlo simulations.

Prompt gamma analysis of fly ash, silica fume and Superpozz blended cement concrete specimen

International Nuclear Information System (INIS)

Naqvi, A.A.; Garwan, M.A.; Maslehuddin, M.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Khateeb-ur-Rehman,; Raashid, M.

2009-01-01

Preventive measures against corrosion of reinforcing steel require making the concrete dense by adding pozzolanic materials, such as fly ash, silica fume, Superpozz, blast furnace slag, etc. to Portland cement. In order to obtain the desired strength and durability of concrete, it is desirable to monitor the concentration of the pozzolan in the blended cement concrete. Addition of pozzolan to blended cement changes the overall concentration of calcium and silicon in the blended cement concrete. The resulting variation in calcium and silicon gamma-ray yield ratio from blended cement concrete has found to have an inverse correlation with concentration of fly ash, silica fume, Superpozz, blast furnace slag in the blended cement concrete. For experimental verification of the correlation, intensities of calcium and silicon prompt gamma-ray due to capture of thermal neutrons in blended cement concrete samples containing 5-80% (by weight of cement) silica fume, fly ash and Superpozz were measured. The gamma-ray intensity ratio was measured from 6.42 MeV gamma-rays from calcium and 4.94 MeV gamma-ray from silicon. The experimentally measured values of calcium to silicon gamma-ray yield ratio in the fly ash, silica fume and Superpozz cement concrete specimens agree very well with the results of the Monte Carlo simulations.

Applied machining technology

CERN Document Server

Tschätsch, Heinz

2010-01-01

Machining and cutting technologies are still crucial for many manufacturing processes. This reference presents all important machining processes in a comprehensive and coherent way. It includes many examples of concrete calculations, problems and solutions.

Prevention of Blast-Related Injuries

Science.gov (United States)

2017-09-01

in a canvas harness. The harness was further supported by a steel frame which was suspended from a metal beam (3.7 m off the ground) mounted on...direction of the wave propagation (Figure 5). After proper alignment of the head with respect to the center of the C4 charge, the steel frame was...further tied to four hooks cemented to the concrete ground with straps to prevent excessive motion during the blast exposure. The intensity of the two

Behaviour of high-strength concrete incorporating ground ...

African Journals Online (AJOL)

of tests were carried out on concrete incorporating Ground Granulated Blast Furnace Slag (GGBFS) of “Mittal ... mechanical properties by using the existing materials on the local market and HSC ..... general shape of the curves whether at 28 days ... Figure.7. Residual compressive strength as a function of temperature.

Environmental performance and mechanical analysis of concrete containing recycled asphalt pavement (RAP) and waste precast concrete as aggregate.

Science.gov (United States)

Erdem, Savaş; Blankson, Marva Angela

2014-01-15

The overall objective of this research project was to investigate the feasibility of incorporating 100% recycled aggregates, either waste precast concrete or waste asphalt planning, as replacements for virgin aggregates in structural concrete and to determine the mechanical and environmental performance of concrete containing these aggregates. Four different types of concrete mixtures were designed with the same total water cement ratio (w/c=0.74) either by using natural aggregate as reference or by totally replacing the natural aggregate with recycled material. Ground granulated blast furnace slag (GGBS) was used as a mineral addition (35%) in all mixtures. The test results showed that it is possible to obtain satisfactory performance for strength characteristics of concrete containing recycled aggregates, if these aggregates are sourced from old precast concrete. However, from the perspective of the mechanical properties, the test results indicated that concrete with RAP aggregate cannot be used for structural applications. In terms of leaching, the results also showed that the environmental behaviour of the recycled aggregate concrete is similar to that of the natural aggregate concrete. Copyright © 2013 Elsevier B.V. All rights reserved.

Radiological impact of cement, concrete and admixtures in Spain

International Nuclear Information System (INIS)

Chinchon-Paya, S.; Piedecausa, B.; Hurtado, S.; Sanjuan, M.A.; Chinchon, S.

2011-01-01

It has been analyzed samples of portland cement (PC) with and without admixtures, samples of calcium aluminate cement (CAC) with different content of Al 2 O 3 and specimens of concrete made with PC and CAC using High Resolution Gamma Spectrometry. The activity concentration index (I) is much less than 0.5 mSv y -1 for all the concrete specimens according to the Radiation protection document 112 of the European Commission. The PC without admixtures (CEM I 52,5 R) and the PC with addition of limestone (CEM II/BL 32,5 N) also have an I value much lower than 0.5 and the PC with the addition of fly ash and blast furnace slag (CEM IV/B (V) 32,5 N and III/A 42.5 N/SR) have an I value close to 0.6. The I value of the CAC used in the manufacture of structural precast concrete is of the order of 1 mSv y -1 . Some of the CAC used in refractory concrete reaches a value close to 2 mSv y -1 . - Highlights: → The activity values (I) of spanish portland cement and admixtures studied are similar to those described by other authors. → For the first time in scientific publications we have shown results of several calcium aluminate cements (CAC). → CAC used in structural concrete has an approximate I value = 1 (similar to blast furnace slag and fly ash). → One type of CAC with Al 2 O 3 content of 51% used in refractory concretes has a value of I = 2.

Chloride-binding Effect of Blast Furnace Slag in Cement Pastes ...

African Journals Online (AJOL)

NICO

2017-05-16

May 16, 2017 ... ground granulated blast furnace slag (GGBS) and silica fume (SF), to concrete mixtures to increase the corrosion resistance of the reinforcement in the matrix and its subsequent design life span. Various investigations have reported on the effect of mineral admixtures and additions on chloride binding in ...

The Environmental Impact and Cost Analysis of Concrete Mixing Blast Furnace Slag Containing Titanium Gypsum and Sludge in South Korea

Directory of Open Access Journals (Sweden)

Tae Hyoung Kim

2016-05-01

Full Text Available This study assessed the environmental effects and cost of the Industrial Waste addictive Blast Furnace Slag (W-BFS using Life Cycle Assessment (LCA and compared it to general BFS. The environmental impacts of W-BFS were as follows: 1.12 × 10−1 kg-CO2 eq/kg, 3.18 × 10−5 kg-Ethylene eq/kg, 4.79 × 10−4 kg-SO2 eq/kg, 7.15 × 10−4 kg-PO43− eq/kg, 7.15 × 10−4 kg-CFC11 eq/kg and 3.94 × 10−3 kg-Antimony eq/kg. Among the environmental impact category, GWP and AP were 9.28 × 10−2 kg-CO2 eq/kg and 3.33 × 10−4 kg-SO2 eq/kg at a raw material stage, accounting for 80% and 70% of total environmental impact respectively. In EP, POCP and ADP, in addition, raw material stage accounted for a great portion in total environmental impact because of “W” among input materials. In ODP, however, compared to the environmental impact of raw materials, oil, which was used in transporting BFS to the W-BFS manufacturing factory, was more influential. In terms of GWP, POCP and ODP, W-BFS was higher than general BFS. In terms of AP, EP and ADP, in contrast, the former was lower than the latter. In terms of cost, W-BFS (41.7 US$/ton was lower than general BFS by about 17% because of the use of waste additives comprised of industrial wastes instead of natural gypsum ,which has been commonly used in general BFS. In terms of GWP and POCP, the W-BFS mixed (30% concrete was lower than plain concrete by 25%. In terms of AP and EP, the former was lower than the latter by 30%. In terms of ADP, furthermore, W-BFS mixed (30% concrete was lower than plain concrete by 11%. In aggregate-related ODP, however, almost no change was found. In terms of cost, when W-BFS was added by 10% and 30%, it was able to reduce cost by 3% and 7% respectively, compared to plain concrete. Compared to BFS-mixed concrete as well, cost could be saved by 1% additionally because W-BFS (US$41.7/ton is lower than common cement (US$100.3/ton by about 60% in terms of production costs.

Tunnel blasting - recent developments

Energy Technology Data Exchange (ETDEWEB)

White, T.E.

1999-05-01

While tunnelling machines are more efficient than previously, there are still areas where blasting is a more efficient method of advance. Drilling and design methods are increasingly sophisticated, as is choice of explosive. Explosive deployment must be carefully calculated so as to avoid desensitisation. Nitroglycerine may be used as slurries; bulk mixing on site of ANFO is also practised in mining in the UK. Electric detonators, Nonel tubes, and electronic detonators are also increasingly employed.

Prompt gamma-ray analysis of steel slag in concrete

International Nuclear Information System (INIS)

Naqvi, Akhtar Abbas; Garwan, Muhammad Ahmad; Nagadi, Mahmoud Mohammad; Rehman, Khateeb-ur; Raashid, Mohammad; Masalehuddin Mohiuddin, Mohammad; Al-Amoudi, Omar Saeed Baghabra

2009-01-01

Blast furnace slag (BFS) is added to Portland cement concrete to increase its durability, particularly its corrosion resistance. Monitoring the concentration of BFS in concrete for quality control purposes is desired. In this study, the concentration of BFS in concrete was measured by utilizing an accelerator-based prompt gamma-ray neutron activation analysis (PGNAA) setup. The optimum size of the BFS cement concrete specimen that produces the maximum intensity of gamma rays at the detector location was calculated through Monte Carlo simulations. The simulation results were experimentally validated through the gamma-ray yield measurement from BFS cement concrete specimens having different radii. The concentration of BFS in the cement concrete specimens was assessed through calcium and silicon gamma-ray yield measurement from cement concrete specimens containing 5 to 80 wt% BFS. The yield of calcium gamma rays decreases with increasing BFS concentration in concrete while the yield of silicon gamma rays increases with increasing BFS concentration in concrete. The calcium-to-silicon gamma-ray yield ratio has an inverse relation with BFS concentration in concrete. (author)

Construction of the Kashiwazaki-Kariwa Nuclear Power Plant. Preparation and quality control of concrete for RCCV of the No. 6/7 machines

International Nuclear Information System (INIS)

Morishita, Hideki; Tsuchiya, Yoshimasa; Eguchi, Kiyoshi; Hosaka, Hiroshi

1998-01-01

In construction engineering of the Kashiwazaki-Kariwa Nuclear Power Plant, about 3,400 km 3 of concrete was used for whole machines from No. 1 to No. 7. For the Nos. 6 and 7 plants (K-6/7), the improved boiling-water reactor (ABWR) was adopted first in the world, a reinforced concrete reactor vessel (RCCV) was used in alternative with the conventional steel one. The RCCV is composed of a cylindrical shell, a planar top-slab and a mat, which are required to have functions such as shielding pressure resistance and seismic resistance. Each of every portions has a large section and is required to deal for mass concrete. As the K-6/7 have a lot of steel reinforcements for their mass concrete is necessary to pay careful attention to their fillings on a standpoint of their operations, high performance AE dewatering agent concrete with high fluidity was used. When the AE dewatering agent concrete was designed to prepare, various fundamental experiments were conducted to confirm their superior performance. As result, the concrete with high quality in material property could be processed. (G.K.)

Quality assurance of polymer concrete

International Nuclear Information System (INIS)

Schulz, H.

1984-01-01

With polymer concrete, a whole range of organisational and functional measures have to be met in order to assure the required quality with an economic expenditure. Quality assurance begins in the design and does not end in the production, rather includes all fields of the enterprise. The following deals with a particular range of the total complex, the inspection methods for assuring the quality of machine components of polymer concrete, particularly machine tool bases, this being through the control of the raw material, the production and the finished product. (orig.) [de

Two-point concrete resistivity measurements: interfacial phenomena at the electrode–concrete contact zone

International Nuclear Information System (INIS)

McCarter, W J; Taha, H M; Suryanto, B; Starrs, G

2015-01-01

Ac impedance spectroscopy measurements are used to critically examine the end-to-end (two-point) testing technique employed in evaluating the bulk electrical resistivity of concrete. In particular, this paper focusses on the interfacial contact region between the electrode and specimen and the influence of contacting medium and measurement frequency on the impedance response. Two-point and four-point electrode configurations were compared and modelling of the impedance response was undertaken to identify and quantify the contribution of the electrode–specimen contact region on the measured impedance. Measurements are presented in both Bode and Nyquist formats to aid interpretation. Concretes mixes conforming to BSEN206-1 and BS8500-1 were investigated which included concretes containing the supplementary cementitious materials fly ash and ground granulated blast-furnace slag. A measurement protocol is presented for the end-to-end technique in terms of test frequency and electrode–specimen contacting medium in order to minimize electrode–specimen interfacial effect and ensure correct measurement of bulk resistivity. (paper)

Preventive measures against concrete damage to ASR in the Netherlands current state-of-affairs

NARCIS (Netherlands)

Heijnen, W.M.M.; Larbi, J.A.

1999-01-01

In CUR-Recommendation 38, various vital measures that need to be taken during design of new concrete-mixtures in order to prevent damage due to ASR in the concrete have been outlined. The most important of these measures are: - the use of blast furnace slag cement (with a high slag content: ≥50% by

Behaviour of high-strength concrete incorporating ground ...

African Journals Online (AJOL)

106. Behaviour of high-strength concrete incorporating ground granulated blast furnace slag at high-temperature. Comportement à haute température du béton à haute résistance à base de laitier granulé de haut fourneau. Imene Saadi*1 & Abdelaziz Benmarce2. 1Laboratoire Matériaux Géométraux et Environnement, ...

Ultimate deformation capacity of reinforced concrete slabs underblast load

NARCIS (Netherlands)

Doormaal, J.C.A.M. van; Weerheijm, J.

1996-01-01

In this paper a test method to determine the deformation capacity and the resistance-deformation curve of blast-loaded slabs is described. This method was developed at TNO-PML. The method has been used to determine the ultimate deformation capacity of some simply supported reinforced concrete slabs

Performance Evaluation and Field Application of Porous Vegetation Concrete Made with By-Product Materials for Ecological Restoration Projects

Directory of Open Access Journals (Sweden)

Hwang-Hee Kim

2016-03-01

Full Text Available The purpose of this study was to evaluate the performance of porous vegetation concrete block made from blast furnace slag cement containing industrial by-products such as blast furnace slag aggregate and powder. The blocks were tested for void ratio, compressive strength and freeze-thaw resistance to determine the optimal mixing ratio for the porous vegetation block. An economic analysis of the mixing ratio showed that the economic efficiency increased when blast furnace slag aggregate and cement were used. Porous vegetation concrete blocks for river applications were designed and produced. Hydraulic safety, heavy metal elution and vegetation tests were completed after the blocks were applied in the field. The measured tractive force ranged between 7.0 kg/m2 for fascine revetment (vegetation revetment and 16.0 kg/m2 for stone pitching (hard revetment, which ensured sufficient hydraulic stability in the field. Plant growth was measured after the porous vegetation concrete block was placed in the field. Seeds began to sprout one week after seeding; after six weeks, the plant length exceeded 300 mm. The average coverage ratio reached as high as 90% after six weeks of vegetation. These results clearly indicated that the porous vegetation concrete block was suitable for environmental restoration projects.

Characterisation of chloride transport and reinforcement corrosion in concrete under cyclic wetting and drying by electrical resistivity

NARCIS (Netherlands)

Polder, R.B.; Peelen, W.H.A.

2002-01-01

Concrete prisms were made with four cement types including cements with fly ash and/or blast furnace slag and three waterto- cement (w/c) ratios. Chloride penetration and corrosion of rebars were stimulated by subjecting prisms to cyclic loading with salt solution and drying. Concrete resistivity,

GPR identification of voids inside concrete based on the support vector machine algorithm

International Nuclear Information System (INIS)

Xie, Xiongyao; Li, Pan; Qin, Hui; Liu, Lanbo; Nobes, David C

2013-01-01

Voids inside reinforced concrete, which affect structural safety, are identified from ground penetrating radar (GPR) images using a completely automatic method based on the support vector machine (SVM) algorithm. The entire process can be characterized into four steps: (1) the original SVM model is built by training synthetic GPR data generated by finite difference time domain simulation and after data preprocessing, segmentation and feature extraction. (2) The classification accuracy of different kernel functions is compared with the cross-validation method and the penalty factor (c) of the SVM and the coefficient (σ2) of kernel functions are optimized by using the grid algorithm and the genetic algorithm. (3) To test the success of classification, this model is then verified and validated by applying it to another set of synthetic GPR data. The result shows a high success rate for classification. (4) This original classifier model is finally applied to a set of real GPR data to identify and classify voids. The result is less than ideal when compared with its application to synthetic data before the original model is improved. In general, this study shows that the SVM exhibits promising performance in the GPR identification of voids inside reinforced concrete. Nevertheless, the recognition of shape and distribution of voids may need further improvement. (paper)

Improvement of impact-resistance of a nuclear containment building using fiber reinforced concrete

International Nuclear Information System (INIS)

Jeon, Se-Jin; Jin, Byeong-Moo

2016-01-01

Highlights: • Impact-resistance of a structure can be improved by fiber reinforced concrete (FRC). • Material modeling of FRC is incorporated into finite element analysis of a structure. • A new index for impact-resistance is proposed based on plastic dissipation energy. • A nuclear power plant made of FRC shows improved resistance against aircraft crashes. - Abstract: Since the act of terrorism that occurred in the USA on September 11, 2001, the protection of nuclear power plants against large commercial aircraft crashes has been an emerging issue. Besides the verification of the safety of nuclear power plants in operation or in design, efficient methods for improving the impact-resistance of these structures have been investigated. Fiber reinforced concrete (FRC) has been generally accepted as an effective material for this purpose. In particular, FRC has been developed to improve the tensile behavior of concrete such as tensile strength, ductility and toughness. One of the main fields of application of FRC can be found in blast-protective or blast-resistant concrete structures. It is expected, therefore, that safety-related structures in a nuclear power plant can also be effectively protected from external blast, aircraft crash, etc. by applying FRC. In order to analytically verify the effect on structural behavior of applying FRC, the particular material properties of FRC should be incorporated into the material modeling of a structural analysis program. This study investigates the mathematical modeling of FRC, which represents various aspects of material behavior. Two numerical examples are provided to show the improved impact-resistance of a nuclear containment building that is expected when applying FRC in comparison with ordinary concrete. The analysis results show that the displacement decreases by 43–67% while the impact-resistance increases by 40–82%, depending on a fiber type.

Improvement of impact-resistance of a nuclear containment building using fiber reinforced concrete

Energy Technology Data Exchange (ETDEWEB)

Jeon, Se-Jin, E-mail: conc@ajou.ac.kr [Ajou University, 206, World cup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16499 (Korea, Republic of); Jin, Byeong-Moo [DAEWOO E& C, Institute of Construction Technology, 20, Suil-ro 123beon-gil, Jangan-gu, Suwon-si, Gyeonggi-do 16297 (Korea, Republic of)

2016-08-01

Highlights: • Impact-resistance of a structure can be improved by fiber reinforced concrete (FRC). • Material modeling of FRC is incorporated into finite element analysis of a structure. • A new index for impact-resistance is proposed based on plastic dissipation energy. • A nuclear power plant made of FRC shows improved resistance against aircraft crashes. - Abstract: Since the act of terrorism that occurred in the USA on September 11, 2001, the protection of nuclear power plants against large commercial aircraft crashes has been an emerging issue. Besides the verification of the safety of nuclear power plants in operation or in design, efficient methods for improving the impact-resistance of these structures have been investigated. Fiber reinforced concrete (FRC) has been generally accepted as an effective material for this purpose. In particular, FRC has been developed to improve the tensile behavior of concrete such as tensile strength, ductility and toughness. One of the main fields of application of FRC can be found in blast-protective or blast-resistant concrete structures. It is expected, therefore, that safety-related structures in a nuclear power plant can also be effectively protected from external blast, aircraft crash, etc. by applying FRC. In order to analytically verify the effect on structural behavior of applying FRC, the particular material properties of FRC should be incorporated into the material modeling of a structural analysis program. This study investigates the mathematical modeling of FRC, which represents various aspects of material behavior. Two numerical examples are provided to show the improved impact-resistance of a nuclear containment building that is expected when applying FRC in comparison with ordinary concrete. The analysis results show that the displacement decreases by 43–67% while the impact-resistance increases by 40–82%, depending on a fiber type.

Machine learning techniques in disease forecasting: a case study on rice blast prediction

Directory of Open Access Journals (Sweden)

Kapoor Amar S

2006-11-01

Full Text Available Abstract Background Diverse modeling approaches viz. neural networks and multiple regression have been followed to date for disease prediction in plant populations. However, due to their inability to predict value of unknown data points and longer training times, there is need for exploiting new prediction softwares for better understanding of plant-pathogen-environment relationships. Further, there is no online tool available which can help the plant researchers or farmers in timely application of control measures. This paper introduces a new prediction approach based on support vector machines for developing weather-based prediction models of plant diseases. Results Six significant weather variables were selected as predictor variables. Two series of models (cross-location and cross-year were developed and validated using a five-fold cross validation procedure. For cross-year models, the conventional multiple regression (REG approach achieved an average correlation coefficient (r of 0.50, which increased to 0.60 and percent mean absolute error (%MAE decreased from 65.42 to 52.24 when back-propagation neural network (BPNN was used. With generalized regression neural network (GRNN, the r increased to 0.70 and %MAE also improved to 46.30, which further increased to r = 0.77 and %MAE = 36.66 when support vector machine (SVM based method was used. Similarly, cross-location validation achieved r = 0.48, 0.56 and 0.66 using REG, BPNN and GRNN respectively, with their corresponding %MAE as 77.54, 66.11 and 58.26. The SVM-based method outperformed all the three approaches by further increasing r to 0.74 with improvement in %MAE to 44.12. Overall, this SVM-based prediction approach will open new vistas in the area of forecasting plant diseases of various crops. Conclusion Our case study demonstrated that SVM is better than existing machine learning techniques and conventional REG approaches in forecasting plant diseases. In this direction, we have also

Crumb Rubber-Concrete Panels Under Blast Loads

Science.gov (United States)

2010-05-01

and the samples were labeled. Samples were picked up with an overhead crane and a form spreader connected to two points on the sample, each outside...uniform loading. Shortly after test started 8 to 9 cracks developed within quarter points and 2 cracks developed through pick points where form spreader ...dynamic behaviour of recycled tyre rubber-filled concrete.” Cem. Concr. Res., 32, 1587–1596. Huang, B., Li, G., Pang, S. S., and Eggers, J. (2004

Performance Evaluation and Field Application of Porous Vegetation Concrete Made with By-Product Materials for Ecological Restoration Projects

OpenAIRE

Hwang-Hee Kim; Chan-Gi Park

2016-01-01

The purpose of this study was to evaluate the performance of porous vegetation concrete block made from blast furnace slag cement containing industrial by-products such as blast furnace slag aggregate and powder. The blocks were tested for void ratio, compressive strength and freeze-thaw resistance to determine the optimal mixing ratio for the porous vegetation block. An economic analysis of the mixing ratio showed that the economic efficiency increased when blast furnace slag aggregate and c...

Sorption of Cs, I, and actinides in concrete systems

International Nuclear Information System (INIS)

Allard, B.; Eliasson, L.; Andersson, K.

1984-09-01

Samples of seven different concretes were prepared (Standard Portland cement of two kinds; sulphate resistant, blast furnace slag, high alumina, fly ash, and silica cements) and the corresponding pore waters were analyzed. Batch-wise distribution studies were performed in the various concrete/pore water systems, as well as for three old concrete samples from a hydro power station dam (more than 60 years old), for the elements Cs, I, Th, U, Np, Pu, and Am at trace concentration levels. Generally the sorption of Cs was low, and somewhat higher for I. All the actinides, including U and Np in their hexa- and pentavalent states, respectively, were strongly sorbed on the cement phase. (Author)

A Concrete Framework for Environment Machines

DEFF Research Database (Denmark)

Biernacka, Malgorzata; Danvy, Olivier

2007-01-01

We materialize the common understanding that calculi with explicit substitutions provide an intermediate step between an abstract specification of substitution in the lambda-calculus and its concrete implementations. To this end, we go back to Curien’s original calculus of closures (an early...

High performance concrete with blended cement

International Nuclear Information System (INIS)

Biswas, P.P.; Saraswati, S.; Basu, P.C.

2012-01-01

Principal objectives of the proposed project are two folds. Firstly, to develop the HPC mix suitable to NPP structures with blended cement, and secondly to study its durability necessary for desired long-term performance. Three grades of concrete to b considered in the proposed projects are M35, M50 and M60 with two types of blended cements, i.e. Portland slag cement (PSC) and Portland pozzolana cement (PPC). Three types of mineral admixtures - silica fume, fly ash and ground granulated blast furnace slag will be used. Concrete mixes with OPc and without any mineral admixture will be considered as reference case. Durability study of these mixes will be carried out

Histomorphometric and removal torque analysis for TiO2-blasted titanium implants. An experimental study on dogs

DEFF Research Database (Denmark)

Gotfredsen, K; Nimb, L; Hjörting-Hansen, E

1992-01-01

The aim of the present study was to compare the anchorage of TiO2-blasted screw and cylindrical implants with conventionally used machine-produced screw and cylindrical implants inserted immediately in extraction sockets on dogs. 6 adult mongrel dogs had 3rd and 4th mandibular premolars extracted...... bilaterally and 24 commercial pure titanium implants were placed immediately in extraction sockets and covered with mucoperiosteum. Each dog had inserted 4 implants: 1 screw implant and 1 cylindrical implant blasted with titanium-dioxide-particles; 1 screw implant and 1 cylindrical implant with machine...

Durability of heavyweight concrete containing barite

International Nuclear Information System (INIS)

Binici, Hanifi

2010-01-01

The supplementary waste barite aggregates deposit in Osmaniye, southern Turkey, has been estimated at around 500 000 000 tons based on 2007 records. The aim of the present study is to investigate the durability of concrete incorporating waste barite as coarse and river sand (RS), granule blast furnace slag (GBFS), granule basaltic pumice (GBP) and ≤ 4 mm granule barite (B) as fine aggregates. The properties of the fresh concrete determined included the air content, slump, slump loss and setting time. They also included the compressive strength, flexural and splitting tensile strengths and Young's modulus of elasticity, resistance to abrasion and sulphate resistance of hardened concrete. Besides these, control mortars were prepared with crushed limestone aggregates. The influence of waste barite as coarse aggregates and RS, GBFS, GBP and B as fine aggregates on the durability of the concretes was evaluated. The mass attenuation coefficients were calculated at photon energies of 1 keV to 100 GeV using XCOM and the obtained results were compared with the measurements at 0.66 and 1.25 MeV. The results showed the possibility of using these waste barite aggregates in the production of heavy concretes. In several cases, some of these properties have been improved. Durability of the concrete made with these waste aggregates was improved. Thus, these materials should be preferably used as aggregates in heavyweight concrete production. (orig.)

Influence of Charge Shape and Orientation on the Response of Steel-Concrete Composite Panels

Directory of Open Access Journals (Sweden)

Abraham Christian

2016-09-01

Full Text Available Blast design codes usually generalize the shape of the charge as spherical or hemispherical. However, it was found that the blast overpressure of cylindrical charges differ greatly when compared with relevant analytical results generated with the charges assumed to be spherical. The objective is to use fully coupled 3D multi-material arbitrary Lagrangian Eulerian (MMALE modelling technique in LS Dyna software to simulate the cylindrical charge blast loading. Comparison of spherical and cylindrical charge blast simulation was carried out to show the influence on peak overpressure and total impulse. Two steel-concrete composite specimens were subjected to blast testing under cylinder charges for benchmarking against numerical results. It was found that top detonated, vertical cylinder charge could give much higher blast loading compared to horizontal cylinder charge. The MMALE simulation could generate the pressure loading of various charge shape and orientation to be used for predicting the response of the composite panel.

Alkali-activated concrete with Serbian fly ash and its radiological impact.

Science.gov (United States)

Nuccetelli, Cristina; Trevisi, Rosabianca; Ignjatović, Ivan; Dragaš, Jelena

2017-03-01

The present paper reports the results of a study on different types of fly ash from Serbian coal burning power plants and their potential use as a binder in alkali-activated concrete (AAC) depending on their radiological and mechanical properties. Five AAC mixtures with different types of coal burning fly ash and one type of blast furnace slag were designed. Measurements of the activity concentrations of 40 K, 226 Ra and 232 Th were done both on concrete constituents (fly ash, blast furnace slag and aggregate) and on the five solid AAC samples. Experimental results were compared by using the activity concentration assessment tool for building materials - the activity concentration index I, as introduced by the EU Basic Safety Standards (CE, 2014). All five designed alkali-activated concretes comply with EU BSS screening requirements for indoor building materials. Finally, index I values were compared with the results of the application of a more accurate index - I(ρd), which accounts for thickness and density of building materials (Nuccetelli et al., 2015a). Considering the actual density and thickness of each concrete sample index - I(ρd) values are lower than index I values. As an appendix, a synthesis of main results concerning mechanical and chemical properties is provided. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pilot tests for dismantling by blasting of the biological shield of a shut down nuclear power station

International Nuclear Information System (INIS)

Freund, H.U.

1995-01-01

Following free-field tests on concrete blocks the feasibility of explosive dismantling of the biological shield of nuclear power stations has been succesfully tested at the former hotsteam reaction in Karlstein/Main Germany. For this purpose a model shield of scale 1:2 was embedded into the reactor structure at which bore-hole blasting tests employing up to about 15 kg of explosive were performed. An elaborate measurement system allowed to receive detailed information on the blast side-effects: Special emphasis was focussed on the quantitative registration of the dynamic blast loads; data for the transfer of the dismantling method to the removal of real ractor structures were obtained. (orig.) [de

Microstructural and Microanalytical Study on Concrete Exposed to the Sulfate Environment

Science.gov (United States)

Qing, Fang; Beixing, Li; Jiangang, Yin; Xiaolu, Yuan

2017-11-01

Microstructural properties have been examined to investigate the effect of mineral admixtures on the sulfate resistance of concrete. Concrete and cement paste specimens made with ordinary Portland cement (OPC) or ordinary Portland cement incorporating 20% fly ash (FA) or 30% ground blast furnace slag (GBFS), were made and exposed to 250 cycles of the cyclic sulfate environment. Microstructural and Microanalytical study was conducted by means of x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and mercury intrusion porosimetry (MIP). Results indicate that the pore structure of concrete after sulfate exposure possesses the fractal feature. The OPC concrete presents more complex pore internal surface, higher porosity and less micro-pores than the concrete incorporating fly ash and GBFS. Portlandite in OPC concrete and OPC-FA concrete is mainly converted to gypsum; while for OPC-GBFS concrete, both gypsum and ettringite are formed. In the cyclic sulfate environment, repeated hydration and dehydration of sulfates produce the expansive stress in pores, aggravating the demolishment of concrete structure.

Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress.

Science.gov (United States)

Wang, Hailong; Sun, Xiaoyan; Wang, Junjie; Monteiro, Paulo J M

2016-03-30

The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ).

Measures to prevent concrete damage due to alkali-silica reaction in the Netherlands: Current state-of-affairs

NARCIS (Netherlands)

Heijnen, W.M.M.; Larbi, J.A.

1999-01-01

In CUR-Recommendation 38, various vital measures that need to be taken during design of new concrete-mixtures in order to prevent damage due to ASR in the concrete have been outlined. The most important of these measures are: • the use of blast furnace slag cement (with a high slag content: 50 % by

Durability of recycled aggregate concrete using pozzolanic materials.

Science.gov (United States)

Ann, K Y; Moon, H Y; Kim, Y B; Ryou, J

2008-01-01

In this study, pulverized fuel ash (PFA) and ground granulated blast furnace slag (GGBS) were used to compensate for the loss of strength and durability of concrete containing recycled aggregate. As a result, 30% PFA and 65% GGBS concretes increased the compressive strength to the level of control specimens cast with natural granite gravel, but the tensile strength was still lowered at 28 days. Replacement with PFA and GGBS was effective in raising the resistance to chloride ion penetrability into the concrete body, measured by a rapid chloride ion penetration test based on ASTM C 1202-91. It was found that the corrosion rate of 30% PFA and 65% GGBS concretes was kept at a lower level after corrosion initiation, compared to the control specimens, presumably due to the restriction of oxygen and water access. However, it was less effective in increasing the chloride threshold level for steel corrosion. Hence, it is expected that the corrosion time for 30% PFA and 65% GGBS concrete containing recycled aggregate mostly equates to the corrosion-free life of control specimens.

Effect of prolonged mixing time on concrete properties

International Nuclear Information System (INIS)

Mohd Noorul Ikhsan Mohamed; Sidek, H.A.A.; Wahab, Z.A.

2009-01-01

The correlation between workability, compressive strength and mixing time of fresh concrete has been studied. The concrete samples used in the study are normal concrete of grade 30. The mix design of the concrete samples was estimated using software called Calcrete. Three concrete cubes of 150 mm size were cast immediately after mixing. The same grade of concrete was prepared with the mixing time of 30 minutes to 5 hours. All of the concrete samples were cured for 28 days under room temperature before they were compressed using a compression machine. Result shows that the compressive strength of concrete decreases when mixing time is increased. (author)

The permeability of concrete for reactor containment vessels

International Nuclear Information System (INIS)

Mills, R.H.

1983-07-01

Review of the literature pertaining to water, water vapour and gas transmission through concrete revealed conflicting views on the mechanisms involved and the influence of mix design parameters such as initial porosities and water/cement ratio. Consideration of the effects of ageing and of construction defects in field concrete were totally neglected in published work. Permeability data from three published papers were compared with permeability calculated according to Powers. The ratio of calculated to observed permeability varied from 40 x 10 -3 to 860 x 10 -3 for one group: from 0.17 x 10 3 to 8.6 x 10 3 in the second; and from 24 x 10 3 to 142 x 10 3 for the third. There were therefore wide discrepancies within each group of data and between groups. A bibliography was prepared and an exploratory experimental programme was mounted to determine the relative importance of key parameters such as cement type, porosity and water/cement ratio. Contrary to frequently cited references it was found that permeability of concrete was not significantly influenced by water/cement ratio when the starting porosity was constant. If water/cement ratio was held constant, however, the permeability was strongly influenced by starting porosity. It was also found that with constant water/cement ratio permeability increased with cement content. The value of fly ash and blast furnace slag in partial substitution for Portland cement is neglected in the literature but it is important since such substitutions alleviate alkali-silicate reactions. Permeability of concrete was significantly decreased by partial substitution of Portland cement with fly ash but there was no benefit in the use of blast furnace slag

Calculation of driling and blasting parameters in blasting performance

OpenAIRE

Dambov, Risto; Karanakova Stefanovska, Radmila; Dambov, Ilija

2015-01-01

In all mining technology drilling and blasting parameters and works are one of the main production processes at each mine. The parameters of drilling and blasting and explosives consumption per ton of blasting mass are define economic indicators of any blasting no matter for what purpose and where mining is performed. The calculation of rock blasting should always have in mind that the methodology of calculation of all drilling and blasting parameters in blasting performance are performed for...

Reliability of engineered basements as blast shelters

International Nuclear Information System (INIS)

Longinow, A.; Mohammadi, J.; Robinson, R.R.

1983-01-01

A method for predicting the probability of failure of structures by considering multiple failure modes was formulated. It was applied to the analysis of a reinforced concrete slab when subjected to a uniformly distributed blast load over its surface. Currently available criteria for failure due to flexure and shear were used in predicting the probability of failure. This method is capable of considering all major components of a structure, the respective failure modes of each component, and of predicting the probability of failure of the structure as a whole

Eco-friendly GGBS Concrete: A State-of-The-Art Review

Science.gov (United States)

Saranya, P.; Nagarajan, Praveen; Shashikala, A. P.

2018-03-01

Concrete is the most commonly used material in the construction industry in which cement is its vital ingredient. Although the advantages of concrete are many, there are side effects leading to environmental issues. The manufacturing process of cement emits considerable amount of carbon dioxide (CO2). Therefore is an urgent need to reduce the usage of cement. Ground Granulated Blast furnace Slag (GGBS) is a by-product from steel industry. It has good structural and durable properties with less environmental effects. This paper critically reviews the literatures available on GGBS used in cement concrete. In this paper, the literature available on GGBS are grouped into engineering properties of GGBS concrete, hydraulic action of GGBS in concrete, durability properties of GGBS concrete, self- compacting GGBS concrete and ultrafine GGBS are highlighted. From the review of literature, it was found that the use of GGBS in concrete construction will be eco-friendly and economical. The optimum percentage of replacement of cement by GGBS lies between 40 - 45 % by weight. New materials that can be added in addition to GGBS for getting better strength and durability also highlighted.

Effect of supplementary cementing materials on the concrete corrosion control

International Nuclear Information System (INIS)

Mejia de Gutierrez, R.

2003-01-01

Failure of concrete after a period of years, less than the life expected for which it was designed, may be caused by the environment to which it has been exposed or by a variety of internal causes. The incorporation of supplementary materials has at the Portland cement the purpose of improving the concrete microstructure and also of influence the resistance of concrete to environmental attacks. Different mineral by-products as ground granulated blast furnaces slag (GGBS), silica fume (SF), meta kaolin (MK), fly ash (FA) and other products have been used as supplementary cementing materials. This paper is about the behavior of concrete in the presence of mineral additions. Compared to Portland cements, blended cements show lower heat of hydration, lower permeability, greater resistance to sulphates and sea water. These blended cements find the best application when requirements of durability are regarded as a priority specially on high performance concrete: (Author) 11 refs

Analysis of Mechanical Properties of Self Compacted Concrete by Partial Replacement of Cement with Industrial Wastes under Elevated Temperature

Directory of Open Access Journals (Sweden)

Junaid Mansoor

2018-03-01

Full Text Available Self-Compacting Concrete (SCC differs from the normal concrete as it has the basic capacity to consolidate under its own weight. The increased awareness regarding environmental disturbances and its hazardous effects caused by blasting and crushing procedures of stone, it becomes a delicate and obvious issue for construction industry to develop an alternative remedy as material which can reduce the environmental hazards and enable high-performance strength to the concrete, which would make it durable and efficient for work. A growing trend is being established all over the world to use industrial byproducts and domestic wastes as a useful raw material in construction, as it provides an eco-friendly edge to the construction process and especially for concrete. This study aims to enlighten the use and comparative analysis for the performance of concrete with added industrial byproducts such as Ground Granulated Blast Furnace Slag (GGBFS, Silica fumes (SF and Marble Powder (MP in the preparation of SCC. This paper deals with the prediction of mechanical properties (i.e., compressive, tensile and flexural Strength of self-compacting concrete by considering four major factors such as type of additive, percentage additive replaced, curing days and temperature using Artificial Neural Networks (ANNs.

Proposal for the Evaluation of Eco-Efficient Concrete

Directory of Open Access Journals (Sweden)

Taehyoung Kim

2016-07-01

Full Text Available The importance of environmental consequences due to diverse substances that are emitted during the production of concrete is recognized, but environmental performance tends to be evaluated separately from the economic performance and durability performance of concrete. In order to evaluate concrete from the perspective of sustainable development, evaluation technologies are required for comprehensive assessment of environmental performance, economic performance, and durability performance based on a concept of sustainable development called the triple bottom line (TBL. Herein, an assessment method for concrete eco-efficiency is developed as a technique to ensure the manufacture of highly durable and eco-friendly concrete, while minimizing both the load on the ecological environment and manufacturing costs. The assessment method is based on environmental impact, manufacturing costs, and the service life of concrete. According to our findings, eco-efficiency increased as the compressive strength of concrete increased from 21 MPa to 40 MPa. The eco-efficiency of 40 MPa concrete was about 50% higher than the eco-efficiency of 24 MPa concrete. Thus eco-efficiency is found to increase with an increasing compressive strength of concrete because the rate of increase in the service life of concrete is larger than the rate of increase in the costs. In addition, eco-efficiency (KRW/year was shown to increase for all concrete strengths as mixing rates of admixtures (Ground Granulated Blast furnace Slag increased to 30% during concrete mix design. However, when the mixing rate of admixtures increased to 40% and 60%, the eco-efficiency dropped due to rapid reduction in the service life values of concrete to 74 (year/m3 and 44 (year/m3, respectively.

Application of super workable concrete to main tower of cable-stayed prestressed concrete bridge. ; Kiba park grand bridge. PC shachokyo no shuto eno tekiyo. ; Kiba koen ohashi

Energy Technology Data Exchange (ETDEWEB)

Matsuoka, Y.; Shindo, T.; Sakamoto, A. (Taisei Corp., Tokyo (Japan))

1993-08-01

The Kiba Park Grand Bridge is a cable-stayed prestressed concrete (PC) bridge with a length of 186m. The main tower of this PC cable-stayed bridge consists of a pair of vertical columns with height of 60m and a beam connecting the columns. For the purpose of the advanced efficiency of construction without formwork and removal work and the improvement of durability, the precast buried formwork made of polymer impregnated concrete formwork was adopted. Approximate 650 cubic meter of super workable concrete was placed for the upper part ranging from 7th to 17th blocks of vertical columns and the beam. Blast furnace cement B and fly ash were used as binder. Naphthalenesulfonic acid type high performance water reducing agent and lignosulfonic acid type AE (air-entraining) water reducing agent were used as admixtures. Super workable concrete was mixed using forced double-axle mixers in the ready-mixed concrete plant. Satisfactory quality of the fresh concrete and strength of the hardened concrete were obtained. 2 refs., 11 figs., 3 tabs.

Study on the durability of concrete using granulated blast furnace slag as fine aggregate

Science.gov (United States)

Shi, Dongsheng; Liu, Qiang; Xue, Xinxin; He, Peiyuan

2018-03-01

In order to assessing the durability of concrete using granulated blastfurnace slag (GBS) as fine aggregate and compare it with natural river sand concrete, three different size of specimen were produced by using the same mix proportion with 3 different water cement ratios and 3 replacement ratios, and using it to measure the three aspects on the durability of concrete including freeze-thaw performance, dry-shrinkage performance and anti-chloride-permeability performance. In this paper. The test results show that using GBS as fine aggregate can slightly improve anti-chloride-permeability performance and dry-shrinkage performance of concrete in the condition of low water cement ratio, on the other hand, using GBS or natural river sand as fine aggregate has almost similar durability of concrete.

Late-Age Properties of Concrete with Different Binders Cured under 45°C at Early Ages

Directory of Open Access Journals (Sweden)

Hu Jin

2017-01-01

Full Text Available It is commonly accepted that high curing temperature (near 60°C or above results in reduced mechanical properties and durability of concrete compared to normal curing temperature. The internal temperature of concrete structures at early ages is not so high as 60°C in many circumstances. In this paper, concretes were cured at 45°C at early ages and their late-age properties were studied. The concrete cured at 20°C was employed as the reference sample. Four different concretes were used: plain cement concrete, concrete containing fly ash, concrete containing ground granulate blast furnace slag (GGBS, and concrete containing silica fume. The results show that, for each concrete, high-temperature curing after precuring does not have any adverse effect on the nonevaporable water content, compressive strength, permeability to chloride ions, and the connected porosity of concrete at late ages compared with standard curing. Additionally, high-temperature curing improves the late-age properties of concrete containing fly ash and GGBS.

An Experimental Study On Carbonation Of Plain And Blended Cement Concrete

Directory of Open Access Journals (Sweden)

Yunusa Alhassan

2017-08-01

Full Text Available This paper presents a laboratory investigation on the early age properties and carbonation of concrete containing Ground Granulated Blast Furnace GGBS in an inland environment. Properties of concrete made with GGBS blended cement was characterized in terms of physical and chemical composition at early-age. In addition the effects of inland exposure condition on the durability performance of companion concrete were also investigated in the medium term. Concrete cubes were made using various concrete mixtures of water-binder ratios wb 0.40 0.50 0.60 0.75 and binder contents 300 350 400 450 kgm3. Concrete cube of 100 mm size were cast and cured in water for 3 7 or 28 days then characterized at early-ages in terms of its physical and chemical properties. Companion concrete samples were exposed indoor or outdoors to undergo carbonation under natural environment. At the end of the varying exposure period 6 12 18 and 24 months the concrete cube samples were characterized in terms of carbonation depths. The results of the concrete early-age properties and medium-term durability characterisation were analyzed. The results show that increased knowledge of concrete materials concrete early-age properties and its exposure conditions are vital in durability considerations for RC structures.

Determination of test methods for the prediction of the behavior of mass concrete

Science.gov (United States)

Ferraro, Christopher C.

Hydration at early ages results from chemical and physical processes that take place between Portland cement and water, and is an exothermic process. The resultant heat evolution and temperature rise for massive concrete placements can be so great that the temperature differentials between the internal concrete core and outer concrete stratum can cause cracking due to thermal gradients. Accurate prediction of temperature distribution and stresses in mass concrete is needed to determine if a given concrete mixture design may have problems in the field, so that adjustments to the design can be made prior to its use. This research examines calorimetric, strength, and physical testing methods in an effort to predict the thermal and physical behavior of mass concrete. Four groups of concrete mixture types containing different cementitious materials are examined. One group contains Portland cement, while the other three groups incorporate large replacements of supplementary cementitious materials: granulated blast furnace slag, fly ash, and a ternary blend (combining Portland cement, fly ash, and slag).

Effect of recycling blast furnace flue dust as pellets on the sintering performance

Directory of Open Access Journals (Sweden)

El-Hussiny N.A.

2010-01-01

Full Text Available The Egyptian Iron and Steel Company generates a great amount of blast furnace flue dust. The recovery of metals and carbon from this flue dust becomes a very important demand due to the increase of the price of coke breeze and the decrease of the primary source of metals. At the same time, it make the environment more safe by decreasing pollution. Introducing these dust fines in the sintering process proves to be very harmful for different operating parameters. Thus, this study aims at investigating the production of pellets resulting from these fines, using molasses as organic binder and its application in sintering of iron ore. The sintering experiments were performed using flue dust as pellets as a substitute of coke breeze. The results revealed that, sintering properties such as inter strength increases with using the flue dust pellets, while productivity of both the sinter machine and sinter machine at blast furnace yard decreases. Also the vertical velocity of the sinter machine and the weight loss during the reduction of produced the sinter by hydrogen decrease.

Resistance to Corrosion of Reinforcement of High Volume Fly Ash Concrete

International Nuclear Information System (INIS)

Kwon, S. O.; Bae, S. H.; Lee, H. J.; Lee, K. M.; Jung, S. H.

2014-01-01

Due to the increasing of interest about the eco-friendly concrete, it is increased to use concretes containing by-products of industry such as fly ash(FA), ground granulated blast furnace slag(GGBFS), silica fume(SF), and etc. Especially, these are well known for improving the resistances to reinforcement corrosion in concrete and decreasing chloride ion penetration. The purpose of this experimental research is to evaluate the resistance against corrosion of reinforcement of high volume fly ash(HVFA) concrete which is replaced with high volume fly ash for cement volume. For this purpose, the concrete test specimens were made for various strength level and replacement ratio of FA, and then the compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91, and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that the compressive strength of HVFA concrete was decreased with increasing replacement ratio of FA but long-term resistances against reinforcement corrosion and chloride ion penetration of that were increased

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.

Penetration analysis of projectile with inclined concrete target

Science.gov (United States)

Kim, S. B.; Kim, H. W.; Yoo, Y. H.

2015-09-01

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.

Effects of different mineral admixtures on the properties of fresh concrete.

Science.gov (United States)

Khan, Sadaqat Ullah; Nuruddin, Muhammad Fadhil; Ayub, Tehmina; Shafiq, Nasir

2014-01-01

This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer.

Development of high-performance concrete having high resistance to chloride penetration

International Nuclear Information System (INIS)

Oh, Byung Hwan; Cha, Soo Won; Jang, Bong Seok; Jang, Seung Yup

2002-01-01

The resistance to chloride penetration is one of the simplest measures to determine the durability of concrete, e.g. resistance to freezing and thawing, corrosion of steel in concrete and other chemical attacks. Thus, high-performance concrete may be defined as the concrete having high resistance to chloride penetration as well as high strength. The purpose of this paper is to investigate the resistance to chloride penetration of different types of concrete and to develop high-performance concrete that has very high resistance to chloride penetration, and thus, can guarantee high durability. A large number of concrete specimens have been tested by the rapid chloride permeability test method as designated in AASHTO T 277 and ASTM C 1202. The major test variables include water-to-binder ratios, type of cement, type and amount of mineral admixtures (silica fume, fly ash and blast-furnace slag), maximum size of aggregates and air-entrainment. Test results show that concrete containing optimal amount of silica fume shows very high resistance to chloride penetration, and high-performance concrete developed in this study can be efficiently employed to enhance the durability of concrete structures in severe environments such as nuclear power plants, water-retaining structures and other offshore structures

Computerized Hammer Sounding Interpretation for Concrete Assessment with Online Machine Learning.

Science.gov (United States)

Ye, Jiaxing; Kobayashi, Takumi; Iwata, Masaya; Tsuda, Hiroshi; Murakawa, Masahiro

2018-03-09

Developing efficient Artificial Intelligence (AI)-enabled systems to substitute the human role in non-destructive testing is an emerging topic of considerable interest. In this study, we propose a novel hammering response analysis system using online machine learning, which aims at achieving near-human performance in assessment of concrete structures. Current computerized hammer sounding systems commonly employ lab-scale data to validate the models. In practice, however, the response signal patterns can be far more complicated due to varying geometric shapes and materials of structures. To deal with a large variety of unseen data, we propose a sequential treatment for response characterization. More specifically, the proposed system can adaptively update itself to approach human performance in hammering sounding data interpretation. To this end, a two-stage framework has been introduced, including feature extraction and the model updating scheme. Various state-of-the-art online learning algorithms have been reviewed and evaluated for the task. To conduct experimental validation, we collected 10,940 response instances from multiple inspection sites; each sample was annotated by human experts with healthy/defective condition labels. The results demonstrated that the proposed scheme achieved favorable assessment accuracy with high efficiency and low computation load.

A study in cost analysis of aggregate production as depending on drilling and blasting design

Science.gov (United States)

Bilim, Niyazi; Çelik, Arif; Kekeç, Bilgehan

2017-10-01

Since aggregate production has vital importance for many engineering projects-such as construction, highway and plant-mixed concrete production-this study was undertaken to determine how the costs for such production are affected by the design of drilling and blasting processes used. Aggregates are used in the production of concrete and asphalt, which are critical resources for the construction sector. The ongoing population increase and the growth of living standards around the world drive the increasing demand for these products. As demand grows, competition has naturally arisen among producers in the industry. Competition in the market has directly affected prices, which leads to the need for new measures and cost analysis on production costs. The cost calculation is one of the most important parameters in mining activities. Aggregate production operations include drilling, blasting, secondary crushing (if necessary), loading, hauling and crushing-screening, and each of these factors affects cost. In this study, drilling and blasting design parameters (such as hole diameter, hole depth, hole distance and burden) were investigated and evaluated for their effect on the total cost of quarrying these products, based on a particular quarry selected for this research. As the result of evaluation, the parameters actually driving costs have been identified, and their effects on the cost have been determined. In addition, some suggestions are presented regarding production design which may lead to avoiding increased production costs.

Economic lifetime of a drilling machine:a case study on mining industry

OpenAIRE

Hamodi, Hussan; Lundberg, Jan; Jonsson, Adam

2013-01-01

Underground mines use many different types of machinery duringthe drift mining processes of drilling, charging, blasting, loading, scaling andbolting. Drilling machines play a critical role in the mineral extraction processand thus are important economically. However, as the machines age, theirefficiency and effectiveness decrease, negatively affecting productivity andprofitability and increasing total cost. Hence, the economic replacementlifetime of the machine is a key performance indicator...

Mass transfer in water-saturated concretes

International Nuclear Information System (INIS)

Atkinson, A.; Claisse, P.A.; Harris, A.W.; Nickerson, A.K.

1990-01-01

Cements and concretes are often considered as components of barriers for the containment of radioactive waste. The performance of such materials as mainly physical barriers to the transport of dissolved radionuclides depends on the mass transfer characteristics of the material. In particular the diffusion and sorption behavior of the radionuclides and the water permeability are important. These parameters also influence how the chemistry of the concrete is imposed on the repository. In addition, the transport of gas through concrete controls the way in which gases escape from the repository. Diffusion and gas transport have been measured in a variety of cementitious materials, covering both structural concretes and cementitious backfills; all possible repository construction materials. Measurements have been made using aqueous iodide, strontium and caesium ions and tritiated water as diffusants. The results show that the diffusion of tritiated water is more rapid than that of other species, whilst the transport of strontium and caesium is hindered by sorption; particularly in materials containing blast furnace slag. The transport of gas in these materials has been found to be very sensitive to the degree of water saturation and is extremely low in fully saturated structural concretes. Cementitious backfills have, nevertheless, been identified that have appreciable gas transport even when almost water saturated. The consequences of the results for the performance of cementitious barriers are discussed

Reliability Analysis of Retaining Walls Subjected to Blast Loading by Finite Element Approach

Science.gov (United States)

GuhaRay, Anasua; Mondal, Stuti; Mohiuddin, Hisham Hasan

2018-02-01

Conventional design methods adopt factor of safety as per practice and experience, which are deterministic in nature. The limit state method, though not completely deterministic, does not take into account effect of design parameters, which are inherently variable such as cohesion, angle of internal friction, etc. for soil. Reliability analysis provides a measure to consider these variations into analysis and hence results in a more realistic design. Several studies have been carried out on reliability of reinforced concrete walls and masonry walls under explosions. Also, reliability analysis of retaining structures against various kinds of failure has been done. However, very few research works are available on reliability analysis of retaining walls subjected to blast loading. Thus, the present paper considers the effect of variation of geotechnical parameters when a retaining wall is subjected to blast loading. However, it is found that the variation of geotechnical random variables does not have a significant effect on the stability of retaining walls subjected to blast loading.

Non-destructive analysis of chlorine in fly ash cement concrete

International Nuclear Information System (INIS)

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

2009-01-01

Preventive measures against reinforcement corrosion in concrete require increasing concrete density to prevent the diffusion of chloride ions to the steel surface. Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to concrete to increase its density. Monitoring the chloride concentration in concrete is required to assess the chances of reinforcement corrosion. In this study, FA was added to Portland cement concrete to increase its density. Prompt gamma neutron activation analysis (PGNAA) technique was utilized to analyze the concentration of chlorine in concrete. The chlorine concentration in the FA cement concrete was evaluated by determining the yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV gamma-rays of chlorine from the FA concrete specimen containing 0.4-3.5 wt% chlorine. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the calculated yield obtained through the Monte Carlo simulations. The Minimum Detectable Concentration (MDC) of chlorine in FA cement concrete was also calculated. The best value of MDC limit of chlorine in the FA cement concrete was found to be 0.022±0.007 and 0.038±0.017 wt% for 1.16 and 6.11 MeV prompt gamma-rays, respectively. Within the statistical uncertainty, the lower bound of MDC meets the maximum permissible limit of 0.03 wt% of chlorine in concrete set by American Concrete Institute Committee 318.

Non-destructive analysis of chlorine in fly ash cement concrete

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: aanaqvi@kfupm.edu.sa; Garwan, M.A.; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khateeb-ur-Rehman [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2009-08-11

Preventive measures against reinforcement corrosion in concrete require increasing concrete density to prevent the diffusion of chloride ions to the steel surface. Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to concrete to increase its density. Monitoring the chloride concentration in concrete is required to assess the chances of reinforcement corrosion. In this study, FA was added to Portland cement concrete to increase its density. Prompt gamma neutron activation analysis (PGNAA) technique was utilized to analyze the concentration of chlorine in concrete. The chlorine concentration in the FA cement concrete was evaluated by determining the yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV gamma-rays of chlorine from the FA concrete specimen containing 0.4-3.5 wt% chlorine. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the calculated yield obtained through the Monte Carlo simulations. The Minimum Detectable Concentration (MDC) of chlorine in FA cement concrete was also calculated. The best value of MDC limit of chlorine in the FA cement concrete was found to be 0.022{+-}0.007 and 0.038{+-}0.017 wt% for 1.16 and 6.11 MeV prompt gamma-rays, respectively. Within the statistical uncertainty, the lower bound of MDC meets the maximum permissible limit of 0.03 wt% of chlorine in concrete set by American Concrete Institute Committee 318.

Preliminary study of tin slag concrete mixture

Science.gov (United States)

Hashim, Mohd Jamil; Mansor, Ishak; Pauzi Ismail, Mohamad; Sani, Suhairy; Azmi, Azhar; Sayuti, Shaharudin; Zaidi Ibrahim, Mohd; Adli Anuar, Abul; Rahim, Abdul Adha Abdul

2018-01-01

The study focuses on practices to facilitate tin smelting industry to reduce radioactive waste product (Tin Slag) by diluting its radioactivity to a safe level and turning it to a safer infrastructural building product. In the process the concrete mix which include Portland cement, sand, tin slag, water and plasticizer are used to produce interlocking brick pavements, piles and other infrastructural products. The mixing method follows DOE (UK) standard method of mixing targeted at in selected compressive strength suitable for its function and durability. A batching machine is used in the mixing and six test cubes are produced for the test. The testing equipment used are a compressional machine, ultrasonic measurement and a Geiger Muller counter to evaluate of the concrete mix to find the lowest emission of radiation surface dose without compromising the strength of concrete mix. The result obtained indicated the radioactivity of tin slag in the mixing process has reduced to background level that is 0.5μSv/h while the strength and workability of the concrete has not been severely affected. In conclusion, the concrete mix with tin slag has shown the potential it can be turned into a safe beneficial infrastructural product with good strength.

Effect of incorporation of fly ash and granulated blast furnace in the electrochemical behavior of concretes of commercial cement; Efecto de la incorporacion de ceniza volante y escoria de horno alto en el comportamiento electroquimico de concretos de cemento comercial

Energy Technology Data Exchange (ETDEWEB)

Gutierrez-Junco, O. J.; Pineda-Triana, Y.; Vera-Lopez, E.

2015-07-01

This paper presents the findings of the research properties evaluation pastes of commercial cement (CPC), mixed with fly ash (FA) and granulated blast furnace slag (GBFS). Initially, the sample of 30 combinations were evaluated in terms of compressive strength to establish the optimal proportions from raw material. After that, four optimized blends were characterized during the setting and hardening process. Electrochemical tests were performed on concrete cylinders samples prepared with cementitious materials and a structural steel rod placed in the center of the specimen. With the objective to evaluate the performance before corrosion, thermodynamic and kinetic aspects were taken into consideration. The findings showed that commercial cements blended with fly ash and blast furnace slag as the ones used in this research presents a decreased behavior in mechanical and corrosion strength regarding to CPC. (Author)

Engineering properties of inorganic polymer concretes (IPCs)

International Nuclear Information System (INIS)

Sofi, M.; Deventer, J.S.J. van; Mendis, P.A.; Lukey, G.C.

2007-01-01

This paper presents the engineering properties of inorganic polymer concretes (IPCs) with a compressive strength of 50 MPa. The study includes a determination of the modulus of elasticity, Poisson's ratio, compressive strength, and the splitting tensile strength and flexural strength of IPCs, formulated using three different sources of Class-F fly ash. Six IPC mix designs were adopted to evaluate the effects of the inclusion of coarse aggregates and granulated blast furnace slag into the mixes. A total of 90 cylindrical and 24 small beam specimens were investigated, and all tests were carried out pursuant to the relevant Australian Standards. Although some variability between the mixes was observed, the results show that, in most cases, the engineering properties of IPCs compare favorably to those predicted by the relevant Australian Standards for concrete mixtures

Brain injuries from blast.

Science.gov (United States)

Bass, Cameron R; Panzer, Matthew B; Rafaels, Karen A; Wood, Garrett; Shridharani, Jay; Capehart, Bruce

2012-01-01

Traumatic brain injury (TBI) from blast produces a number of conundrums. This review focuses on five fundamental questions including: (1) What are the physical correlates for blast TBI in humans? (2) Why is there limited evidence of traditional pulmonary injury from blast in current military field epidemiology? (3) What are the primary blast brain injury mechanisms in humans? (4) If TBI can present with clinical symptoms similar to those of Post-Traumatic Stress Disorder (PTSD), how do we clinically differentiate blast TBI from PTSD and other psychiatric conditions? (5) How do we scale experimental animal models to human response? The preponderance of the evidence from a combination of clinical practice and experimental models suggests that blast TBI from direct blast exposure occurs on the modern battlefield. Progress has been made in establishing injury risk functions in terms of blast overpressure time histories, and there is strong experimental evidence in animal models that mild brain injuries occur at blast intensities that are similar to the pulmonary injury threshold. Enhanced thoracic protection from ballistic protective body armor likely plays a role in the occurrence of blast TBI by preventing lung injuries at blast intensities that could cause TBI. Principal areas of uncertainty include the need for a more comprehensive injury assessment for mild blast injuries in humans, an improved understanding of blast TBI pathophysiology of blast TBI in animal models and humans, the relationship between clinical manifestations of PTSD and mild TBI from blunt or blast trauma including possible synergistic effects, and scaling between animals models and human exposure to blasts in wartime and terrorist attacks. Experimental methodologies, including location of the animal model relative to the shock or blast source, should be carefully designed to provide a realistic blast experiment with conditions comparable to blasts on humans. If traditional blast scaling is

Electromagnetic Shielding Characteristics of Eco-Friendly Foamed Concrete Wall

Directory of Open Access Journals (Sweden)

Sung-Sil Cho

2017-01-01

Full Text Available The electromagnetic shielding characteristics according to the material composition of foamed concrete, which was manufactured to reduce environmental pollution and to economically apply it in actual building walls, were researched herein. Industrial by-products such as ladle furnace slag (LFS, gypsum, and blast furnace slag (BFS were added to manufacture foamed concrete with enhanced functionalities such as lightweight, heat insulation, and sound insulation. The electrical characteristics such as permittivity and loss tangent according to the foam and BFS content were calculated and measured. Free space measurement was used to measure the electromagnetic shielding characteristics of the actually manufactured foamed concrete. It was confirmed that electromagnetic signals were better blocked when the foam content was low and the BFS content was high in the measured frequency bands (1–8 GHz and that approximately 90% of the electromagnetic signals were blocked over 4 GHz.

Utilizing of the metallurgical slag for production of cementless concrete mixtures

Directory of Open Access Journals (Sweden)

D. Baricová

2012-10-01

Full Text Available In process of pig iron, steel and cast iron production besides main product, also secondary products are formed, that have character of secondary raw materials and industrial wastes. The most abundant secondary product originating in the metallurgical process is furnace slag. Total amount of accured slag, also its chemical, mineralogical, physical – chemical properties and similarity with natural stones predestinate its utilisation in different fields of industry. The contribution deals with production of cementless concrete mixtures, where the main parts were formed by blast furnace granulated slag grinded and different gravel slag from blast furnace, oxygen converter and electric arc furnace. As activators of solidification different kinds of water glass were tested.

Sustainability assessment and physical characterization of pervious concrete pavement made with GGBS

Directory of Open Access Journals (Sweden)

El-Hassan Hilal

2017-01-01

Full Text Available The increasing use of pervious concrete as sustainable and environment-friendly paving materials is primarily owed to its ability to reduce pavement runoff. The mechanical and transport properties of pervious concrete with 50% ground-granulated blast furnace slag (GGBS replacement are examined in this paper. Open-graded 10 mm and 20 mm aggregates were used to attain porosity of 10%, 15%, and 20%. Polypropylene short cut fibers were added to the mix. The clogging potential of pervious concrete exposed to dust was also investigated. The results indicated that increasing the porosity led to a decrease in compressive and tensile strength. Similar findings were reported when smaller aggregates were used. The fiber addition was only effective in low-porosity concrete. Permeability, characterized by its coefficient k, was proportional to porosity and inversely proportional to aggregate size. After 40-year simulated dust exposure, the concrete permeability could be restored with water flushing maintenance process. In comparison to ordinary Portland cement (OPC concrete, pervious concrete incorporating GGBS is a more sustainable paving solution, offering a reduction in heat island effect and electricity consumption while also alleviating carbon emissions.

Effects of waste PET bottles aggregate on the properties of concrete

International Nuclear Information System (INIS)

Choi, Yun-Wang; Moon, Dae-Joong; Chung, Jee-Seung; Cho, Sun-Kyu

2005-01-01

This paper investigates the surface microstructure of waste polyethylene terephthalate (PET) bottles lightweight aggregate (WPLA) to examine the effect of granulated blast-furnace slag (GBFS) on WPLA. The WPLA was made from the waste PET bottles and GBFS, and experimental tests were conducted on compressive strength, splitting tensile strength, modulus of elasticity, slump, and density of waste PET bottles lightweight aggregate concrete (WPLAC). The 28-day compressive strength of WPLAC with the replacement ratio of 75% reduces about 33% compared to the control concrete in the water-cement ratio of 45%. The density of WPLAC varies from 1940 to 2260 kg/m 3 by the influence of WPLA. The structural efficiency of WPLAC decreases as the replacement ratio increases. The workability of concrete with 75% WPLA improves about 123% compared to that of the normal concrete in the water-cement ratio of 53%. The adhered GBFS is able to strengthen the surface of WPLA and to narrow the transition zone owing to the reaction with calcium hydroxide

Waste-Based Pervious Concrete for Climate-Resilient Pavements.

Science.gov (United States)

Ho, Hsin-Lung; Huang, Ran; Hwang, Lih-Chuan; Lin, Wei-Ting; Hsu, Hui-Mi

2018-05-27

For the sake of environmental protection and circular economy, cement reduction and cement substitutes have become popular research topics, and the application of green materials has become an important issue in the development of building materials. This study developed green pervious concrete using water-quenched blast-furnace slag (BFS) and co-fired fly ash (CFFA) to replace cement. The objectives of this study were to gauge the feasibility of using a non-cement binder in pervious concrete and identify the optimal binder mix design in terms of compressive strength, permeability, and durability. For filled percentage of voids by cement paste (FPVs) of 70%, 80%, and 90%, which mixed with CFFA and BFS as the binder (40 + 60%, 50 + 50%, and 60 + 40%) to create pervious concrete with no cement. The results indicate that the complete (100%) replacement of cement with CFFA and BFS with no alkaline activator could induce hydration, setting, and hardening. After a curing period of 28 days, the compressive strength with different FPVs could reach approximately 90% that of the control cement specimens. The cementless pervious concrete specimens with BFS:CFFA = 7:3 and FPV = 90% presented better engineering properties and permeability.

Loading functions generated by solid explosive detonations inside concrete containment structures

International Nuclear Information System (INIS)

Freund, H.W.; Schumann, S.; Rischbieter, F.; Schmitz, C.

1989-01-01

Partial dismantling of concrete structures by controlled blasting is being considered for nuclear power reactor decommissioning /1,2/. Quantitative prediction of both the desired destructive effects and the side effects caused by the dynamic load is based on knowledge of the time dependent forces acting on the structure, availability of data abut the dynamic material properties, realistic structural models. This work describes investigations performed to obtain time dependent forces for the case where solid explosive charges embedded into concrete are being detonated. The resulting multi component loading function is shown to constitute a set of input data for pre-test safety calculations of the building vibrational response

Evaluation of the suitability for concrete using fly ash in N.P.P. structures

International Nuclear Information System (INIS)

Cho, M. S.; Song, Y. C.; Kim, S. W.; Ko, K. T.

2002-01-01

The nuclear power plant structures constructed in Korea has been generally used type V cement(sulfate-resisting Portland cement), but according to the study results reported recently, it shows that type V cement is superior the resistance of sulfate attack, but the resistance of salt damage is weaker than type I cement. It is increased the demands on the use of mineral admixtures such as fly ash, ground granulated blast-furnace slag instead of type V cement in order to improve the durability of concrete structures. But the study on concrete mixed with fly ash in Korea has been mainly performed on rheology and strength properties of the concrete. Therefore, this study is to improve the durability of concrete structures of N.P.P. as using fly ash cement instead of type V cement. As a results, the concrete containing fly ash is improved the resistance to salt attack, sulfate attack and freezing-thawing and is deteriorated the carbonation. But if it is used the concrete with high strength or low water-powder ratio, the concrete have not problem on the durability

Preventive measures against concrete damage to ASR in the Netherlands current state-of-affairs

OpenAIRE

Heijnen, W.M.M.; Larbi, J.A.

1999-01-01

In CUR-Recommendation 38, various vital measures that need to be taken during design of new concrete-mixtures in order to prevent damage due to ASR in the concrete have been outlined. The most important of these measures are: - the use of blast furnace slag cement (with a high slag content: ≥50% by mass of cement as slag); - or the use of portland fly ash cement (containing at least 25% by mass of cement as fly ash). If one of these cement types is used, then the potential reactivity of the a...

Mechanical characteristics of hardened concrete with different mineral admixtures: a review.

Science.gov (United States)

Ayub, Tehmina; Khan, Sadaqat Ullah; Memon, Fareed Ahmed

2014-01-01

The available literature identifies that the addition of mineral admixture as partial replacement of cement improves the microstructure of the concrete (i.e., porosity and pore size distribution) as well as increasing the mechanical characteristics such as drying shrinkage and creep, compressive strength, tensile strength, flexural strength, and modulus of elasticity; however, no single document is available in which review and comparison of the influence of the addition of these mineral admixtures on the mechanical characteristics of the hardened pozzolanic concretes are presented. In this paper, based on the reported results in the literature, mechanical characteristics of hardened concrete partially containing mineral admixtures including fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA) are discussed and it is concluded that the content and particle size of mineral admixture are the parameters which significantly influence the mechanical properties of concrete. All mineral admixtures enhance the mechanical properties of concrete except FA and GGBS which do not show a significant effect on the strength of concrete at 28 days; however, gain in strength at later ages is considerable. Moreover, the comparison of the mechanical characteristics of different pozzolanic concretes suggests that RHA and SF are competitive.

Primary blast survival and injury risk assessment for repeated blast exposures.

Science.gov (United States)

Panzer, Matthew B; Bass, Cameron R Dale; Rafaels, Karin A; Shridharani, Jay; Capehart, Bruce P

2012-02-01

The widespread use of explosives by modern insurgents and terrorists has increased the potential frequency of blast exposure in soldiers and civilians. This growing threat highlights the importance of understanding and evaluating blast injury risk and the increase of injury risk from exposure to repeated blast effects. Data from more than 3,250 large animal experiments were collected from studies focusing on the effects of blast exposure. The current study uses 2,349 experiments from the data collection for analysis of the primary blast injury and survival risk for both long- and short-duration blasts, including the effects from repeated exposures. A piecewise linear logistic regression was performed on the data to develop survival and injury risk assessment curves. New injury risk assessment curves uniting long- and short-duration blasts were developed for incident and reflected pressure measures and were used to evaluate the risk of injury based on blast over pressure, positive-phase duration, and the number of repeated exposures. The risk assessments were derived for three levels of injury severity: nonauditory, pulmonary, and fatality. The analysis showed a marked initial decrease in injury tolerance with each subsequent blast exposure. This effect decreases with increasing number of blast exposures. The new injury risk functions showed good agreement with the existing experimental data and provided a simplified model for primary blast injury risk. This model can be used to predict blast injury or fatality risk for single exposure and repeated exposure cases and has application in modern combat scenarios or in setting occupational health limits. .Copyright © 2012 by Lippincott Williams & Wilkins

Performance of concrete blended with pozzolanic materials in marine environment

Directory of Open Access Journals (Sweden)

Khan Asad-ur-Rehman

2017-01-01

Full Text Available Reinforced concretes structures located at or near the coast line needs to be repaired more frequently when compared to structures located elsewhere. This study is continuation of previous studies carried out at the Department of Civil Engineering, NED University of Engineering and Technology, Karachi, Pakistan to study the performance of concrete made up of cements blended by pozzolonic materials. Different pozzolanic materials (blast furnace slag, fly ash and silica fume were used in the study. Tests conducted during the study to compare the performance of samples cast from concrete of different mix designs were Compressive Strength Test (ASTM C 39, Flexural Strength Test (ASTM C 293, Rapid Migration Test (NT Build 492, Absorptivity of the oven-dried samples (ASTM C 642 and Half Cell Potential (ASTM C 876. Use of cements blended with pozzolanic materials, used during the study, proved to be effective in enhancing the performance of the concrete exposed to marine environment. Use of pozzolans in concrete not only provides a sustainable and feasible solution to the durability problems in coastal areas, it also helps in conservation of natural resources and reduction of pollution and energy leading to a green environment.

FEATURES OF DRILLING-AND-BLASTING AT CONSTRUCTION OF BESKIDSKIY TUNNEL

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V. D. Petrenko

2016-10-01

Full Text Available Purpose. In this article it is necessary to analyze the possibility of developing technology and increasing its efficiency during the Beskidskiy tunnel construction in difficult engineering and geological conditions. Methodology. The authors have performed analysis of the technological level of mining and construction works, new technique, equipment and production. One of the important issues of blasting operation is to ensure the seismic safety, acting at a distance of 30 m in the axes of single-track tunnel, as the distance to it will be 20 m from the nearest charge in the laying tunnel. This problem was solved by applying the combined blasting of blast-hole charges with delay-action and long-delay ways. Herewith the total mass of charges in the stope was divided into three groups, in which the first group is exploded by short-delay firing with, and the second one is exploded by short-delay firing too with intervals of 200…400 ms, the third is exploded by long-delay blasting at intervals of 500…10000 ms. The combined blasting of short-delay charges and delay action ones let significantly reduce seismic action at a mass explosion of charges when driving of double-track railway tunnel of a large cross-section. Findings. The paper presents the developed technology model, describing dependence of the machines from engineering and geological conditions. The methodology of drilling and blasting works at the construction of the tunnel callote and stross as well as a technique of arrangement determination and intervals of shot-delay and delay blasting of blasthole explosive charges was developed. Maximum permissible concentration of gases and vapours at blasting was presented. The calculations showed that the maximum level of gas contamination of the working area in Beskidskiy tunnel is achieved at blast operations. In accordance with this ventilation of the tunnel when driving is carried out by independent systems with mechanical ventilation by

A Novel Online Sequential Extreme Learning Machine for Gas Utilization Ratio Prediction in Blast Furnaces

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Yanjiao Li

2017-08-01

Full Text Available Gas utilization ratio (GUR is an important indicator used to measure the operating status and energy consumption of blast furnaces (BFs. In this paper, we present a soft-sensor approach, i.e., a novel online sequential extreme learning machine (OS-ELM named DU-OS-ELM, to establish a data-driven model for GUR prediction. In DU-OS-ELM, firstly, the old collected data are discarded gradually and the newly acquired data are given more attention through a novel dynamic forgetting factor (DFF, depending on the estimation errors to enhance the dynamic tracking ability. Furthermore, we develop an updated selection strategy (USS to judge whether the model needs to be updated with the newly coming data, so that the proposed approach is more in line with the actual production situation. Then, the convergence analysis of the proposed DU-OS-ELM is presented to ensure the estimation of output weight converge to the true value with the new data arriving. Meanwhile, the proposed DU-OS-ELM is applied to build a soft-sensor model to predict GUR. Experimental results demonstrate that the proposed DU-OS-ELM obtains better generalization performance and higher prediction accuracy compared with a number of existing related approaches using the real production data from a BF and the created GUR prediction model can provide an effective guidance for further optimization operation.

A Novel Online Sequential Extreme Learning Machine for Gas Utilization Ratio Prediction in Blast Furnaces.

Science.gov (United States)

Li, Yanjiao; Zhang, Sen; Yin, Yixin; Xiao, Wendong; Zhang, Jie

2017-08-10

Gas utilization ratio (GUR) is an important indicator used to measure the operating status and energy consumption of blast furnaces (BFs). In this paper, we present a soft-sensor approach, i.e., a novel online sequential extreme learning machine (OS-ELM) named DU-OS-ELM, to establish a data-driven model for GUR prediction. In DU-OS-ELM, firstly, the old collected data are discarded gradually and the newly acquired data are given more attention through a novel dynamic forgetting factor (DFF), depending on the estimation errors to enhance the dynamic tracking ability. Furthermore, we develop an updated selection strategy (USS) to judge whether the model needs to be updated with the newly coming data, so that the proposed approach is more in line with the actual production situation. Then, the convergence analysis of the proposed DU-OS-ELM is presented to ensure the estimation of output weight converge to the true value with the new data arriving. Meanwhile, the proposed DU-OS-ELM is applied to build a soft-sensor model to predict GUR. Experimental results demonstrate that the proposed DU-OS-ELM obtains better generalization performance and higher prediction accuracy compared with a number of existing related approaches using the real production data from a BF and the created GUR prediction model can provide an effective guidance for further optimization operation.

Early age shrinkage pattern of concrete on replacement of fine aggregate with industrial by-product

Directory of Open Access Journals (Sweden)

R.K. Mishra

2016-10-01

Full Text Available This is an experimental work carried out to investigate early age shrinkage pattern of concrete, prepared, on 50% replacement of industrial by-product (like pond ash and granulated blast furnace slag as fine aggregate using OPC, PPC and PSC as a binder. This is to observe the effect of pond ash and slag as they are having some cementitious properties and effect of cement type is also discussed. All the mixes were prepared keeping in view of pumpable concrete without any super plasticizers. Higher shrinkage value indicates the presence of more bleed water or internal moisture. It is concluded that slag is the best option for fine aggregate replacement for concrete making and durable structure.

Analysis of the Optimum Usage of Slag for the Compressive Strength of Concrete.

Science.gov (United States)

Lee, Han-Seung; Wang, Xiao-Yong; Zhang, Li-Na; Koh, Kyung-Taek

2015-03-18

Ground granulated blast furnace slag is widely used as a mineral admixture to replace partial Portland cement in the concrete industry. As the amount of slag increases, the late-age compressive strength of concrete mixtures increases. However, after an optimum point, any further increase in slag does not improve the late-age compressive strength. This optimum replacement ratio of slag is a crucial factor for its efficient use in the concrete industry. This paper proposes a numerical procedure to analyze the optimum usage of slag for the compressive strength of concrete. This numerical procedure starts with a blended hydration model that simulates cement hydration, slag reaction, and interactions between cement hydration and slag reaction. The amount of calcium silicate hydrate (CSH) is calculated considering the contributions from cement hydration and slag reaction. Then, by using the CSH contents, the compressive strength of the slag-blended concrete is evaluated. Finally, based on the parameter analysis of the compressive strength development of concrete with different slag inclusions, the optimum usage of slag in concrete mixtures is determined to be approximately 40% of the total binder content. The proposed model is verified through experimental results of the compressive strength of slag-blended concrete with different water-to-binder ratios and different slag inclusions.

Experimental study on workability of alkali activated fly ash and slag-based geopolymer concretes

NARCIS (Netherlands)

Arbi, K.A.; Nedeljkovic, M.; Zuo, Y.; Grunewald, S.; Keulen, A.; Ye, G.

2015-01-01

This paper presents an investigation on workability and strength of geopolymer concrete made of fly ash (FA), blast furnace slag (BFS) and a multicompound activator of Na2SiO3 and NaOH solutions. The FA/BFS ratios were 100:0, 70:30, 60:40, 50:50, 40:60, 30:70 and 0:100. The workability of geopolymer

Water in blast holes can improve blasting efficiency and cut costs

Energy Technology Data Exchange (ETDEWEB)

O' Regan, G.

1983-08-01

Water in blast holes has been a traditional problem faced by blasting engineers and foremen in surface mining. Presently accepted techniques for blasting in water-filled holes include the use of more expensive water-gel explosives which are denser than water, dewatering of holes by pumping, and blowing out the water with a small charge before loading the main ANFO charge column. These methods involve considerable expense and delay to the normal charge-loading procedure. The author describes a method of using the water in blast holes to improve blasting efficiency and reduce the consumption of explosive.

Diffusion Decay Coefficient for Chloride Ions of Concrete Containing Mineral Admixtures

Directory of Open Access Journals (Sweden)

Jae-Im Park

2016-01-01

Full Text Available The diffusion coefficient for chloride ions and the diffusion decay coefficient for chloride ions are essential variables for a service life evaluation of concrete structures. They are influenced by water-binder ratio, exposure condition, curing temperature, cement type, and the type and use of mineral admixture. Mineral admixtures such as ground granulated blast furnace slag, fly ash, and silica fume have been increasingly used to improve resistance against chloride ions penetration in concrete structures built in an offshore environment. However, there is not enough measured data to identify the statistical properties of diffusion decay coefficient for chloride ions in concrete using mineral admixtures. This paper is aimed at evaluating the diffusion decay coefficient for chloride ions of concrete using ordinary Portland cement or blended cement. NT BUILD 492 method, an electrophoresis experiment, was used to measure the diffusion coefficient for chloride ions with ages. It was revealed from the test results that the diffusion decay coefficient for chloride ions was significantly influenced by W/B and the replacement ratio of mineral admixtures.

Power Tillers for Demining: Blast Test

Directory of Open Access Journals (Sweden)

Emanuela Elisa Cepolina

2007-06-01

Full Text Available Power tillers are very simple and versatile machines with large scale diffusion in developing countries, where they are commonly used both for agriculture and for transportation purposes. A new integrated participatory approach that makes use of and improves local end-users knowledge has been used to design a new robotic system for humanitarian demining applications in Sri Lanka, using power tiller as core module. A demining machine composed by a tractor unit, a ground processing tool and a vegetation cutting tool is here presented together with results obtained from the first blast test on the preliminary version of tractor unit armouring. Different breakable connections between wheels and axle have been designed to cause physical detachment and interrupt the transmission of the shock wave released by the explosion of a mine under one wheel. Effects of explosions on different types of wheels and on the chassis have been recorded and commented.

Power Tillers for Demining: Blast Test

Directory of Open Access Journals (Sweden)

Emanuela Elisa Cepolina

2008-11-01

Full Text Available Power tillers are very simple and versatile machines with large scale diffusion in developing countries, where they are commonly used both for agriculture and for transportation purposes. A new integrated participatory approach that makes use of and improves local end-users knowledge has been used to design a new robotic system for humanitarian demining applications in Sri Lanka, using power tiller as core module. A demining machine composed by a tractor unit, a ground processing tool and a vegetation cutting tool is here presented together with results obtained from the first blast test on the preliminary version of tractor unit armouring. Different breakable connections between wheels and axle have been designed to cause physical detachment and interrupt the transmission of the shock wave released by the explosion of a mine under one wheel. Effects of explosions on different types of wheels and on the chassis have been recorded and commented.

The use of computer blast simulations to improve blast quality

International Nuclear Information System (INIS)

Favreau, R.F.; Kuzyk, G.W.; Babulic, P.J.; Tienkamp, N.J.

1989-01-01

Atomic Energy of Canada Limited is constructing an Underground Research Laboratory (URL) as part of a comprehensive program to evaluate the concept of nuclear fuel waste disposal deep in crystalline rock formations. Careful blasting methods have been used to minimize damage to the excavation surfaces. Good wall quality is desirable in any excavation. In excavations required for nuclear waste disposal, the objective will be to minimize blast-induced fractures which may complicate the sealing requirements necessary to control subsequent movement of groundwater around a sealed disposal vault. The construction of the URL has provided an opportunity for the development of controlled blasting methods, especially for drilling accuracy and optimization of explosive loads in the perimeter and cushion holes. The work has been assisted by the use of blast simulations with the mathematical model Blaspa. This paper reviews the results of a recent project to develop a controlled method of full-face blasting, and compares the observed field results with the results of a blast simulator called Blaspa. Good agreement is found between the two, and the Blaspa results indicate quantitatively how the blasting may induce damage in the final excavation surface. In particular, the rock in the final wall may be stressed more severely by the cushion holes than by the perimeter holes. Bootleg of the rock between the perimeter and cushion rows occurs when the burst-out velocity imparted to it by the explosive loads in the perimeter holes is inadequate. In practice, these findings indicate that quantitative rock stress and rock burst-out velocity criteria can be established to minimize wall damage and bootleg. Thus, blast simulations become an efficient way to design controlled blasting and to optimize quality of the excavation surface

Corrosion rate of rebars from linear polarization resistance and destructive analysis in blended cement concrete after chloride loading

NARCIS (Netherlands)

Polder, R.B.; Peelen, W.H.A.; Bertolini, L.; Guerriere, M.

2002-01-01

Concrete specimens with various binders including Portland cement, fly ash, blast furnace slag and composite cement and three water-to-cement ratios were subjected to cyclic wetting with salt solution and drying. Specimens contained six mild steel bars at two cover depths and two activated titanium

Crack classification in concrete beams using AE parameters

Science.gov (United States)

Bahari, N. A. A. S.; Shahidan, S.; Abdullah, S. R.; Ali, N.; Zuki, S. S. Mohd; Ibrahim, M. H. W.; Rahim, M. A.

2017-11-01

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm × 250 mm × 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams.

Behaviour of Nano Silica in Tension Zone of High Performance Concrete Beams

Science.gov (United States)

Jaishankar, P.; Vivek, D.

2017-07-01

High performance concrete (HPC) is similar to High strength concrete (HSC).It is because of lowering of water to cement ratio, which is needed to attain high strength and generally improves other properties. This concrete contains one or more cementitious materials such as fly ash, Silica fume or ground granulated blast furnace slag and usually a super plasticizer. The term ‘high performance’ is somewhat different because the essential feature of this concrete is that it’s ingredients and proportions are specifically chosen so as to have particularly appropriate properties for the expected use of the structure such as high strength and low permeability. Usage of nano scale properties such as Nano SiO2 can result in dramatically improved properties from conventional grain size materials of same chemical composition. This project is more interested in evaluate the behaviour of nano silica in concrete for 5%, 10%, and 15% volume fraction of cement. Flexural test for beams were conducted with two point loads, at different percentage as mentioned above. From results interpolated, Nano silica with higher order replacement gives optimized results compared to control specimens.

An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete

International Nuclear Information System (INIS)

Akcaoezoglu, Semiha; Atis, Cengiz Duran; Akcaoezoglu, Kubilay

2010-01-01

In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependant on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.

An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete.

Science.gov (United States)

Akçaözoğlu, Semiha; Atiş, Cengiz Duran; Akçaözoğlu, Kubilay

2010-02-01

In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependent on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.

Preparation of Autoclaved Foamed Concrete Block from Fly Ash and Carbide Slag

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Tan Xing

2018-01-01

Full Text Available To achieve the comprehensive utilization of solid waste and reduce costs, fly ash, carbide slag, and low-clinker cement were used to produce lightweight foamed concrete block. Granulated blast-furnace slag (GBFS was used as composition correction material in the block. The effects of curing temperature and dosage of low-clinker cement on the performance of foamed concrete block were investigated. The optimal material proportioning is obtained: fly ash 58.5%, carbide slag 20%, GBFS 10%, gypsum 1.5% and low-clinker cement 10%. The proper curing regime is “temperature rising 4h-180°C constant temperature 4h-natural cooling”. The results indicate that the compressive strength of the block reaches 3.55 MPa while the density is 616.9 kg/m3. The performance of the product meets JC/T 1062-2007 (China professional standard of foamed concrete block.

Concrete under severe conditions. Environment and loading

International Nuclear Information System (INIS)

2007-01-01

The objective of the CONSEC Conferences is to focus on concrete infrastructures, either subjected to severe environment or severe loading, or any combination of severe conditions. Experience from the performance of existing concrete structures, and especially under severe environmental conditions, severe accidental loading or extended lifespan, has demonstrated the need for better integration of structural and durability design, new design concepts including reliability-based durability design, performance-based material requirements, structural robustness, and an improved basis for documentation of obtained construction quality and durability properties during concrete construction. An improved basis for operation and preventive maintenance of concrete structures including repairs and retrofitting is also very important. Premature corrosion of reinforcing steel, inadequate structural design for seismic or blast loading, are examples of reduced service life of concrete structures that not only represent technical and economical problems, but also a huge waste of natural resources and hence also, an environmental and ecological problem. Experience of structures effectively submitted to severe conditions represents a unique benchmark for quantifying the actual safety and durability margin of concrete structures. In fact for several reasons, most concrete design codes, job specifications and other requirements for concrete structures have frequently shown to yield insufficient and unsatisfactory results and ability to solve the above problems, as well as issues raised by specific very long-term or very severe requirements for nuclear and industrial waste management, or civil works of strategic relevance. Recently available high to ultra-high performance concrete may find rational and valuable application in such cases. It is very important, therefore, to bring people with different professional backgrounds together to exchange experience and develop multi

Sulphuric Acid Resistant of Self Compacted Geopolymer Concrete Containing Slag and Ceramic Waste

Directory of Open Access Journals (Sweden)

Shafiq I.

2017-01-01

Full Text Available Malaysia is a one of the developing countries where the constructions of infrastructure is still ongoing, resulting in a high demand for concrete. In order to gain sustainability factors in the innovations for producing concrete, geopolymer concrete containing granulated blast-furnace slag and ceramics was selected as a cement replacement in concrete for this study. Since Malaysia had many ceramic productions and uses, the increment of the ceramic waste will also be high. Thus, a new idea to reuse this waste in construction materials have been tested by doing research on this waste. Furthermore, a previous research stated that Ordinary Portland Cement concrete has a lower durability compared to the geopolymer concrete. Geopolymer binders have been reported as being acid resistant and thus are a promising and alternative binder for sewer pipe manufacture. Lack of study regarding the durability of the geopolymer self-compacting concrete was also one of the problems. The waste will be undergoing a few processes in the laboratory in order to get it in the best form before undergoing the next process as a binder in geopolymer concrete. This research is very significant in order to apply the concept of sustainability in the construction field. In addition, the impact of this geopolymer binder is that it emits up to nine times less CO2 than Portland Cement.

Effects of slag and fly ash on reinforcement corrosion in concrete in chloride environment : Research from the Netherlands

NARCIS (Netherlands)

Polder, R.B.

2012-01-01

A review is given of research on the durability performance of concrete made with blast furnace slag and fly ash related to chloride induced reinforcement corrosion, carried out in the Netherlands, where slag has been used in cement for almost a century. Results are presented from field studies on

Effects of slag and fly ash on reinforcement corrosion in concrete in chloride environment. Research from the Netherlands

NARCIS (Netherlands)

Polder, R.B.

2012-01-01

A review is given of research on the durability performance of concrete made with blast furnace slag and fly ash related to chloride induced reinforcement corrosion, carried out in the Netherlands, where slag has been used in cement for almost a century. Results are presented from field studies on

Crumb Rubber Recycling in Enhancing Damping Properties of Concrete

Science.gov (United States)

Sugapriya, P.; Ramkrishnan, R.

2018-02-01

Damping plays a major role in the design of roadside structures that gets affected due to vibrations transmitted from moving traffic. In this study, fine aggregates were partially replaced with crumb rubber in concrete, at varying percentages of 5, 10, 15 and 20% by weight. Three different sets of concrete, mixed with crumb rubber were prepared using raw rubber, treated rubber and treated rubber with partial replacement of cement. Cement was partially replaced with Ultra-Fine Ground Granulated Blast furnace Slag (UFGGBS) for this study. Samples were cast, cured and tested for various properties on the 7th and 28th day. The damping ratio and frequency of the peak value from a number of waves in rubber incorporated beams were found out using a FFT Analyser along with its Strength, Damping and Sorptivity characteristics. SEM analysis was conducted to analyse the micro structural bonding between rubber and concrete. The mode shapes of pavement slabs were modelled and analysed using a FEM tool, ANSYS. From the results, the behaviour of the three sets of rubberized concrete were compared and analysed, and an optimum percentage for crumb rubber and UFGGBS was proposed to achieve best possible damping without compromising the strength properties.

Effect of silica fume addition on the PGNAA measurement of chlorine in concrete

International Nuclear Information System (INIS)

Naqvi, A.A.; Maslehuddin, M.; Garwan, M.A.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Raashid, M.; Khateeb-ur-Rehman

2010-01-01

Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to Portland cement in concrete to prevent reinforcement steel corrosion in concrete. Further preventive measure against reinforcement steel corrosion require monitoring of chloride salts concentration in concrete using non-destructive techniques, such as the prompt gamma-ray neutron activation analysis (PGNAA) technique. Due to interferences between gamma-rays from chlorine and calcium in PGNAA technique, detection limit of chlorine in concrete strongly depends upon calcium concentration in concrete. SF mainly contains silica and its addition to cement concrete reduces overall concentration of calcium in concrete. This may result in an improvement in detection limit of chlorine in SF-based concrete in PGNAA studies. Particularly for chlorine detection using 6.11 and 6.62 MeV prompt gamma-rays that strongly interfere with 6.42 MeV prompt gamma-rays from calcium. In this study, SF was added to Portland cement to prevent concrete reinforcement steel from corrosion. The chlorine concentration in SF cement concrete specimens containing 0.2-3.0 wt% chlorine was measured through yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV chlorine gamma-rays using PGNAA technique. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the gamma-ray yield calculated through the Monte Carlo simulations. Further the minimum detectable concentration (MDC) of chlorine in SF cement concrete was calculated and compared with the MDC values of chlorine in plain concrete and concrete mixed with fly ash cement. The MDC of chlorine in SF-based concrete through 6.11 MeV, and 6.62 MeV chlorine gamma-rays was found to be improved as compared to those in plain concrete and concrete mixed with fly ash cement.

Effect of silica fume addition on the PGNAA measurement of chlorine in concrete

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: aanaqvi@kfupm.edu.sa; Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Garwan, M.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Nagadi, M.M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Raashid, M.; Khateeb-ur-Rehman [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2010-03-15

Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to Portland cement in concrete to prevent reinforcement steel corrosion in concrete. Further preventive measure against reinforcement steel corrosion require monitoring of chloride salts concentration in concrete using non-destructive techniques, such as the prompt gamma-ray neutron activation analysis (PGNAA) technique. Due to interferences between gamma-rays from chlorine and calcium in PGNAA technique, detection limit of chlorine in concrete strongly depends upon calcium concentration in concrete. SF mainly contains silica and its addition to cement concrete reduces overall concentration of calcium in concrete. This may result in an improvement in detection limit of chlorine in SF-based concrete in PGNAA studies. Particularly for chlorine detection using 6.11 and 6.62 MeV prompt gamma-rays that strongly interfere with 6.42 MeV prompt gamma-rays from calcium. In this study, SF was added to Portland cement to prevent concrete reinforcement steel from corrosion. The chlorine concentration in SF cement concrete specimens containing 0.2-3.0 wt% chlorine was measured through yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV chlorine gamma-rays using PGNAA technique. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the gamma-ray yield calculated through the Monte Carlo simulations. Further the minimum detectable concentration (MDC) of chlorine in SF cement concrete was calculated and compared with the MDC values of chlorine in plain concrete and concrete mixed with fly ash cement. The MDC of chlorine in SF-based concrete through 6.11 MeV, and 6.62 MeV chlorine gamma-rays was found to be improved as compared to those in plain concrete and concrete mixed with fly ash cement.

Fabrication of Biochips with Micro Fluidic Channels by Micro End-milling and Powder Blasting

Directory of Open Access Journals (Sweden)

Dong Sam Park

2008-02-01

Full Text Available For microfabrications of biochips with micro fluidic channels, a large number of microfabrication techniques based on silicon or glass-based Micro-Electro-Mechanical System (MEMS technologies were proposed in the last decade. In recent years, for low cost and mass production, polymer-based microfabrication techniques by microinjection molding and micro hot embossing have been proposed. These techniques, which require a proper photoresist, mask, UV light exposure, developing, and electroplating as a preprocess, are considered to have some problems. In this study, we propose a new microfabrication technology which consists of micro end-milling and powder blasting. This technique could be directly applied to fabricate the metal mold without any preprocesses. The metal mold with micro-channels is machined by micro end-milling, and then, burrs generated in the end-milling process are removed by powder blasting. From the experimental results, micro end-milling combined with powder blasting could be applied effectively for fabrication of the injection mold of biochips with micro fluidic channels.

Application of a clay-slag geopolymer matrix for repairing damaged concrete: Laboratory and industrial-scale experiments

Czech Academy of Sciences Publication Activity Database

Perná, Ivana; Hanzlíček, Tomáš; Boura, P.; Lučaník, A.

2017-01-01

Roč. 59, č. 10 (2017), s. 929-937 ISSN 0025-5300 Institutional support: RVO:67985891 Keywords : blast-furnace slag * geopolymer * scanning electron microscopy (SEM) * damaged concrete repair * long-term monitoring Subject RIV: JJ - Other Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 0.418, year: 2016

Investigation of compressive strength of concrete with slag and silica fu

International Nuclear Information System (INIS)

Mostofinejad, D.; Mirtalee, K.; Sadeghi, M.

2002-01-01

Without doubt, concrete has special place in construction of different types of structures, and used as one of the most important materials in construction industry. Today, with development and modernization of human knowledge in construction industry, it is possible to reach h igh performance concrete . Mechanical properties and durability of high performance concrete is quite better than that of conventional concrete. In present, the use of supplementary cementitious materials, mainly silica fume, fly ash and blast furnace slag has become increasingly common for reasons of economy and technical benefits imparted by these materials. The aim of present research is investigation and comparison compressive strength of concrete specimens due to variation of water to cementitious materials ratio (W/C M), silica fume and slag percent and their proportions as cement replacement. Furthermore, it is intended to determine best combination of these materials with cement in concrete (optimum percent) to reach to maximum compressive strength. In the current study, specimens were made in 0.5,0.4 and 0.3 W/C M ratio contained 0,20,35 and 50 percent of slag as cement replacement, where in each slag replacement percent, 0, 5, 10 and 15 percent of of silica fume were used as cement replacement. Results of the current study show that the combination effect of slag and silica fume replacement in concrete leads to the maximum compressive strength in concrete; also there are some optimum percents for replacement of slag and silica fume to cement to get the best results

In situ treatment of concrete surfaces by organic impregnation and polymerization

International Nuclear Information System (INIS)

Ursella, P.; Moretti, G.; Pellecchia, V.

1990-01-01

The impregnation by resins of concrete structures is a process well known at PIC (Polymer Impregnated Concrete). This process improves the physical-chemical features of concrete matrixes in order to extend their durability when severe environmental conditions may occur. The main objective of this research contract has been the verification of a proper impregnation 'in situ' of existing concrete surfaces, of any laying in the space, by means of a prototype machine, expressly designed and implemented, and verification of the increase of mechanical resistance, leach resistance, durability of treated material. In a nuclear facility this goal is very important in relation to the long term integrity of concrete structures during operating lifetime and, in particular, after final shutdown. (author)

Stress-strain curve of concretes with recycled concrete aggregates: analysis of the NBR 8522 methodology

Directory of Open Access Journals (Sweden)

D. A. GUJEL

Full Text Available ABSTRACT This work analyses the methodology "A" (item A.4 employed by the Brazilian Standard ABNT 8522 (ABNT, 2008 for determining the stress-strain behavior of cylindrical specimens of concrete, presenting considerations about possible enhancements aiming it use for concretes with recycled aggregates with automatic test equipment. The methodology specified by the Brazilian Standard presents methodological issues that brings distortions in obtaining the stress-strain curve, as the use of a very limited number of sampling points and by inducing micro cracks and fluency in the elastic behavior of the material due to the use of steady stress levels in the test. The use of a base stress of 0.5 MPa is too low for modern high load test machines designed do high strength concrete test. The work presents a discussion over these subjects, and a proposal of a modified test procedure to avoid such situations.

Comparison of Some Blast Vibration Predictors for Blasting in Underground Drifts and Some Observations

Science.gov (United States)

Bhagwat, Vaibhab Pramod; Dey, Kaushik

2016-04-01

Drilling and blasting are the most economical excavation techniques in underground drifts driven through hard rock formation. Burn cut is the most popular drill pattern, used in this case, to achieve longer advance per blast round. The ground vibration generated due to the propagation of blast waves on the detonation of explosive during blasting is the principal cause for structural and rock damage. Thus, ground vibration is a point of concern for the blasting engineers. The ground vibration from a blast is measured using a seismograph placed at the blast monitoring station. The measured vibrations, in terms of peak particle velocity, are related to the maximum charge detonated at one instant and the distance of seismograph from the blast point. The ground vibrations from a number of blast rounds of varying charge/delay and distances are monitored. A number of scaling factors of these dependencies (viz. Distance and maximum charge/delay) have been proposed by different researchers, namely, square root, cube root, CMRI, Langefors and Kihlstrom, Ghosh-Daemon, Indian standard etc. Scaling factors of desired type are computed for all the measured blast rounds. Regression analysis is carried out between the scaling factors and peak particle velocities to establish the coefficients of the vibration predictor equation. Then, the developed predictor equation is used for designing the blast henceforth. Director General of Mine Safety, India, specified that ground vibrations from eight to ten blast rounds of varying charge/delay and distances should be monitored to develop a predictor equation; however, there is no guideline about the type of scaling factor to be used. Further to this, from the statistical point of view, a regression analysis on a small sample population cannot be accepted without the testing of hypothesis. To show the importance of the above, in this paper, seven scaling factors are considered for blast data set of a hard-rock underground drift using burn

Concrete road barriers subjected to impact loads: An overview

Directory of Open Access Journals (Sweden)

Muhammad Fauzi Bin Mohd. Zain

Full Text Available Abstract Concrete barriers prevent vehicles from entering the opposite lane and going off the road. An important factor in the design of concrete barriers is impact load, which a vehicle exerts upon collision with a concrete barrier. This study suggests that a height of 813 mm, a base width of 600 mm, and a top width of 240 mm are optimum dimensions for a concrete barrier. These dimensions ensure the stability of concrete barriers during vehicle collisions. An analytical and experimental model is used to analyze the concrete barrier design. The LS-DYNA software is utilized to create the analytical models because it can effectively simulate vehicle impact on concrete barriers. Field tests are conducted with a vehicle, whereas laboratory tests are conducted with machines that simulate collisions. Full-scale tests allow the actual simulation of vehicle collisions with concrete barriers. In the vehicle tests, a collision angle of 25°, collision speeds of 100 km per hour, and a vehicle weighing more than 2 t are considered in the reviewed studies. Laboratory tests are performed to test bridge concrete barriers in static condition.

Shear transfer capacity of reinforced concrete exposed to fire

Science.gov (United States)

Ahmad, Subhan; Bhargava, Pradeep; Chourasia, Ajay

2018-04-01

Shear transfer capacity of reinforced concrete elements is a function of concrete compressive strength and reinforcement yield strength. Exposure of concrete and steel to elevated temperature reduces their mechanical properties resulting in reduced shear transfer capacity of RC elements. The objective of present study is to find the effect of elevated temperature on shear transfer capacity of reinforced concrete. For this purpose pushoff specimens were casted using normal strength concrete. After curing, specimens were heated to 250°C and 500°C in an electric furnace. Cooled specimens were tested for shear transfer capacity in a universal testing machine. It was found that shear transfer capacity and stiffness (slope of load-slip curve) were reduced when the specimens were heated to 250°C and 500°C. Load level for the initiation of crack slip was found to be decreased as the temperature was increased. A simple analytical approach is also proposed to predict the shear transfer capacity of reinforced concrete after elevated temperature.

Effect of Different Supplementary Cementitious Materials on Mechanical and Durability Properties of Concrete

Directory of Open Access Journals (Sweden)

Rahul Sharma

2016-09-01

Full Text Available Concrete is the most widely used composite in the world. Ordinary Portland cement (OPC is the most commonly used binding material but the energy required for its production is large and its production leads to release of green house gases in the atmosphere therefore, the need for supplementary cementitious material is real. The utilization of Fly Ash (FA, Silica Fume (SF,Metakaolin (MK and Ground Granulated Blast Furnace Slag (GGBS, as a pozzolanic material for concrete has received considerable attention in the recent years. This interest is a part of the widely spread attention directed towards the utilization of wastes and industrial byproducts in order to minimize the Portland cement consumption, the manufacture of which is being environment damaging. The paper reviews were carried out on the use of FA, SF, MK and GGBS as partial pozzolanic replacement for cement in concrete. The literature demonstrates that GGBS was found to increase the mechanical and durability properties at later age depending upon replacement level. Silica fume concrete performed better than OPC concrete even at early period for production of high strength concrete and high performance concrete. Fly ash increases the later age strength due to slow rate of pozzlanic reaction. Metakaolin was found to improve early age strength as well as long term strength but had poor workability.

Identification of Bacteria and the Effect on Compressive Strength of Concrete

Directory of Open Access Journals (Sweden)

Anneza L. H.

2016-01-01

Full Text Available This paper presents the species of bacteria used in this study as well as the effect of the bacteria on compressive strength of bioconcrete. Bioconcrete is not only more environmentally friendly but it is easy to procure. The objective of this research is to identify the ureolytic bacteria and sulphate reduction bacteria that have been isolated and further use the bacteria in concrete to determine the effect of bacteria on compressive strength. Identification of bacteria is conducted through Polymerase chain reaction (PCR method and DNA sequencing. The DNA of the bacteria was run through BLAST algorithm to determine the bacterial species.The bacteria were added into the concrete mix as a partial replacement of water. 3% of water is replaced by ureolytic bacteria and 5% of water is replaced by sulphate reduction bacteria. After running BLAST algorithm the bacteria were identified as Enterococcus faecalis (ureolytic bacteria and Bacillus sp (sulphate reduction bacteria. The result of the compressive strength for control is 36.0 Mpa. Partial replacement of 3% water by ureolytic bacteria has strength of 38.2Mpa while partial replacement of 5% of water by sulphate reduction bacteria has strength of 42.5Mpa. The significant increase of compressive strength with the addition of bacteria shows that bacteria play a significant role in the improvement of compressive strength.

Determination of protective concrete thickness for medical application of X-rays

International Nuclear Information System (INIS)

Ogbanje, G. O.

2011-01-01

Work was carried out to determine the appropriate thickness of concrete block that would be sufficient to protect the radiation worker and the public from X-rays for medical purpose. The results obtained from four X-ray machines are discussed. However, a minimum thickness of 36.0cm of concrete block was found to be sufficient to protect the two groups mentioned here.

Effects of hydrostatic pressure on the integrity of concrete

International Nuclear Information System (INIS)

Dawson, D.M.; McGahan, P.

1986-04-01

The effects of model inclusions on the properties of concrete subjected to simulated sea disposal conditions are described. From measurements of ultrasound transit time and diametral compression strength it has been shown that metal, ceramic and polymeric inclusions, or voids, at up to 11sup(v)/o loading, have no deleterious effect on cementitious matrix properties during pressurisation to 50 MPa and subsequent depressurisation. The formation of a narrow compaction zone around hard inclusions has been confirmed and its formation can be attributed to the difference in local elastic modulus between the cement matrix and the inclusion. No other matrix cracking was observed. A number of cementitious matrix systems have been studied and from mechanical strength, and strength degradation during pressurisation it is suggested that a 9:1 blast furnace slag/ordinary Portland cement composition is more suitable for the sea-disposal route for wastes than the currently used concrete. (author)

SDOF models for reinforced concrete beams under impulsive loads accounting for strain rate effects

Energy Technology Data Exchange (ETDEWEB)

Stochino, F., E-mail: fstochino@unica.it [Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy); Carta, G., E-mail: giorgio_carta@unica.it [Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy)

2014-09-15

Highlights: • Flexural failure of reinforced concrete beams under blast and impact loads is studied. • Two single degree of freedom models are formulated to predict the beam response. • Strain rate effects are taken into account for both models. • The theoretical response obtained from each model is compared with experimental data. • The two models give a good estimation of the maximum deflection at collapse. - Abstract: In this paper, reinforced concrete beams subjected to blast and impact loads are examined. Two single degree of freedom models are proposed to predict the response of the beam. The first model (denoted as “energy model”) is developed from the law of energy balance and assumes that the deformed shape of the beam is represented by its first vibration mode. In the second model (named “dynamic model”), the dynamic behavior of the beam is simulated by a spring-mass oscillator. In both formulations, the strain rate dependencies of the constitutive properties of the beams are considered by varying the parameters of the models at each time step of the computation according to the values of the strain rates of the materials (i.e. concrete and reinforcing steels). The efficiency of each model is evaluated by comparing the theoretical results with experimental data found in literature. The comparison shows that the energy model gives a good estimation of the maximum deflection of the beam at collapse, defined as the attainment of the ultimate strain in concrete. On the other hand, the dynamic model generally provides a smaller value of the maximum displacement. However, both approaches yield reliable results, even though they are based on some approximations. Being also very simple to implement, they may serve as an useful tool in practical applications.

Membranes replace irradiated blast cells as growth requirement for leukemic blast progenitors in suspension culture

International Nuclear Information System (INIS)

Nara, N.; McCulloch, E.A.

1985-01-01

The blast cells of acute myeloblastic leukemia (AML) may be considered as a renewal population, maintained by blast stem cells capable of both self-renewal and the generation of progeny with reduced or absent proliferative potential. This growth requires that two conditions be met: first, the cultures must contain growth factors in media conditioned either by phytohemagglutinin (PHA)-stimulated mononuclear leukocytes (PHA-LCM), or by cells of the continuous bladder carcinoma line HTB9 (HTB9-CM). Second, the cell density must be maintained at 10(6) blasts/ml; this may be achieved by adding irradiated cells to smaller numbers of intact blasts. The authors are concerned with the mechanism of the feeding function. They present evidence that (a) cell-cell contact is required. (b) Blasts are heterogeneous in respect to their capacity to support growth. (c) Fractions containing membranes from blast cells will substitute for intact cells in promoting the generation of new blast progenitors in culture. (d) This membrane function may be specific for AML blasts, since membranes from blasts of lymphoblastic leukemia or normal marrow cells were inactive

Fiber reinforced concrete as a material for nuclear reactor containment buildings

International Nuclear Information System (INIS)

Mallikarjuna; Banthia, N.; Mindess, S.

1991-01-01

The fiber reinforced concrete as a constructional material for nuclear reactor containment buildings calls for an examination of its individual characteristics and potentialities due to its inherent superiority over normal plain and reinforced concrete. In the present investigation, first, to study the static behavior of straight, hooked-end and crimped fibers, recently developed nonlinear three-dimensional interface (contact) element has been used in conjunction with the eight nodded hexahedron and two nodded bar elements for concrete and steel fiber respectively. Then impact tests were carried out on fiber reinforced concrete beams with an instrumented drop weight impact machine. Two different concrete mixes were tested: normal strength and high strength concrete specimens. Fibers in the concrete mix found to significantly increase the ductility and the impact resistance of the composite. Deformed fibers increase peak pull-out load and pull-out distance, and perform better in the steel fiber reinforced concrete (SFRC) structures. (author)

Decontamination of surfaces by blasting with crystals of H2O and CO2

International Nuclear Information System (INIS)

Benson, C.E.; Parfitt, J.E.; Patton, B.D.

1995-02-01

A major mission of the US Department of Energy during the 1990s is site and environmental cleanup. In pursuit of this mission, numerous remediation projects are under way and many others are being planned at Oak Ridge National Laboratory (ORNL). In this report, tests using two proposed methods for decontaminating surfaces one using water ice crystals [Crystalline Ice Blast (CIB)], the other using dry ice crystals (CO 2 Cleanblast trademark) -- are described. Both methods are adaptations of the commonly used sand blasting technology. The two methods tested differ from sand blasting in that the particles are not particularly abrasive and do not accumulate as particles in the wastes. They differ from each other in that the CO 2 particles sublime during and after impact and the ice particles melt. Thus, the two demonstrations provide important information about two strong candidate decontamination methodologies. Each process was tested at ORNL using contaminated lead bricks and contaminated tools and equipment. Demonstrations with the prototype Crystalline Ice Blast and the CO 2 Cleanblast systems showed that paint, grease, and oil can be removed from metal, plastic, asphalt, and concrete surfaces. Furthermore, removal of contamination from lead bricks was highly effective. Both processes were found to be less effective, under the conditions tested, with contaminated tools and equipment that had chemically bonded contamination or contamination located in crevices since neither technology abrades the substrates or penetrates deeply into crevices to remove particulates. Some process improvements are recommended

Study of some health physics parameters of bismuth-ground granulated blast furnace slag shielding concretes

Energy Technology Data Exchange (ETDEWEB)

Kumar, Sandeep, E-mail: sandeep0078monu@gmail.com [Department of Physics, Punjabi University, Patiala (India); Singh, Sukhpal, E-mail: sukhpal-78@rediffmail.com [Department of Basic and Applied Sciences, Punjabi University, Patiala (India)

2016-05-06

The Bismuth-ground granulated blastfurnace slang (Bi-GGBFS) concrete samples were prepared. The weight percentage of different elements present in Bi-GGBFS Shielding concretewas evaluated by Energy Dispersive X-ray Microanalysis (EDX). The exposure rate and absorbed dose rate characteristics were calculated theoretically for radioactive sources namely {sup 241}Am and {sup 137}Cs. Our calculations reveal that the Bi-GGBFS concretes are effective in shielding material for gamma radiations.

Study of some health physics parameters of bismuth-ground granulated blast furnace slag shielding concretes

Science.gov (United States)

Kumar, Sandeep; Singh, Sukhpal

2016-05-01

The Bismuth-ground granulated blastfurnace slang (Bi-GGBFS) concrete samples were prepared. The weight percentage of different elements present inBi-GGBFS Shielding concretewas evaluated by Energy Dispersive X-ray Microanalysis (EDX). The exposure rate and absorbed dose rate characteristics were calculated theoretically for radioactive sources namely 241Am and 137Cs. Our calculations reveal that the Bi-GGBFS concretes are effective in shielding material for gamma radiations.

Blast-Induced Acceleration in a Shock Tube: Distinguishing Primary and Tertiary Blast Injury

Science.gov (United States)

2016-10-01

injury conditions (blast and acceleration vs acceleration alone) undergo neurobehavioral and histopathological assessments to comprehensively... reversal . To facilitate mid-air blasts, a release mechanism was devised. Balls were attached to the bail of the mechanism. The blast wave would cause

Properties of slag concrete for low-level waste containment

International Nuclear Information System (INIS)

Langton, C.A.; Wong, P.B.

1991-01-01

Ground granulated blast furnace slag was incorporated in the concrete mix used for construction of low-level radioactive waste disposal vaults. The vaults were constructed as six 100 x 100 x 25 ft cells with each cell sharing internal walls with the two adjacent cells. The vaults were designed to contain a low-level radioactive wasteform called saltstone and to isolate the saltstone from the environment until the landfill is closed. Closure involves backfilling with native soil, installation of clay cap, and run-off control. The design criteria for the slag-substituted concrete included compressive strength, 4000 psi after 28 days; slump, 6 inch; permeability, less than 10 -7 cm/sec; and effective nitrate, chromium and technetium diffusivities of 10 -8 , 10 -12 and 10 -12 cm 2 /sec, respectively. The reducing capacity of the slag resulted in chemically reducing Cr +6 to Cr +3 and Tc +7 to Tc +4 and subsequent precipitation of the respective hydroxides in the alkaline pore solution. Consequently, the concrete vault enhances containment of otherwise mobile waste ions and contributes to the overall protection of the groundwater at the disposal site

Finite Element Simulation and Assessment of Single-Degree-of-Freedom Prediction Methodology for Insulated Concrete Sandwich Panels Subjected to Blast Loads

Science.gov (United States)

2011-02-01

Precast /prestressed components, along with their connections to the structure, should be designed to withstand the blast to prevent falling or...response of the component. Connections used for precast components subjected to blast are normally designed with small to zero dynamic increase...methodology considers fixed boundary condition to be more similar to continuous beams or columns . Figure 71 and Table 14 present the comparisons

Study of some health physics parameters of bismuth-ground granulated blast furnace slag shielding concretes

International Nuclear Information System (INIS)

Kumar, Sandeep; Singh, Sukhpal

2016-01-01

The Bismuth-ground granulated blastfurnace slang (Bi-GGBFS) concrete samples were prepared. The weight percentage of different elements present in Bi-GGBFS Shielding concretewas evaluated by Energy Dispersive X-ray Microanalysis (EDX). The exposure rate and absorbed dose rate characteristics were calculated theoretically for radioactive sources namely "2"4"1Am and "1"3"7Cs. Our calculations reveal that the Bi-GGBFS concretes are effective in shielding material for gamma radiations.

Properties of ambient cured blended alkali activated cement concrete

Science.gov (United States)

Talha Junaid, M.

2017-11-01

This paper presents results of the development and strength properties of ambient-cured alkali activated geopolymer concrete (GPC). The study looks at the strength properties, such as compressive strength, splitting tensile strength, and elastic modulus of such concretes and its dependency on various parameters. The parameters studied in this work are the type and proportions of pre-cursor materials, type of activator and their respective ratios and the curing time. Two types of pre-cursor material; low calcium fly ash (FA) and ground granulated blast furnace slag (GGBFS) were activated using different proportions of sodium silicate and sodium hydroxide solutions. The results indicate that ambient cured geopolymer concrete can be manufactured to match strength properties of ordinary Portland cement concrete (OPC). The strength properties of GPC are dependent on the type and ratio of activator and the proportion of GGBFS used. Increasing the percentage of GGBFS increased the compressive and tensile strengths, while reducing the setting time of the mix. The effect of GGBFS on strength was more pronounced in mixes that contained sodium silicate as activator solution. Unlike OPC, ambient-cured GPC containing sodium silicate gain most of their strength in the first 7 days and there is no change in strength thereafter. However, GPC mixes not containing sodium silicate only achieve a fraction of their strength at 7 days and extended curing is required for such concretes to gain full strength. The results also indicate that the elastic modulus values of GPC mixes without sodium silicate are comparable to OPC while mixes with sodium silicate have elastic modulus values much lower than ordinary concrete.

NOBLAST and JAMBLAST: New Options for BLAST and a Java Application Manager for BLAST results.

Science.gov (United States)

Lagnel, Jacques; Tsigenopoulos, Costas S; Iliopoulos, Ioannis

2009-03-15

NOBLAST (New Options for BLAST) is an open source program that provides a new user-friendly tabular output format for various NCBI BLAST programs (Blastn, Blastp, Blastx, Tblastn, Tblastx, Mega BLAST and Psi BLAST) without any use of a parser and provides E-value correction in case of use of segmented BLAST database. JAMBLAST using the NOBLAST output allows the user to manage, view and filter the BLAST hits using a number of selection criteria. A distribution package of NOBLAST and JAMBLAST including detailed installation procedure is freely available from http://sourceforge.net/projects/JAMBLAST/ and http://sourceforge.net/projects/NOBLAST. Supplementary data are available at Bioinformatics online.

Development of Practical Remediation Process for Uranium-Contaminated Concrete

Energy Technology Data Exchange (ETDEWEB)

Kim, S. S.; Kim, W. S.; Kim, G. N.; Moon, J. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

A volume reduction of the concrete waste by the appropriate treatment technologies will decrease the amount of waste to be disposed of and result in a reduction of the disposal cost and an enhancement of the efficiency of the disposal site. Our group has developed a 100 drums/year decontamination process and facilities for the decontamination of radioactive concrete. This practical scale process is little known. A practical decontamination process was developed to remove uranium from concrete pieces generated from the decommissioning of a uranium conversion plant. The concrete pieces are divided into two groups: concrete coated with and without epoxy. For the removal of epoxy from the concrete, direct burning by an oil flame is preferable to an electric heating method. The concrete blocks are crushed to below 30 mm and sifted to 1 mm. When the concrete pieces larger than 1 mm are sequentially washed with a clear washing solution and 1.0 M of nitric acid, most of their radioactivity reaches below the limit value of uranium for self-disposal. The concrete pieces smaller than 1 mm are decontaminated in a rotary washing machine by nitric acid, and an electrokinetic equipment is also used if their radioactivity is high.

Development of Practical Remediation Process for Uranium-Contaminated Concrete

International Nuclear Information System (INIS)

Kim, S. S.; Kim, W. S.; Kim, G. N.; Moon, J. K.

2013-01-01

A volume reduction of the concrete waste by the appropriate treatment technologies will decrease the amount of waste to be disposed of and result in a reduction of the disposal cost and an enhancement of the efficiency of the disposal site. Our group has developed a 100 drums/year decontamination process and facilities for the decontamination of radioactive concrete. This practical scale process is little known. A practical decontamination process was developed to remove uranium from concrete pieces generated from the decommissioning of a uranium conversion plant. The concrete pieces are divided into two groups: concrete coated with and without epoxy. For the removal of epoxy from the concrete, direct burning by an oil flame is preferable to an electric heating method. The concrete blocks are crushed to below 30 mm and sifted to 1 mm. When the concrete pieces larger than 1 mm are sequentially washed with a clear washing solution and 1.0 M of nitric acid, most of their radioactivity reaches below the limit value of uranium for self-disposal. The concrete pieces smaller than 1 mm are decontaminated in a rotary washing machine by nitric acid, and an electrokinetic equipment is also used if their radioactivity is high

Determination of permeability to gases of concrete used as repository for radioactive wastes; Determinacao da permeabilidade a gas em concreto usado em repositorios para rejeitos radioativos

Energy Technology Data Exchange (ETDEWEB)

Miyake, Eloisa Tamie

1994-12-31

Concrete is widely used in final radioactive waste repository construction and must have well defined characteristics. The permeability is a property that allows to evaluate the durability of concrete which guarantee the protection of the surroundings. Durable concretes have low permeability which reduces liquids intrusion into the repository and decreases the probability of leaching of soluble radioactive compounds and gases escapes to the human habitat. This work includes: the construction of a camera to measure the permeability coefficient of hydraulic products, by using gaseous nitrogen as a permeation fluid; determination of characteristics of material used in concrete compositions; and tests in concretes with different compositions in which ordinary Portland cement and blast-furnace cement were used. (author). 61 refs., 33 figs., 16 tabs.

Effect of Large Negative Phase of Blast Loading on Structural Response of RC Elements

Directory of Open Access Journals (Sweden)

Syed Zubair Iman

2016-01-01

Full Text Available Structural response of reinforced concrete (RC elements for analysis and design are often obtained using the positive phase of the blast pressure curve disregarding the negative phase assuming insignificant contribution from the negative phase of the loading. Although, some insight on the effect of negative phase of blast pressure based on elastic single-degree-of-freedom (SDOF analysis was presented before, the influence of negative phase on different types of resistance functions of SDOF models and on realistic finite element analysis has not been explored. In this study, the effects of inclusion of pulse negative phase on structural response of RC elements from SDOF analysis and from more detailed finite element analysis have been investigated. Investigation of SDOF part has been conducted using MATLAB code that utilizes non-linear resistance functions of SDOF model. Detailed numerical investigation using finite element code DIANA was conducted on the significance of the negative phase on structural response. In the FE model, different support stiffness was used to explore the effect of support stiffness on the structural response due to blast negative phase. Results from SDOF and FE analyses present specific situations where the effect of large negative phase was found to be significant on the structural response of RC elements.

Effects of using blended binder of RHA and GGBS on the properties of concrete: A review

Science.gov (United States)

Ishak, Nuril Izzeaty; Johari, Megat Azmi Megat; Hashim, Syed Fuad Saiyid

2017-10-01

Concern about protecting and preserving the environment has driven many researchers to innovate the concrete materials in pursuing better mechanical and physical properties of the fresh and hardened concrete. This paper presents an overview of the microstructural properties, workability, and strength performance of concrete incorporated with mineral admixtures from rice husk ash (RHA) and ground granulated blast-furnace slag (GGBS). The substitution of these supplementary cementitious materials as a ternary blended binder concrete has also been included. It was found that, the average of RHA replacement in concrete is about 10%, while for GGBS is in the range of 40 to 50 % replacement of Portland cement. The results from previous studies yield to a better strength and could potentially be used as high performance concrete, but the high replacement with RHA decreased workability and required more water demand due to the micro porous character, high specific surface area and higher in carbon content of the material. Thus, the necessity of using superlasticizer is crucial to improve the workability and strength. The collection of comprehensive literatures elaborated that the usage of RHA and GGBS enhanced the properties of concrete while gives a better solution for the plenteous of waste produced from the agricultural and industrial sectors.

Divide and Conquer (DC BLAST: fast and easy BLAST execution within HPC environments

Directory of Open Access Journals (Sweden)

Won Cheol Yim

2017-06-01

Full Text Available Bioinformatics is currently faced with very large-scale data sets that lead to computational jobs, especially sequence similarity searches, that can take absurdly long times to run. For example, the National Center for Biotechnology Information (NCBI Basic Local Alignment Search Tool (BLAST and BLAST+ suite, which is by far the most widely used tool for rapid similarity searching among nucleic acid or amino acid sequences, is highly central processing unit (CPU intensive. While the BLAST suite of programs perform searches very rapidly, they have the potential to be accelerated. In recent years, distributed computing environments have become more widely accessible and used due to the increasing availability of high-performance computing (HPC systems. Therefore, simple solutions for data parallelization are needed to expedite BLAST and other sequence analysis tools. However, existing software for parallel sequence similarity searches often requires extensive computational experience and skill on the part of the user. In order to accelerate BLAST and other sequence analysis tools, Divide and Conquer BLAST (DCBLAST was developed to perform NCBI BLAST searches within a cluster, grid, or HPC environment by using a query sequence distribution approach. Scaling from one (1 to 256 CPU cores resulted in significant improvements in processing speed. Thus, DCBLAST dramatically accelerates the execution of BLAST searches using a simple, accessible, robust, and parallel approach. DCBLAST works across multiple nodes automatically and it overcomes the speed limitation of single-node BLAST programs. DCBLAST can be used on any HPC system, can take advantage of hundreds of nodes, and has no output limitations. This freely available tool simplifies distributed computation pipelines to facilitate the rapid discovery of sequence similarities between very large data sets.

Calcium Extraction from Blast-Furnace-Slag-Based Mortars in Sulphate Bacterial Medium

Directory of Open Access Journals (Sweden)

Adriana Estokova

2018-01-01

Full Text Available Wastewater structures, such as treatment plants or sewers can be easily affected by bio-corrosion influenced by microorganisms living in waste water. The activity of these microbes results in deterioration and can cause the reduction in structural performance of such structures. In order to improve the durability of mortar and concrete, different admixtures are being used and the best impact is observed in cement based materials combined with blast furnace slag. In this study, mortar samples with blast furnace slag were exposed to bacterial sulphate attack for 90 and 180 days. The leaching of calcium ions from the cement matrix and equivalent damaged depths of studied mortar samples were evaluated. The results showed more significant leaching of samples placed in bacterial environment, compared to the samples placed in non-bacterial environment. Similarly, the equivalent damaged depths of mortars were much higher for the bacteria-influenced samples. The slag-based cement mortars did not clearly show improved resistance in bacterial medium in terms of calcium leaching.

Analysis of the Dynamic Response in Blast-Loaded CFRP-Strengthened Metallic Beams

Directory of Open Access Journals (Sweden)

Zhenyu Wang

2013-01-01

Full Text Available Carbon fiber-reinforced polymer composites (CFRPs are good candidates in enhancing the blast resistant performance of vulnerable public buildings and in reinforcing old buildings. The use of CFRP in retrofitting and strengthening applications is traditionally associated with concrete structures. Nevertheless, more recently, there has been a remarkable aspiration in strengthening metallic structures and components using CFRP. This paper presents a relatively simple analytical solution for the deformation and ultimate strength calculation of hybrid metal-CFRP beams when subjected to pulse loading, with a particular focus on blast loading. The analytical model is based on a full interaction between the metal and the FRP and is capable of producing reasonable results in a dynamic loading scenario. A nonlinear finite element (FE model is also developed to reveal the full dynamic behavior of the CFRP-epoxy-steel hybrid beam, considering the detailed effects, that is, large strains, high strain rates in metal, and different failure modes of the hybrid beam. Experimental results confirm the analytical and the FE results and show a strong correlation.

Removal of concrete layers from biological shields by microwaves

International Nuclear Information System (INIS)

Wace, P.F.; Harker, A.H.; Hills, D.L.

1990-01-01

A comprehensive literature review has been carried out, to provide information for an experimental programme and equipment design. Mathematical modelling of the microwave and power fields in a concrete block, both steel reinforced and unreinforced, subjected to a microwave attack at two frequencies, has been carried out and estimates of the likely temperature rise with time obtained. A method of launching microwaves into concrete has been established from theoretical considerations and from the findings of the literature review. Equipment for laboratory trials has been designed and assembled using an 896 MHz, 25 kW microwave generator. Reinforced concrete blocks, 0.6 m in dimension and representing the concrete in a Magnox reactor biological shield, have been attacked at different power levels and the surface removed to the depth of the reinforcing steel (100 mm). Outline proposals for the design of a remotely operated prototype microwave machine for stripping the surface of large concrete test panels have been prepared. (author)

Research on Effects of Blast Casting Vibration and Vibration Absorption of Presplitting Blasting in Open Cast Mine

Directory of Open Access Journals (Sweden)

Li Ma

2016-01-01

Full Text Available The impact energy produced by blast casting is able to break and cast rocks, yet the strong vibration effects caused at the same time would threaten the safety of mines. Based on the theory of Janbu’s Limit Equilibrium Method (LEM, pseudo-static method has been incorporated to analyze the influence of dynamic loads of blasting on slope stability. The horizontal loads produced by blast vibrations cause an increase in sliding forces, and this leads to a lower slope stability coefficient. When the tensile stresses of the two adjacent blast holes are greater than the tensile strength of rock mass, the radical oriented cracks are formed, which is the precondition for the formation of presplit face. Thus, the formula for calculating the blast hole spacing of presplit blasting can be obtained. Based on the analysis of the principles of vibration tester and vibration pick-up in detecting blast vibrations, a detection scheme of blast vibration is worked out by taking the blast area with precrack rear and non-precrack side of the detection object. The detection and research results of blast vibration show that presplit blasting can reduce the attenuation coefficient of stress wave by half, and the vibration absorption ratio could reach 50.2%; the impact of dynamic loads on the end-wall slope stability coefficient is 1.98%, which proves that presplit blasting plays an important role in shock absorption of blast casting.

The Complexity of Abstract Machines

Directory of Open Access Journals (Sweden)

Beniamino Accattoli

2017-01-01

Full Text Available The lambda-calculus is a peculiar computational model whose definition does not come with a notion of machine. Unsurprisingly, implementations of the lambda-calculus have been studied for decades. Abstract machines are implementations schema for fixed evaluation strategies that are a compromise between theory and practice: they are concrete enough to provide a notion of machine and abstract enough to avoid the many intricacies of actual implementations. There is an extensive literature about abstract machines for the lambda-calculus, and yet—quite mysteriously—the efficiency of these machines with respect to the strategy that they implement has almost never been studied. This paper provides an unusual introduction to abstract machines, based on the complexity of their overhead with respect to the length of the implemented strategies. It is conceived to be a tutorial, focusing on the case study of implementing the weak head (call-by-name strategy, and yet it is an original re-elaboration of known results. Moreover, some of the observation contained here never appeared in print before.

Development of highly workable concrete, 'Neuro-crete'. Part 1. ; Basic properties of Neuro-crete and application to large-scale structures with heavy-reinforcement. Koryudo concrete (Neuro crete) no kaihatsu. 1. ; Neuro crete no kiso bussei to kamitsu haikin wo yusuru doboku kozobutsu eno tekiyo

Energy Technology Data Exchange (ETDEWEB)

Miura, N; Chikamatsu, R; Sogo, S; Haga, T; Iriya, K; Taniguchi, M [Obayashi Corp., Tokyo (Japan)

1993-08-10

This paper introduces a highly workable concrete, 'Neuro-crete' developed for the purpose of simplifying construction of concrete structures and improving their guality. This concrete has a feature that it can reduce or eliminate a compacting process. Resistance to separation of coarse aggregate from mortar (separation resistance) is required. A difference of the material from conventional concrete is an increased unit particulate amount (binder + inert particulate). The binders may include cement, blast furnace slag particulate, flyash, silica fume, and expander. The inert particulate may be limestone powder. Kinds and mixing ratio of binders are important in improving fluidity. The separation resistivity is largely affected by a water-cement ratio and a water-binder ratio. A flow distance limit exists to maintain the fluidity without decreasing the compression strength after curing. The internal structure having become denser suppresses progress of neutralization or salt penetration. Drying contraction is equivalent to or less than the conventional concrete. 5 refs., 30 figs., 3 tabs.

Evaluation of workability and strength of green concrete using waste steel scrap

Science.gov (United States)

Neeraja, D.; Arshad, Shaik Mohammed; Nawaz Nadaf, Alisha K.; Reddy, Mani Kumar

2017-11-01

This project works on the study of workability and mechanical properties of concrete using waste steel scrap from the lathe industry. Lathe industries produce waste steel scrap from the lathe machines. In this study, an attempt is made to use this waste in concrete, as accumulation of waste steel scrap cause disposal problem. Tests like compressive test, split tensile test, NDT test (UPV test) were conducted to determine the impact of steel scrap in concrete. The percentages of steel scrap considered in the study were 0%, 0.5%, 1%, 1.5%, and 2% respectively by volume of concrete, 7 day, 28 days test were conducted to find out strength of steel scrap concrete. It is observed that split tensile strength of steel scrap concrete is increased slightly. Split tensile strength of Steel scrap concrete is found to be maximum with volume fraction of 2.0% steel scrap. The steel scrap gives good result in split tensile strength of concrete. From the study concluded that steel scrap can be used in concrete to reduce brittleness of concrete to some extent.

An analysis of the heap construction by long hole blasting for in-situ leaching of blasted ore

International Nuclear Information System (INIS)

Yang Shijiao

1999-01-01

The author establishes specific requirements for heap construction by blasting on the basis of the mechanism for in situ leaching of blasted ore, analyses the feasibility of heap construction by long hole blasting, selection of the blast plan and the relevant technological problems, and gives a case of heap construction by long hole blasting in Renhua uranium mine

Degradation of normal portland and slag cement concrete under load, due to reinforcement corrosion

International Nuclear Information System (INIS)

Philipose, K.E.; Beaudoin, J.J.; Feldman, R.F.

1992-08-01

The corrosion of reinforcement is one of the major degradation mechanisms of reinforced concrete elements. The majority of studies published on concrete-steel corrosion have been conducted on unstressed specimens. Structural concrete, however, is subjected to substantial strain near the steel reinforcing bars that resist tensile loads, which results in a system of microcracks. This report presents the initial results of an investigation to determine the effect of applied load and microcracking on the rate of ingress of chloride ion and corrosion of steel in concrete. Simply-supported concrete beam specimens were loaded to give a maximum strain of about 600 με on the tension face. Chloride ion ingress on cores taken from loaded specimens was monitored using energy-dispersive X-ray analysis techniques. Corrosion current and rate measurements using linear polarization electrochemical techniques were also obtained on the same loaded specimens. Variables investigated included two concrete types, two steel cover-depths, three applied load levels, bonded and unbonded rebars and the exposure of tension and compression beam faces to chloride solution. One concrete mixture was made with type 10 Portland cement, the other with 75% blast furnace slag, 22% type 50 cement and 3% silica fume. The rate of chloride ion ingress into reinforced concrete, and hence the time for chloride ion to reach the reinforcing steel, is shown to be dependent on applied load and the concrete quality. The dependence of corrosion process descriptors - passive layer formation, initiation period and propagation period - on the level of applied load is discussed. (Author) (6 refs., 3 tabs., 10 figs.)

Concrete decontamination and demolition methods

International Nuclear Information System (INIS)

LaGuardia, T.S.

1980-01-01

The US Department of Energy (DOE), Division of Environmental Control Technology, requested Nuclear Energy Services to prepare a handbook for the decontamination and decommissioning (D and D) of DOE-owned and commercially-owned radioactive facilities. the objective of the handbook is to provide the nuclear industry with guidance on the state-of-the-art methods and equipment available for decommissioning and to provide the means to estimate decommissioning costs and environmental impact. The methods available for concrete decontamination and demolition are summarized to provide an overview of some of the state-of-the-art techniques to be discussed at this workshop. The pertinent information on each method will include the selection factors such as the rate of performance in terms of concrete removal per unit time (cubic yards per day), manpower required by craft, unit cost (dollars per cubic yard) and the advantages and disadvantages. The methods included in this overview are those that have been routinely used in nuclear and nonnuclear applications or demonstrated in field tests. These methods include controlled blasting, wrecking ball or slab, backhoe mounted ram, flame torch, thermic lance, rock splitter, demolition compound, sawing, core stitch drilling, explosive cutting, paving breaker and power chisel, drill and spall, scarifying, water cannon and grinding

Machine for winding under tension a prestressing wire

International Nuclear Information System (INIS)

Perez, M.A.; Thillet, Georges.

1975-01-01

This invention concerns a machine for winding under tension a prestressing wire or cable. It is used in the wrapping of cylindrical structures, particularly concrete vessels, for the purpose of achieving radial prestressing in them [fr

Decontamination and concrete core sampling by teleoperated robot at Fukushima Daiichi reactor buildings

International Nuclear Information System (INIS)

Watanabe, Masaru; Onitsuka, Hironori; Shimonabe, Noriaki; Fujita, Jun; Matsumura, Takumi; Okumura, Atsushi

2015-01-01

For decommissioning of Fukushima daiichi nuclear power station, reduction of the dose equivalent rates inside the reactor buildings is an important issue. Concrete core sampling from the buildings to investigate the contamination is necessary for study about effective decontamination. However, dose rate inside the reactor buildings is very high. For example, dose rate of 1st floor on the Unit 1 is 1.2 - 1820 [mSv / h], the Unit 2 is 2.5 - 220 [mSv / h] and Unit 3 is 2.2 - 4780 [mSv / h]. So it is difficult for workers to work long hours. Therefore, a teleoperated robot, named 'MHI-MEISTeR (Mitsubishi Heavy Industries - Maintenance Equipment Integrated System of Telecontrol Robot)', has been developed to conduct operations like concrete core samples from the reactor buildings. Actually, some concrete core samples from Fukushima daiichi were taken by MHI-MEISTeR. In addition, MHI-MEISTeR is designed as a versatile robot, and so it can conduct suction / blast decontamination works as well as concrete core sampling. The above operations were performed by MHI-MEISTeR in Fukushima daiichi nuclear power station. (author)

Soft projectile impacts on thin reinforced concrete slabs: tests, modelling and simulations

International Nuclear Information System (INIS)

Pontiroli, C.; Rouquand, A.

2011-01-01

Numerical simulations of reinforced concrete structures subjected to high velocity impacts and explosions remain a difficult task today. Since ten years and more now, the CEA-Gramat has maintained a continuous research effort with the help of different French universities in order to overcome encountered difficulties in modelling the behaviour of concrete structures under severe loading. These difficulties are related to numerical aspects (convergence difficulties of the non linear stress strain relation in 3D configuration, efficiency of the numerical procedure and robustness), but also due to the ability of the material model to simulate the accurately behaviour of a very complex and heterogeneous material like concrete. A new concrete model, named PRM model, has been developed at CEA-Gramat (Pontiroli, Rouquand and Mazars) to predict the concrete response under a large range of dynamic loadings. Works presented in this paper have been performed in the framework of the French VULCAIN PGCU 2007 research project (founded by the French National Research Agency). This project aims at defining a theoretical and probabilistic methodology in order to assess the structural safety of industrial structures that might be submitted to transient loadings such as blasts or impacts generated by various projectiles. A complementary objective is to improve diagnosis, prevention or protection actions. This scientific program gathers well-known and complementary scientific institutes, firms and universities in France. (authors)

Uncertainties Concerning the Free Vibration of Inhomogeneous Orthotropic Reinforced Concrete Plates

Science.gov (United States)

Shahsavar, Vahid Lal; Tofighi, Samira

2014-09-01

Analyzing nearly collapsed and broken structures gives good insights into possible architectural and engineering design mistakes and faults in the detailing and mismanagement of a construction by building contractors. Harmful vibration effects of construction operations occur frequently. The background reviews have demonstrated that the problem of the vibration serviceability of long-span concrete floors in buildings is complex and interdisciplinary in nature. In public buildings, floor vibration control is required in order to meet Serviceability Limit States that ensure the comfort of the users of a building. In industrial buildings, machines are often placed on floors. Machines generate vibrations of various frequencies, which are transferred to supporting constructions. Precision machines require a stable floor with defined and known dynamic characteristics. In recent years there has been increasing interest in the motion of elastic bodies whose material properties (density, elastic moduli, etc.) are not constant, but vary with their position, perhaps in a random manner. Concrete is a non-homogeneous and anisotropic material. Modeling the mechanical behavior of reinforced concrete (RC) is still one of the most difficult challenges in the field of structural engineering. One of several methods for determining the dynamic modulus of the elasticity of engineering materials is the vibration frequency procedure. In this method, the required variables except for the modulus of elasticity are accurately and certainly determined. In this research, the uncertainly analysis of the free vibration of inhomogeneous orthotropic reinforced concrete plates has been investigated. Due to the numerous outputs obtained, the software package has been written in Matlab, and an analysis of the data and drawing related charts has been done.

The anaerobic corrosion of carbon steel in concrete

International Nuclear Information System (INIS)

Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

1990-11-01

The report describes the work of a two year programme investigating the anaerobic corrosion of carbon steel embedded in a range of candidate repository cements and concretes at laboratory ambient temperatures. The factors investigated in the study were the rate of the anaerobic corrosion reaction, the effect of hydrogen overpressure on the reaction rate and the form of the corrosion product. Both electrochemical and sample weight loss corrosion rate measurements were used. The cements and concretes used were prepared both with and without small additions of chloride (2% by weight of mix water). The results indicate that the corrosion rate is low, <1 μm/year, the effect of hydrogen overpressure is not significant over the range of pressures investigated, 1-100 atmospheres, and that the corrosion product is dependent on the cement used to cast the samples. Magnetite was identified in the case of blast furnace slag replacement cements but for pulverised fuel ash and ordinary Portland cements no corrosion product was evident either from X-ray diffraction or laser Raman measurements. (Author)

Human Injury Criteria for Underwater Blasts.

Directory of Open Access Journals (Sweden)

Rachel M Lance

Full Text Available Underwater blasts propagate further and injure more readily than equivalent air blasts. Development of effective personal protection and countermeasures, however, requires knowledge of the currently unknown human tolerance to underwater blast. Current guidelines for prevention of underwater blast injury are not based on any organized injury risk assessment, human data or experimental data. The goal of this study was to derive injury risk assessments for underwater blast using well-characterized human underwater blast exposures in the open literature. The human injury dataset was compiled using 34 case reports on underwater blast exposure to 475 personnel, dating as early as 1916. Using severity ratings, computational reconstructions of the blasts, and survival information from a final set of 262 human exposures, injury risk models were developed for both injury severity and risk of fatality as functions of blast impulse and blast peak overpressure. Based on these human data, we found that the 50% risk of fatality from underwater blast occurred at 302±16 kPa-ms impulse. Conservatively, there is a 20% risk of pulmonary injury at a kilometer from a 20 kg charge. From a clinical point of view, this new injury risk model emphasizes the large distances possible for potential pulmonary and gut injuries in water compared with air. This risk value is the first impulse-based fatality risk calculated from human data. The large-scale inconsistency between the blast exposures in the case reports and the guidelines available in the literature prior to this study further underscored the need for this new guideline derived from the unique dataset of actual injuries in this study.

Blasting agents and initiation systems

Energy Technology Data Exchange (ETDEWEB)

Fiscor, S.

2000-01-01

Although blasting differs between and within each industry, as a whole, the mines and quarries are making a shift from a purely ammonium nitrate/fuel oil (ANFO) mixture to a blend of emulsion and ANFO on a straight emulsion. Non-electric (shock tube) initiation systems have provided a viable alternative to the electric detonator (blasting cap). Explosives manufacturers are seeing their roles changes to being blasting contractors or consultants rather than just suppliers. The article discusses these trends and gives examples of typical blasting techniques and amounts of blasting agent used at large USA surface coal mines. Electric caps are still used in blasting underground coal. The Ensign Bickford Co. (EBCo) is developing electronic detonators and has been field testing an electronic initiator, the DIGIDET detonator, for the last four years. When commercially available, electronic detonators will be accurate but will come with a hefty price tag. 2 photos.

Low-cost blast wave generator for studies of hearing loss and brain injury: blast wave effects in closed spaces.

Science.gov (United States)

Newman, Andrew J; Hayes, Sarah H; Rao, Abhiram S; Allman, Brian L; Manohar, Senthilvelan; Ding, Dalian; Stolzberg, Daniel; Lobarinas, Edward; Mollendorf, Joseph C; Salvi, Richard

2015-03-15

Military personnel and civilians living in areas of armed conflict have increased risk of exposure to blast overpressures that can cause significant hearing loss and/or brain injury. The equipment used to simulate comparable blast overpressures in animal models within laboratory settings is typically very large and prohibitively expensive. To overcome the fiscal and space limitations introduced by previously reported blast wave generators, we developed a compact, low-cost blast wave generator to investigate the effects of blast exposures on the auditory system and brain. The blast wave generator was constructed largely from off the shelf components, and reliably produced blasts with peak sound pressures of up to 198dB SPL (159.3kPa) that were qualitatively similar to those produced from muzzle blasts or explosions. Exposure of adult rats to 3 blasts of 188dB peak SPL (50.4kPa) resulted in significant loss of cochlear hair cells, reduced outer hair cell function and a decrease in neurogenesis in the hippocampus. Existing blast wave generators are typically large, expensive, and are not commercially available. The blast wave generator reported here provides a low-cost method of generating blast waves in a typical laboratory setting. This compact blast wave generator provides scientists with a low cost device for investigating the biological mechanisms involved in blast wave injury to the rodent cochlea and brain that may model many of the damaging effects sustained by military personnel and civilians exposed to intense blasts. Copyright © 2015 Elsevier B.V. All rights reserved.

Exploring cluster Monte Carlo updates with Boltzmann machines.

Science.gov (United States)

Wang, Lei

2017-11-01

Boltzmann machines are physics informed generative models with broad applications in machine learning. They model the probability distribution of an input data set with latent variables and generate new samples accordingly. Applying the Boltzmann machines back to physics, they are ideal recommender systems to accelerate the Monte Carlo simulation of physical systems due to their flexibility and effectiveness. More intriguingly, we show that the generative sampling of the Boltzmann machines can even give different cluster Monte Carlo algorithms. The latent representation of the Boltzmann machines can be designed to mediate complex interactions and identify clusters of the physical system. We demonstrate these findings with concrete examples of the classical Ising model with and without four-spin plaquette interactions. In the future, automatic searches in the algorithm space parametrized by Boltzmann machines may discover more innovative Monte Carlo updates.

Exploring cluster Monte Carlo updates with Boltzmann machines

Science.gov (United States)

Wang, Lei

2017-11-01

Boltzmann machines are physics informed generative models with broad applications in machine learning. They model the probability distribution of an input data set with latent variables and generate new samples accordingly. Applying the Boltzmann machines back to physics, they are ideal recommender systems to accelerate the Monte Carlo simulation of physical systems due to their flexibility and effectiveness. More intriguingly, we show that the generative sampling of the Boltzmann machines can even give different cluster Monte Carlo algorithms. The latent representation of the Boltzmann machines can be designed to mediate complex interactions and identify clusters of the physical system. We demonstrate these findings with concrete examples of the classical Ising model with and without four-spin plaquette interactions. In the future, automatic searches in the algorithm space parametrized by Boltzmann machines may discover more innovative Monte Carlo updates.

ANALYSIS AND APPLICATION PROSPECTS OF EFFECTIVE RESOURCES-SAVING TECHNOLOGIES IN CONCRETE MANUFACTURE

Directory of Open Access Journals (Sweden)

H. P. Ivanova

2014-10-01

Full Text Available Purpose. Prospectivity assessments of the nano-materials usage in construction technologies at the same time meeting the requirements of environmental safety and rational use of the natural resources. Methodology. During the study the building composites, in particular concretes, which are obtained on the base of the raw materials, which are introduced in the array of micro- and nanolevels were researched and analyzed. The deformation and deterioration processes of nanostructured concrete depending on their composition and manufacture parameters were simulated. Findings. Concrete manufacture is in the direct dependence on its components. Due to the extraction and processing of these components land degradation occurs because of soil destruction with oversize pits, which threatens the ecology of the environment. In this connection there is a need for another concept of building materials receiving for concrete manufacture. The new branch of science based on nanotechnologies, nanomaterials and nanostructuring is a key to its foundation. The special features of nanostructured concretes are the nanoagents in their composition (carbon nanotubes, mechanoactivated slags of blast furnace production. The study of deformation patterns and concrete deterioration based on the mechanoactivated material will purposefully affect the structure, physical and chemical properties, as well as the mechanical and deformational ones. Originality. The researches have shown that nano-structured concrete had high fluidity. The strength of such compositions is enhanced up to 13 % without reduction of concrete consumption and up to 8.8% at 10% reduced concrete consumption. Practical value. The application of the structured concretes based on the mechanoactivated material will increase the efficiency of the industrial wastes recycling and improve the physical, mechanical and technological properties of the produced composites. From the standpoint of the economic benefits

Fragment Size Distribution of Blasted Rock Mass

Science.gov (United States)

Jug, Jasmin; Strelec, Stjepan; Gazdek, Mario; Kavur, Boris

2017-12-01

Rock mass is a heterogeneous material, and the heterogeneity of rock causes sizes distribution of fragmented rocks in blasting. Prediction of blasted rock mass fragmentation has a significant role in the overall economics of opencast mines. Blasting as primary fragmentation can significantly decrease the cost of loading, transport, crushing and milling operations. Blast fragmentation chiefly depends on the specific blast design (geometry of blast holes drilling, the quantity and class of explosive, the blasting form, the timing and partition, etc.) and on the properties of the rock mass (including the uniaxial compressive strength, the rock mass elastic Young modulus, the rock discontinuity characteristics and the rock density). Prediction and processing of blasting results researchers can accomplish by a variety of existing software’s and models, one of them is the Kuz-Ram model, which is possibly the most widely used approach to estimating fragmentation from blasting. This paper shows the estimation of fragmentation using the "SB" program, which was created by the authors. Mentioned program includes the Kuz-Ram model. Models of fragmentation are confirmed and calibrated by comparing the estimated fragmentation with actual post-blast fragmentation from image processing techniques. In this study, the Kuz-Ram fragmentation model has been used for an open-pit limestone quarry in Dalmatia, southern Croatia. The resulting calibrated value of the rock factor enables the quality prognosis of fragmentation in further blasting works, with changed drilling geometry and blast design parameters. It also facilitates simulation in the program to optimize blasting works and get the desired fragmentations of the blasted rock mass.

Cement-free Binders for Radioactive Waste Produced from Blast-furnace Slag using Vortex Layer Activation Technology

Directory of Open Access Journals (Sweden)

Mazov Ilya

2017-01-01

Full Text Available The paper addresses the issue of recycling granulated blast-furnace slag (gBFS as a source for production of cement-free binder materials for further usage in rare-earth metals production for radioactive waste disposal. The use of the vortex layer activator was provided as main technique allowing to produce high-dispersed chemically activated binders. The paper examines the effect of processing conditions on the physical-chemical and mechanical properties of the resulting BFS-based cement-free materials and gBFS-based concretes.

Flexural strength of structural concrete repaired with HBPMM cement

International Nuclear Information System (INIS)

Memon, G.H.; Khaskheli, G.B.; Kumar, A.

2009-01-01

To repair damaged concrete structures, Dadabhoy Cement Factory in Sindh has launched a product known as HBPMM (Hi-Bond Polymer Modified Mortar) cement. HBPMM is used to repair various concrete structures in Pakistan but the experimental back up regarding the real performance of the product, as far as flexural strength of concrete is concerned, is not well known yet. This study is thus aimed to investigate the flexural strength of structural concrete repaired with HBPMM compared to that repaired with OPC (Ordinary Portland Cement). In total 32 concrete beams (6x6x18) having compressive strength of 3000 and 5000 psi were manufactured. To obtain flexural strength of the beams, these were splitted by using a UTM (Universal Testing Machine). Beams were then repaired with different applications of HBPMM and OPC. After 28 days of curing, the repaired beams were re-splitted to determine the flexural strength of repaired beams. Results show that both HBPMM and OPC are not very effective. However, the performance of HBPMM remained slightly better than that of OPC. Both OPC and HBPMM remained more efficient in case of 5000 psi concrete than that of 3000 psi concrete. Flexural strength of repaired beams could be increased by increasing application of the repairing material. (author)

The structural response and manner of progressive collapse in RC buildings under the blast and Provide approaches to retrofitting columns against blast

Directory of Open Access Journals (Sweden)

GholamReza Havaei

2017-05-01

Full Text Available In accidents caused by explosion, the initial damage is usually caused by direct hit blast that it causes damage and serious destruction of structural components. In this state, the collapse of structural components and the subsequent progressive collapse may cause an increase in damages and eventually collapse of the structure. On the other hand, observations show that most of these buildings designed and built without consideration of their vulnerability to such events. In this study, global and local response of reinforced concrete buildings and their damages evaluated against explosion. First the global stability of building using SAP2000 is evaluated against explosion and then the amount and behaviour of damages in The key structural components of the building after the explosion is investigated using LS DYNA. The study involved four important areas in structural engineering that includes blast load determination, numerical modelling with FEM techniques, material performance under high strain rate and non-linear dynamic analysis. Two types of design methods are recommended for RC columns to provide superior residual capacities. They are RC columns detailing with additional steel reinforcement cages and a composite columns including a central structural steel core. The results showed that the use of this type of columns compared to typical RC column against explosion can have a significant impact in increasing the bearing capacity of structural components against gravity loads after the explosion.

DYNAMIC TIME HISTORY ANALYSIS OF BLAST RESISTANT DOOR USING BLAST LOAD MODELED AS IMPACT LOAD

Directory of Open Access Journals (Sweden)

Y. A. Pranata

2012-06-01

Full Text Available A blast resistant single door was designed to withstand a 0.91 bar blast pressure and 44 ms blast duration. The analysis was done using Dynamic Time History Analysis using Blast Load modeled as Impact Load for given duration. The material properties used have been modified to accommodate dynamic effects. The analysis was done using dynamic finite element method (fem for time of the blast duration, and the maximum/minimum internal forces and displacement were taken from the time history output, in order to know the behavior under blast load and estimate the safety margin of the door. Results obtained from this research indicated that the maximum z-displacement is 1.709 mm, while in the term of serviceability, the permitted is 25 mm. The maximum reaction force is 73,960 N, while the maximum anchor capacity is 82,069 N. On blast condition, the maximum frame stress is 71.71 MPa, the maximum hinge shear stress is 45.28 MPa. While on rebound condition, the maximum frame stress is 172.11 MPa, the maximum hinge shear stress is 29.46 MPa. The maximum door edge rotation is 0.44 degree, which is not exceed the permitted boundary (1.2 degree. Keywords: Dynamic time history, blast resistant door, single door, finite element method.

A new concept for the targeted cutting of concrete structures

International Nuclear Information System (INIS)

Reinhardt, Steffen; Gentes, Sascha; Weidemann, Roman; Geimer, Marcus

2011-01-01

The decontamination and crushing of reinforced concrete is a main part during deconstruction of nuclear facilities. The selective treatment of contaminated or activated material is of special interest, since the non-contaminated material can be transferred into the normal reprocessing cycle. In the frame of a project concerning the innovative cutting of massive reinforced concrete structures an all-purpose system for spatially restricted and defined cutting of strongly reinforced concrete including packaging suitable for final disposal was developed. Due to the remote handling of the machine the dose rate for personnel can be reduced significantly. Main part of the system is the tool that can cut highly reinforced concrete without system or component replacement. The authors describe preliminary tests of these tools, further experiments and process optimization are necessary before the tools can be integrated into the new system.

NCBI BLAST+ integrated into Galaxy.

Science.gov (United States)

Cock, Peter J A; Chilton, John M; Grüning, Björn; Johnson, James E; Soranzo, Nicola

2015-01-01

The NCBI BLAST suite has become ubiquitous in modern molecular biology and is used for small tasks such as checking capillary sequencing results of single PCR products, genome annotation or even larger scale pan-genome analyses. For early adopters of the Galaxy web-based biomedical data analysis platform, integrating BLAST into Galaxy was a natural step for sequence comparison workflows. The command line NCBI BLAST+ tool suite was wrapped for use within Galaxy. Appropriate datatypes were defined as needed. The integration of the BLAST+ tool suite into Galaxy has the goal of making common BLAST tasks easy and advanced tasks possible. This project is an informal international collaborative effort, and is deployed and used on Galaxy servers worldwide. Several examples of applications are described here.

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

International Nuclear Information System (INIS)

McPhee, William S.

1999-01-01

The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and

Study on properties of mortar using silica fume and ground blast furnace slag. Silica fume oyobi koro slag funmatsu wo mochiita mortar no tokusei ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Shiiba, H; Honda, S; Araki, A [Fukuoka University, Fukuoka (Japan). Faculty of Engineering

1992-09-01

The effect of silica fume and ground blast furnace slag in concrete on the content of superplasticizer, and dynamic properties of hardened mortar with such admixtures were studied experimentally. Although the dependence of a flow value on the superplasticizer was dominated by kinds of superplasticizers, blast furnace slag enhanced the flow value resulting in a high fluidity. Adsorption of superplasticizers onto admixtures was dependent on kinds of superplasticizers, and adsorption onto blast furnace slag was 1.3-2 times that onto normal Portland cement (NPC). The compressive strength of mortar increased by mixing admixtures, while the bending strength was enhanced only by mixing silica fume. Mixing mortar was lower in dynamic elastic modulus than NPC mortar at the same compressive strength, and the velocity of supersonic wave in mortar was scarcely affected by mixing. 11 refs., 14 figs., 3 tabs.

Tensile strength of structural concrete repaired with hi-bond polymer modified mortar

International Nuclear Information System (INIS)

Khaskheli, G.B.

2009-01-01

Repair of cracks in concrete is often required to save the concrete structures. Appearance of crack in concrete is bound with the tensile strength of concrete. Recently a cement factory in Sindh has launched a HBPMM (Hi-Bond Polymer Modified Mortar) that can be used as a concrete repairing material instead of normal OPC (Ordinary Portland Cement). It is needed to investigate its performance compared to that of OPC. In total 144 concrete cylinders (150x300mm) having strength of 3000 and 5000 psi were manufactured. These cylinders were then splitted by using a UTM (Universal Testing Machine) and their actual tensile strength was obtained. The concrete cylinders were then repaired with different applications of HBPMM and arc. The repaired samples were again splitted at different curing ages (3, 7 and 28 days) and their tensile strength after repair was obtained. The results show that the concrete cylinders repaired with HBPMM could give better tensile strength than that repaired with arc, the tensile strength of concrete cylinders after repair could increase with increase in the application of repairing material i.e. HBPMM or OPC and with curing time, and HBPMM could remain more effective in case of rich mix concrete than that of normal mix concrete. (author)

Blast-induced traumatic brain injury: a new trend of blast injury research.

Science.gov (United States)

Zhao, Yan; Wang, Zheng-Guo

2015-01-01

Blast injury has become the major life- and function-threatening injuries in recent warfares. There is increased research interest in the mental disorders caused by blast-induced traumatic brain injury (bTBI), which has been proved as one of the "signature wounds" in modern battlefield. We reviewed the recent progresses in bTBI-related researches and concluded that the new era of blast injury research has shifted from the traditional physical impairments to cognitive dysfunctional/mental disorders that are proved to be more related to the outcome of combat casualty care.

Blast management

OpenAIRE

Shouraki, Mohammad Kargar; Naserkheil, Ali Asghar

2011-01-01

Blast Management (BM) is composed of the combination of human resources management (HRM) principles and concepts and various methods of quality management (QM) with a financial approach. BM is made up of three aspects: hard, soft and concept and BLAST means an explosive shift in organization's mindset and thought and rapid action against it. The first aspect, hard, includes a set of managerial toots and philosophies to improve the quality and productivity with a financial approach.

Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury

Energy Technology Data Exchange (ETDEWEB)

Moss, W C; King, M J; Blackman, E G

2011-01-21

In their Contributed Article, Nyein et al. (1,2) present numerical simulations of blast waves interacting with a helmeted head and conclude that a face shield may significantly mitigate blast induced traumatic brain injury (TBI). A face shield may indeed be important for future military helmets, but the authors derive their conclusions from a much smaller explosion than typically experienced on the battlefield. The blast from the 3.16 gm TNT charge of (1) has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 10 atm, 0.25 ms, and 3.9 psi-ms at the front of the head (14 cm from charge), and 1.4 atm, 0.32 ms, and 1.7 psi-ms at the back of a typical 20 cm head (34 cm from charge). The peak pressure of the wave decreases by a factor of 7 as it traverses the head. The blast conditions are at the threshold for injury at the front of the head, but well below threshold at the back of the head (4). The blast traverses the head in 0.3 ms, roughly equal to the positive phase duration of the blast. Therefore, when the blast reaches the back of the head, near ambient conditions exist at the front. Because the headform is so close to the charge, it experiences a wave with significant curvature. By contrast, a realistic blast from a 2.2 kg TNT charge ({approx} an uncased 105 mm artillery round) is fatal at an overpressure of 10 atm (4). For an injury level (4) similar to (1), a 2.2 kg charge has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 2.1 atm, 2.3 ms, and 18 psi-ms at the front of the head (250 cm from charge), and 1.8 atm, 2.5 ms, and 16.8 psi-ms at the back of the head (270 cm from charge). The peak pressure decreases by only a factor of 1.2 as it traverses the head. Because the 0.36 ms traversal time is much smaller than the positive phase duration, pressures on the head become relatively uniform when the blast reaches the back of the head. The larger standoff implies

Remote operated vehicle with CO2 blasting (ROVCO2): Volume 1. Final report, September 1993--July 1996

International Nuclear Information System (INIS)

1996-06-01

This report documents the second phase of the Remote Operated Vehicle with CO 2 Blasting (ROVCO 2 ) Program. The ROVCO 2 Program's goal is to develop and demonstrate a tool to improve the productivity of concrete floor decontamination. The second phase integrated non-developmental subsystems on to the ROVCO 2 system and performed quantitative decontamination effectiveness, productivity, and reliability testings. The report documents these development activities and the analysis of cost and performance. The results show that the ROVCO 2 system is an efficient decontamination tool

Development of high integrity, maximum durability concrete structures for LLW disposal facilities

International Nuclear Information System (INIS)

Taylor, W.P.

1992-01-01

A number of disposal facilities for Low-Level Radioactive Wastes have been planned for the Savannah River Site. Design has been completed for disposal vaults for several waste classifications and construction is nearly complete or well underway on some facilities. Specific design criteria varies somewhat for each waste classification. All disposal units have been designed as below-grade concrete vaults, although the majority will be above ground for many years before being encapsulated with earth at final closure. Some classes of vaults have a minimum required service life of 100 years. All vaults utilize a unique blend of cement, blast furnace slag and pozzolan. The design synthesizes the properties of the concrete mix with carefully planned design details and construction methodologies to (1) eliminate uncontrolled cracking; (2) minimize leakage potential; and (3) maximize durability. The first of these vaults will become operational in 1992. 9 refs

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

FastBLAST: homology relationships for millions of proteins.

Directory of Open Access Journals (Sweden)

Morgan N Price

Full Text Available BACKGROUND: All-versus-all BLAST, which searches for homologous pairs of sequences in a database of proteins, is used to identify potential orthologs, to find new protein families, and to provide rapid access to these homology relationships. As DNA sequencing accelerates and data sets grow, all-versus-all BLAST has become computationally demanding. METHODOLOGY/PRINCIPAL FINDINGS: We present FastBLAST, a heuristic replacement for all-versus-all BLAST that relies on alignments of proteins to known families, obtained from tools such as PSI-BLAST and HMMer. FastBLAST avoids most of the work of all-versus-all BLAST by taking advantage of these alignments and by clustering similar sequences. FastBLAST runs in two stages: the first stage identifies additional families and aligns them, and the second stage quickly identifies the homologs of a query sequence, based on the alignments of the families, before generating pairwise alignments. On 6.53 million proteins from the non-redundant Genbank database ("NR", FastBLAST identifies new families 25 times faster than all-versus-all BLAST. Once the first stage is completed, FastBLAST identifies homologs for the average query in less than 5 seconds (8.6 times faster than BLAST and gives nearly identical results. For hits above 70 bits, FastBLAST identifies 98% of the top 3,250 hits per query. CONCLUSIONS/SIGNIFICANCE: FastBLAST enables research groups that do not have supercomputers to analyze large protein sequence data sets. FastBLAST is open source software and is available at http://microbesonline.org/fastblast.

Impact capacity reduction in railway prestressed concrete sleepers with vertical holes

Science.gov (United States)

Ngamkhanong, Chayut; Li, Dan; Kaewunruen, Sakdirat

2017-09-01

Railway prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground as well as to secure rail gauge for dynamic safe movements of trains. In spite of the most common use of the prestressed concrete sleepers in railway tracks, the concrete sleepers are often modified on construction sites to fit in other systems such as cables, signalling gears, drainage pipes, etc. This is because those signalling, fibre optic, equipment cables are often damaged either by ballast corners or by tamping machine. It is thus necessary to modify concrete sleepers to cater cables internally so that the cables or drainage pipes would not experience detrimental or harsh environments. Accordingly, this study will extend from the previous study into the design criteria of holes and web openings. This paper will highlight structural capacity of concrete sleepers under dynamic transient loading. The modified compression field theory for ultimate strength design of concrete sleepers will be highlighted in this study. The outcome of this study will improve the understanding into dynamic behavior of prestressed concrete sleepers with vertical holes. The insight will enable predictive track maintenance regime in railway industry.

Underground roadway drivage with heading machines in Indian coal industry

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, T.K.

1983-03-01

Heading machines have assumed a very important place in underground roadway drivage. They are not only a compromise between ''drill-and-blast'' technique and full-face machines, but are also an economic and versatile form of mechanised roadway drivage. Since the advantages gained by heading machines are considerable, the use of these machines is becoming popular in underground roadway drivage. Experience with continuous miner and heading machines in Indian coal mines is very limited compared to that of Western countries. In 1964-65, for the first time, two units of Lee Norse Miner were used at Kunostoria Colliery of Bengal Coal Company. In 1966, two units of Joy Continuous Miner were introduced at Chalkari Colliery of National Coal Development Corporation, but had to be adandoned because of heavy make of water at the installation site. A Russian PK-3 heading machine was used limitedly during the development of Banki Colliery, Madhya Pradesh. A Demag Unicorn VS-1 machine operated for the development of roadways at Jitpur and Chasnala Collieries of IISCO between 1967-70. With this machine, progress of 7 m per day was attained in level roadways and of about 2 m per day in steep raises.

The use of computer blast simulations to improve blast quality

International Nuclear Information System (INIS)

Favreau, R.F.; Kuzzyk, G.W.; Babulic, P.J.; Morin, R.A.; Tienkamp, N.J.

1987-01-01

An underground research laboratory (URL) has been constructed as part of a comprehensive program to evaluate the concept of nuclear fuel waste disposal in deep crystalline rock formations. Careful blasting methods have been used to minimize damage to the excavation surfaces. This paper reviews the results of the program to develop controlled blasting for the full-face method, comparing the field observed results achieved with the simulated theoretical results. The simulated results indicate how the blasting may damage the excavation surface. Results suggest that the rock around the final wall is stressed more severely by the cushion holes than by the perimeter holes and that bootleg of the rock between the perimeter and cushion rows occurs when the burst-out velocity imparted to it by the explosive loads in the perimeter holes is inadequate

Material equations for the calculations of steel fiber reinforced concrete members

International Nuclear Information System (INIS)

Jonas, W.

1993-01-01

Steel fiber reinforced concrete (SFRC) is made by the addition of steel fibers to fresh concrete. Usually the fibers are about 0.4-0.8mm in diameter and 25-80mm long. The addition of about 50-120 kg/m 3 is a practical and useful amount. That is about 0.6-1.5% by volume. The fibers are uniformly dispersed with a suitable concrete mix, so that clusters and uneven concentrations are prevented. The tensile strength of steel fiber reinforced concrete is scarcely better compared to that of plain concrete, but the fibers are very effective at preventing the propagation of tensile cracks. Thereby the tensile strength of fiber reinforced concrete is a reliable value. The addition of steel fibers also leads to a considerable increase of plastic deformations in the post cracking region, in comparison to plain concrete members. For nuclear power plant construction the use of steel fiber concrete with additional reinforcement of normal or prestressing steel is of special interest. The finished members exhibit good crack behaviour, increased shear strength and a considerable ability to absorb mechanical energy. These are valuable properties for members providing protection against extreme load cases (e.g. aircraft crash, earthquake, blast caused by explosion, debris due to hurricane, internal pressure loads or debris due to bursting of vessels or pipes). The behaviour of a reinforced concrete beam with steel fiber reinforced concrete against that of a reinforced beam without is shown. Until now the use of steel fiber reinforced concrete in civil engineering has been restricted because of the lack of design rules. For the preparation of fundamental principles and for the development of design rules HOCHTIEF has undertaken a series of tests on steel fiber reinforced concrete members with and without additional bar reinforcement. For this purpose HOCHTIEF has carried out several series of tests using either static, impact or cyclic loadings. In section 2 of this paper the elements

Using natural local materials for developing special radiation shielding concretes, and deduction of its shielding characteristics

International Nuclear Information System (INIS)

Kharita, M. H.; Takeyeddin, M.; Al-Nassar, M.; Yousef, S.

2006-06-01

Concrete is considered as the most important material to be used for radiation shielding in facilities contain radioactive sources and radiation generating machines. The concrete shielding properties may vary depending on the construction of the concrete, which is highly relative to the composing aggregates i.e. aggregates consist about 70 - 80% of the total weight of normal concrete. In this project tow types of concrete used in Syria (in Damascus and Aleppo) had been studied and their shielding properties were defined for gamma ray from Cs-137 and Co-60 sources, and for neutrons from Am-Be source. About 10% reduction in HVL was found in the comparison between the tow concrete types for both neutrons and gammas. Some other types of concrete were studied using aggregates from different regions in Syria, to improve the shielding properties of concrete, and another 10% of reduction was achieved in comparison with Damascene concrete (20% in comparison with the concrete from Aleppo) for both neutrons and gamma rays. (author)

Reinforced concrete in the intermediable-level nuclear waste repository

International Nuclear Information System (INIS)

Duffo, Gustavo

2009-01-01

The National Atomic Energy Commission (CNEA) is responsible for developing the nuclear waste disposal management programme. This programme contemplates the design and construction of a facility for the final disposal of intermediate-level radioactive wastes. The proposed model is a near-surface monolithic repository similar to those in operation in El Cabril, Spain. The design of this type of repository is based on the use of multiple, independent and redundant barriers and the model foresees a period of 300 years of institutional post-closure control. Since the vault and cover are major components of the engineered barriers, the durability of these concrete structures is an important aspect for the facility integrity. This work presents laboratory investigations performed on the corrosion susceptibility of steel rebars embedded in two different types of high performance reinforced concretes, recently developed by the National Institute of Industrial Technology (Argentine). Concretes were made with cement with Blast Furnace Slag (CAH) and Silica Fume cement (CAH + SF). The aim of this work is to predict the service life of the intermediate level radioactive waste disposal vaults from data obtained from electrochemical techniques. Besides, the diffusion coefficients of aggressive species, such as chloride and carbon dioxide, were also determined. On the other hand, data obtained with corrosion sensors embedded in a vault prototype is also included. These sensors allow on-line measurements of several parameters related to the corrosion process such as rebar corrosion potential and corrosion current density; incoming oxygen flow that reaches the metal surface; concrete electrical resistivity; chloride concentration and internal concrete temperature. All the information obtained from both, laboratory tests and sensors will be used for the final design of the container in order to achieve a service life more or equal than the foreseen durability for this type of

30 CFR 780.13 - Operation plan: Blasting.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Operation plan: Blasting. 780.13 Section 780.13... SURFACE MINING PERMIT APPLICATIONS-MINIMUM REQUIREMENTS FOR RECLAMATION AND OPERATION PLAN § 780.13 Operation plan: Blasting. (a) Blasting plan. Each application shall contain a blasting plan for the proposed...

Modernity Evaluation of the Machines Used During Production Process of Metal Products

OpenAIRE

Ingaldi, Manuela; Dziuba, Szymon T.

2015-01-01

Most manufacturing companies realize its technologies, implemented through concrete machinery parts. They differ in terms of importance, the relevance of their selection and the level of their modernity. Modernity and efficiency of the machine are also very important during production process of the metal products. They have an influence on the quality of these products. The purpose of this article is to analyse the chosen production machine (CNC machine AFE-3D8-T) used during pro...

Python for probability, statistics, and machine learning

CERN Document Server

Unpingco, José

2016-01-01

This book covers the key ideas that link probability, statistics, and machine learning illustrated using Python modules in these areas. The entire text, including all the figures and numerical results, is reproducible using the Python codes and their associated Jupyter/IPython notebooks, which are provided as supplementary downloads. The author develops key intuitions in machine learning by working meaningful examples using multiple analytical methods and Python codes, thereby connecting theoretical concepts to concrete implementations. Modern Python modules like Pandas, Sympy, and Scikit-learn are applied to simulate and visualize important machine learning concepts like the bias/variance trade-off, cross-validation, and regularization. Many abstract mathematical ideas, such as convergence in probability theory, are developed and illustrated with numerical examples. This book is suitable for anyone with an undergraduate-level exposure to probability, statistics, or machine learning and with rudimentary knowl...

Water-Depth-Based Prediction Formula for the Blasting Vibration Velocity of Lighthouse Caused by Underwater Drilling Blasting

Directory of Open Access Journals (Sweden)

Wenbin Gu

2017-01-01

Full Text Available Lighthouses are the most important hydraulic structures that should be protected during underwater drilling blasting. Thus, the effect of blasting vibration on lighthouse should be studied. On the basis of the dimensional analysis, we deduced a revised formula for water depth based on Sodev’s empirical formula and established the linear fitting model. During the underwater reef project in the main channel of Shipu Harbor in the Ningbo–Zhoushan Port, the blasting vibration data of the lighthouse near the underwater blasting area were monitored. The undetermined coefficient, resolvable coefficient, and F value of the two formulas were then obtained. The comparison of the data obtained from the two formulas showed that they can effectively predict the blasting vibration on the lighthouse. The correction formula that considers water depth can obviously reduce prediction errors and accurately predict blasting vibration.

Interactions of Various types between Rock and Alkali-Activated Blast Furnace Slag

Directory of Open Access Journals (Sweden)

Mec Pavel

2017-03-01

Full Text Available Alkali-activated binders (AAB are very intensively studied materials nowadays. Because of possible usage as secondary raw materials, they can be environmentally efficient. Intensive research is focused especially on binder matrix, composition and its structure. For industrial usage, it is necessary to work with some aggregate for the preparation of mortars and concretes. Due to different structures of alkali-activated binders, the interaction with the aggregate will be different in comparison to an ordinary Portland cement binder. This paper deals with the study of interactions between several types of rocks used as aggregate and alkali-activated blast furnace slag. The research was focused especially on mechanical properties of prepared mortars.

Treatment of Uranium-Contaminated Concrete for Reducing Secondary Radioactive Waste

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Soo; Han, G. S; Park, U. K; Kim, G. N.; Moon, J. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-10-15

A volume reduction of the concrete waste by appropriate treatment technologies will decrease the amount of waste to be disposed of and result in a reduction of the disposal cost and an enhancement of the efficiency of the disposal site. Our group has developed a decontamination process for uranium-contaminated (U-contaminated) concrete, and some experiments were performed to reduce the second radioactive waste. A decontamination process was developed to remove uranium from concrete waste. The yellow or brown colored surface of the wall brick with high concentration of uranium was removed by a chisel until the radioactivity of remaining block reached less than 1 Bq/g. The concrete waste coated with epoxy was directly burned by an oil flame, and the burned surface was then removed using the same method as the treatment of the brick. The selective mechanical removal of the concrete block reduced the amount of secondary radioactive waste. The concrete blocks without an epoxy were crushed to below 30 mm and sifted to 1 mm. When the concrete pieces larger than 1 mm were sequentially washed with a clear recycle solution and 1.0 M of nitric acid, their radioactivity reached below the limit value of uranium for self-disposal. For the concrete pieces smaller than 1 mm, a rotary washing machine and electrokinetic equipment were also used.

Treatment of Uranium-Contaminated Concrete for Reducing Secondary Radioactive Waste

International Nuclear Information System (INIS)

Kim, Seung Soo; Han, G. S; Park, U. K; Kim, G. N.; Moon, J. K.

2014-01-01

A volume reduction of the concrete waste by appropriate treatment technologies will decrease the amount of waste to be disposed of and result in a reduction of the disposal cost and an enhancement of the efficiency of the disposal site. Our group has developed a decontamination process for uranium-contaminated (U-contaminated) concrete, and some experiments were performed to reduce the second radioactive waste. A decontamination process was developed to remove uranium from concrete waste. The yellow or brown colored surface of the wall brick with high concentration of uranium was removed by a chisel until the radioactivity of remaining block reached less than 1 Bq/g. The concrete waste coated with epoxy was directly burned by an oil flame, and the burned surface was then removed using the same method as the treatment of the brick. The selective mechanical removal of the concrete block reduced the amount of secondary radioactive waste. The concrete blocks without an epoxy were crushed to below 30 mm and sifted to 1 mm. When the concrete pieces larger than 1 mm were sequentially washed with a clear recycle solution and 1.0 M of nitric acid, their radioactivity reached below the limit value of uranium for self-disposal. For the concrete pieces smaller than 1 mm, a rotary washing machine and electrokinetic equipment were also used

Consideration on local blast vibration control by delay blasting; Danpatsu happa ni yoru kyokuchiteki shindo seigyo ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Mogi, Gento; Adachi, Tsuyoshi; Yamatomi, Jiro [The University of Tokyo School of Engineering Department of Geosystem Engineering, Tokyo (Japan); Hoshino, Tatsuya [Mitsui Mining and Smelting Corp., Tokyo (Japan)

1999-10-31

In this research, local blast vibration control based on the theory of superposition of waves was investigated. Firstly, the influence of delay time errors of conventional electric detonators upon the level of local blast vibration was examined. Secondly, for a further effective local blast vibration control, a new delay blasting design concept 'combined delay blasting' that postulates the use of electronic detonators, which virtually have no delay time errors, is proposed. For a delay blasting with uniform detonation time intervals, an optimum time interval to minimize the local PPV (Peak Particle Velocity) is obtained based on the relationship between the PPV and the time interval, which is derived by superposing identical vibration time histories of each single hole shot. However, due to the scattering of the actual delay time caused by errors, PPV of a production blast seldom coincides with the estimated one. Since the expected value and the variance of PPV mainly depend on sensitivity of PPV around the nominal delay time, it is proposed that not only the optimum but also several sub-optimum candidates of delay time should be examined taking error into consideration. Concerning the 'combined delay blasting', its concept and some simulation results are presented. The estimated reduction effect of blast vibration of a delay blast based on this concept was quite favorable, indicating a possibility for further effective local blast vibration control. (author)

EVALUATION OF THE MACHINE MODERNITY IN THE MOTOR INDUSTRY

OpenAIRE

Manuela Krystyna Ingaldi

2014-01-01

Most manufacturing companies realize its technologies, implemented through concrete machinery parts. They differ in terms of importance, the relevance of their selection and the level of their modernity. The purpose of this article is to analyse the chosen production machine in terms of its modernity. The ABC technology method was chosen do this research. All parts of the machine were divided into three groups: parts of main subassembly A, parts of supportive subassembly B, parts of collatera...

BLEVE blast by expansion-controlled evaporation

NARCIS (Netherlands)

Berg, A.C. van den; Voort, M.M. van der; Weerheijm, J.; Versloot, N.H.A.

2006-01-01

This report presents a new method to calculate the blast effects originating from an exploding vessel of liquefied gas. Adequate blast calculation requires full knowledge of the blast source characteristics, that is, the release and subsequent evaporation rate of the flashing liquid. Because the

Finite Element Modeling of Compressive and Splitting Tensile Behavior of Plain Concrete and Steel Fiber Reinforced Concrete Cylinder Specimens

Directory of Open Access Journals (Sweden)

Md. Arman Chowdhury

2016-01-01

Full Text Available Plain concrete and steel fiber reinforced concrete (SFRC cylinder specimens are modeled in the finite element (FE platform of ANSYS 10.0 and validated with the experimental results and failure patterns. Experimental investigations are conducted to study the increase in compressive and tensile capacity of cylindrical specimens made of stone and brick concrete and SFRC. Satisfactory compressive and tensile capacity improvement is observed by adding steel fibers of 1.5% volumetric ratio. A total of 8 numbers of cylinder specimens are cast and tested in 1000 kN capacity digital universal testing machine (UTM and also modeled in ANSYS. The enhancement of compressive strength and splitting tensile strength of SFRC specimen is achieved up to 17% and 146%, respectively, compared to respective plain concrete specimen. Results gathered from finite element analyses are validated with the experimental test results by identifying as well as optimizing the controlling parameters to make FE models. Modulus of elasticity, Poisson’s ratio, stress-strain behavior, tensile strength, density, and shear transfer coefficients for open and closed cracks are found to be the main governing parameters for successful model of plain concrete and SFRC in FE platform. After proper evaluation and logical optimization of these parameters by extensive analyses, finite element (FE models showed a good correlation with the experimental results.

30 CFR 75.1323 - Blasting circuits.

Science.gov (United States)

2010-07-01

...) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made by different manufacturers shall not be combined in the same blasting circuit. (c) Detonator leg wires shall be... used between the blasting cable and detonator circuitry shall— (1) Be undamaged; (2) Be well insulated...

Blast wave parameters at diminished ambient pressure

Science.gov (United States)

Silnikov, M. V.; Chernyshov, M. V.; Mikhaylin, A. I.

2015-04-01

Relation between blast wave parameters resulted from a condensed high explosive (HE) charge detonation and a surrounding gas (air) pressure has been studied. Blast wave pressure and impulse differences at compression and rarefaction phases, which traditionally determine damage explosive effect, has been analyzed. An initial pressure effect on a post-explosion quasi-static component of the blast load has been investigated. The analysis is based on empirical relations between blast parameters and non-dimensional similarity criteria. The results can be directly applied to flying vehicle (aircraft or spacecraft) blast safety analysis.

Perforation of a concrete slab by a missile: finite element approach

International Nuclear Information System (INIS)

Jamet, P.; Berriaud, C.; Millard, A.; Nahas, G.; Yuritzin, T.

1983-08-01

A specific concrete model has been developed to investigate the problem of concrete walls perforation by a missile: three types of damage are accounted for: traction damage, shear damage, hydrostatic pressure damage. In order to investigate the validity of this concrete model in simple compressive conditions, tests are performed in following configuration: microconcrete used in perforation tests is cast in a cylindrical mould 100 mm diameter, 50 mm wall thickness made of very strong steel. The concrete height is 400 mm. A silver layer is put on the inner face to decrease the friction coefficient. The load is transmitted to the contrete by means of a metal piston. A quasi static test is first performed using a hydraulic testing machine. A second one is then impacted by a 32 kg mass dropping from 19 meters. In both cases the displacement and the forces are recorded for comparison with calculation

Drying shrinkage of mortars with limestone filler and blast-furnace slag

Directory of Open Access Journals (Sweden)

Carrasco, M. F.

2003-12-01

Full Text Available During the 1990's the use of cements made with port land clinker and two mineral admixtures, called ternary or blended cements, has grown considerably. Nowadays, cements containing several combinations of fly ash and silica fume, blast-furnace slag and silica fume or blast-furnace slag and limestone filler are commonly used. There are numerous works on the influence of blended cements on the fresh state and mechanical properties of mortar and concrete, but the their deformations due to drying shrinkage are not so well described. Analysis of drying shrinkage is relevant because this property influences the possibility of cracking occurrence and, hence, the deterioration of mechanical and durable properties of concrete structures. This paper evaluates the influence on the drying shrinkage of mortars of variable contents of limestone filler and/or blast-furnace slag in Portland cement. Additionally, flexion strength and non evaporable water content were evaluated. Test results show that the inclusion of these mineral admixtures, Joint or separately, increments drying shrinkage of mortars at early ages. Despite this fact, mortars made with limestone filler cement are less susceptible to cracking than mortars made with cements incorporating blast-furnace slag or both admixtures.

Durante los años 90 el uso de cementos fabricados con clínker Portland y dos adiciones suplementarias (cementos ternarios o compuestos se ha incrementado en forma considerable. En la práctica, es cada vez más común el empleo de estos cementos conteniendo combinaciones de ceniza volante y humo de sílice, escoria y humo de sílice o escoria y filler calcáreo. En la actualidad existen numerosos estudios sobre la influencia de los cementos compuestos en las características en estado fresco y las propiedades mecánicas de morteros y hormigones, pero las deformaciones que estos materiales sufren debido a la retracción por secado no son tan conocidas. El análisis de

Offshore high - Titanic challenge: Mastering moving mountains of ice tests men and machines

Energy Technology Data Exchange (ETDEWEB)

Will, G.

1998-06-01

Hibernia`s iceberg management program, which includes the difficult but occasional lassoing and towing of an iceberg to alter its direction away from the platform, was described. The platform has a concrete ice wall built around it which can withstand a six-million tonne iceberg, however, even small `bergy bits` or `growlers`, no larger than a typical bungalow, can inflict serious damage on semi-submersibles and other oil and gas installations on the Grand Banks. In the case of these smaller ice structures, propeller washing and water blasting are the favored techniques. With water blasting two water cannons are turned on the growler bobbing in the waves, the force of the jets driving it away from potential danger. Propeller washing is a similar technique, but instead of water cannons the ship`s churning propellers are used to send a bergy bit on its way, away from oil and gas installations.

Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids

Science.gov (United States)

Pontalier, Q.; Loiseau, J.; Goroshin, S.; Frost, D. L.

2018-04-01

The attenuation of a blast wave from a high-explosive charge surrounded by a layer of inert material is investigated experimentally in a spherical geometry for a wide range of materials. The blast wave pressure is inferred from extracting the blast wave velocity with high-speed video as well as direct measurements with pressure transducers. The mitigant consists of either a packed bed of particles, a particle bed saturated with water, or a homogeneous liquid. The reduction in peak blast wave overpressure is primarily dependent on the mitigant to explosive mass ratio, M/C, with the mitigant material properties playing a secondary role. Relative peak pressure mitigation reduces with distance and for low values of M/C (pressure levels in the mid-to-far field. Solid particles are more effective at mitigating the blast overpressure than liquids, particularly in the near field and at low values of M/C, suggesting that the energy dissipation during compaction, deformation, and fracture of the powders plays an important role. The difference in scaled arrival time of the blast and material fronts increases with M/C and scaled distance, with solid particles giving the largest separation between the blast wave and cloud of particles. Surrounding a high-explosive charge with a layer of particles reduces the positive-phase blast impulse, whereas a liquid layer has no influence on the impulse in the far field. Taking the total impulse due to the blast wave and material impact into account implies that the damage to a nearby structure may actually be augmented for a range of distances. These results should be taken into consideration in the design of explosive mitigant systems.

Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids

Science.gov (United States)

Pontalier, Q.; Loiseau, J.; Goroshin, S.; Frost, D. L.

2018-05-01

The attenuation of a blast wave from a high-explosive charge surrounded by a layer of inert material is investigated experimentally in a spherical geometry for a wide range of materials. The blast wave pressure is inferred from extracting the blast wave velocity with high-speed video as well as direct measurements with pressure transducers. The mitigant consists of either a packed bed of particles, a particle bed saturated with water, or a homogeneous liquid. The reduction in peak blast wave overpressure is primarily dependent on the mitigant to explosive mass ratio, M/ C, with the mitigant material properties playing a secondary role. Relative peak pressure mitigation reduces with distance and for low values of M/ C (compaction, deformation, and fracture of the powders plays an important role. The difference in scaled arrival time of the blast and material fronts increases with M/ C and scaled distance, with solid particles giving the largest separation between the blast wave and cloud of particles. Surrounding a high-explosive charge with a layer of particles reduces the positive-phase blast impulse, whereas a liquid layer has no influence on the impulse in the far field. Taking the total impulse due to the blast wave and material impact into account implies that the damage to a nearby structure may actually be augmented for a range of distances. These results should be taken into consideration in the design of explosive mitigant systems.

Effect of Coarse Aggregate and Slag Type on the Mechanical Behavior of High and Normal Weight Concrete Used at Barrage Structure

Directory of Open Access Journals (Sweden)

Muhammad Sanaullah

2017-04-01

Full Text Available Present study is an effort to assess the composite effect of limestone aggregate and blast furnace slag on the mechanical characteristics of normal and high weight concrete at various structural units (barrage girders, main weir and block apron of New Khanki Barrage Project, Punjab. Mix designs for different concrete classes falling under the domain of high and normal weight concrete were prepared after aggregate quality testing. On attaining satisfactory results of quality testing nine concrete mixes were designed (three for each class: A1, A and B by absolute volume method (ACI- 211.1. The required compressive strength of normal and high strength was set at 6200, 5200 and 4200 Psi for the concrete types A1, A and B respectively after 28 days (ACI -318. For compressive strength assessment, a total 27 concrete cylinders were casted (9-cylinders for each mix and were water cured. The achieved average UCS of cylinder concrete specimens at 3, 7 and 28 days are 5170, 6338 and 7320 Psi for A1 – type, 3210, 4187 and 5602 Psi for A-type and 2650, 3360 and 4408 Psi for B- type mix. It has been found that all concrete mixes for suggested classes attained target strength at age of 7-days. The coarse aggregate (Margala Hill limestone and fine aggregates (from Lawrancepur /Qibla Bandi quarries used in all concrete mix designs have demonstrated a sound mechanical suitability for high and normal weight concrete.

Ultra Safe And Secure Blasting System

Energy Technology Data Exchange (ETDEWEB)

Hart, M M

2009-07-27

The Ultra is a blasting system that is designed for special applications where the risk and consequences of unauthorized demolition or blasting are so great that the use of an extraordinarily safe and secure blasting system is justified. Such a blasting system would be connected and logically welded together through digital code-linking as part of the blasting system set-up and initialization process. The Ultra's security is so robust that it will defeat the people who designed and built the components in any attempt at unauthorized detonation. Anyone attempting to gain unauthorized control of the system by substituting components or tapping into communications lines will be thwarted in their inability to provide encrypted authentication. Authentication occurs through the use of codes that are generated by the system during initialization code-linking and the codes remain unknown to anyone, including the authorized operator. Once code-linked, a closed system has been created. The system requires all components connected as they were during initialization as well as a unique code entered by the operator for function and blasting.

WImpiBLAST: web interface for mpiBLAST to help biologists perform large-scale annotation using high performance computing.

Directory of Open Access Journals (Sweden)

Parichit Sharma

Full Text Available The function of a newly sequenced gene can be discovered by determining its sequence homology with known proteins. BLAST is the most extensively used sequence analysis program for sequence similarity search in large databases of sequences. With the advent of next generation sequencing technologies it has now become possible to study genes and their expression at a genome-wide scale through RNA-seq and metagenome sequencing experiments. Functional annotation of all the genes is done by sequence similarity search against multiple protein databases. This annotation task is computationally very intensive and can take days to obtain complete results. The program mpiBLAST, an open-source parallelization of BLAST that achieves superlinear speedup, can be used to accelerate large-scale annotation by using supercomputers and high performance computing (HPC clusters. Although many parallel bioinformatics applications using the Message Passing Interface (MPI are available in the public domain, researchers are reluctant to use them due to lack of expertise in the Linux command line and relevant programming experience. With these limitations, it becomes difficult for biologists to use mpiBLAST for accelerating annotation. No web interface is available in the open-source domain for mpiBLAST. We have developed WImpiBLAST, a user-friendly open-source web interface for parallel BLAST searches. It is implemented in Struts 1.3 using a Java backbone and runs atop the open-source Apache Tomcat Server. WImpiBLAST supports script creation and job submission features and also provides a robust job management interface for system administrators. It combines script creation and modification features with job monitoring and management through the Torque resource manager on a Linux-based HPC cluster. Use case information highlights the acceleration of annotation analysis achieved by using WImpiBLAST. Here, we describe the WImpiBLAST web interface features and architecture

WImpiBLAST: web interface for mpiBLAST to help biologists perform large-scale annotation using high performance computing.

Science.gov (United States)

Sharma, Parichit; Mantri, Shrikant S

2014-01-01

The function of a newly sequenced gene can be discovered by determining its sequence homology with known proteins. BLAST is the most extensively used sequence analysis program for sequence similarity search in large databases of sequences. With the advent of next generation sequencing technologies it has now become possible to study genes and their expression at a genome-wide scale through RNA-seq and metagenome sequencing experiments. Functional annotation of all the genes is done by sequence similarity search against multiple protein databases. This annotation task is computationally very intensive and can take days to obtain complete results. The program mpiBLAST, an open-source parallelization of BLAST that achieves superlinear speedup, can be used to accelerate large-scale annotation by using supercomputers and high performance computing (HPC) clusters. Although many parallel bioinformatics applications using the Message Passing Interface (MPI) are available in the public domain, researchers are reluctant to use them due to lack of expertise in the Linux command line and relevant programming experience. With these limitations, it becomes difficult for biologists to use mpiBLAST for accelerating annotation. No web interface is available in the open-source domain for mpiBLAST. We have developed WImpiBLAST, a user-friendly open-source web interface for parallel BLAST searches. It is implemented in Struts 1.3 using a Java backbone and runs atop the open-source Apache Tomcat Server. WImpiBLAST supports script creation and job submission features and also provides a robust job management interface for system administrators. It combines script creation and modification features with job monitoring and management through the Torque resource manager on a Linux-based HPC cluster. Use case information highlights the acceleration of annotation analysis achieved by using WImpiBLAST. Here, we describe the WImpiBLAST web interface features and architecture, explain design

Porcine head response to blast.

Science.gov (United States)

Shridharani, Jay K; Wood, Garrett W; Panzer, Matthew B; Capehart, Bruce P; Nyein, Michelle K; Radovitzky, Raul A; Bass, Cameron R 'dale'

2012-01-01

Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposes porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110 to 740 kPa peak incident overpressure with scaled durations from 1.3 to 6.9 ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. Instrumentation was placed on the porcine head to measure bulk acceleration, pressure at the surface of the head, and pressure inside the cranial cavity. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within 30 s and the remaining two recovered within 8 min following respiratory assistance and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80 to 390 kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300-2830 kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385 to 3845 G's and were well correlated with peak incident overpressure (R(2) = 0.90). One SD corridors for the surface pressure, intracranial pressure (ICP), and head acceleration are

Alkaline carbonates in blast furnace process

Directory of Open Access Journals (Sweden)

P. Besta

2014-10-01

Full Text Available The production of iron in blast furnaces is a complex of physical, chemical and mechanical processes. The input raw materials contain not only metallic components, but also a number of negative elements. The most important negative elements include alkaline carbonates. They can significantly affect the course of the blast furnace process and thus the overall performance of the furnace. As a result of that, it is essential to accurately monitor the alkali content in the blast furnace raw materials. The article analyzes the alkali content in input and output raw materials and their impact on the blast furnace process.

Linking blast physics to biological outcomes in mild traumatic brain injury: Narrative review and preliminary report of an open-field blast model.

Science.gov (United States)

Song, Hailong; Cui, Jiankun; Simonyi, Agnes; Johnson, Catherine E; Hubler, Graham K; DePalma, Ralph G; Gu, Zezong

2018-03-15

Blast exposures are associated with traumatic brain injury (TBI) and blast-induced TBIs are common injuries affecting military personnel. Department of Defense and Veterans Administration (DoD/VA) reports for TBI indicated that the vast majority (82.3%) has been mild TBI (mTBI)/concussion. mTBI and associated posttraumatic stress disorders (PTSD) have been called "the invisible injury" of the current conflicts in Iraq and Afghanistan. These injuries induce varying degrees of neuropathological alterations and, in some cases, chronic cognitive, behavioral and neurological disorders. Appropriate animal models of blast-induced TBI will not only assist the understanding of physical characteristics of the blast, but also help to address the potential mechanisms. This report provides a brief overview of physical principles of blast, injury mechanisms related to blast exposure, current blast animal models, and the neurological behavioral and neuropathological findings related to blast injury in experimental settings. We describe relationships between blast peak pressures and the observed injuries. We also report preliminary use of a highly reproducible and intensity-graded blast murine model carried out in open-field with explosives, and describe physical and pathological findings in this experimental model. Our results indicate close relationships between blast intensities and neuropathology and behavioral deficits, particularly at low level blast intensities relevant to mTBI. Copyright © 2016 Elsevier B.V. All rights reserved.

Study of measurement method of tritium induced in concrete of high-energy proton accelerator facilities

International Nuclear Information System (INIS)

Ohtsuka, N.; Ishihama, S.; Kunifuda, T.; Hayasaka, N.; Miura, T.

2001-01-01

Various long-loved radionuclides, 3 H, 7 Be, 22 Na, 51 Cr, 54 Mn, 56 Co, 57 Co, 60 Co, 134 Cs, 152 Eu and 154 Eu, have been produced in the shielding concrete of high energy proton accelerator facility through both nuclear spallation reactions and thermal neutron capture reactions of concrete elements, during machine operation. Tritium is the most important nuclide from the radiation protection. There were, however, few measurements of tritium concentration induced in the shielding concrete. In this study, the conditions of measurement method of tritium concentration induced in shielding concrete have been investigated using the activated shielding concrete of the 12 GeV proton beam-line tunnel at KEK and the standard rock (JG-1) irradiated of thermal neutron at the reactor. And the depth profiles of tritium induced in the shielding concrete of slow extracted proton beam line at KEK were determined using this method. (author)

CO2 pellet blasting literature search and decontamination scoping tests report

International Nuclear Information System (INIS)

Archibald, K.E.

1993-12-01

Past decontamination and solvent recovery activities at the Idaho Chemical Processing Plant (ICPP) have resulted in the accumulation of 1.5 million gallons of radioactively contaminated sodium-bearing liquid waste. Future decontamination activities at the ICPP could result in the production of 5 million gallons or more of sodium-bearing waste using current decontamination techniques. Chemical decontamination flushes have provided a satisfactory level of decontamination. However, this method generates large amounts of sodium-bearing secondary waste. Steam jet cleaning has also been used with a great deal of success but cannot be used on concrete or soft materials. With the curtailment of reprocessing at the ICPP, the focus of decontamination is shifting from maintenance for continued operation of the facilities to decommissioning. Treatment of sodium-bearing waste is a particularly difficult problem due to the high content of alkali metals in the sodium-bearing liquid waste. It requires a very large volume of cold chemical additive for calcination. In addition, the sodium content of the sodium-bearing waste exceeds the limit that can be incorporated into vitrified waste without the addition of glass-forming compounds (primarily silicon) to produce an acceptable immobilized waste form. The primary initiatives of the Decontamination Development Program is the development of methods to eliminate/minimize the use of sodium-bearing decontamination chemicals and to minimize all liquid decontamination wastes. One method chosen for cold scoping studies during FY-93 was CO 2 pellet blasting. CO 2 pellet blasting has been used extensively by commercial industries for general cleaning. However, using this method for decontamination of nuclear materials is a fairly new concept. The following report discusses the research and scoping tests completed on CO 2 pellet blasting

Development of special radiation shielding concretes using natural local materials and evaluation of their shielding characteristics

International Nuclear Information System (INIS)

Kharita, M. H.; Takeyeddin, M.; Al-Nassri, M.; Yousef, S.

2008-01-01

Concrete is one of the most important materials used for radiation shielding in facilities containing radioactive sources and radiation generating machines. The concrete shielding properties may vary depending on the composite of the concrete. Aggregates is the largest constituent (about 70-80% of the total weight of normal concrete). The aim of this work is to develop special concrete with good shielding properties for gamma and neutrons, using natural local materials. For this reason two types of typical concrete widely used in Syria (in Damascus and Aleppo) and four other types of concrete, using aggregates from different regions, have been prepared. The shielding properties of these six types were studied for gamma ray (from Cs-137 and Co-60 sources)and for neutrons (from am-Be source). A reduction of about 10% in the HVL was obtained for the concrete from Damascus in comparison with that from Aleppo, for both neutrons and gammas. One of the other four types of concrete (from Rajo site, mostly Hematite), was found to further reduce the HVL by about 10% for both neutrons and gamma rays.(author)

BLAST-EXPLORER helps you building datasets for phylogenetic analysis

Directory of Open Access Journals (Sweden)

Claverie Jean-Michel

2010-01-01

Full Text Available Abstract Background The right sampling of homologous sequences for phylogenetic or molecular evolution analyses is a crucial step, the quality of which can have a significant impact on the final interpretation of the study. There is no single way for constructing datasets suitable for phylogenetic analysis, because this task intimately depends on the scientific question we want to address, Moreover, database mining softwares such as BLAST which are routinely used for searching homologous sequences are not specifically optimized for this task. Results To fill this gap, we designed BLAST-Explorer, an original and friendly web-based application that combines a BLAST search with a suite of tools that allows interactive, phylogenetic-oriented exploration of the BLAST results and flexible selection of homologous sequences among the BLAST hits. Once the selection of the BLAST hits is done using BLAST-Explorer, the corresponding sequence can be imported locally for external analysis or passed to the phylogenetic tree reconstruction pipelines available on the Phylogeny.fr platform. Conclusions BLAST-Explorer provides a simple, intuitive and interactive graphical representation of the BLAST results and allows selection and retrieving of the BLAST hit sequences based a wide range of criterions. Although BLAST-Explorer primarily aims at helping the construction of sequence datasets for further phylogenetic study, it can also be used as a standard BLAST server with enriched output. BLAST-Explorer is available at http://www.phylogeny.fr

Empirical Strengths of Concrete Roof Slabs After 34 Years Service ...

African Journals Online (AJOL)

The results were compared with those from standard compressive strength machine in the laboratory, and subjected to statistical analysis. The final results showed that the lowest slab compressive strength was 14 N/mm2 below the minimum concrete grade of 25N/mm2; and percentage defective was 29.5% more than the ...

Observation of the dynamic movement of fragmentations by high-speed camera and high-speed video

Science.gov (United States)

Suk, Chul-Gi; Ogata, Yuji; Wada, Yuji; Katsuyama, Kunihisa

1995-05-01

The experiments of blastings using mortal concrete blocks and model concrete columns were carried out in order to obtain technical information on fragmentation caused by the blasting demolition. The dimensions of mortal concrete blocks were 1,000 X 1,000 X 1,000 mm. Six kinds of experimental blastings were carried out using mortal concrete blocks. In these experiments precision detonators and No. 6 electric detonators with 10 cm detonating fuse were used and discussed the control of fragmentation. As the results of experiment it was clear that the flying distance of fragmentation can be controlled using a precise blasting system. The reinforced concrete model columns for typical apartment houses in Japan were applied to the experiments. The dimension of concrete test column was 800 X 800 X 2400 mm and buried 400 mm in the ground. The specified design strength of the concrete was 210 kgf/cm2. These columns were exploded by the blasting with internal loading of dynamite. The fragmentation were observed by two kinds of high speed camera with 500 and 2000 FPS and a high speed video with 400 FPS. As one of the results in the experiments, the velocity of fragmentation, blasted 330 g of explosive with the minimum resisting length of 0.32 m, was measured as much as about 40 m/s.

Analysis of ways to control the supply of the blast, and their impact on gas-dynamic processes in the blast furnace

Directory of Open Access Journals (Sweden)

Віктор Петрович Кравченко

2016-07-01

Full Text Available The article presents the analysis of two methods of control over hot blast supply into a blast furnace with constant pressure and constant amount (consumption. The analysis of these two methods was performed with the aim of determining their influence upon changes in gas pressure in the blast furnace top. The blast furnace was considered as a unity of vessels (furnace hearth, the top and gas-dynamic resistance (a column of charge materials. A differential equation was obtained, with regard to the dynamic balance of gas flow at the inlet and outlet of the top; the equation relates the pressure and gas consumption at the top to the pressure and hot blast consumption at the inlet and outlet of the furnace and to the resistance of the column of charge materials. The column of charge materials is considered as n-th number of channels through which gas flow inside the furnace moves and which resist to the flow. By the analysis of this equation at steady state (automatic stabilization of gas pressure in the top, the conditions were obtained to be satisfied with the specified value of gas pressure in the top. This value is equal to a half of the sum of the value of hot blast pressure at the inlet into the furnace and the value of pressure inside the collector of blast furnace gas. This conclusion is verified by the operation practice of blast furnaces in Ukraine. While analyzing the second method of controlling the supply of blast supply-stabilization of consumption (amount of hot blast supplied into the furnace it has been shown that the method could be realized in condition of stabilization of the amount of blast furnace gas, going out of the furnace. As the resistance of the column of charge materials constantly changes it is necessary to change the hot blast pressure in order to ensure the constant amount of blast, supplied into the furnace. It is often connected with possible substantial pressure fluctuations of hot blast at the inlet of the

Study on Mechanical Properties of Barite Concrete under Impact Load

Science.gov (United States)

Chen, Z. F.; Cheng, K.; Wu, D.; Gan, Y. C.; Tao, Q. W.

2018-03-01

In order to research the mechanical properties of Barite concrete under impact load, a group of concrete compression tests was carried out under the impact load by using the drop test machine. A high-speed camera was used to record the failure process of the specimen during the impact process. The test results show that:with the increase of drop height, the loading rate, the peak load, the strain under peak load, the strain rate and the dynamic increase factor (DIF) all increase gradually. The ultimate tensile strain is close to each other, and the time of impact force decreases significantly, showing significant strain rate effect.

Raydet non-electric blast initiation system for efficient and environment-friendly surface blasts

Energy Technology Data Exchange (ETDEWEB)

Sarathy, M.O. [IDL Chemicals Ltd., Hyderabad (India). Technical Services Cell

1995-08-01

This paper discusses the advantages of using the Raydet shock tube based blast initiation system and reviews research work carried out on release of explosive energy in the drillhole, effect of stemming retention (stemming effectiveness) and advantages of `true bottom hole initiation` of drillholes in surface blasting. Some case studies are presented. 6 refs., 5 figs., 1 tab.

The second generation of electronic blasting systems

Energy Technology Data Exchange (ETDEWEB)

Hammelmann, F.; Petzold, J. [Dynamit Nobel GmbH (Germany)

2001-07-01

8 years after the market introduction of the first commercial electronic detonator - DYNATRONIC - the paper describes a new area of electronic blasting systems Made in Germany: i-kon. The results of a joint development between Dynamit Nobel and Orica is a unique universal electronic detonator, which is as simple to use as a standard non-electric detonator. The delay time or delay interval is not factory preprogrammed and the system is not based on a numbered system like conventional detonators. The miner or Blaster decides on site which delay timing he likes to use and is programming the whole blast on site. The new i-kon system allows delay times between 0 and 8000 ms by increments of 1 ms. With the control equipment it is possible to blast up to 1600 detonators in a single blast. The paper describes the construction and functionality of this new electronic blasting system - manufactured and developed by Precision Blasting Systems, a joint venture between Orica and Dynamic Nobel. (orig.)

The anaerobic corrosion of carbon steel in concrete

International Nuclear Information System (INIS)

Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

1990-11-01

The report describes the work of a two year programme investigating the anaerobic corrosion of carbon steel embedded in a range of candidate repository cements and concretes at laboratory temperatures. The factors investigated in the study were the rate of the anaerobic corrosion reaction, the effect of hydrogen overpressure on the reaction rate and the form of the corrosion product. Both electrochemical and sample weight loss corrosion rate measurements were used. The cements and concretes used were prepared both with and without small additions of chloride (2% by weight of mix water). The results indicate that the corrosion rate is low, < 1 μm/year, the effect of hydrogen overpressure is not significant over the range of pressures investigated, 1-100 atmospheres, and that the corrosion product is dependent on the cement used to cast the samples. Magnetite was identified in the case of blast furnace slag replacement cements but for pulverised fuel ash and ordinary Portland cements no corrosion product was evident either from X-ray diffraction or laser Raman measurements. Further work is presently underway to investigate the effects of elevated temperatures and chloride levels on the anaerobic corrosion reaction and the rate of hydrogen gas production. (author)

30 CFR 75.1316 - Preparation before blasting.

Science.gov (United States)

2010-07-01

... two working faces are approaching each other, cutting, drilling and blasting shall be done at only one... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Preparation before blasting. 75.1316 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1316 Preparation...

Condition for Contur Blasting use on Openpit Mines

OpenAIRE

Krsmanovic, I; Dambov, Risto

2010-01-01

For purpose of obtaining a stable final slope in open pit mines practice, the most common approach is the contour blasting method and investigation of possible applications of various primary blasting methods for purpose of gaining the optimal techno-economical effects. This paper presents one of the contour blasting methods, drilling and blasting parameters, construction of explosive charges and method of initiation.

Nineteen-Foot Diameter Explosively Driven Blast Simulator; TOPICAL

International Nuclear Information System (INIS)

VIGIL, MANUEL G.

2001-01-01

This report describes the 19-foot diameter blast tunnel at Sandia National Laboratories. The blast tunnel configuration consists of a 6 foot diameter by 200 foot long shock tube, a 6 foot diameter to 19 foot diameter conical expansion section that is 40 feet long, and a 19 foot diameter test section that is 65 feet long. Therefore, the total blast tunnel length is 305 feet. The development of this 19-foot diameter blast tunnel is presented. The small scale research test results using 4 inch by 8 inch diameter and 2 foot by 6 foot diameter shock tube facilities are included. Analytically predicted parameters are compared to experimentally measured blast tunnel parameters in this report. The blast tunnel parameters include distance, time, static, overpressure, stagnation pressure, dynamic pressure, reflected pressure, shock Mach number, flow Mach number, shock velocity, flow velocity, impulse, flow duration, etc. Shadowgraphs of the shock wave are included for the three different size blast tunnels

Pentek concrete scabbling system: Baseline report; Greenbook (chapter)

International Nuclear Information System (INIS)

1997-01-01

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, SQUIRREL-I, and SQUIRREL-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 conducted during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure was minimal, but noise exposure was significant. Further testing for each of these exposures is recommended. Because of the outdoor environment where the testing demonstration took place, results may be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed operating environment. Other areas of concern were arm-hand vibration, whole-body vibration, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout

CO2 pellet blasting studies

International Nuclear Information System (INIS)

Archibald, K.E.

1997-01-01

Initial tests with CO 2 pellet blasting as a decontamination technique were completed in 1993 at the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory (INEL). During 1996, a number of additional CO 2 pellet blasting studies with Alpheus Cleaning Technologies, Oak Ridge National Laboratory, and Pennsylvania State University were conducted. After the testing with Alpheus was complete, an SDI-5 shaved CO 2 blasting unit was purchased by the ICPP to test and determine its capabilities before using in ICPP decontamination efforts. Results of the 1996 testing will be presented in this report

Pilot-scale treatability testing -- Recycle, reuse, and disposal of materials from decontamination and decommissioning activities: Soda blasting demonstration

International Nuclear Information System (INIS)

1995-08-01

The US Department of Energy (DOE) is in the process of defining the nature and magnitude of decontamination and decommissioning (D and D) obligations at its sites. With disposal costs rising and available storage facilities decreasing, DOE is exploring and implementing new waste minimizing D and D techniques. Technology demonstrations are being conducted by LMES at a DOE gaseous diffusion processing plant, the K-25 Site, in Oak Ridge, Tennessee. The gaseous diffusion process employed at Oak Ridge separated uranium-235 from uranium ore for use in atomic weapons and commercial reactors. These activities contaminated concrete and other surfaces within the plant with uranium, technetium, and other constituents. The objective of current K-25 D and D research is to make available cost-effective and energy-efficient techniques to advance remediation and waste management methods at the K-25 Site and other DOE sites. To support this objective, O'Brien and Gere tested a decontamination system on K-25 Site concrete and steel surfaces contaminated with radioactive and hazardous waste. A scouring system has been developed that removes fixed hazardous and radioactive surface contamination and minimizes residual waste. This system utilizes an abrasive sodium bicarbonate medium that is projected at contaminated surfaces. It mechanically removes surface contamination while leaving the surface intact. Blasting residuals are captured and dissolved in water and treated using physical/chemical processes. Pilot-scale testing of this soda blasting system and bench and pilot-scale treatment of the generated residuals were conducted from December 1993 to September 1994

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.

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,…

Simulating geometrically complex blast scenarios

Directory of Open Access Journals (Sweden)

Ian G. Cullis

2016-04-01

Full Text Available The effects of blast waves generated by energetic and non-energetic sources are of continuing interest to the ballistics research community. Modern conflicts are increasingly characterised by asymmetric urban warfare, with improvised explosive devices (IEDs often playing a dominant role on the one hand and an armed forces requirement for minimal collateral effects from their weapons on the other. These problems are characterised by disparate length- and time-scales and may also be governed by complex physics. There is thus an increasing need to be able to rapidly assess and accurately predict the effects of energetic blast in topologically complex scenarios. To this end, this paper presents a new QinetiQ-developed advanced computational package called EAGLE-Blast, which is capable of accurately resolving the generation, propagation and interaction of blast waves around geometrically complex shapes such as vehicles and buildings. After a brief description of the numerical methodology, various blast scenario simulations are described and the results compared with experimental data to demonstrate the validation of the scheme and its ability to describe these complex scenarios accurately and efficiently. The paper concludes with a brief discussion on the use of the code in supporting the development of algorithms for fast running engineering models.

Attenuation of blast pressure behind ballistic protective vests.

Science.gov (United States)

Wood, Garrett W; Panzer, Matthew B; Shridharani, Jay K; Matthews, Kyle A; Capehart, Bruce P; Myers, Barry S; Bass, Cameron R

2013-02-01

Clinical studies increasingly report brain injury and not pulmonary injury following blast exposures, despite the increased frequency of exposure to explosive devices. The goal of this study was to determine the effect of personal body armour use on the potential for primary blast injury and to determine the risk of brain and pulmonary injury following a blast and its impact on the clinical care of patients with a history of blast exposure. A shock tube was used to generate blast overpressures on soft ballistic protective vests (NIJ Level-2) and hard protective vests (NIJ Level-4) while overpressure was recorded behind the vest. Both types of vest were found to significantly decrease pulmonary injury risk following a blast for a wide range of conditions. At the highest tested blast overpressure, the soft vest decreased the behind armour overpressure by a factor of 14.2, and the hard vest decreased behind armour overpressure by a factor of 56.8. Addition of body armour increased the 50th percentile pulmonary death tolerance of both vests to higher levels than the 50th percentile for brain injury. These results suggest that ballistic protective body armour vests, especially hard body armour plates, provide substantial chest protection in primary blasts and explain the increased frequency of head injuries, without the presence of pulmonary injuries, in protected subjects reporting a history of blast exposure. These results suggest increased clinical suspicion for mild to severe brain injury is warranted in persons wearing body armour exposed to a blast with or without pulmonary injury.

prfectBLAST: a platform-independent portable front end for the command terminal BLAST+ stand-alone suite.

Science.gov (United States)

Santiago-Sotelo, Perfecto; Ramirez-Prado, Jorge Humberto

2012-11-01

prfectBLAST is a multiplatform graphical user interface (GUI) for the stand-alone BLAST+ suite of applications. It allows researchers to do nucleotide or amino acid sequence similarity searches against public (or user-customized) databases that are locally stored. It does not require any dependencies or installation and can be used from a portable flash drive. prfectBLAST is implemented in Java version 6 (SUN) and runs on all platforms that support Java and for which National Center for Biotechnology Information has made available stand-alone BLAST executables, including MS Windows, Mac OS X, and Linux. It is free and open source software, made available under the GNU General Public License version 3 (GPLv3) and can be downloaded at www.cicy.mx/sitios/jramirez or http://code.google.com/p/prfectblast/.

Usage of Crushed Concrete Fines in Decorative Concrete

Science.gov (United States)

Pilipenko, Anton; Bazhenova, Sofia

2017-10-01

The article is devoted to the questions of usage of crushed concrete fines from concrete scrap for the production of high-quality decorative composite materials based on mixed binder. The main problem in the application of crushed concrete in the manufacture of decorative concrete products is extremely low decorative properties of crushed concrete fines itself, as well as concrete products based on them. However, crushed concrete fines could have a positive impact on the structure of the concrete matrix and could improve the environmental and economic characteristics of the concrete products. Dust fraction of crushed concrete fines contains non-hydrated cement grains, which can be opened in screening process due to the low strength of the contact zone between the hydrated and non-hydrated cement. In addition, the screening process could increase activity of the crushed concrete fines, so it can be used as a fine aggregate and filler for concrete mixes. Previous studies have shown that the effect of the usage of the crushed concrete fines is small and does not allow to obtain concrete products with high strength. However, it is possible to improve the efficiency of the crushed concrete fines as a filler due to the complex of measures prior to mixing. Such measures may include a preliminary mechanochemical activation of the binder (cement binder, iron oxide pigment, silica fume and crushed concrete fines), as well as the usage of polycarboxylate superplasticizers. The development of specific surface area of activated crushed concrete fines ensures strong adhesion between grains of binder and filler during the formation of cement stone matrix. The particle size distribution of the crushed concrete fines could achieve the densest structure of cement stone matrix and improve its resistance to environmental effects. The authors examined the mechanisms of structure of concrete products with crushed concrete fines as a filler. The results of studies of the properties of

Sustainable concrete with high volume GGBFS to build Masdar City in the UAE

Directory of Open Access Journals (Sweden)

Mohamed Elchalakani

2014-01-01

Full Text Available Masdar City (MC is leading the Middle East in the development of energy and resource efficient low-carbon construction in the United Arab Emirates (UAE. One of its major goals is to develop and specify materials and processes that will help reducing its environmental footprint through resource and energy conservation, as well as renewable energy generation. In 2010 MC announced on its website a prized-competition for the best proposal of “Sustainable Concrete” and “Lowest Carbon Footprint” to build MC with a total of two million cubic meter of concrete on 4 years period. This paper presents the experimental test results of 13 types of concrete mixes made with high volume of ground granulated blast furnace slag (GGBFS cement with 50%, 60%, 70% and 80% replacement of ordinary Portland cement (OPC to reduce the carbon emissions. A fly ash-blended mix made with 30% fly ash was also tested. The paper provides more information on the mix design parameter, full justification of CO2 footprint, and cost reduction for each concrete type. The hardened and plastic properties and durability test parameters for each mix are presented. The results show that the slag concrete mixes significantly reduce the carbon footprint and meet the requirements of MC. An economical mix with 80% GGBFS and 20% OPC was nominated for use in the future construction of MC with 154 kg/m3 carbon foot print.

Short-Term Behavior of Slag Concretes Exposed to a Real In Situ Mediterranean Climate Environment.

Science.gov (United States)

Ortega, José Marcos; Sánchez, Isidro; Cabeza, Marta; Climent, Miguel Ángel

2017-08-08

At present, one of the most suitable ways to get a more sustainable cement industry is to reduce the CO₂ emissions generated during cement production. In order to reach that goal, the use of ground granulated blast-furnace slag as clinker replacement is becoming increasingly popular. Although the effects of this addition in the properties of cementitious materials are influenced by their hardening conditions, there are not too many experimental studies in which slag concretes have been exposed to real in situ environments. Then, the main objective of this research is to study the short-term effects of exposure to real Mediterranean climate environment of an urban site, where the action of airborne chlorides from sea water and the presence of CO₂ are combined, in the microstructure and service properties of a commercial slag cement concrete, compared to ordinary Portland cement (OPC). The microstructure was studied with mercury intrusion porosimetry. The effective porosity, capillary suction coefficient, chloride migration coefficient, carbonation front depth, and compressive strength were also analyzed. Considering the results obtained, slag concretes exposed to a real in situ Mediterranean climate environment show good service properties in the short-term (180 days), in comparison with OPC.

Tunnel boring machine applications

International Nuclear Information System (INIS)

Bhattacharyya, K.K.; McDonald, R.; Saunders, R.S.

1992-01-01

This paper reports that characterization of Yucca Mountain for a potential repository requires construction of an underground Exploratory Studies Facility (ESF). Mechanical excavating methods have been proposed for construction of the ESF as they offer a number of advantages over drilling and blasting at the Yucca Mountain site, including; less ground disturbance and therefore a potential for less adverse effects on the integrity of the site, creation of a more stable excavation cross section requiring less ground support, and an inherently safer and cleaner working environment. The tunnel boring machine (TBM) provides a proven technology for excavating the welded and unwelded Yucca Mountain tuffs. The access ramps and main underground tunnels form the largest part of the ESF underground construction work, and have been designed for excavation by TBM

Blasting in hot zone - a case study

Energy Technology Data Exchange (ETDEWEB)

Nabiullah, B.M.P.; Pingua, J.; Dhar, B.B. [Central Mining Research Institute, Dhanbad (India)

1997-12-31

A significant quantity of coking coal reserves in the country are under fire particularly in Jharia coalfield. To control the fire and prevent loss of coal, an opencast mining method is adopted. The main problem with these opencast mines is drilling in hot strata and selection of suitable explosives and blasting in the fire zone. Trial blasts were conducted at two open cast mines. The problem was tackled by quenching the hot blast holes with water. Temperature of blast holes were recorded soon after drilling, after quenching with water and just before charging with explosives. The rise in temperature of charged explosives with time was also recorded until blasting. The thermal behaviour of commercially available explosives (including slurry, emulsion, ANFO and detonating cord) was investigated in laboratory and field simulated conditions. Emulsion, slurry compositions and detonating cord were found safe to use in hot holes up to 120{degree}C for duration of two hours. This paper describes the blasting practices adopted in the fire zones. 4 refs., 6 figs., 8 tabs.

Analysis of the spectrum distribution of oscillation amplitudes of the concrete mix at shock vibration molding

Directory of Open Access Journals (Sweden)

Sharapov Rashid

2017-01-01

Full Text Available In the production of concrete structures widespread shaking tables of various designs. The effectiveness of vibroforming concrete items largely depends on the choice of rational modes of vibroeffect to the compacting mixture. The article discusses the propagation of a wave packet in the concrete mixture under shock and vibration molding. Studies have shown that the spectrum of a wave packet contains a large number of harmonics. The main parameter influencing the amplitude-frequency spectrum is the stiffness of elastic gaskets between mold and forming machine vibrating table. By varying the stiffness of the elastic gaskets can widely change the spectrum of the oscillations propagating in the concrete mix. Thus, it is possible to adjust the intensity of the process of vibroforming.

Modelling human eye under blast loading.

Science.gov (United States)

Esposito, L; Clemente, C; Bonora, N; Rossi, T

2015-01-01

Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues.

Numerical simulation of muzzle blast

NARCIS (Netherlands)

Tyler-Street, M.

2014-01-01

Structural design methods for naval ships include environmental, operational and military load cases. One of the operational loads acting on a typical naval vessel is the muzzle blast from a gun. Simulating the muzzle blast load acting on a ship structure with CFD and ALE methods leads to large

Efficacy of dry-ice blasting in preventive maintenance of auto robotic assemblies

Science.gov (United States)

Baluch, Nazim; Mohtar, Shahimi; Abdullah, Che Sobry

2016-08-01

Welding robots are extensively applied in the automotive assemblies and `Spot Welding' is the most common welding application found in the auto stamping assembly manufacturing. Every manufacturing process is subject to variations - with resistance welding, these include; part fit up, part thickness variations, misaligned electrodes, variations in coating materials or thickness, sealers, weld force variations, shunting, machine tooling degradation; and slag and spatter damage. All welding gun tips undergo wear; an elemental part of the process. Though adaptive resistance welding control automatically compensates to keep production and quality up to the levels needed as gun tips undergo wear so that the welds remain reliable; the system cannot compensate for deterioration caused by the slag and spatter on the part holding fixtures, sensors, and gun tips. To cleanse welding robots of slag and spatter, dry-ice blasting has proven to be an effective remedy. This paper describes Spot welding process, analyses the slag and spatter formation during robotic welding of stamping assemblies, and concludes that the dry ice blasting process's utility in cleansing of welding robots in auto stamping plant operations is paramount and exigent.

Predictive control of thermal state of blast furnace

Science.gov (United States)

Barbasova, T. A.; Filimonova, A. A.

2018-05-01

The work describes the structure of the model for predictive control of the thermal state of a blast furnace. The proposed model contains the following input parameters: coke rate; theoretical combustion temperature, comprising: natural gas consumption, blasting temperature, humidity, oxygen, blast furnace cooling water; blast furnace gas utilization rate. The output parameter is the cast iron temperature. The results for determining the cast iron temperature were obtained following the identification using the Hammerstein-Wiener model. The result of solving the cast iron temperature stabilization problem was provided for the calculated values of process parameters of the target area of the respective blast furnace operation mode.

Water-Depth-Based Prediction Formula for the Blasting Vibration Velocity of Lighthouse Caused by Underwater Drilling Blasting

OpenAIRE

Gu, Wenbin; Wang, Zhenxiong; Liu, Jianqing; Xu, Jinglin; Liu, Xin; Cao, Tao

2017-01-01

Lighthouses are the most important hydraulic structures that should be protected during underwater drilling blasting. Thus, the effect of blasting vibration on lighthouse should be studied. On the basis of the dimensional analysis, we deduced a revised formula for water depth based on Sodev’s empirical formula and established the linear fitting model. During the underwater reef project in the main channel of Shipu Harbor in the Ningbo–Zhoushan Port, the blasting vibration data of the lighthou...

The technopolitics of big infrastructure and the Chinese water machine

Directory of Open Access Journals (Sweden)

Britt Crow-Miller

2017-06-01

Full Text Available Despite widespread recognition of the problems caused by relying on engineering approaches to water management issues, since 2000 China has raised its commitment to a concrete-heavy approach to water management. While, historically, China’s embrace of modernist water management could be understood as part of a broader set of ideas about controlling nature, in the post-reform era this philosophical view has merged with a technocratic vision of national development. In the past two decades, a Chinese Water Machine has coalesced: the institutional embodiment of China’s commitment to large infrastructure. The technocratic vision of the political and economic elite at the helm of this Machine has been manifest in the form of some of the world’s largest water infrastructure projects, including the Three Gorges Dam and the South-North Water Transfer Project, and in the exporting of China’s vision of concrete-heavy development beyond its own borders. This paper argues that China’s approach to water management is best described as a techno-political regime that extends well beyond infrastructure, and is fundamentally shaped by both past choices and current political-economic conditions. Emerging from this regime, the Chinese Water Machine is one of the forces driving the (return to big water infrastructure globally.

Proceedings of the eighteenth annual conference on explosives and blasting technique

International Nuclear Information System (INIS)

Anon.

1993-01-01

This edition of the Proceedings of the Annual Conference on Explosives and Blasting Techniques is the eighteenth in a series published by the International Society of Explosives Engineers. The papers cover a wide variety of explosives and blasting techniques, including: rock mechanics, rock drilling, perimeter control handling and documenting blasting complaints, blast vibration frequencies, blasting techniques for surface and underground coal mines, explosives for permafrost blasting, lightning detection, use of slow motion video to analyze blasts, tunneling, and close-in blasting control. Papers have been processed individually for inclusion on the data base

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...

Static and dynamic behaviours of railway prestressed concrete sleepers with longitudinal through hole

Science.gov (United States)

Ngamkhanong, C.; Kaewunruen, S.; Remennikov, A. M.

2017-10-01

As the crosstie beam in railway track systems, the prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed concrete has played a significant role as to maintain the high endurance of the sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed concrete sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of concrete sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by ballast corners or by tamping machine. There has been a need to re-design concrete sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study will investigate the effects of through hole or longitudinal hole on static and dynamic behaviours of concrete sleepers under rail shock loading. The modified compression field theory for ultimate strength design of concrete sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed concrete sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry.

Effect of Slag Content and Hardening Accelerator Dosage on the Physico Mechanical Properties of Cement and Concrete

International Nuclear Information System (INIS)

Derabla, R.; Mokrani, I.; Benmalek, M.L.

2011-01-01

Our contribution consists at the study of the effect of (0 %, 0.2 % and 0.34 %) dosage of an hardening accelerating plasticizer (Plastocrete 160, produced by Sika Aldjazair) on the properties of normal mortar and concretes prepared with portland cement artificial of Hadjar Soud cement factory (Skikda - Algeria) with addition of (10 % and 20 %) of granulated blast furnace slag finely crushed of the El Hadjar blast furnace (Annaba - Algeria). The tests are focused to the physical and mechanical characteristics of elaborated materials to knowing: setting time, porosity, water absorption capacity and the test of compressive strength at 2, 7 and 28 days. The results obtained show clearly the reliability of the additive used to accelerate the hardening and to obtain high strengths at early age, which increase by increasing of the additive dosage. For the slag, its low hydraulic capacity does not make it profitable than at the long term (beyond 28 days). (author)

The Future Concrete: Self-Compacting Concrete

OpenAIRE

Iureş, Liana; Bob, Corneliu

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.

New techniques for improved performance in surface blasting operation and optimisation of blast design parameters

Energy Technology Data Exchange (ETDEWEB)

Roy, P.P. [Central Mining Research Institute, Dhanbad (India). Blasting Dept.

1999-02-01

Experimental blasts were conducted for optimisation of blasting parameters using separate technologies involving non-electric initiation systems, air decking accessories in conjunction with different explosive products like emulsion (cartridge and site-mixed), slurries (cartridge and site-mixed) and ANFO. The cost associated with each such technology was then compared with the conventional methods of drilling and blasting operations. The results of cost analyses are given. Theoretical and practical aspects of such technologies and their best possible usage in order to establish the desired fragmentation, muck profile, wall control and ultimately the accepted level of costs are mentioned in subsequent sections. 16 refs., 17 figs., 8 plates, 11 tabs.

Blasting at a Superfund chemical waste site

International Nuclear Information System (INIS)

Burns, D.R.

1991-01-01

During the summer of 1989, Maine Drilling and Blasting of Gardiner, Maine was contracted by Cayer Corporation of Harvard, Massachusetts to drill and blast an interceptor trench at the Nyanza Chemical Superfund Site in Ashland, Massachusetts. The interceptor trench was to be 1,365 feet long and to be blasted out of granite. The trench was to be 12 feet wide at the bottom with 1/1 slopes, the deepest cut being 30 feet deep. A French drain 12 feet wide by 15 to 35 feet deep was blasted below the main trench on a 2% slope from its center to each end. A French drain is an excavation where the rock is blasted but not dug. The trench would be used as a perimeter road with any ground water flow going through the French drain flowing to both ends of the trench. Being a Superfund project turned a simple blasting project into a regulatory nightmare. The US Environmental Protection Agency performed all the chemical related functions on site. The US Army Corps of Engineers was overseeing all related excavation and construction on site, as was the Massachusetts Department of Environmental Quality Engineering, the local Hazardous Wastes Council, and the local Fire Department. All parties had some input with the blasting and all issues had to be addressed. The paper outlines the project, how it was designed and completed. Also included is an outline of the blast plan to be submitted for approval, an outline of the Safety/Hazardous Waste training and a description of all the problems which arose during the project by various regulatory agencies

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.

Correlation between hydrogen release and degradation of limestone concrete exposed to hot liquid sodium in inert atmosphere

International Nuclear Information System (INIS)

Parida, F.C.; Das, S.K.; Sharma, A.K.; Ramesh, S.S.; Somayajulu, P.A.; Kannan, S.E.

2005-01-01

Full text of publication follows: Concrete is used as a structural material in a Fast Breeder Reactor (FBR) plant for the construction of its foundation, containment, radiation shield and equipment support structures. An accidental leakage of hot sodium on these civil structures can bring about thermo-chemical reactions, with concrete producing hydrogen gas and causing structural degradation. The concrete damage and hydrogen generation take place concurrently due to conduction of heat from sodium into the concrete and migration of steam / moisture in counter current direction towards sodium. In a series of experiments conducted with limestone concrete for two different types of design corresponding to composition and geometry, were exposed to liquid sodium (∼2 kg) at initial temperatures varying from 180 deg. C to 500 deg. C in an inerted test vessel (Capacity = 203 L). Immersion heater was employed to heat the sodium pool on the concrete cavity during the test period in some test runs. On-line continuous measurement of pressure, temperature, hydrogen gas and oxygen gas was carried out. Pre- and post- test nondestructive testing such as colour photography, spatial profiling of ultrasonic pulse velocity and measurement of dimensions were also conducted. Solid samples were collected from sodium debris by manual core drilling machine and from concrete block by hand held electric drilling machine. These samples were subjected to chemical analysis for the determination of free and bound water along with unburnt and burnt sodium. The hydrogen generation parameters such as average and peak release rate as well as release efficiency are derived from measured test variables. These test variables include temperature, pressure and hydrogen concentration in the argon atmosphere contained in the test vessel. The concrete degradation parameters encompass percentage reduction in ultrasonic pulse velocity, depth of physical and chemical dehydration and sodium penetration. These

Effect of supplementary cementing materials on the concrete corrosion control

Directory of Open Access Journals (Sweden)

Mejía de Gutiérrez, R.

2003-12-01

Full Text Available Failure of concrete after a period of years, less than the life expected for which it was designed, may be caused by the environment to which it has been exposed or by a variety of internal causes. The incorporation of supplementary materials has at the Portland cement the purpose of improving the concrete microstructure and also of influence the resistance of concrete to environmental attacks. Different mineral by-products as ground granulated blast furnace slag (GGBS, silica fume (SF, metakaolin (MK, fly ash (FA and other products have been used as supplementary cementing materials. This paper is about the behavior of concrete in the presence of mineral additions. Compared to Portland cements, blended cements show lower heat of hydration, lower permeability, greater resistance to sulphates and sea water. These blended cements find the best application when requirements of durability are regarded as a priority specially on high performance concrete.

La falla del concreto en un tiempo inferior a la vida útil para la cual se diseñó puede ser consecuencia del medio ambiente al cual ha estado expuesto o de algunas otras causas de tipo interno. La incorporación de materiales suplementarios al cemento Portland tiene el propósito de mejorar la microestructura del concreto y también de contribuir a la resistencia del concreto a los ataques del medio ambiente. Diferentes minerales y subproductos tales como escorias granuladas de alto horno, humo de sílice, metacaolín, ceniza volante y otros productos han sido usados como materiales suplementarios cementantes. Este documento presenta el comportamiento del hormigón en presencia de diferentes adiciones. Los cementos adicionados, comparados con los cementos Portland muestran bajos calores de hidratación, baja permeabilidad, mayor resistencia a sulfatos y a agua de mar. Estos cementos adicionados encuentran un campo de aplicación importante cuando los requerimientos de durabilidad son

Blasting as a method for abandoned mine land reclamation

International Nuclear Information System (INIS)

Workman, J.L.; Fletcher, L.R.

1991-01-01

Blasting methods have been proposed for reclaiming abandoned underground coal mine sites having unstable conditions. The objective of blasting is twofold: the permanent stabilization of an area by the collapse of underground workings to prevent any future subsidence, and the use of blasting to close existing sinkholes. This paper presents the results of two research projects funded by the Bureau of Mines Abandoned Mine Land Research Program to investigate the feasibility of blasting to assist in the reclamation of shallow abandoned coal mine sites. Blasting tests were conducted at Beulah, North Dakota and at Scobey, Montana, involving different configurations. The first test was a 10-acre site where blasting was used to collapse regular room and pillar panels for which good mine layout information was available. The second test involved a one acre site containing very irregular workings for which there was little available information. Finally, blasting techniques were used to close 13 individual vertical openings. The depths to the coal seams were 60 feet or less at all sites. When blasting for Abandoned Mine Land Reclamation, material must be cast downward into the abandoned developments or laterally into the sinkhole. Designs based on cratering concepts and spherical charges worked well. The blasting techniques successfully collapsed and stabilized the test areas. Cost of reclamation for the two test sites are presented. Data from blast vibration monitoring are presented because control of vibrations is of concern when mitigation efforts are conducted near homes

Predicting genome-wide redundancy using machine learning

Directory of Open Access Journals (Sweden)

Shasha Dennis E

2010-11-01

Full Text Available Abstract Background Gene duplication can lead to genetic redundancy, which masks the function of mutated genes in genetic analyses. Methods to increase sensitivity in identifying genetic redundancy can improve the efficiency of reverse genetics and lend insights into the evolutionary outcomes of gene duplication. Machine learning techniques are well suited to classifying gene family members into redundant and non-redundant gene pairs in model species where sufficient genetic and genomic data is available, such as Arabidopsis thaliana, the test case used here. Results Machine learning techniques that combine multiple attributes led to a dramatic improvement in predicting genetic redundancy over single trait classifiers alone, such as BLAST E-values or expression correlation. In withholding analysis, one of the methods used here, Support Vector Machines, was two-fold more precise than single attribute classifiers, reaching a level where the majority of redundant calls were correctly labeled. Using this higher confidence in identifying redundancy, machine learning predicts that about half of all genes in Arabidopsis showed the signature of predicted redundancy with at least one but typically less than three other family members. Interestingly, a large proportion of predicted redundant gene pairs were relatively old duplications (e.g., Ks > 1, suggesting that redundancy is stable over long evolutionary periods. Conclusions Machine learning predicts that most genes will have a functionally redundant paralog but will exhibit redundancy with relatively few genes within a family. The predictions and gene pair attributes for Arabidopsis provide a new resource for research in genetics and genome evolution. These techniques can now be applied to other organisms.

Blast densification trials for oilsands tailings

Energy Technology Data Exchange (ETDEWEB)

Port, A. [Klohn Crippen Berger Ltd., Vancouver, BC (Canada); Martens, S. [Klohn Crippen Berger Ltd., Calgary, AB (Canada); Eaton, T. [Shell Canada Ltd., Calgary, AB (Canada)

2010-07-01

The Shell Canada Muskeg River Mine External Tailings Facility (ETF) is an upstream constructed tailings facility located near Fort McMurray, Alberta. Raises have incrementally stepped out over the beach since construction of the starter dam and deposition within standing water has left some parts of the beach in a loose state. In order to assess the effectiveness of blast densification, a blast densification trial program that was conducted in 2006 at the ETF. The primary purpose of the test program was to determine the effectiveness of blast densification in tailings containing layers and zones of bitumen. The paper described the site characterization and explosive compaction trial program, with particular reference to test layout; drilling methodology; and blasting and timing sequence. The paper also described the instrumentation, including the seismographs; high pressure electric piezometers; low pressure electric piezometers; vibrating wire piezometers; inclinometers; settlement gauges; and surveys. Trial observations and post-trial observations were also presented. It was concluded that controlled blasting techniques could be used to safely induce liquefaction in localized areas within the tailings deposit, with a resulting increase in the tailings density. 5 refs., 1 tab., 14 figs.

Full-scale testing of leakage of blast waves inside a partially vented room exposed to external air blast loading

Science.gov (United States)

Codina, R.; Ambrosini, D.

2018-03-01

For the last few decades, the effects of blast loading on structures have been studied by many researchers around the world. Explosions can be caused by events such as industrial accidents, military conflicts or terrorist attacks. Urban centers have been prone to various threats including car bombs, suicide attacks, and improvised explosive devices. Partially vented constructions subjected to external blast loading represent an important topic in protective engineering. The assessment of blast survivability inside structures and the development of design provisions with respect to internal elements require the study of the propagation and leakage of blast waves inside buildings. In this paper, full-scale tests are performed to study the effects of the leakage of blast waves inside a partially vented room that is subjected to different external blast loadings. The results obtained may be useful for proving the validity of different methods of calculation, both empirical and numerical. Moreover, the experimental results are compared with those computed using the empirical curves of the US Defense report/manual UFC 3-340. Finally, results of the dynamic response of the front masonry wall are presented in terms of accelerations and an iso-damage diagram.

Appendix to rationally designing of machine tools for example of universal lathe

Directory of Open Access Journals (Sweden)

Pejović Branko B.

2015-01-01

Full Text Available In this paper, for the universal machine tool for turning and function of the thrust of the cutting speed for blasting area efficiency and stability of the tool and sectional filings. These dependencies were used to determine the main characteristics of the optimal and maximum operating power equipment. Based on this, an analysis of the increase in operating power equipment typical cases in order to adapt to the new needs of exploitation properties and improve productivity. Using the previous analysis, it was determined the best solution in terms of the rational design of machines, by ensuring the simultaneous use of the main features on the basis of increase in speed with the use of tools and higher stability. In order to better display problems, an analysis of the appropriate diagrams P-V and V-D. On a typical example of the manufacturing practice at the end of the work, we demonstrate improvement of exploitation characteristics of a universal machine through appropriate calculations in terms of new needs adjustment feature, where it is expected that the reconstruction of the smallest machines.

Environmental problems associated with blasting in mines: public apprehensions of damage due to blast vibrations - case studies

Energy Technology Data Exchange (ETDEWEB)

Padhi, S.N. [DGMS, Bhubaneswar (India)

1994-12-31

Blast vibrations may be felt in intensities as small as 1/100 of that required to cause any damage to structures. Therefore, the public response and thus complaints regarding damages are often imaginary. The paper deals with three case studies, involving alleged damage from blasting in surface and underground coal mines where public litigations and agitations resulted due to such apprehensions. The paper is written in simple technical language as the situations warranted that the blast vibration studies should be understood by the general public. 7 tabs.

Low-pH concrete: design, characterisation and durability

International Nuclear Information System (INIS)

Codina, M.

2007-09-01

Using of Portland cement in association with clay in a deep geological repository could present some difficulties. The clay properties may be altered by the high pH conditions set by the cement pore water. Moreover, a high temperature rise caused by cement hydration in massive concrete elements could induce microcracking of the material. Investigations have thus been carried out to formulate low alkalinity and low-heat blended cements referred as 'low-pH' binders, which would show an improved compatibility with the repository environment and which could be used to elaborate high-strength concrete. A list of specifications to be checked by the concrete materials has been defined including pore solution pH around 11, temperature rise during hydration less than 20 C, moderate shrinkage and high compression strength (superior to 70 MPa). Several systems comprising Portland cement, a pozzolana (silica fume or fly ash) and blast furnace slag were compared. All blends were characterized by high amounts of additions, the OPC fractions ranging only from 20 to 60%. The pore solution pH values of the blended pastes were within the range [11.7 - 12.2] after one year of hydration. The decrease in pH as compared to a reference made with OPC was due to a i) strong reduction of the alkali concentration in the pore water, ii) depletion or decrease of the portlandite content in the blends and iii) enrichment of C-S-H with silica. These low pH binders were successfully used to prepare high strength concretes (pH pore-water values within the range [10.7 - 11.6] according to the binders) with usual tools of civil engineering. Finally, leaching tests carried out in pure water indicated a very slow decalcification (reduced by a factor 4) of the blended pastes, as compared to a Portland cement paste. The mineralogical evolution and leached fluxes could be modelled by using a coupled reactive transport code (HYTEC). (author)

Massive injection of coal and superoxygenated blast into the blast furnace

Energy Technology Data Exchange (ETDEWEB)

Toxopeus, H.L.; Danloy, G.; Franssen, R.; Havelange, O. [Corus, IJmuiden (Netherlands)

2002-07-01

The aim of the present project was to demonstrate the industrial feasibility of a massive injection of coal, {+-}270 kg/tHM, combined with a high O{sub 2} enrichment of the blast. The coke rate would thus be reduced to well below 250 kg/tHM. A reference level of 200-220 kg coal/tHM was successfully accomplished. However, the technical condition of the blast furnace hearths overruled all ambitions, the anticipated trial scheme had to be abandoned and no further trials were performed. A very short trial was aborted shortly after reaching an injection level of around 265 coal/tHM, due to excessive generation of very fine sludge originating from incomplete combustion. This forced the operators to investigate the merits of combustion more in depth. At the aimed low coke-rate detailed information about the gas distribution is of utmost importance. Therefore, in conjunction with the industrial tests, CRM designed a gas tracing method. Measurement of the transfer time between the injection point (a tuyere) and the sampling points (on an above-burden probe) would allow deduction of the radial gas distribution. CRM made the design and the start-up of an installation built by Hoogovens on blast furnace 7 of IJmuiden. Since then, repeated measurements have shown that the gas transfer time profiles are consistent with the data measured at the blast furnace top and at the wall. The modifications of the moveable armour position are reflected better and faster on the gas distribution as measured by helium tracing than on the skin flow temperatures.

Manufacture and quality control of concrete for Ikata Nuclear Power Station, Shikoku Electric Power Co., Inc

International Nuclear Information System (INIS)

Tada, Akiomi; Kitada, Takao

1989-01-01

Ikata Nuclear Power Station, only one nuclear power station in Shikoku, is located at the root of Sada Peninsula on Seto Inland sea side. At present, No.1 and No.2 plants of 566 MW each are in commercial operation, and on the east side, No.3 plant is under construction. No.3 plant is a PWR type plant of 890 MWe output, and the start of commercial operation is scheduled in March, 1995. In the construction of No.3 plant, the concrete used for civil engineering and building works is about 430,000 m 3 , and for the improvement of the quality control of concrete, the pursuit of economic efficiency, the fostering of concrete technology of employee and the coprosperity with local industries, the facilities for manufacturing concrete were constructed within the premise of the power station. The amount of use of concrete and respective materials classified by respective fiscal years, and the amount of manufacture of concrete that determines the scale of the concrete plant are shown. As to the construction of the concrete plant, the foundation work was started in March, 1987, and the machine foundation and building works were started in May, 1987. The acceptance was completed on August 17, 1987. The facilities of manufacturing concrete, the manufacture of concrete, and the quality control of materials and concrete are reported. (author)

Bomb blast imaging: bringing order to chaos.

Science.gov (United States)

Dick, E A; Ballard, M; Alwan-Walker, H; Kashef, E; Batrick, N; Hettiaratchy, S; Moran, C G

2018-06-01

Blast injuries are complex, severe, and outside of our everyday clinical practice, but every radiologist needs to understand them. By their nature, bomb blasts are unpredictable and affect multiple victims, yet require an immediate, coordinated, and whole-hearted response from all members of the clinical team, including all radiology staff. This article will help you gain the requisite expertise in blast imaging including recognising primary, secondary, and tertiary blast injuries. It will also help you understand the fundamental role that imaging plays during mass casualty attacks and how to avoid radiology becoming a bottleneck to the forward flow of severely injured patients as they are triaged and treated. Copyright © 2018. Published by Elsevier Ltd.

On firework blasts and qualitative parameter dependency.

Science.gov (United States)

Zohdi, T I

2016-01-01

In this paper, a mathematical model is developed to qualitatively simulate the progressive time-evolution of a blast from a simple firework. Estimates are made for the blast radius that one can expect for a given amount of detonation energy and pyrotechnic display material. The model balances the released energy from the initial blast pulse with the subsequent kinetic energy and then computes the trajectory of the material under the influence of the drag from the surrounding air, gravity and possible buoyancy. Under certain simplifying assumptions, the model can be solved for analytically. The solution serves as a guide to identifying key parameters that control the evolving blast envelope. Three-dimensional examples are given.

The removal of concrete layers from biological shields by microwaves

International Nuclear Information System (INIS)

Hills, D.L.

1989-01-01

Concrete blocks reinforced with steel bars have been subjected to microwave attack at a frequency of 896 MHz at power levels up to 25 kW. The surface concrete has been explosively removed to the depth of the reinforcement, 10 cm, at a rate of about 2 litres per kWh. Heating was localized around the point of attack, with temperatures up to 300 0 C at the fractured face being attained. A simple mathematical model of the propagation and absorption of micro-waves was used to estimate the temperature rise of concrete at microwave frequencies of 896 wand 2450 MHz, at different power levels with and without the presence of reinforcing bars. This demonstrated that reinforcement is expected to significantly increase the temperature rise in the concrete between the irradiated surface and the reinforcement, and that near-surface heating should be more rapid at the higher frequency. There was reasonable agreement between predicted and observed temperature at the higher power levels. Further desk and laboratory studies are proposed before proceeding to a fullscale practical demolition machine and the requirements for a prototype remotely-operated demonstration system have been identified. This consists of a static generator of high power (at least 50 kW) transmitting microwaves via a steerable waveguide to a remote applicator mounted on a simple three-axis manipulator capable of traversing realistically large concrete test panels

HYDRAULIC AND PHYSICAL PROPERTIES OF SALTSTONE GROUTS AND VAULT CONCRETES

International Nuclear Information System (INIS)

Dixon, K.; Harbour, J.; Phifer, M.

2008-01-01

The Saltstone Disposal Facility (SDF), located in the Z-Area of the Savannah River Site (SRS), is used for the disposal of low-level radioactive salt solution. The SDF currently contains two vaults: Vault 1 (6 cells) and Vault 4 (12 cells). Additional disposal cells are currently in the design phase. The individual cells of the saltstone facility are filled with saltstone. Saltstone is produced by mixing the low-level radioactive salt solution, with blast furnace slag, fly ash, and cement (dry premix) to form a dense, micro-porous, monolithic, low-level radioactive waste form. The saltstone is pumped into the disposal cells where it subsequently solidifies. Significant effort has been undertaken to accurately model the movement of water and contaminants through the facility. Key to this effort is an accurate understanding of the hydraulic and physical properties of the solidified saltstone. To date, limited testing has been conducted to characterize the saltstone. The primary focus of this task was to estimate the hydraulic and physical properties of three types of saltstone and two vault concretes. The saltstone formulations included saltstone premix batched with (1) Deliquification, Dissolution, and Adjustment (DDA) salt simulant (w/pm 0.60), (2) Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) salt simulant (w/pm 0.60), and (3) Salt Waste Processing Facility (SWPF) salt simulant (w/pm 0.60). The vault concrete formulations tested included the Vault 1/4 concrete and two variations of the Vault 2 concrete (Mix 1 and Mix 2). Wet properties measured for the saltstone formulations included yield stress, plastic viscosity, wet unit weight, bleed water volume, gel time, set time, and heat of hydration. Hydraulic and physical properties measured on the cured saltstone and concrete samples included saturated hydraulic conductivity, moisture retention, compressive strength, porosity, particle density, and dry bulk density. These properties

Experimental Investigation into Pull-Out Strength of Foamed Concrete Using Different Types of Screw

Directory of Open Access Journals (Sweden)

Othuman Mydin M.A.

2014-01-01

Full Text Available This study focuses on the results of the comprehensive strength test to quantify the mechanical properties of the screw’s pullout strength on foamed concrete. Foamed concrete is classified as lightweight concrete that been produced by cement paste or mortar in which air-voids are entrapped in the mortar by a suitable foaming agent. These days, the use of foamed concrete has been recognized in the construction industry as wall blocks, wall panels and also material floor and roof screeds. Hence, the applications of this material should be maximized as it is multi-functional. As we know, the use of screws on the wall or ceiling is common in a building. The objective of this research is to examine and determine the pullout strength of various properties and types of screws in lightweight foamed concrete with various densities that may depict the best result of the pullout strength on foamed concrete. To visualize the different results of pullout strength, screws with and without wall plug will be used as well. The pullout strength will be tested using the Universal Testing Machine where it shall measure the ultimate load of the screws attached to the foamed concrete may resist.

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...

Study of axial protections of unloading machines of graphite piles

International Nuclear Information System (INIS)

Duco, Jacques; Pepin, Pierre; Cabaret, Guy; Dubor, Monique

1969-10-01

As previous studies resulted in the development of a simple calculation formula based on experimental results for the calculation of neutron protection thicknesses for loading machines, this study aimed at determining axial protections of these machines which represent a specific problem: scattering of delayed neutrons in the machine inner cavity may result in an important neutron leakage through the upper part, at the level of the winch enclosure. In an experimental part, this study comprises the measurement of the neutron dose in a 2.60 m long and 54 cm diameter cylindrical cavity, and in the thickness of the surrounding concrete protection. In the second part, the authors present a calculation method which uses the Zeus and Mercure codes to interpret the results [fr

Excavation of the SPS tunnel (view of a section prior to lining by a concrete shell)

CERN Multimedia

1974-01-01

The SPS ring (6911 m in circumference) is housed at a depth of 40 m (average) under the surface. The tunnel with an overall cross-sectional diameter of 4.8 m was drilled by big tunnelling machines (see 7406022X, 7406027X) into the molasse rock present in the Geneva basin. After the passage of the tunnelling machine the tunnel walls were lined with a concrete layer of about 30cm thickness.

Production and quality control of concrete for the Rajasthan Atomic Power Station - [Part 1

International Nuclear Information System (INIS)

Singha Roy, P.K.; Sukhtankar, K.D.; Prasad, K.

1975-01-01

The production and quality control of concrete and concrete materials for the construction of the twin-reactor Rajasthan Atomic Power Station with its 400 MW net capacity posed many challenges since many of the requirements for the properties of concrete were new and were being laid down for the first time in India. Some of the conditions for the concrete included leak-tightness against gas pressure, total absence of shrinkage in the containment even when the ambient temperature during concreting was as high as 45degC, placing concrete at a temperature as low as 8degC, the use of non-shrink and high strength grout, absolute impermeability against water, high density for radiation shielding, controlled modulus of elasticity for large machine foundations, high strength with high slump for the prestressed concrete dome, etc. Though the total quantity of concrete was not very much compared with a large river valley or steel plant project, (e.g., about 1.2 X 10 6 m 3 for a 2-million tonne steel plant) it was quite significant, being about 70,000 m 3 of normal density and 2,100 m 3 of high density concrete. The production of these quantities entailed intensive material study and investigation, development of new mixes with additives not tried out before in the country, and design and quality control techniques which were unique in many respects. The paper deals with the production and quality control of concrete, including grouts used in the projects, but the actual concreting and construction operations are not discussed. (author)

Use of pulsating water jet technology for removal of concrete in repair of concrete structures

Czech Academy of Sciences Publication Activity Database

Sitek, Libor; Foldyna, Josef; Martinec, Petr; Ščučka, Jiří; Bodnárová, L.; Hela, R.

2011-01-01

Roč. 6, č. 4 (2011), s. 235-242 ISSN 1822-427X R&D Projects: GA ČR GA103/07/1662; GA ČR GP101/07/P512; GA AV ČR 1QS300860501; GA MŠk ED2.1.00/03.0082 Grant - others:GA MPO(CZ) FR-TI2/390 Program:FR Institutional research plan: CEZ:AV0Z30860518 Keywords : high-speed water jet technology * pulsating jet * rotating jets * removal of concrete layer Subject RIV: JQ - Machines ; Tools Impact factor: 1.610, year: 2011 http://www.bjrbe.vgtu.lt/volumes/en/volume6/number4/03.php

Experience with drilling and blasting work during construction of Mochovce nuclear power plant

International Nuclear Information System (INIS)

Mraz, M.; Vojta, A.; Podel, R.

1986-01-01

The results are discussed of four years of investigating the technical and economic parameters of drilling and blasting equipment employed on the building site of the Mochovce nuclear power plant. The technical and operating characteristics are given of tested breaking and drilling sets manufactured by various foreign companies. The final choice was based on output, hard currency prices, power demand, operating reliability and number of personnel required for operation. The optimal set consists of two Hausherr HBM 70 drilling systems (holes with a diameter of 130 to 150 mm) and two ROC 601-02 Atlas Copco machines (auxiliary work, breaking foundation holes for nuclear reactors). (J.C.)

Proceedings of the twenty-seventh annual conference on explosives and blasting techniques

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

Various aspects of explosives and blasting techniques are covered. Those of particular interest to the coal industry buffer blasting versus cast blasting, post-blast cast profile shape prediction, fragmentation model to estimate ROM size distribution of soft rocks, blasting accidents, blast vibrations, ANFO explosives and carbon monoxide poisoning.

Study on vibration alleviating properties of glass fiber reinforced polymer concrete through orthogonal tests

International Nuclear Information System (INIS)

Bai Wenfeng; Zhang Jianhua; Yan Peng; Wang Xinli

2009-01-01

Polymer concrete (PC), because of its good vibration alleviating properties, is a proper material for elementary machine parts in high-precision machine tools. Glass fiber was applied in PC to improve its mechanical properties, and the material obtained is called glass fiber reinforced polymer concrete (GFRPC). The best parameter to estimate the vibration alleviating property is damping ratio. Orthogonal tests were carried out to prepare GFRPC specimens with different component proportions. Damping ratio of the GFRPC specimens was measured. The effect of the factors considered in the experiments on damping ratio of GFRPC was studied. Results of the tests show that granite proportion plays the most important role in determining damping ratio of GFRPC, then flexibilizer dosage and glass fiber length, while epoxy resin dosage and glass fiber dosage play a comparatively less important part. Detailed descriptions were made about how the considered factors affect damping ratio of GFRPC in this paper

Blast mitigation experimental and numerical studies

CERN Document Server

2013-01-01

Presents experimental methods of material and structural response to dynamic blast loads Includes computational analysis of material and structural response to dynamic blast loads Offers mitigation measures for structures in various environments Relates lab experiments to larger field tests Features more than 150 illustrations

Experimental Study and Engineering Practice of Pressured Water Coupling Blasting

Directory of Open Access Journals (Sweden)

J. X. Yang

2017-01-01

Full Text Available Overburden strata movement in large space stope is the major reason that induces the appearance of strong mining pressure. Presplitting blasting for hard coal rocks is crucial for the prevention and control of strong pressure in stope. In this study, pressured water coupling blasting technique was proposed. The process and effect of blasting were analyzed by orthogonal test and field practice. Results showed that the presence of pressure-bearing water and explosive cartridges in the drill are the main influence factors of the blasting effect of cement test block. The high load-transmitting performance of pore water and energy accumulation in explosive cartridges were analyzed. Noxious substances produced during the blasting process were properly controlled because of the moistening, cooling, and diluting effect of pore water. Not only the goal of safe and static rock fragmentation by high-explosive detonation but also a combination of superdynamic blast loading and static loading effect of the pressured water was achieved. Then the practice of blasting control of hard coal rocks in Datong coal mine was analyzed to determine reasonable parameters of pressured water coupling blasting. A good presplitting blasting control effect was achieved for the hard coal rocks.

Effectiveness of eye armor during blast loading.

Science.gov (United States)

Bailoor, Shantanu; Bhardwaj, Rajneesh; Nguyen, Thao D

2015-11-01

Ocular trauma is one of the most common types of combat injuries resulting from the interaction of military personnel with improvised explosive devices. Ocular blast injury mechanisms are complex, and trauma may occur through various injury mechanisms. However, primary blast injuries (PBI) are an important cause of ocular trauma that may go unnoticed and result in significant damage to internal ocular tissues and visual impairment. Further, the effectiveness of commonly employed eye armor, designed for ballistic and laser protection, in lessening the severity of adverse blast overpressures (BOP) is unknown. In this paper, we employed a three-dimensional (3D) fluid-structure interaction computational model for assessing effectiveness of the eye armor during blast loading on human eyes and validated results against free field blast measurements by Bentz and Grimm (2013). Numerical simulations show that the blast waves focused on the ocular region because of reflections from surrounding facial features and resulted in considerable increase in BOP. We evaluated the effectiveness of spectacles and goggles in mitigating the pressure loading using the computational model. Our results corroborate experimental measurements showing that the goggles were more effective than spectacles in mitigating BOP loading on the eye. Numerical results confirmed that the goggles significantly reduced blast wave penetration in the space between the armor and the eyes and provided larger clearance space for blast wave expansion after penetration than the spectacles. The spectacles as well as the goggles were more effective in reducing reflected BOP at higher charge mass because of the larger decrease in dynamic pressures after the impact. The goggles provided greater benefit of reducing the peak pressure than the spectacles for lower charge mass. However, the goggles resulted in moderate, sustained elevated pressure loading on the eye, that became 50-100% larger than the pressure loading

22 CFR 121.11 - Military demolition blocks and blasting caps.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Military demolition blocks and blasting caps... blasting caps. Military demolition blocks and blasting caps referred to in Category IV(a) do not include the following articles: (a) Electric squibs. (b) No. 6 and No. 8 blasting caps, including electric...

Investigations of primary blast-induced traumatic brain injury

Science.gov (United States)

Sawyer, T. W.; Josey, T.; Wang, Y.; Villanueva, M.; Ritzel, D. V.; Nelson, P.; Lee, J. J.

2018-01-01

The development of an advanced blast simulator (ABS) has enabled the reproducible generation of single-pulse shock waves that simulate free-field blast with high fidelity. Studies with rodents in the ABS demonstrated the necessity of head restraint during head-only exposures. When the head was not restrained, violent global head motion was induced by pressures that would not produce similar movement of a target the size and mass of a human head. This scaling artefact produced changes in brain function that were reminiscent of traumatic brain injury (TBI) due to impact-acceleration effects. Restraint of the rodent head eliminated these, but still produced subtle changes in brain biochemistry, showing that blast-induced pressure waves do cause brain deficits. Further experiments were carried out with rat brain cell aggregate cultures that enabled the conduct of studies without the gross movement encountered when using rodents. The suspension nature of this model was also exploited to minimize the boundary effects that complicate the interpretation of primary blast studies using surface cultures. Using this system, brain tissue was found not only to be sensitive to pressure changes, but also able to discriminate between the highly defined single-pulse shock waves produced by underwater blast and the complex pressure history exposures experienced by aggregates encased within a sphere and subjected to simulated air blast. The nature of blast-induced primary TBI requires a multidisciplinary research approach that addresses the fidelity of the blast insult, its accurate measurement and characterization, as well as the limitations of the biological models used.

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

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...

Oil injection into the blast furnace

Energy Technology Data Exchange (ETDEWEB)

Dongsheng Liao; Mannila, P.; Haerkki, J.

1997-12-31

Fuel injection techniques have been extensively used in the commercial blast furnaces, a number of publications concerning the fuels injection have been reported. This present report only summarizes the study achievements of oil injection due to the research need the of authors, it includes the following parts: First, the background and the reasons reducing coke rate of oil injection are analyzed. Reducing coke rate and decreasing the ironmaking costs are the main deriving forces, the contents of C, H and ash are direct reasons reducing coke rate. It was also found that oil injection had great effects on the state of blast furnace, it made operation stable, center gas flow develop fully, pressure drop increase, descent speed of burden materials decrease and generation of thermal stagnation phenomena, the quality of iron was improved. Based on these effects, as an ideal mean, oil injection was often used to adjust the state of blast furnace. Secondly, combustion behavior of oil in the raceway and tuyere are discussed. The distribution of gas content was greatly changed, the location of CO, H{sub 2} generation was near the tuyere; the temperature peak shifts from near the raceway boundary to the tuyere. Oxygen concentration and blast velocity were two important factors, it was found that increasing excess oxygen ratio 0.9 to 1.3, the combustion time of oil decreases 0.5 msec, an increase of the blast velocity results in increasing the flame length. In addition, the nozzle position and oil rate had large effects on the combustion of oil. Based on these results, the limit of oil injection is also discussed, soot formation is the main reason limiting to further increase oil injection rate, it was viewed that there were three types of soot which were generated under blast furnace operating conditions. The reason generating soot is the incomplete conversion of the fuel. Finally, three methods improving combustion of oil in the raceway are given: Improvement of oil

Effect of insulating concrete forms in concrete compresive strength

Science.gov (United States)

Martinez Jerez, Silvio R.

The subject presented in this thesis is the effect of Insulating Concrete Forms (ICF's) on concrete compressive strength. This work seeks to identify if concrete cured in ICF's has an effect in compressive strength due to the thermal insulation provided by the forms. Modern construction is moving to energy efficient buildings and ICF's is becoming more popular in new developments. The thesis used a concrete mixture and a mortar mixture to investigate the effects of ICF's on concrete compressive strength. After the experimentations were performed, it was concluded that the ICF's do affect concrete strength. It was found that the forms increase concrete strength without the need for additional curing water. An increase of 50% in strength at 56 days was obtained. It was concluded that the longer concrete cures inside ICF's, the higher strength it reaches, and that ICF's effect on concrete strength is proportional to volume of concrete.

30 CFR 56.6312 - Secondary blasting.

Science.gov (United States)

2010-07-01

... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Use § 56.6312 Secondary blasting. Secondary blasts fired at the same time in the same work area shall be initiated from...

Characterization of mixed mode crack opening in concrete

DEFF Research Database (Denmark)

Jacobsen, Jonas Sejersbøl; Poulsen, Peter Noe; Olesen, John Forbes

2012-01-01

components of the mixed mode displacement are measured using a custom made orthogonal gauge, and the measurements are used directly as the closed loop control signals. A double notch, concrete specimen is used for the crack investigation. The tests are divided into two steps, a pure Mode I opening step......In real concrete structures cracks often open in mixed mode after their initiation. To capture the direct material behavior of a mixed mode crack opening a stiff biaxial testing machine, capable of imposing both normal and shear loads on a given crack area, has been applied. The opening and sliding......, where a macro crack is initiated in the specimen followed by the mixed mode opening step. The high stiffness of the set-up together with the closed control loop ensures a stable crack initiation followed by a controllable mixed mode opening. The deep notches result in a plane crack, only influenced...

Safety management system during rock blasting at FRFCF construction site

International Nuclear Information System (INIS)

Vijayakumaran, C.; Kandasamy, S.; Satpathy, K.K.

2016-01-01

Blasting is an important activity during rock excavation to reach required depth for obtaining stability of the civil structure. For the construction of various Plant Buildings of Fast Reactor Fuel Cycle Facility (FRFCF), IGCAR at Kalpakkam, based on the geological survey it is required to reach a depth of 21.4 meters from existing ground level. This paper details about the procedures and precaution adopted during the rock blasting activities at FRFCF site. The volume of rock removed by blasting was 3 lakh cubic meters. The total number of blasting carried out was 304 using 105.73 tons of blasting material. The entire blasting work could be completed within 174 days without any incident. (author)

Application of Carbon Composite Bricks for Blast Furnace Hearth

Science.gov (United States)

Zuo, Haibin; Wang, Cong; Zhang, Jianliang; Zhao, Yongan; Jiao, Kexin

Traditional refractory materials for blast furnace hearth lining are mainly composed of carbon bricks and the ceramic cup. However, these materials can't meet the demands for long service life design of blast furnaces. In this paper, a new refractory called carbon composite brick (CCB) was introduced, which combined the advantages of carbon bricks and the ceramic cup. In this case, the resistance of the CCB against corrosion was equal to the ceramic cup and the thermal conductivity of the CCB was equal to carbon bricks. From the results of more than 20 blast furnaces, the CCB could be well used in small blast furnaces and large blast furnaces. In the bad condition of low grade burden and high smelting intensity, the CCB gave full play to the role of cooling system, and effectively resisted the erosion of hot metal to improve the service life of blast furnaces.

Blast effects physical properties of shock waves

CERN Document Server

2018-01-01

This book compiles a variety of experimental data on blast waves. The book begins with an introductory chapter and proceeds to the topic of blast wave phenomenology, with a discussion Rankine-Hugoniot equations and the Friedlander equation, used to describe the pressure-time history of a blast wave. Additional topics include arrival time measurement, the initiation of detonation by exploding wires, a discussion of TNT equivalency, and small scale experiments. Gaseous and high explosive detonations are covered as well. The topics and experiments covered were chosen based on the comparison of used scale sizes, from small to large. Each characteristic parameter of blast waves is analyzed and expressed versus scaled distance in terms of energy and mass. Finally, the appendix compiles a number of polynomial laws that will prove indispensable for engineers and researchers.

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 ...

A computational model of blast loading on the human eye.

Science.gov (United States)

Bhardwaj, Rajneesh; Ziegler, Kimberly; Seo, Jung Hee; Ramesh, K T; Nguyen, Thao D

2014-01-01

Ocular injuries from blast have increased in recent wars, but the injury mechanism associated with the primary blast wave is unknown. We employ a three-dimensional fluid-structure interaction computational model to understand the stresses and deformations incurred by the globe due to blast overpressure. Our numerical results demonstrate that the blast wave reflections off the facial features around the eye increase the pressure loading on and around the eye. The blast wave produces asymmetric loading on the eye, which causes globe distortion. The deformation response of the globe under blast loading was evaluated, and regions of high stresses and strains inside the globe were identified. Our numerical results show that the blast loading results in globe distortion and large deviatoric stresses in the sclera. These large deviatoric stresses may be indicator for the risk of interfacial failure between the tissues of the sclera and the orbit.

EXPERIMENTAL STUDY ON THE STABILITY OF SURROUNDING ROCK IN TUNNEL BLASTING CONSTRUCTION

Directory of Open Access Journals (Sweden)

Hongxian Fu

2018-04-01

Full Text Available In this study, criteria and blasting technologies are introduced in order to control the stability of surrounding rock of tunnel built using drill-and-blast safety. The paper is composed of three parts, namely, a blast vibration propagation law in roof surrounding rock in close proximity to tunnel face, two formulae to calculate particle critical vibration velocity of shotcrete and key structural element at the roof of tunnel, and innovative technologies of tunnel blasting. The blast vibration propagation law is the base to control the stability of surrounding rock during tunnel blasting. Based on Morhr-Coulomb criterion and the dynamic analysis, two formulae to calculate the critical particle vibration velocity are proposed. Based on a series of trial blasts using electronic detonators, two innovative blasting technologies are derived. One is the blast holes detonated one by one by using electronic detonator, and another is the blast holes detonated by combining initiation system of electronic detonators and nonel detonators. The use of electronic detonators in tunnel blasting not only leads to a smaller blast vibration but also to a smaller extent of the EDZ (excavation damaged zone.

Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips

Directory of Open Access Journals (Sweden)

Myeong-Woo Cho

2007-08-01

Full Text Available Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip, has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

Comprehensive Numerical Modeling of the Blast Furnace Ironmaking Process

Science.gov (United States)

Zhou, Chenn; Tang, Guangwu; Wang, Jichao; Fu, Dong; Okosun, Tyamo; Silaen, Armin; Wu, Bin

2016-05-01

Blast furnaces are counter-current chemical reactors, widely utilized in the ironmaking industry. Hot reduction gases injected from lower regions of the furnace ascend, reacting with the descending burden. Through this reaction process, iron ore is reduced into liquid iron that is tapped from the furnace hearth. Due to the extremely harsh environment inside the blast furnace, it is difficult to measure or observe internal phenomena during operation. Through the collaboration between steel companies and the Center for Innovation through Visualization and Simulation, multiple computational fluid dynamics (CFD) models have been developed to simulate the complex multiphase reacting flow in the three regions of the furnace, the shaft, the raceway, and the hearth. The models have been used effectively to troubleshoot and optimize blast furnace operations. In addition, the CFD models have been integrated with virtual reality. An interactive virtual blast furnace has been developed for training purpose. This paper summarizes the developments and applications of blast furnace CFD models and the virtual blast furnace.

Survey of rice blast race identity for blast resistance gene identification in the USA and Puerto Rico

Science.gov (United States)

Rice blast disease is a significant threat to stable rice production in the USA and worldwide. The major resistance gene (Pi-ta) located within a cluster of resistance genes on rice chromosome 12 has been demonstrated to confer resistance to the rice blast disease. Katy, a rice cultivar released in ...

Micro Dot Patterning on the Light Guide Panel Using Powder Blasting

Directory of Open Access Journals (Sweden)

Dong Sam Park

2008-02-01

Full Text Available This study is to develop a micromachining technology for a light guidepanel(LGP mold, whereby micro dot patterns are formed on a LGP surface by a singleinjection process instead of existing screen printing processes. The micro powder blastingtechnique is applied to form micro dot patterns on the LGP mold surface. The optimalconditions for masking, laminating, exposure, and developing processes to form the microdot patterns are first experimentally investigated. A LGP mold with masked micro patternsis then machined using the micro powder blasting method and the machinability of themicro dot patterns is verified. A prototype LGP is test- injected using the developed LGPmold and a shape analysis of the patterns and performance testing of the injected LGP arecarried out. As an additional approach, matte finishing, a special surface treatment method,is applied to the mold surface to improve the light diffusion characteristics, uniformity andbrightness of the LGP. The results of this study show that the applied powder blastingmethod can be successfully used to manufacture LGPs with micro patterns by just singleinjection using the developed mold and thereby replace existing screen printing methods.

Computational modeling of blast induced whole-body injury: a review.

Science.gov (United States)

Chanda, Arnab; Callaway, Christian

2018-02-01

Blast injuries affect millions of lives across the globe due to its traumatic after effects on the brain and the whole body. To date, military grade armour materials are designed to mitigate ballistic and shrapnel attacks but are less effective in resisting blast impacts. In order to improve blast absorption characteristics of armours, the first key step is thoroughly understands the effects of blasts on the human body itself. In the last decade, a plethora of experimental and computational work has been carried out to investigate the mechanics and pathophysiology of Traumatic Brain Injury (TBI). However, very few attempts have been made so far to study the effect of blasts on the various other parts of the body such as the sensory organs (eyes and ears), nervous system, thorax, extremities, internal organs (such as the lungs) and the skeletal system. While an experimental evaluation of blast effects on such physiological systems is difficult, developing finite element (FE) models could allow the recreation of realistic blast scenarios on full scale human models and simulate the effects. The current article reviews the state-of-the-art in computational research in blast induced whole-body injury modelling, which would not only help in identifying the areas in which further research is required, but would also be indispensable for understanding body location specific armour design criteria for improved blast injury mitigation.

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

Study of the action of blast deck charge in rocky soils

Directory of Open Access Journals (Sweden)

Boiko V.V.

2017-04-01

Full Text Available Blasting (B in the industry, including the mining extraction of minerals, are carried out mostly with the use of blasthole charges that systematically distributed on the block that is undermined, by individual groups. The latter are blasted according to the scheme of short-delay firing (SDF through the intervals that are accepted not less than 20 Ms. Thus, the seismic effect of group charge explosion, consisting of individual blasthole charges and that actually is a group located charge determined by the formula of concentrated charge. Blast deck charges are effectively used in the driving of the trenches in the mining, formation of screens and cracks near the security objects. Only this method of performing blasting allows to define seismic effect in the transition from one diameter of a charge to another, as well as to determine the actual number of detonated charges in one group, which may differ from the calculated in drilling and blasting project. The work analyzes the physical essence of processes happened while blasting of blast deck charges. The effect of the orientation of the seismic action of blasting of blast deck charges towards the allocation line of charges is investigated. The results of generalized dependence of the speed of the displacement of the ground by the blast parameters and epicentral distance are obtained. We demonstrate with specific examples that blast deck charges that blasting simultaneously make a major chain of the career massive explosions at mining. Keywords: seismic fluctuations; the number of charges; the interaction of charges; the distance between the charges; the coefficients of the seismicity and the attenuation of the intensity of the waves; the unit charge; blast deck and blasthole charges; phase shifting; effective charge.

Ice blasting device for washing pump

International Nuclear Information System (INIS)

Hirose, Yasuo.

1992-01-01

In a nuclear power plant, when the inside of a pump casing such as a recycling pump is scrubbed, since operator's safety should be ensured, it requires a large-scaled operation. Then, a cover is attached to a flange of the pump casing, in which a driving portion is disposed passing through the cover vertically movably and rotatably, an arm is disposed bendably to the top end of the arm, and a blast nozzle is disposed to the top end of the arm for jetting ice particles, with a camera being disposed to the blast nozzle. The inside of the casing can be scrubbed safely and rapidly by an ice blast method by remote operation while monitoring the state of scrubbing for the inside of the casing by a camera. Further, since the flange of the pump casing for installing the ice blast device is covered by the cover, mists are not scattered to the outside. In addition, mists may be sucked and removed by an exhaustion duct. (N.H.)

Analysis of laboratory compaction methods of roller compacted concrete

Science.gov (United States)

Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

2017-09-01

Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

ORGANISATIONAL-TECHNOLOGICAL CHARACTERISTICS OF BLASTING WORKS ON THE GRIČ TUNNEL

Directory of Open Access Journals (Sweden)

Zvonimir Deković

2005-12-01

Full Text Available The paper describes organisational-technological characteristics of blasting works during the excavation of the Grič Tunnel. The significance of blasting works during the excavation of the tunnel is shown through adjustment of blasting parameters taking into consideration the dynamics of the works, cost-effectiveness and influence of geological circumstances. Successfulness of blasting directly influences the subsequent tunnel excavation cycle both in terms of duration as well as eventually in terms of influence on the entire tunnel investment. Comparison of changes of basic blasting parameters during tunnel excavation ensured optimal excavation progress with minimal price per meter of tunnel progress.

Dynamic behaviour of “Collapsible” concrete

Directory of Open Access Journals (Sweden)

Caverzan Alessio

2015-01-01

Full Text Available In this work a particular cement composite material for protection of structures and infrastructures against accidental actions, such as blast or impact, has been investigated. An experimental procedure has been developed in order to assess static and dynamic behaviour of energy absorbing cementitious composites. The granular cementitious composite has been studied focusing attention to compressive strength, high deformation and energy dissipation capacity which are important characteristics for an absorber material. An experimental characterization of the material behaviour under compressive static and dynamic loadings has been carried out. Different deformation velocities have been studied in order to define the material behaviour in a wide range of strain rates. The velocity range up to 0.1 m/s is investigated by means of a universal servo-hydraulic MTS 50 kN testing machine. Some preliminary results have been reported and discussed in the present work.

Determination of Destress Blasting Effectiveness Using Seismic Source Parameters

Science.gov (United States)

Wojtecki, Łukasz; Mendecki, Maciej J.; Zuberek, Wacaław M.

2017-12-01

Underground mining of coal seams in the Upper Silesian Coal Basin is currently performed under difficult geological and mining conditions. The mining depth, dislocations (faults and folds) and mining remnants are responsible for rockburst hazard in the highest degree. This hazard can be minimized by using active rockburst prevention, where destress blastings play an important role. Destress blastings in coal seams aim to destress the local stress concentrations. These blastings are usually performed from the longwall face to decrease the stress level ahead of the longwall. An accurate estimation of active rockburst prevention effectiveness is important during mining under disadvantageous geological and mining conditions, which affect the risk of rockburst. Seismic source parameters characterize the focus of tremor, which may be useful in estimating the destress blasting effects. Investigated destress blastings were performed in coal seam no. 507 during its longwall mining in one of the coal mines in the Upper Silesian Coal Basin under difficult geological and mining conditions. The seismic source parameters of the provoked tremors were calculated. The presented preliminary investigations enable a rapid estimation of the destress blasting effectiveness using seismic source parameters, but further analysis in other geological and mining conditions with other blasting parameters is required.

Evaluation of blast-induced vibration effects on structures 1

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Rim; Jeon, Gyu Shick; Lee, Dae Soo; Joo, Kwang Ho; Lee, Woong Keon [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of); Ryu, Chang Ha; Chung, So Keul; Lee, Kyung Won; Shin, Hee Soon; Chun, Sun Woo; Park, Yeon Jun; Synn, Joong Ho; Choi, Byung Hee [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-31

Due to the difficulties of obtaining construction site for new plants, following ones are inevitably being built in the site adjacent to existing power plants. Therefore considerable thought has been recently given to the dynamic loading generated by blasting works near the plants to maintain the safety of structures and facilities in power plants. Our own standard for safety level of blast vibration is not prepared yet, and foreign standards have been generally employed without theoretical and experimental verification. Safety-related structures of power plants and facilities have to be protected against the effects of possible hazards due to blast vibration. Earthquakes have been considered a major dynamic design loading as a requirement of plant design, but the effects of blast-induced vibration are not. In order to ensure the safety, rational safe criterion should be established and blast design should be satisfy it, which requires the development of a model for prediction of vibration level through more systematic measurement and analysis. The main objectives of the study are : to provide background data for establishing the rational safe vibration limits, to develop models for prediction of blast vibration level, to establish safe blast design criterion, and to accumulate techniques for field measurements, data acquisition and analysis (author). 80 refs., 347 figs.

Evaluation of the corrosion of reinforced concrete designed for low and medium activity level radioactive waste containers

International Nuclear Information System (INIS)

Duffo, G.S.; Arva, E.A; Schulz, F.M; Vasquez, D.R

2010-01-01

The National Atomic Energy Commission of Argentina (CNEA) is responsible for the design and construction of a monolithic repository for the final disposal of low and medium level radioactive wastes. In order to ensure the protection of people and the environment, the useful life of the repository should be 300 years and the conceptual design selected is based on the use of multiple, independent and redundant barriers. These barriers consist mainly of reinforced concrete. This work aims to establish a methodology to determine the concrete's useful life, evaluating parameters of interest using chemical and electrochemical techniques. For this purpose, reinforced concrete test pieces were made with two formulations - blast furnace cement (BFC) and with BFC plus silica fume admixture (BFC+SF)- and in each of the test pieces segments of reinforcement were included. The development over time of the corrosion potential and speed were evaluated, together with the resistivity of the concrete in the test pieces exposed to the laboratory environment, with an average relative humidity of 50%, a condition that favors the carbonation process. The diffusion coefficients of aggressive species, such as chloride and carbon dioxide, were also determined in test pieces made with the two formulations. In the test pieces exposed to the laboratory environment the reinforcements embedded in the BFC+SF concrete showed a lower corrosion speed compared to the BFC concrete. These results agree with the lower values for the speeds of carbonation and of chloride diffusion that show that the concrete with BFC+SF is more resistant to incoming aggressive species compared with the BFC. A container prototype for mid-level radioactive wastes was built and outfitted with instruments in order to monitor the development over time of the corrosion speed of the reinforcement rods by using corrosion sensors developed by the group. The prototype, exposed to atmospheric conditions, was manufactured with BFC

Enhancing cuttings removal with gas blasts while drilling on Mars

Science.gov (United States)

Zacny, K. A.; Quayle, M. C.; Cooper, G. A.

2005-04-01

Future missions to Mars envision use of drills for subsurface exploration. Since the Martian atmosphere precludes the use of liquids for cuttings removal, proposed drilling machines utilize mechanical cuttings removal systems such as augers. However, an auger can substantially contribute to the total power requirements, and in the worst scenario it can choke. A number of experiments conducted under Martian pressures showed that intermittent blasts of gas at low differential pressures can effectively lift the cuttings out of the hole. A gas flushing system could be incorporated into the drill assembly for assistance in clearing the holes of rock cuttings or for redundancy in case of auger jamming. A number of variables such as the particle size distribution of the rock powder, the type of gas used, the bit and auger side clearances, the initial mass of cuttings, and the ambient pressure were investigated and found to affect the efficiency. In all tests the initial volume of gas was close to 1 L and the differential pressure was varied to achieve desired clearing efficiencies. Particles were being lifted out of the hole at a maximum speed of 6 m/s at a differential pressure of 25 torr and ambient pressure of 5 torr. Flushing tests lasted on average for 2 s. The power required to compress the thin Martian atmosphere to achieve a sufficient gas blast every minute or so at 10% efficiency was calculated to be of the order of a few watts.

A multiscale approach to blast neurotrauma modeling:Part II: Methodology for inducing blast injury to in vitro models

Directory of Open Access Journals (Sweden)

Gwen B. Effgen

2012-02-01

Full Text Available Due to the prominent role of improvised explosive devices (IEDs in wounding patterns of U.S. war-fighters in Iraq and Afghanistan, blast injury has risen to a new level of importance and is recognized to be a major cause of injuries to the brain. However, an injury risk-function for microscopic, macroscopic, behavioral, and neurological deficits has yet to be defined. While operational blast injuries can be very complex and thus difficult to analyze, a simplified blast injury model would facilitate studies correlating biological outcomes with blast biomechanics to define tolerance criteria. Blast-induced traumatic brain injury (bTBI results from the translation of a shock wave in air, such as that produced by an IED, into a pressure wave within the skull-brain complex. Our blast injury methodology recapitulates this phenomenon in vitro, allowing for control of the injury biomechanics via a compressed-gas shock tube used in conjunction with a custom-designed, fluid-filled receiver that contains the living culture. The receiver converts the air shock wave into a fast-rising pressure transient with minimal reflections, mimicking the intracranial pressure history in blast. We have developed an organotypic hippocampal slice culture model that exhibits cell death when exposed to a 530  17.7 kPa peak overpressure with a 1.026 ± 0.017 ms duration and 190 ± 10.7 kPa-ms impulse in-air. We have also injured a simplified in vitro model of the blood-brain barrier, which exhibits disrupted integrity immediately following exposure to 581  10.0 kPa peak overpressure with a 1.067 ms ± 0.006 ms duration and 222 ± 6.9 kPa-ms impulse in-air. To better prevent and treat bTBI, both the initiating biomechanics and the ensuing pathobiology must be understood in greater detail. A well-characterized, in vitro model of bTBI, in conjunction with animal models, will be a powerful tool for developing strategies to mitigate the risks of bTBI.

Numerical analysis of blast flow-field of baffle type muzzle brake

Energy Technology Data Exchange (ETDEWEB)

Kim, D.H. [Graduate School, Chungnam National University, Taejon (Korea); Ko, S. [Chungnam National University, Taejon (Korea)

1998-11-01

A three-dimensional unsteady, inviscid blast flow-field of a baffle type muzzle brake has been simulated by solving the Euler equation. The blast flow-field includes the effect of the free air blast, precursor blast flow and the propellant blast gas flow. Chimera grid scheme was used to generate 9 multi-block volume grids for the complex geometry. The evolution of the blast flow-field is presented by showing the contours of pressure, density and Mach number for certain time step. The comparison of the calculated and measured peak pressures on the surfaces of the muzzle brake is also presented. (author). 4 refs., 5 figs., 1 tab.

Mechanical behaviour of steel fibre-reinforced alkali activated slag concrete

Directory of Open Access Journals (Sweden)

Puertas, F.

2009-03-01

Full Text Available This study addressed the mechanical behaviour of a steel fibre-reinforced alternative concrete made from waterglass (Na2SiO3.nH2O+NaOH- activated Colombian blast furnace slag. The mixes studied were prepared with 400 kg of cement and the fibres were added in proportions of 40 and 120 kg per cubic metre of concrete. 7-, 14- and 28-day concrete was tested for compressive, splitting tensile and flexural strength. The results obtained showed that adding steel fibre to alkaline concrete lowered early age compressive strength, and that this decline was more intense with rising volumes of steel. Flexural and splitting tensile strength grew, however, enhancing the toughness of the material. As a general rule, the mechanical strength of the plain and fibre-reinforced alkaline concretes studied was higher than exhibited by conventional ordinary Portland cement concrete prepared with similar proportions of cement and fibre.En este estudio se investigó el comportamiento mecánico de hormigones alternativos reforzados con fibras de acero, basados en una escoria siderúrgica colombiana activada alcalinamente con waterglass (Na2SiO3.nH2O+NaOH. Las mezclas en estudio fueron preparadas con 400 kg de cemento y las fibras fueron incorporadas en proporciones de 40 kg y 120 kg por metro cúbico de hormigón, respectivamente. Se evaluó el comportamiento mecánico de los hormigones frente a esfuerzos de compresión, tracción indirecta y flexión a edades de curado de 7, 14 y 28 días. Los resultados obtenidos indican que la incorporación de fibras de acero en los hormigones alcalinos reduce la resistencia a la compresión a edades tempranas siendo superior la pérdida de resistencia a mayores volúmenes de fibra incorporados, mientras que la resistencia a la flexión y tracción indirecta se incrementan significativamente, mejorando la tenacidad del material. En términos generales, es posible concluir que el comportamiento mecánico exhibido por los hormigones

Decontamination of large horizontal concrete surfaces outdoors

International Nuclear Information System (INIS)

Barbier, M.M.; Chester, C.V.

1980-01-01

A study is being conducted of the resources and planning that would be required to clean up an extensive contamination of the outdoor environment. As part of this study, an assessment of the fleet of machines needed for decontaminating large outdoor surfaces of horizontal concrete will be attempted. The operations required are described. The performance of applicable existing equipment is analyzed in terms of area cleaned per unit time, and the comprehensive cost of decontamination per unit area is derived. Shielded equipment for measuring directional radiation and continuously monitoring decontamination work are described. Shielding of drivers' cabs and remote control vehicles is addressed

Preparation and Mechanical Properties of Pressed Straw Concrete Brick

Science.gov (United States)

Sumarni, S.; Wijanarko, W.

2018-03-01

Rice straws have been widely used as wall filler material in China, Australia, and United States, by spinning them into hays with an approximate dimension of 40 cm of height, 40cm of thickness and 60 cm of width, using a machine. Then, the hays are placed into a wall frame until they fill it completely. After that, the wall frame is covered with wire mesh and plastered. In this research, rice straws are to be used as concrete brick fillers, by pressing the straws into hays and then putting them into the concrete brick mold along with mortar. The objective of this research is to investigate the mechanical properties of concrete brick, namely: compressive strength, specific gravity, and water absorption power. This research used experimental research method. It was conducted by using concrete bricks which had 400 cm of width, 200 cm of height, and 100 cm of thickness, made from rice straws, cement, sand, and water as the test sample. The straws were each made different by their volume. The mortars used in this research were made from cement, sand, and water, with the ratio of 1:7:0.5. The concrete bricks were made by pressing straws mixed with glue into hays, and then cut by determined variations of volume. The variations of hays volume were 0 m3, 0.000625 m3, 0.00075 m3, 0.000875 m3, 0.00125 m3, 0.0015 m3, 0.00175 m3, 0.001875 m3, 0.00225 m3, and 0.002625 m3. There were 3 samples for each volumes of hays. The result shows that the straw concrete bricks reached the maximum compressive strength of 1.92 MPa, specific gravity of 1,702 kg/m3, and water absorption level of 3.9 %. Based on the provided measurements of products in the Standar Nasional Indonesia (Indonesian product standardization), the concrete bricks produced attained the prescribed standard quality.

Determinants of dust exposure in tunnel construction work.

Science.gov (United States)

Bakke, Berit; Stewart, Patricia; Eduard, Wijnand

2002-11-01

In tunnel construction work, dust is generated from rock drilling, rock bolting, grinding, scaling, and transport operations. Other important dust-generating activities are blasting rock and spraying wet concrete on tunnel walls for strength and finishing work. The aim of this study was to identify determinants of dust exposure in tunnel construction work and to propose control measures. Personal exposures to total dust, respirable dust, and alpha-quartz were measured among 209 construction workers who were divided into 8 job groups performing similar tasks: drill and blast workers, shaft drilling workers, tunnel boring machine workers, shotcreting operators, support workers, concrete workers, outdoor concrete workers, and electricians. Information on determinants was obtained from interviewing the workers, observation by the industrial hygienist responsible for the sampling, and the job site superintendent. Multivariate regression models were used to identify determinants associated with the dust exposures within the job groups. The geometric mean exposure to total dust, respirable dust, and alpha-quartz for all tunnel workers was 3.5 mg/m(3) (GSD = 2.6), 1.2 mg/m(3) (GSD = 2.4), and 0.035 mg/m(3) (GSD = 5.0), respectively. A total of 15 percent of the total dust measurements, 5 percent of the respirable dust, and 21 percent of the alpha-quartz exceeded the Norwegian OELs of 10 mg/m(3), 5 mg/m(3), and 0.1 mg/m(3), respectively. Job groups with highest geometric mean total dust exposure were shotcreting operators (6.8 mg/m(3)), tunnel boring machine workers (6.2 mg/m(3)), and shaft drilling workers (6.1 mg/m(3)). The lowest exposed groups to total dust were outdoor concrete workers (1.0 mg/m(3)), electricians (1.4 mg/m(3)), and support workers (1.9 mg/m(3)). Important determinants of exposure were job group, job site, certain tasks (e.g., drilling and scaling), the presence of a cab, and breakthrough of the tunnel. The use of ventilated, closed cabs appeared to be

Blast-Resistant Improvement of Sandwich Armor Structure with Aluminum Foam Composite

OpenAIRE

Yang, Shu; Qi, Chang

2013-01-01

Sandwich armor structures with aluminum foam can be utilized to protect a military vehicle from harmful blast load such as a landmine explosion. In this paper, a system-level dynamic finite element model is developed to simulate the blast event and to evaluate the blast-resistant performance of the sandwich armor structure. It is found that a sandwich armor structure with only aluminum foam is capable of mitigating crew injuries under a moderate blast load. However, a severe blast load causes...

Control of City Shallow Buried Tunnel Blasting Hazard to Surface Buildings

Directory of Open Access Journals (Sweden)

Yang Deqiang

2015-01-01

Full Text Available Combining with the blasting test of an under-construction tunnel, this paper optimizes the overall blasting construction scheme. The optimized blasting scheme is used in the site construction test and the peak particle vibration velocity is strictly controlled under working conditions through blasting vibration monitoring to ensure the safety of surrounding buildings and structures in the construction process. The corresponding control measures are proposed to reduce the blasting vibration which brings certain guiding significance to the following construction project.

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.

Crack growth and development of fracture zones in plain concrete and similar materials

International Nuclear Information System (INIS)

Petersson, P.-E.

1981-12-01

A calculation model (the Fictitious Crack Model), based on fracture mechanics and the finite element method, is presented. In the model the fracture zone in front of a crack is represented by a fictitious crack that is able to transfer stress. The stress transferring capability of the fictitious crack normally decreases when the crack width increases. The applicability of linear elastic fracture mechanics to concrete and similar materials is analysed by use of the Fictitious Crack Model. The complete tensile stress-strain curve is introduced as a fracture mechanical parameter. The curve can be approximately determined if the tensile strength, the Young's modulus and the fracture energy are known. Suitable test methods for determining these properties are presented and test results are reported for a number of concrete qualities. A new type of very stiff tensile testing machine is presented by which it is possible to carry out stable tensile tests on concrete. The complete tensile stress-strain curves have been determined for a number of concrete qualities. A complete system for analysing crack propagation in concrete is covered, as a realistic material model, a functional calculation model and methods for determining the material properties necessary for the calculations are included. (Auth.)

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

Properties of high-workability concrete with recycled concrete aggregate

OpenAIRE

Safiuddin,; Alengaram,Ubagaram Johnson; Salam,Abdus; Jumaat,Mohd Zamin; Jaafar,Fahrol Fadhli; Saad,Hawa Binti

2011-01-01

This study presents the effects of recycled concrete aggregate (RCA) on the key fresh and hardened properties of concrete. RCA was used to produce high-workability concrete substituting 0-100% natural coarse aggregate (NCA) by weight. The slump and slump flow of fresh concretes were determined to ensure high workability. In addition, the compressive, flexural and splitting tensile strengths, modulus of elasticity, and permeable voids of hardened concretes were determined. The test results rev...

A Blast Wave Model With Viscous Corrections

International Nuclear Information System (INIS)

Yang, Z; Fries, R J

2017-01-01

Hadronic observables in the final stage of heavy ion collision can be described well by fluid dynamics or blast wave parameterizations. We improve existing blast wave models by adding shear viscous corrections to the particle distributions in the Navier-Stokes approximation. The specific shear viscosity η/s of a hadron gas at the freeze-out temperature is a new parameter in this model. We extract the blast wave parameters with viscous corrections from experimental data which leads to constraints on the specific shear viscosity at kinetic freeze-out. Preliminary results show η/s is rather small. (paper)

Behavior of coke in large blast furnaces

Energy Technology Data Exchange (ETDEWEB)

Nakamura, N

1978-01-01

Three blast furnaces were quenched in operation and the contents were examined; the temperature distribution was also measured, using Tempil pellets. The furnaces examined included a low productivity one, which was examined to see what was wrong. Changes in the quality of coke as it descends in the furnace, and coke behavior in the raceway and hearth are reported. The functions required of coke, and the effects of poor coke quality, are explained, together with the coke quality required in large blast furnaces. A theoretical study of the role of coke in large blast furnaces is included.

A Blast Wave Model With Viscous Corrections

Science.gov (United States)

Yang, Z.; Fries, R. J.

2017-04-01

Hadronic observables in the final stage of heavy ion collision can be described well by fluid dynamics or blast wave parameterizations. We improve existing blast wave models by adding shear viscous corrections to the particle distributions in the Navier-Stokes approximation. The specific shear viscosity η/s of a hadron gas at the freeze-out temperature is a new parameter in this model. We extract the blast wave parameters with viscous corrections from experimental data which leads to constraints on the specific shear viscosity at kinetic freeze-out. Preliminary results show η/s is rather small.

Use of Cement Kiln Dust, Blast Furnace Slag and Marble Sludge in the Manufacture of Sustainable Artificial Aggregates by Means of Cold Bonding Pelletization.

Science.gov (United States)

Colangelo, Francesco; Cioffi, Raffaele

2013-07-25

In this work, three different samples of solid industrial wastes cement kiln dust (CKD), granulated blast furnace slag and marble sludge were employed in a cold bonding pelletization process for the sustainable production of artificial aggregates. The activating action of CKD components on the hydraulic behavior of the slag was explored by evaluating the neo-formed phases present in several hydrated pastes. Particularly, the influence of free CaO and sulfates amount in the two CKD samples on slag reactivity was evaluated. Cold bonded artificial aggregates were characterized by determining physical and mechanical properties of two selected size fractions of the granules for each studied mixture. Eighteen types of granules were employed in C28/35 concrete manufacture where coarser natural aggregate were substituted with the artificial ones. Finally, lightweight concretes were obtained, proving the suitability of the cold bonding pelletization process in artificial aggregate sustainable production.

Use of Cement Kiln Dust, Blast Furnace Slag and Marble Sludge in the Manufacture of Sustainable Artificial Aggregates by Means of Cold Bonding Pelletization

Directory of Open Access Journals (Sweden)

Raffaele Cioffi

2013-07-01

Full Text Available In this work, three different samples of solid industrial wastes cement kiln dust (CKD, granulated blast furnace slag and marble sludge were employed in a cold bonding pelletization process for the sustainable production of artificial aggregates. The activating action of CKD components on the hydraulic behavior of the slag was explored by evaluating the neo-formed phases present in several hydrated pastes. Particularly, the influence of free CaO and sulfates amount in the two CKD samples on slag reactivity was evaluated. Cold bonded artificial aggregates were characterized by determining physical and mechanical properties of two selected size fractions of the granules for each studied mixture. Eighteen types of granules were employed in C28/35 concrete manufacture where coarser natural aggregate were substituted with the artificial ones. Finally, lightweight concretes were obtained, proving the suitability of the cold bonding pelletization process in artificial aggregate sustainable production.

Collapse of rocks by blasting. Razrusheniye gornykh porod Vzryvom

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, A F; Kutuzov, B N

1983-01-01

Information is provided about drilling boreholes and wells, explosives and the means for initiating them, storage, transporting and calculation of the explosive materials. Physical essence of the destructive, scientific and air effect of the blast are presented, principles of arrangement and calculation of the charges, reasons for malfunctions and methods of eliminating them, measures for protecting the surrounding objects from harmful effect of the industrial blast. Questions are examined of planning, organization and safety of the blasting operations. The second edition (first edition 1967) has been revised with regard for changes that occurred in the field of blasting operations.

Lateral blasts at Mount St. Helens and hazard zonation

Science.gov (United States)

Crandell, D.R.; Hoblitt, R.P.

1986-01-01

Lateral blasts at andesitic and dacitic volcanoes can produce a variety of direct hazards, including ballistic projectiles which can be thrown to distances of at least 10 km and pyroclastic density flows which can travel at high speed to distances of more than 30 km. Indirect effect that may accompany such explosions include wind-borne ash, pyroclastic flows formed by the remobilization of rock debris thrown onto sloping ground, and lahars. Two lateral blasts occurred at a lava dome on the north flank of Mount St. Helens about 1200 years ago; the more energetic of these threw rock debris northeastward across a sector of about 30?? to a distance of at least 10 km. The ballistic debris fell onto an area estimated to be 50 km2, and wind-transported ash and lapilli derived from the lateral-blast cloud fell on an additional lobate area of at least 200 km2. In contrast, the vastly larger lateral blast of May 18, 1980, created a devastating pyroclastic density flow that covered a sector of as much as 180??, reached a maximum distance of 28 km, and within a few minutes directly affected an area of about 550 km2. The May 18 lateral blast resulted from the sudden, landslide-induced depressurization of a dacite cryptodome and the hydrothermal system that surrounded it within the volcano. We propose that lateral-blast hazard assessments for lava domes include an adjoining hazard zone with a radius of at least 10 km. Although a lateral blast can occur on any side of a dome, the sector directly affected by any one blast probably will be less than 180??. Nevertheless, a circular hazard zone centered on the dome is suggested because of the difficulty of predicting the direction of a lateral blast. For the purpose of long-term land-use planning, a hazard assessment for lateral blasts caused by explosions of magma bodies or pressurized hydrothermal systems within a symmetrical volcano could designate a circular potential hazard area with a radius of 35 km centered on the volcano

Impact of Drill and Blast Excavation on Repository Performance Confirmation