bluuebunny/crossref_metadata_2025 huggingface dataset:
Expansive Rock Deep Cutting Slope Treated by Flexible Supporting Technology for Beijing Western Sixth Ring Highway
Authors: Xiao Jie , Yang He Ping , Ni Xiao , Tang Xian Yuan
Published: June 2011

The landslides of expansive rock cutting slope was the most serious and difficultly treating engineering problem for highway construction. The K9+600-K10+800 section of Beijing Western Sixth Ring highway was an expansive rock deep cutting slope, the problem of which was firstly encountered for Beijing highway construction. In this paper, the causes and characteristics of expansive rock slope failure were analyzed based on the engineering geology and rock properties of this section. In addition, the geogrid reinforced flexible supporting treatment measure was presented and its design scheme and construction approach were introduced. This method with the characteristics of “preserving moisture and antiseepage” and “softness and hardness” could resolve this kind of expansive rock slope problem effectively and economically.
Influence Analysis on the Unloading of a Pit Excavation to the Structure of Metro Station Nearby
Authors: Yao Yan Ming , Xu Yong Gang
Published: June 2011

Construction of a real estate project is close to one side of the metro station which has finished main structure building. The diagram of the metro station is used as supporting during the excavation of the pit of the real estate project, which will result in the one side unloading of the metro station. Bearing the unbalanced soil pressure, the metro station will have additional deformation and internal force. During the pit design, the additional deformation and internal force is analyzed for every step of the excavation. And the additional force is superimposed with the original force of the metro station to calculate the final internal force of the metro station. By adjusting the design parameters of the pit, the safety of the metro station is evaluated.
Evaluation of Seismic Simplified Methods for Deep Circular Tunnel
Authors: Dong Zheng Fang , Yao Yi Chao , Wang Jun Jie
Published: June 2011

Firstly several seismic simplified methods commonly used for deep circular tunnel are evaluated and the difficulties in response displacement method are pointed out. Then the analytical solution of soil spring coefficient and soil response of deep circular tunnel is derived from using complex variable theory of planar elastic theory based on pseudo-static hypothesis. The analytical solution has been verified by comparing its predictions with results from an analysis in finite element method. It is concluded that the analytical solution can be regarded as one feasible reference for the simplification of response displacement method.
Impact Experimental Study for Dynamic Character of Reactive Powder Concrete
Authors: Wang Wan Peng , Hu Yong Le , Ren Xin Tao , Xiong Yi Bo , Zhao Kang , She Xiao
Published: June 2011

In order to systematically study dynamic mechanics character of reactive powder concrete (RPC), impact compression experiments and impact flattened Brazilian disc specimens of RPC have been investigated with modified split Hopkinson pressure bar (SHPB) experimental facility using brass pulse shaper, curves about stress versus strain and other parameters at strain rates of 20.3/s~137.0/s were obtained from impact compression. The dynamic tensile strength and tensile failure strain at strain rates of 3.4/s~26.2/s were obtained from impact flattened Brazilian. For comparison, the quasi-static compress and split tension of RPC were obtained with an MTS 810 materials test system and CSS-88500 electron universal material testing machine.The experimental result show that dynamic compression strength , elastic modulus and failure strain,dynamic tensile strength and failure strain significantly increase comparing to quasi-static experiment, RPC have the character of impact harding and ductility enhancement. RPC exhibit excellent failure patterns at high strain rate. Whether impact compression or impact splitting under strain rate including this paper ’s experiments, the relationship between the DIFC or DIFT and the logarithm of strain rateis linear.
Surrounding Rock Mass Quality Evaluation of Huangdao Water Sealed Underground Oil Tank
Authors: Chen Xiang , Qi Xiao Bo , Xu Zhao Yi
Published: June 2011

Huangdao water sealed underground oil tank, which lies in Qingdao, Shandong province, is one of strategic reservoir of oil in China. Targeting at a real pragmatic problem that sometimes the rock mass integrity index is more than 1 and taking Huangdao water sealed underground oil tank as an example, the rock sample wave velocity-stress relation tests are carried out. Then unloading index is put forward and formula of raock integrity index is modified so as to improve rock quality classification method. In the end, the improved rock quality classification method is applied to Huangdao water sealed underground oil tank engineering. The result shows that the quality of most rock masses here is level I or II.
Study on Optimization of Core Pillar in Large-Span Tunnel Excavated with Double-Side Heading Method
Authors: Wang Cheng , Su Zhong Ming
Published: June 2011

Based on the undergroundHongtudistation of Chongqing Rail Transit Line VI, stress and plastic strain of surrounding rock, internal forces of supporting structure and vault settlement are calculated in different widths of core pillar. Comprehensive analyses indicate that there is an optimal value of core pillar width in the construction of tunnel with the double-side heading method. Width of core pillar, 0.3 times as large as the tunnel span, is suggested in other projects with the same construction method, which is of great significance in practices.
Based on the Durability Design of Pile Foundation Concrete Applied Research
Authors: Lv Da Wei , Mei Xing Min
Published: June 2011

Concrete is used in bridge as structural material in a great measure. Problem about durability of concrete was fully realized with the passage of time and accumulation of experience. An effective way of improving the durability of pile concrete was obtained in this paper according to researching and analyzing the durability of concrete used in bored pile of TangWa Bridge in freeway between LuoYang and LuanChuan.
Analysing of the Factors Affecting Pre-Stressing Losing in Pre-Stressing Cable Anchor and Recommending Compensative Measures
Authors: Zhu Xun Guo
Published: June 2011

After the rock bolt or cable bolt installed in rock and soil mass, as the time goes on, the pre-stress load in bolt maybe losing. Through studying and analyzing the field test data, the factors leading to pre-stress losing are both external and internal factors. The internal factors are cable steel wire loose and rock and soil mass creep deformation. In which the cable steel wire has been pre-tensioned, its affection for load losing is very little. While the rock and soil mass creep deformations have great affection to pre-stress loss. There, if the cable bolt is installed in hard rock, the rock creep deformation will be very little and the load losing in cable bolt will be very few. But if the cable bolt is installed in soft rock and soil mass, the creep deformation will be very much greater than in hard rock, and the pre-stress losing in cable bolt will be very great. The external factors are shocking load, such as blasting load, storm rainfall, temperature change and stress change of anchored rock mass. Through analyzing these affecting factors, some recommend the compensative measures which include choosing appropriate steel wire, pre-tensioning and over-tensioning cable bolt, controlling the blasting rigorous and monitoring the cable long time enough in work time.
Effects of Packing Density and Calcium- Silicon Ratio of Ternary Cementitious Material System on Strength of Reactive Powder Concrete
Authors: Ji Tao , Chen Bao Chun , Li Feng , Zhuang Yi Zhou , Huang Zhi Bin , Liang Yong Ning
Published: June 2011

Aim & Goff model was used to predict the packing density of cementitious material including cement, ultra-pulverized fly ash and silica fume. The mix proportions of reactive powder concrete (RPC) with different packing density and calcium-silicon ratio of cementitious material were designed, and a strength test was carried out. The study results reveal that the flexural strength and compressive strength of RPC are related to the packing density and calcium-silicon ratio of cementitious material. For the mix proportion of RPC with the calcium-silicon ratio of 1.179, calcium hydroxide reacts with silicon dioxide fully, and the superfluous ultra-pulverized fly ash and silica fume fill the voids of RPC. The packing density of its cementitious material is the largest, and its strength approaches summit.
The Static Mechanical Property of Concrete at Elevated Temperature
Authors: Tao Jun Lin , Qin Li Bo , Li Kui , Jia Bin
Published: June 2011

Using micro-wave heating method, the previous disadvantages of heating slowly and non-uniform are broken through. And plain concrete high temperature loading experiment system is composed of the method and material experiment machine. Many experiments of self-made concrete are carried out from room temperature to 600°C by this system. The strength and critical strain of concrete with temperature are obtained, and through analysis of the compressive stress-strain curves under different temperature, the constitutive relationship is established. The result shows that this constitutive relationship is greatly agrees with experiment. Meanwhile, the phenomenon is analyzed and explained in the progress of experiment.
Dynamic Failure Surface of Concrete under Multiaxial Dynamic Loads
Authors: Wang Huai Liang , Yuan Jun Yu
Published: June 2011

Study on the dynamic behavior of concrete is important, for the sake of seismic design and safety evaluation of mass concrete structures, such as concrete dams, nuclear reactors and so on. There have been a lot of uniaxial strength experiment data of concrete under dynamic loading, but multiaxial data is scarce, for the test of multiaxial strength of concrete under dynamic loading is difficult, while most mass structures work under multiaxial static and dynamic stress states. In this paper a three-dimension failure criterion of concrete under dynamic loading in octahedral stress space was proposed. Then the multixial strength tests of concrete under dynamic loading were carried out with concrete triaxial static and dynamic apparatus system. The selected loading paths consisted of uniaxial compression and tension, biaxial proportional loading compression, biaxial compression with one constant lateral compression and triaxial compression with two constant lateral compressions. In the test the strain rate range is 10-5~10-2/s. Based on the test data and the literature data, the characteristic of this failure surface is that it considered the influence of the strain rate and the angle of similarity; it is smooth, convex in meridian and deviatoric plane. The proposed model for nonlinear dynamic analysis and design of mass concrete structures under dynamic loading is useful.
Microstructure and Finite Element Analysis about Ceramic Concrete after High Temperature
Authors: Sun Qing Xia , Cao Wan Zhi , Xue Hai Ru , Su Qiang
Published: June 2011

This paper researched the high temperature properties of ceramic concrete though experimental. Test and analysis on the microstructure between the ceramic concrete and ordinary concrete which experience different temperatures using scanning electron microscopy (SEM); and analysis on the high temperature performance of the ceramic concrete using finite element method .The results show that: the C-S-H gel, Ca (OH)2crystals and the interfacial transition zone between aggregate and colloidal and other microstructure have different characteristics, these features can be used to explain the main reasons for changes of the concrete performance indicators after the high temperature and to provide technical basis for the application of ceramic concrete in the high temperature environment.
Research on the Biaxial Tensile Strength Test and Formula of Cement Concrete
Authors: Chen Ji Guang , Zhang Zhen Sen , Li Gang Ling
Published: June 2011

This paper mainly focuses on the cracking problem of concrete structures, researches on the biaxial tensile strength of cement concrete. The biaxial tensile instrument is used for material test, the biaxial tensile strength formula is proposed, and the theoretic formula is deduced by Hill criterion. With the test data analysis, it shows that the calculating value and the testing value fit well. The biaxial tensile strength of cement concrete is about 15%~30% lower than its uniaxial tensile strength, putting up significant biaxial tensile strength weakening effect. This kind of weakening effect is important for designs of large-span beam, plate and shell structures under complex stress.
Research on Strength and Microstructure of Cement with Sodium Sulfate Corrosion
Authors: Li Xiu Juan , Feng Xiao Xin
Published: June 2011

The experimental study on the failure behavior of cement test block in sodium sulfate solution and strength change of specimen in early stage. The microstructure of cement test block attacked by sodium sulfate is observed by means of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD). The mechanism of erosion damage in the sodium sulfate solution is analyzed. It is found that in the early period corrosion intensity will not suffer, but increase, and on the surface no obvious changes can be seen. However, in the attack later coarse surface cracks appear, then there is a serious off and the cement test block eventually collapses.
Effects of Minerals on the Dissolvable Ion Concentration and pH Value of Hardened Cement
Authors: Zhu Hong Bo , Wang Pei Ming , Zhang Ji Dong
Published: June 2011

The influence of grinded blast furnace slag (GBFS), high-calcium fly ash (HF), desulfurized gypsum (DG) and Na2SO4 (NS) on dissolvable ion Moore concentration and pH value of hardened cement is researched. In liquor with hardened cement powder, the dissolvable ion Moore concentration of Mg, Si or Al is according to each ion content in raw materials of cement paste. In materials system of cement-slag-HF, NS reduces the ion Moore concentration of Al and increases that of Mg or Si. PH value of hardened cement is mostly controlled by dissolvable Ca ion Moore concentration in the material system of cement-BBFS-HF. Alkali metal ions, which is introduced with additional materials, effect pH value more remarkably than the dissolvable Ca ion Moore concentration. PH value of hardened cement decreases a little if 50% cement is replaced by same weight of GBFS and HF. HF can reduce pH value more seriously than GBFS. DG enhances S and Ca ion Moore concentration, and decreases pH value of hardened cement.
Research on Damage Evolution of Polypropylene Fiber Concrete under Splitting Load
Authors: Qi Feng , Yang Bo , Li Xi Bin
Published: June 2011

Based on Moelands-Reinhardt single parameter power exponent constitutive equation and Equivalent stain hypothesis, preliminary damage evolution equation of polypropylene fiber concrete is derived. To eliminate mesh correlation of element characteristic length and reflect the action of tensile strength and fracture energy to damage evolution, modified polypropylene fiber concrete’s damage evolution equation is deduced from the preliminary damage evolution equation. The modified damage evolution equation is proved by comparing the Load-displacement curve get from splitting test and theoretical Load-displacement curve obtained by damage FEM calculation. Through the splitting test, it is showed that the modified damage evolution equation reflects the action of polypropylene fiber volume ratio and aspect ratio to polypropylene fiber’s damage evolution.
Evaluation of Human Comfort under Repeated Intermission Vibrations
Authors: Shen Yi Jie , Song Jie , Song Zhi Gang
Published: June 2011

Mining explosions and railway transportation generally result repeated intermission vibrations (RIV). These vibrations, with relatively shorter duration and larger peak acceleration, often repeat several times in a day. A proper evaluation method of human response should consider both the non-stationary nature and the occurrence frequency of RIV. This result the evaluation process has some differences compared with that for ordinary stationary vibration. Current evaluation method for human vibration comfort is first reviewed in this paper. Then the vibration dose value (VDV) and frequency of vibration events are introduced to evaluate vibration comfort under RIV. At last part of the paper, two vibration cases, one for blasting and one for railway transportation, are analyzed to explain above evaluation process.
Influence of Fly Ash and Silica Fume on Anti-Corrosion Characteristics of Mortar in Sulfuric Acid
Authors: Min Hong Guang , Song Zhi Gang , Li Yan Tao , Shen Yi Jie
Published: June 2011

A long term immersion test of mortar in sulfuric acid is carried out to investigate the effects of fly ash (FA) and silica fume (SF) on anti-corrosion characteristics. The mortar specimens have water to binder ratios (W/B) ranging from 0.5 to 0.7 and are divided into two series. Series one uses admixture of FA with replacement ratio from 0~0.3 and series two uses admixture of SF with replacement ratio from 0~0.1. The specimens are soaked in sulfuric acid with a pH value of 3.50 for 150 days. The portable pH meter is used to monitor the pH changing of the soak solution. The titrating sulfuric acid with concentration of 0.125mol/l is added to maintain the original pH value of the solution and then sulfuric acid consumption of specimens is recorded. A partial correlation analysis of experiment results shows that the effects of FA and SF on mortar resistance to sulfuric acid would change with the water binder ratio.
Application of Uniform Design and Non-Parametric Regression in Experimental Study of Permeable Concrete Corroded by Sulfuric Acid
Authors: Yang Sheng Yuan , Song Zhi Gang , Min Hong Guang , Zhang Xue Song
Published: June 2011

Uniform design and non-parametric regression are introduced combined with a long time immersion test of permeable concrete soaked in sulfuric acid. The experiment contains 4 factors and 10 levels and is arranged by uniform design method. The test records the permeable coefficients and volume of acid consumption and then the datum are passed a non-parametric analysis. The results show that cement-aggregate ratio and permeable coefficient have positive, while water-cement ratio have negative, linear relationships with acid consumption.
Study on Corrosion Resistance of N-Vinyl Pyrrole Modified Cement
Authors: Jia Li Li , Wang Qi , Song Peng , Shi Yun Zhong
Published: June 2011

Ordinary Portland cement in corrosive environment such as saline-alkali land, sea water and chemical pollution can easily be corroded, thus cause infrastructure damage. In this paper, N-vinyl pyrrole was added into cement mortar, to improve sulphate erosive resistance of cement material. Through strength testing, quick sulfate corrosion test, XRD and SEM analysis methods in experiment, the researching results have shown that NVP can effectively improve the property of cement.
Effects of Compressive Strength and Carbonation of HCSA Amount on High Volume Fly Ash Concrete
Authors: Liu Juan Hong , Hou Fang Fang , Song Shao Min , Jia Bo Ya
Published: June 2011

In this article, the effects of compressive strength and carbonation depth of HCSA mixing amount on high volume fly ash concrete have been investigated. Besides, the effects of compressive strength and carbonation depth of the fly ash amount on HCSA expansive concrete have been also analyzed. The results show that proper HCSA mixing amount can improve the compressive strength and anti-carbonation resistance. On the condition of 55% mixing amount of fly ash and 6% HCSA, the compressive strength for 28 days enhanced 8MPa, the carbonation depth decreased by 0.7mm, at the age of 70, the strength increased by 12MPa and the depth reduced 1.7mm; when the mixing amount of HCSA reaches 10%, the internal structure of concrete would be destroyed; In the case of 6% HCSA amount, the compressive strength and anti-carbonation resistance decreases with the increase of fly ash mixing amount. While comparing to the concrete without HCSA, the compressive strength and anti-carbonation resistance increase obviously.
Durability of High-Volume GGBS Concrete
Authors: Li Ke Liang , Huang Guo Hong , Lin Jun , Tang Xiu Sheng
Published: June 2011

To improve structure durability of Cao’e River Floodgate in China, durability and lifetime prediction of high-volume ground granulated blast-furnace slag (GGBS) concrete were investigated. Chloride ion permeability was analyzed with nature soaking method and RCM method. High-volume GGBS concrete had better capability to resist chloride ion penetration with lower diffusion coefficient of chloride ion than ordinary Portland concrete (OPC) had. Experiment of steel-bar corrosion in dry-wet environments proved that high-volume GGBS concrete had better performance to protect steel-bar than OPC had. In the sulfate solution, high-volume GGBS mortar bars only produced small expansion which was 40% of that of Portland cement mortar bars. The performance of frost resistance of high-volume GGBS concrete was favorable. GGBS debased the capability of carbonation resistance. Lifetime prediction illuminated high-volume GGBS concrete was beneficial to extended project lifespan. The results show that high-volume GGBS concrete can solve the facing durability problem of Cao’e River Floodgate.
An Experimental Assessment of the Effects of Concrete Mix Proportions on Penetration of Chloride Ions
Authors: Ding Jian Jiang , Zheng Jian Jun , Chen Chun Lei
Published: June 2011

The study on the penetration of chloride ions into concrete is very important for the durability assessment and design of reinforced concrete structures. A cyclic wetting and drying test is conducted to evaluate the effects of concrete mix proportions on the penetration of chloride ions. Based on the experimental results, the variations in chloride ion content at various points in concrete with the water/cement ratio, maximum aggregate diameter, aggregate gradation, fly ash content, and anticorrosion agent content are analyzed quantitatively. It is found that the water/cement ratio, aggregate gradation, maximum aggregate diameter, and fly ash all have a larger influence on the penetration of chloride ions. These conclusions can provide theoretical evidence for the design optimization of concrete properties.
Calculation Model of Compressive Strength of High Fly-AshContent Concrete at Specific Age
Authors: Ai Hong Mei , Wei Jing , Lu Pu Guang , Bai Jun Ying
Published: June 2011

Cementitious coefficient βtwas introduced to reflect the comprehensive effect of fly-ash quality on HFCC strength. On the basis of βt, actual water-binder ratio [W/(C+βtF)] and ash-binder ratio K was proposed, and the strength calculation model of HFCC with specific design age was established. On the basis of economy principal, the formula to determine K was founded. Influence of the design strength of HFCC and βt on K and the content of fly ash was analyzed.
An Elastoplastic-anisotropic Damage Model for Concrete
Authors: Liu Jun , Lin Gao
Published: June 2011

An elastoplastic-anisotropic damage constitutive model for the description of nonlinear behavior of concrete is presented. The yield surface is developed in effective stress spaces, which takes into account the hardening effect and better match the experimental data. The stiffness degradation and softening effect are considered in the framework of continuum damage mechanics formulation. The second-order damage tensor is used to characterize the anisotropy induced by the orientation of microcracks. In order to simulate the unilateral effect, the elastic Helmholtz free energy is decomposed into a volumetric part and a deviatoric part. The different behavior under tensile and compressive loadings is modeled by using different variables in effective stress and damage tensor. Numerical results of the model accord well with experimental results at the material and structural levels.
Study on High Freeze-Resistance of Concrete
Authors: Jin Yan
Published: June 2011

In this paper, the freeze-resistance of concrete is studied for the special requirements of the engineering. Through the analysis of the damage mechanism of concrete’s freezing and thawing; researching the effect on freeze-resistance of concrete when to be mixed into active mineral ingredients additive and admixture; proposing the right mix proportioning to fit the request of project; making a good result by testing the property of mixture and the mechnical property of concrete as well as its freeze-resistance.
Triaxial Compressive Behavior of Two Types of Concrete with Curing Conditions of Construction Site
Authors: Xiong Yi Bo , Peng Lu , Xu Jin , Ma Liang
Published: June 2011

Based on an extensive experimental program under uniaxial and triaxial compression, this paper studies the mechanical behavior of two types of concrete with the same raw materials and the same curing conditions of the construction site. Stress-strain relations and strengths are obtained under triaxial compression with confining pressures from 10MPa to 120MPa. Material constants of different types of failure criterion are determined by the statistical method with the data from this study and public literature, including linear Mohr-Coulomb model, parabolic Willam-Warnke failure criterion and power functional Johnson-Holmquist model. The results indicate that the modulus of both types of concrete decrease as an exponential decay law with the increase of confining pressures in triaxial compression.
Risk Analysis and Assessment for the Face Stability of Tunnel
Authors: Wang Hai Tao , Jia Jin Qing
Published: June 2011

The evaluation of the correct stability factor of tunnel is a critical element in the various design and construction phases of a tunnel excavated in difficult geotechnical conditions. An innovative, and well-applied, procedure for optimize the construction phase management is described in this article. The starting point of this procedure involves the verification of the results of numerical methods obtained from referenced analytical methods. In the first step of the procedure the results obtained through the analytical method are verified by means of a numerical method in order to evaluate the practical consequences in terms of development of deformations and plastic zone. In this manner, the assumed design risk is evaluated for the different methods and the solution that gives the best correspondence with numerical simulation is selected. Finally, residual uncertainties and parametric variations are incorporated in the analysis and Monte Carlo simulation is used to calculate the statistical distribution of the face-stabilizing pressure and the design value is selected on the basis of an acceptable probability of failure.
Relationship between Impact Energy and Flexural Toughness Energy of Steel Fiber Reinforced Lightweight Aggregate Concrete
Authors: Wang Hai Tao , Jia Jin Qing
Published: June 2011

In order to determine the impact resistance of lightweight aggregate concrete (LWC), especially the effect of steel fibers on impact resistance of LWC, a series of drop-weight tests, recommended by the ACI committee 544, have been carried out in the present study. Impact and flexural tests were carried out on lightweight aggregate concrete reinforced with five different percentages of steel fibers 0.0%, 0.5%, 1.0%, 1.5% and 2.0% by volume of concrete. For each volume of fibers, complete load–deflection curves of SFLWC were generated in order to determine the total energy absorbed for each specimen. The addition of steel fibers to concrete has improved impact resistance and also the flexural toughness. The test results showed that a logarithmic relation exists between flexural toughness energy by means of the generated load–deflection curves from the flexural tests and the impact energy by means of drop-weight tests.
Key Techniques of Self-Compacting Concrete
Authors: Liu Shu Hua
Published: June 2011

Self-compacting concrete (SCC) is a new style of concrete with high workability. The key techniques of SCC including workability, strength, dimension stability, thermal properties and durability were investigated in this paper. High workability can be achieved at low water-cement ratio by adding superplasticizer. After adding inert powder such as limestone powder, the low strength SCC can be produced. The dimension stability of SCC can be improved by using expansive agent. Mineral and inert admixture can reduce the hydrate heat of binder and avoid temperature crack of concrete. The durability of SCC can be improved by controlling water-cement ratio, adding chemical admixtures and fibre.
Bending Resistance of Short-Chopped Basalt Fiber Hydraulic Concrete and RC Element
Authors: Zhang Jun Zhi , Liu Hua Ting , Zhu Yan Dong , Fu Zhao Qi , Zhao Jing
Published: June 2011

According to a series experiment for bending resistance of hydraulic concrete and RC element of mixing short-chopped basalt fiber, the reinforcing effect of bending strength and flexural elastic modulus of short-chopped basalt fiber concrete are analyzed, and increased cracking-resistance loads of short-chopped basalt fiber RC beams is also researched. Experimental results show that bending resistances of short-chopped basalt fiber concrete are increased, short-chopped basalt fiber in concrete is useful to reinforce the bending strength of concrete and cracking loads of RC beams.
Research on Secondary Effluent and Reclaimed Water Reusing for Concrete Mixing
Authors: Shi Yong Sheng , Wang Lin , Shi Yu Zhen , Cheng Yong Wei
Published: June 2011

Secondary effluent and reclaimed water reusing as mixing water in concrete production is studied in this paper. The research mainly focuses on the influences of mixing water on the mixture ability of concrete, basic mechanical properties of concrete, concrete admixture (water reducing) and the aging resistance ability of concrete. The experiment shows that the abilities of concrete mixed with the reused secondary effluent and reclaimed water has no obvious difference from concrete mixed with drinking water, and actually it displays better function in terms of certain abilities than the latter.
Investigation of Hydration Heat of Slag in Portland Cement Environment
Authors: Wang Jia Chun
Published: June 2011

The hydration of slag in Portland cement is studied by considering the interaction between the hydrations of slag and Portland cement clinker. The slag hydration heat value that the different dosage of slag is in Portland cement is measured with isothermal calorimetry method as quartz sand sample contrast. The kinetic analysis was used to obtain parameters, which were employed to find out the influence of the slag content on the reaction rate constant value. The reaction stages have been analyzed and explained in accordance with kinetic models. The model predictions show that as the slag proportions in the blended cement changes, water retention in the hydration products changes only slightly if compared to that of Portland cement, The investigations have shown that the addition of silica fume of more than 30 mass% reduces the duration of the phase boundary interaction as a rate-determined process resulting in the fast diffusion rate-determining process. The results of this study have also revealed evidence of the accelerator effect of slag during the first 24 h of hydration when it still exists as chemically inert filler.
Durable Performance of Recycled Concrete Using Coarse and Fine Recycled Concrete Aggregates in Air Environment
Authors: Zhu Ping Hua , Wang Xin Jie , Feng Jin Cai
Published: June 2011

The influence of synchronous use of coarse and fine recycled concrete aggregates on durable performance of recycled aggregate concrete (RAC) in air environment were determined. In this study, three series of concrete mixtures were prepared, in which the coarse recycled aggregate was used as 0%, 30%, 60% and 90% replacements of coarse natural aggregate and fine recycled aggregate as 0%, 10%, 20%, and 30% replacements of fine natural aggregate. Meanwhile, fly ash and slag were used as 15%, 25%, 35% and 45% replacements of cement, respectively. The carbonation depths, compressive cube strength, workability of RACs were tested. The experimental results showed that RAC with synchronous use of coarse and fine recycled concrete aggregates had satisfactory durable performance. When RAC was used as structural concrete in air environment, the optimum synchronous replacements are 60% for coarse recycled aggregate and 20% for fine recycled aggregate.
The Water Requirement of the Cattle Manure Ash
Authors: Zhou Shu Guang , Zhang Xun An , Cao Pu Tian
Published: June 2011

This paper studies the water requirement of the two cattle manure ash in two different experiment conditions. According to the flying ash used in cement and concrete, the water requirement of the cattle manure ash is studied and the flying ash water requirement is compared when two different superplasticizers (the naphthalene-based water reducer and the polycarboxylate-based water reducer) is added into the mortar with cattle manure ash and flying ash. The result shows that the water demand ratio of the cattle manure 2 is more than that of the cattle manure 1, cement and fly ash with superplasticizer and no superplasticizer. The result provide calculation basis to the aiming mixture design of the cattle manure ash concrete.
Influence of Ox Blood on Water Absorption of and Chloride Penetration into Concrete
Authors: Xu Jian Guang , Zhao Tie Jun , Zhang Peng , Jiang Rong
Published: June 2011

Many concrete structures can not reach their designed service life because of their poor durability. Water and aggressive substances such as chloride ions are prerequisite to the deterioration of concrete. In aggressive environments, water repellent treatment is an effective path to delay the repair and improve the durability of concrete structures. Thousands of years ago, people used oils, animal fats or wax to treat the surface of natural stones, bricks or put some animal blood in mortar to make them water repellent. Many historical monuments were protected in these old methods. In this paper, different amounts of ox blood had been added in concrete. Compressive strength, water absorption and chloride penetration tests had been conducted. In this way, the influence of ox blood on water absorption of and chloride penetration into concrete had been investigated. The results indicated that the compressive strength of concrete with addition of ox blood decreased. And water absorption and chloride penetration into concrete were effectively reduced by adding some amounts of ox blood. The concrete with the surface abraded off 5mm, 15mm and 25mm which were mixed with ox blood had higher water absorption than concrete without abrasion.
Waste Clay as a Green Building Material
Authors: Russell Stanley R. , Buchter Jana
Published: June 2011

Two of the primary waste components of the Phosphates benefaction process, sand and clay have been used as building materials for thousands of years. A process known as rammed earth has been used extensively around the world in buildings that have lasted for centuries. Because earth is the main ingredient in rammed earth it has recently enjoyed new popularity as a so called “green” building material. In a similar process earth is compressed into blocks which are then used in the same way as conventional masonry units to build walls. In the compressed earth block [CEB] method, individual units can be manufactured and stockpiled for later use rather than being fabricated on site as in the rammed earth process. This research project will investigate the potential use of waste clay and tailing sand from the phosphate benefaction process as the primary ingredients in compressed earth blocks for commercial and residential construction projects.
Applications of Nanomaterials in Construction with an Approach to Energy Issue
Authors: Ahadi Parisa
Published: June 2011

Construction industry is one of the sectors that would highly benefit from Nanomaterials with new functionalities and enhanced performances. The use of Nanomaterials in this industry should be considered not only for enhancing material properties and functions but also in the context of energy saving. This paper, aims to keep special attention on low energy buildings which utilizes the key resources of energy or construction materials in a more efficient way than the conventional buildings. Using Nanomaterials in these cases include harvest solar or other forms of renewable energy and energy conservation. The paper presents also applications of more efficient and cheaper solar energy collectors with high flexibility, heat absorbing windows, energy coatings and Nanoinsulations. The flexible insulation allowed the panels to be thin enough to fit within the existing window casements without need to modify window and roof fixtures. The NanoHouse represents a successful method of explaining what Nanomaterials are and how they work.
Research on Melamine Formaldehyde Resin Modified by Vetier (Vetiveria zizanioides) Micro/Nano Fibrils
Authors: Wang Xin , Wu Yan , Yang Rui
Published: June 2011

The Vetiver (Vetiveria zizanioides) micro/nano fibrils (VFs) were prepared by high intensity ultrasonication (HIUS). The relative crystallinity, the distribution of diameters and morphologies of VFs were investigated by wide angle X ray (WAXD), laser diameter instrument, optical microscopy and scanning electron microscopy (SEM), respectively. The micro/nano fibrils were used to modify melamine formaldehyde resin (MF) and the property of abrasion resistance of MF before and after modification were evaluated. It showed that when filling with 15% of VFs, the abrasion got the minimum value, i.e. the abrasion resistant was best.
Numerical Simulation of Mechanical Behaviour of Cement Paste under Compressive Pressure
Authors: Qiu Xiu Mei , Bian Han Bing
Published: June 2011

This paper contributes to numerically study the mechanical behavior of cement paste under compressive pressure. First, the main results from an experimental study on the mechanical behavior of cement paste are studied. Then an elastoplastique model with two flow mechanisms is proposed to describe the mechanical behavior of cement paste subjected to confining pressure. A particular emphasis is put on the pore collapse mechanism which is developed at higher confining pressure. Finally, numerical simulations and experimental data are compared in order to verify the capacity of the proposed model to reduce numerically the basic characteristics of cement paste under different levels of confining pressure.
Study on Material Parameters Effects on Smoldering and Transition from Smoldering to Flaming Combustion
Authors: Lu Chang , Meng Die , Yu Ming Gao
Published: June 2011

The polyurethane foam is a most common fuel in smoldering fire. A small scale experimental compartment was built. The width, thickness and density of polyurethane foam material were changed several times in the experiments. Temperature histories measurement and analysis gaseous were used to explore the transition’s mechanism. The results show that with the width increased, the surface area and the air flow rate which access to the inside of material have also increased, and the quantity of oxygen is sufficient, heat release quantity by carbon oxidation is increased. When the width reaches a certain value, polyurethane foam material transformed easier from smoldering to flaming combustion. The polyurethane foam transforms to the flaming combustion not only depends on the length, width size but also relates to the thickness closely. When thickness reached a certain size, the temperature also reaches a whole jump. And the material transforms to the flaming combustion finally. The oxidation of larger density polyurethane foam material produces more heat, and then accumulates heat in the polyurethane foam center to reach the required temperature of gas phase reaction and ultimately transforms to flaming combustion from smoldering.
Study on Fracture Model of the Blunt Crack in Rock-Type Material under Compression
Authors: Li Qiang , Shang Yan Liang , Wang Yang , Fu Ying Chun
Published: June 2011

The stress field around the tip of the blunt crack in rock-type materials under compressive loading is analyzed, and the relation of the stress field is set up. Compared to the stress field of the ideal mathematic crack, the effect on the distribution of the stress field by the thickness or the curvature radius of the blunt crack is considered. Based on the stress field, the two-parameter fracture criterion for the blunt cracks under compressive loading is set up. The two parameters in the criterion are related to the material property, and can be determined by the experiments or theoretical analysis. By the fracture model in the paper, the fracture analysis of the blunt crack under compression are carried out, and the theoretical results are in concordance with the experimental results, which shows the fracture criteria in the paper is available to the fracture analysis of the blunt crack.
Wire Rope Tension Detection System Research and Experimental Analysis
Authors: Chen Chuan Lian , Zhang Qing , Guo Zhi Guang
Published: June 2011

This article puts forward the design of wire rope tension detection system, and emphatically expounds how to design experiment device to simulate the actual movements of jacks. In the experimental process, the adjustable rheostat is altered to change current value, to simulate the output of sensors. Through breakpoint debugging function, every export of program is verified. The comparison between actual output and program output proves the correctness of synchronization algorithms. Technological aspects like measurement system, electrical system and computer communication are verified as well.
Effect of Drought on Dry Shrinkage of Cementitious Materials
Authors: Lu Cai Rong , Ge Xue Liang , Mei Guo Xing , Liu Wei Bao , Wang Heng , Qian Yao Li
Published: June 2011

Shrinkage stress of cementitious materials will generate if the dry shrinkage is restrained in drought condition. Shrinkage stress has influence on crack resistance of cementitious materials. The dry shrinkage of cementitious materials in different relative humidity was studied with Climate Simulation System. The dry shrinkage change law of concrete in 20°C, 60% relative humidity for 500 days and in 20°C, 10% relative humidity for 180 days was compared. The relation between water loss rate and shrinkage rate of cementitious materials in drought condition was analyzed.
Design Method for Flat Geotextile Tubes filled with Inhomogeneous Slurry
Authors: Wang Cui , Yan Shu Wang , Liu Run
Published: June 2011

The circumference tensile force developed in the geotextile during filling the tube is the dominant factor to construct a safe dike. Based on the feature of flat tubes, a iterative procedure is programmed, with which the shape of the large size geotextile tube, as well as the relationship among the tube size, the pumping pressure, the unit weight of the slurry and the tensile stress developed in the geotextile during filing the tube can be determined. In the procedure, the inhomogeneousness induced by the soil grain sedimentation is also considered.
TSMT Technics to Prepare DSP Mortar
Authors: Gao Liang Li
Published: June 2011

This study proposes a new mixing process for producing commercially acceptable DSP mortar of high flowability, using commercial materials and water-bath curing at about 20°C. That is “three- speed mixing technics (TSMT)”. The properties of mortars mixed by TSMT and conventional technics (CT) are compared. At a water-to-binder ratio of 0.2, the compressive strength of the TSMT mixed DSP mortars was about 41.2% higher than that of the CT mixed DSP mortars of the same composition, the workability was also increased. The increase reason was investigated by the wedge-splitting section and Environmental SEM (ESEM) images. Additionally, for TSMT, the influence of mix-design parameters such as cement grade, the water/binder (w/b) ratio, the silicon fume/cement (sf/c) ration and the superplasticizer/cement (sp/c) ratio were studied.
Complex CBR (of BC Soil-RHA-Cement Mix) Estimation: Made Easy by ANN Approach [a Soft Computing Technique]
Authors: Ramakrishna A.N. , Pradeep Kumar A.V. , Gowda Keerthi
Published: June 2011

In past days many researchers have been worked on the expansive soil to determine the California Bearing Ratio (CBR) values in a conventional ways, which are time consuming and require lot of manual involvements. So we the authors of this research paper attempted to develop a soft computing technique to prognosticate CBR value by using Artificial Neural Network (ANN), a data driven technique. ANN is a mathematical model inspired from the human brain’s information-processing characteristics, including the parallel processing ability. Over the last few years, the use of ANN has increased in many areas of engineering. In particular have been applied to many geotechnical engineering problems and have demonstrated some degree of success. A review of the literature reveals that ANN has been used successfully in the pile capacity prediction, site characterization and so on. In the present study the Black Cotton (BC) soil has been stabilized by using Rice Husk Ash (RHA) and cement, several experiments have been conducted for different mix combinations under soaked condition. From the obtained results, it is observed that the CBR value of BC soil increases with the addition of RHA and cement combination. The soaked CBR value found to be maximum for the mix of BC soil + 15% RHA + 12% cement. The present study deals with collection of input data base from experimental results, ANN’s training and its testing are adopted to fix the appropriate weighted matrix (Illustrated in Fig (1)) which in turn Prognosticates the CBR value. Experimental results have been compared with the CBR values prognosticated by using ANN and comparison graphs also plotted (Illustrated in fig (4)). The results of this study will contribute for the prognostication of CBR, which will assist a geotechnical engineer in estimation of CBR, with minimum effort.
Microstructure and Mechanical Properties of Aged Mg-12Gd-2Y-0.5Zr Alloy Addition with Sb
Authors: Li Ke Jie , Li Quan An
Published: June 2011

The Mg-12Gd-2Y-0.5Sm-0.5Sb-0.5Zr (wt.%) alloy was prepared by casting technology. The microstructure was investigated after solution and aging treatment (i.e. T6 heat treatment). Tensile tests were performed at a crosshead speed of 1 mm/min at ambient and elevated temperature atmosphere. The results show that the aged alloy was mainly composed of α-Mg matrix, Mg5Gd phase and dispersed long-period ordered β' precipitates. At 523K, the alloy has shown the superior tensile strength (i.e. 345.5 MPa). The strength mechanism was solution strengthening of RE and precipitation strengthening of dispersive LPO structure β' and stable Mg5Gd precipitatesin Mg matrix.
Influence of Biaxial Magnetic Field on Martensite Reorientation in Magnetic Shape Memory Alloy
Authors: Zhu Yu Ping
Published: June 2011

Based on thermodynamics, a constitutive model for magnetic shape memory alloy (MSMA) is developed under biaxial magnetic field. Considering the driving force provided by Gibbs free energy and resistive force during martensite reorientation, a kinetic equation is got. Of special concern is the influence of biaxial magnetic field on martensite reorientation for a Ni2MnGa single-crystal specimen. The theoretical results are in agreement with experimental data. Some useful conclusions can be obtained.
The Criterion of Variable COD and CTOA for Numerical Simulation with Aluminum Alloy 2524
Authors: Shi Li Jun , Jiang Li Zhong , Yang Bang Cheng
Published: June 2011

The performance research of Friction Stir Weld’s Joints of Aluminum Alloy under different welding parameters is very necessary and valuable in the engineering. Two points is proposed in this paper. One is the new fracture criterion using the function curve of the value of critical crack opening displacement (|CODc|) as a fracture parameter, the other is using critical crack opening angle (CTOA) as a fracture parameter.