bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Research on the Influence of Humidity on the Moisture Diffusion in Cement-Based Materials
Authors: Su Qing , Zhao Tie Jun , Xiao Fan , Cui Tao
Published: December 2010

The migration of ion dissolved in water is known to be main factor inducing the deterioration of porous cement-based materials in aggressive environment. Long-term tests have been carried to study the moisture diffusion in mortar with water cement ratio of 0.5 and 0.6 in different humidity, and then the inverse analysis has been done to determine the moisture diffusion coefficient D. The results indicate that the bigger water cement ratio, the faster moisture migrating in same humidity, and the moisture migration process is longer for the mortar under lower humidity. Furthermore, the results of controlled experiments carried on mortar specimens with sea sand show that the moisture migration is longer for sea sand mortar than that of river sand, and the moisture loss is bigger.
Flexural Capacity of Singly Reinforced CRC Beams(Part-I)
Authors: Zhu Han , Yang Lin Hu , Yuan Lin
Published: December 2010

Crumb rubber concrete (CRC) is made by adding rubber crumbs into conventional concrete, and many studies show that ultimate compressive strains for CRC are much bigger than those for conventional concrete. This article undertakes a mechanical analysis of a reinforced beam based on a proposed CRC stress-strain relationship. The results show that, assuming identical geometrical and material conditions, CRC beam can support more external moment than what conventional concrete beams can do.
An Experimental Study on Improved Mechanical Behavior of Textile-Reinforced Concrete
Authors: Yin Shi Ping , Xu Shi Lang
Published: December 2010

The influences of the mesh sizes, the surface treatment and cover thickness of the textile on anti-crack and bearing capacity of the competent were investigated. Additionally, to prevent the splitting of the concrete, hanging U-shaped hook upon textiles was also experimentally studied. The experiment results indicate that sticking sand on epoxy resin-impregnated textile and reduced cover thickness are helpful to improve the mechanical performance of the component; the textile with 10mm×10mm mesh size is superior than that with 20mm×20mm mesh size regardless of in the respect of enhancing the bearing capacity of the TRC or in the respect of controlling matrix cracking; the novel method of adding U-shape iron hook not only can improve the bonding performance between the textile and the concrete, but also can enhance the shearing capacity of the concrete.
Effect of Fly Ash Content on Mechanical Properties of Cement-Fly Ash Stabilized Crushed Stones
Authors: Chen Xiao , Zhou Ming Kai , Liu Jia
Published: December 2010

This paper investigates the effect of fly ash content on unconfined compressive strength, cleavage strength and resilient modulus of cement-fly ash stabilized crushed stones. The relationships between mechanical parameters were also studied. The results show that with fly ash content increasing, the unconfined compressive strength and cleavage strength were increasing firstly but decreased then, and the resilient modulus were decreasing. The brittleness index was increased by the increment of fly ash content. It can be concluded that the optimal fly ash content in cement-fly ash stabilized crushed stones is between 10% and 15%, and increment of fly ash content can improve its crack-resistance.
Experimental Study of Stress-Strain Characteristics of the Fly Ash Blended with Curing Agent
Authors: Shen Zheng , Zong Lan , Dong Xiang
Published: December 2010

The stress-strain characteristics of the fly ash blended with curing agent was studied using uniaxial and triaxial compression tests. Curing agent JNS-2 was used as the stabilizing agents in sample preparation. Four curing agent JNS-2 contents of 3%, 6%, 9% and 12% were selected for sample preparation. UU triaxial compression tests were conducted in a range of confining pressures from 100 kPa to 300 kPa. The experimental results obtained from the laboratory tests showed that curing age, mixture ratio, compaction degree and confining pressures had significant influence on the shape of curves. Uniaxial stress-strain test results demonstrated that the latter strength and deformation characteristics of the fly ash blended with curing agent grew little and with the increase of curing agent amount and compaction factor, the curve of uniaxial stress-strain changed significantly. On the other hand, triaxial stress-strain test results indicted that the failure strain showed a partial negative growth trend with the increase of curing agent amount, and the failure stress showed a partial positive growth trend with the increase of curing agent amount. When the curve was at high confining pressure, it showed hardening type, when at low confining pressure it showed softening type.
Simulation and Analysis of the Thermal Stress in Concrete under Temperature Fluctuation Condition
Authors: Zhao Ya Ding , Li Xue Ying , Liu Hong Yang
Published: December 2010

The temperature field distribution and thermal stress distribution in concrete has been studied by finite elements method to establish the relationship between the thermal stress and the temperature in this paper. The results show that the maximum thermal gradient and the maximum thermal stress in the concrete appears on the direction of greater structural dimension, and the thermal stress value is positively correlated with thermal gradient or saying temperature difference and elastic modulus, and is negatively correlated with the water content and air content.
Experimental Behavior of Reinforced Shotcrete with Low Fiber Content
Authors: Wang Xing Guo , Cheng Zhao Xia , Hao Yongchao , Wang Yi Xin
Published: December 2010

Mixing three different fiber composites into concrete specimens respectively, compressive strength, splitting tensile strength and flexural strength for fiber-reinforced concrete was done. The results show that the strengths of fiber reinforced concrete are improved to some extent. Due to the addition of fiber, the fiber concrete bears some of the force in tension, thus the time from the initial crack to damage is more prolonged comparing with normal concrete. Fiber concrete specimens did not get the collapse and lower intensity suddenly. Compared with normal concrete, the maximum increase of the reinforced concrete with steel fiber SQB -32 (Ⅱ) is listed, which compressive, tensile and flexural strength are increased by 30%, 40% and 24%, respectively.
Static Behavior of Layered Fiber Reinforced Concrete T-Shaped Beam
Authors: Gu Yin , Zhuo Wei Dong , Qiu Yu Ting
Published: December 2010

This paper proposes a concept of layered fiber reinforced concrete (LFRC) beam. In the concept of a LFRC beam, low-modulus fiber and high-modulus fiber are randomly dispersed and uniformly distributed into the concrete matries of the compression and tension zones, respectively. The static behaviors of LFRC beam are investigated from both experimental and numerical aspects. Four-point bending tests are performed on two simply supported T-shaped LFRC beam specimens and an ordinary T-shaped RC beam specimen with large scales. Comparison between the testing results of LFRC and RC beam specimens shows that the initial cracking load, flexural toughness and post-yielding stiffness of a LFRC beam can be significantly improved, but the ultimate loads are nearly without change. Numerical simulations are also carried out to investigate the static behaviors of the LFRC beam specimens. It is found that the simulation results are agreed well with that of tests. Further numerical parameter analysis for the LFRC beam specimens is conducted. The effects of high-modulus fiber volume fraction on the static behaviors of LFRC beams are studied. The research results show that the additions of high-modulus fibers have little effect on the initial stiffness, yielding loads and ultimate loads of LFRC beams; both the load and displacement at the initial cracking point increase linearly with the increasing volume fraction of the high-modulus fiber, but both the yielding displacement and ultimate displacement decrease linearly with the increasing volume fraction of the high-modulus fiber.
Preparation and Characterization of Nanoscale Silicate Composite Architectural Heat-Insulating Coatings
Authors: Tao Xin Xiu , Qiao Jun , Yin Wan Yun , Jin Ren Cai , Pei Li Zhai , Chen Jun , Zhang Qian Feng
Published: December 2010

The architectural heat-insulating coatings were prepared by means of high speed mechanical agitation when the polymer emulsions were used as binder of the coatings and the mixed nanoscale silicate composites and nano-oxides were used in the presences of some assistants. Two types of nanoscale silicate composites architectural heat-insulating coatings were designedly produced out. The wide-angle X-ray powder diffraction patterns and the SEM images of the products show that the coating films are dense. The thermal conductivities of the heat-insulating coatings are in the ranges of 0.094487~0.148973 W/m•°C which are obviously smaller than the standard rubber sheet, for example, the thermal conductivity of the calcium silicate nanowires composite coating is nearly 0.094487 W/m•°C only. The nanoscale silicate composite architectural heat-insulating coatings are in good agreement with the parameters in the GBT 17371-2008 (Silicate composite insulation coating).
Contrast Investigation on Aseismatic Behavior of Masonry Wall Strengthened with Carbon Fiber Sheet and Steel-Meshed Cement Mortar
Authors: Liu Xi Yuan , Wang Jia Cong , Wang Yan Wu , Li Gang
Published: December 2010

Based on the experiment of four brick masonry walls under low-cyclic lateral loading, the effectiveness of the method of using the continuous carbon fiber sheet(CFS) and steel-meshed cement mortar to strengthen the brick masonry walls for improving their aseismatic performance is studied. The failure mechanism and aseismatic behavior of the walls are analyzed. Finally, the destructive mode, load bearing capacity, deformation, hysteresis characteristics and ductility are also analyzed qualitatively for the individual wall.
Development of U-Anchor CFRP Rod Manufacturing Machine
Authors: Tabuchi Daisuke , Sajima Takao , Onikura Hiromichi , Ohnishi Osamu , Kurokawa Syuhei , Doi Toshiro , Ohta Toshiaki
Published: December 2010

FRP (Fiber Reinforced Plastics) has been suggested as alternatives to steel reinforcement of buildings in corrosive area. In this paper, a new CFRP rod having U-anchor for connection and manufacturing machine of it are reported. With the developed machine, carbon fiber bands were assembled under constant tension carefully, and U-anchor CFRP rods were manufactured experimentally. Tensile test of the CFRP rods was performed, and U-anchor part was found to have enough strength to connect CFRP rods.
Experimental Study and Numerical Simulation of Bond Behaviors Between FRP Bar and Concrete
Authors: Xu Xin Sheng
Published: December 2010

Surface-adhering-sand screw-thread-form FRP bar was produced. By symmetrical pull-out test research to a certain depth in FRP (Fiber Reinforced Polymer) bar concrete, the bond mechanism, the failure mechanism, the bond strength and the slip of FRP bar to concrete were studied systematically. Studies show that the failure mode is not the damage of the ribs or the shearing off of the ribs, but is shear failure between the screw thread and the core of the FRP bar, and the sands on the surface of the bar were grinded into powder. The descending branch of load-slip curve for the FRP bars is gentler than that for the steel bars. The bond strength of FRP bars is a little lower than that of steel bars, but higher than smooth FRP bar greatly. At last the FRP bar concrete specimen were modeled in ANSYS program and the simulation result is satisfactory, which proves the feasibility to model the behavior of bond-slip relationship between FRP bar and concrete accurately.
Research on Bearing Capacity of Short Concrete Filled Double Skin Steel Tubes Columns under Axial Compression
Authors: Chen Jing Yu , Hai Ying
Published: December 2010

The use of steel tube confined concrete columns has been the interests of many structural engineers. For investigation of the axially loading capacity of short concrete filled double skin tubes (CFDST) columns, axial compression loading experiments were carried on 9 short CFDST column samples. According to experimental results and with numerical analysis, an ultimate load estimation equation of CFDST column with one correction parameter is presented, the linear relation between the parameter and the inner-to-outer diameters ratio Di/Do is given out. The ultimate load estimation equation is validated by the test results of short CFDST column samples.
Deflection and Crack-Width Prediction of Partially Boned CFRP Concrete Beams
Authors: Deng Yu , Liang Jiong Feng
Published: December 2010

Concrete beams reinforced with fiber reinforced polymer(FRP)bars exhibit large deflections and crack widths as compared to concrete beams reinforced with steel due to the low modulus of elasticity of FRP. Consequently,in many cases,serviceability requirements may govern the design of such members. This paper describes six partial bonded concrete beams prestressed with CFRP tendons are tested under monotonic loads. deformation and crack width of this kind of beams with varying unbonded length are systematically investigated. The predictions of the 《Code for Design of Concrete Structures》（GB50010－2002）equations are compared with the experimental results obtained by testing six partial bonded concrete beams prestressed with CFRP tendons. Good agreement was shown between the theoretical and the experimental results.
Effect of Semi-Rigid Connection and Pole in Different Flat on the Overall Steady-State Load-Bearing Capacity of the Steel Tubular Scaffold with Couplers
Authors: Zhang Hou Xian , Jin Jian
Published: December 2010

Nonlinear analysis of the steady-state load-bearing capacity of steel tubular and the steady-state load-bearing capacity of scaffold was simulated by ANSYS considering semi-rigid connection and pole in different flat. Quantitative standard of the steady-state load-bearing capacity to the steel tubular and the steel tubular scaffold with couplers is used in ANSYS. The effect of semi-rigid connection on the overall steady-state load-bearing capacity of the steel tubular scaffold with couplers is great. The effect of pole in different flat on the overall steady-state load-bearing capacity of the steel tubular scaffold with couplers is smaller. It’s generally recognized that nodes of vertical bars and horizontal bars of steel tubular scaffold by fasteners is not rigid, but semi-rigid; is not in the same plane, but in a different surface. This structural model directly affects the steady-state load-bearing capacity of scaffold. In this paper, ANSYS software was used for nonlinear analysis of steel tubular scaffold, the same models with experimental value [4] was used to establish standards for determining the instability load [1] [2], to determine the effect of bar coplanar and semi-rigid connections on steel tubular scaffolding overall stability capacity.
Fracture Energy of Steel Fiber Reinforced High Strength Concrete
Authors: Zhang Ting Yi , Wang Zi Li , Gao Dan Ying
Published: December 2010

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC) and plain high strength concrete (HSC) with the size of 100 mm×100 mm×515 mm, the effects of influencing factors including the fiber volume fraction (ρf) and relative notch depth (a/W) upon the fracture energy and the work of applied force (gravity and external force) were studied. The results show that the effect of ρf upon the fracture energy is more obvious; the variation tendencies for the increment ratio of the fracture energy and that of the work of applied force are different under different factors; the fracture energy is dependent on the work of external force. Based on the test results, the formula was established for calculating the fracture energy.
Behavior of through Beam Connections Composed of CFSST Columns and Steel Beams by Finite Element Studying
Authors: Arabnejad Khanouki Mohammad Mehdi , Ramli Sulong Nor Hafizah , Shariati Mahdi
Published: December 2010

Recent studies show that a through beam connections composed of concrete filled square steel tubular column and steel beam have been identified as an ideal rigid connection. In this paper a 3-D nonlinear finite element models were conducted for CFSST column and steel beam connection under monotonic load using ABAQUS software. Each model includes a CFSST column and single steel beam passing through the column. The main scopes are to identify the modes of beam failure and joint shear failure. In addition the effect of an extra shear plate welded to beam web inside the column was investigated. This result can be used for designing of through beam connection.
Novel Surface Treat Technology for Improving Wear-Resistant Properties of Cylinder Liner
Authors: Cai Zhi Hai , Zhang Ping , Zeng Qingqiang
Published: December 2010

In order to solve the problem of wear-out–failure of diesel engine cylinder, the laser-quenching and low temperature ion sulfurizing complex surface treatment technology was operated on the surface of 42MnCr52 steel. And the tribological properties of the complex layer were investigated。Experimental results indicated that the complex layer is composed of soft surface sulphide layer and sub-surface laser-quenching harden layer, represents excellent friction-reduction and wear-resistance performance at high temperature. The synergistic effect of the laser quenching-sulphide layer resulted in 20% increase in hardness, 10% reduction in friction coefficient and 50% reduction in wear weight loss, respectively, compared with those of the standard samples. The bench-test further demonstrated that this technology can improve the lubricating condition between cylinder and piston ring, and reduce both abnormity wear when the lubricating oil is deficiency at the time of start-up and sticking wear at high temperature during the operating period, and then prolong the service life of engine.
Test Study for Earth Embankment Engineering in Kunming New Airport
Authors: Tan Feng Yi , Jiang Zhi Quan , Ren Jia Li , Hu Sheng Gang , Gong Quan
Published: December 2010

The confirmatory test region plays an important role in the Kunming new airport to confirm the compactness and engineering properties of backfilling materials such as red clay, Douposi heavily weathered material and Douposi weak-middlely weathered material by vibration and dynamic consolidation method(DCM). Test results show that (1)the density of red clay is no less than 93.0% after compaction, which is satisfied with the requirement of design.(2)the density of Douposi heavily weathered material is no less than 93.0% after compaction, which is satisfied with the requirement of design.(3) the heavy dynamic penetration test of Douposi heavily weathered material shows that the blow count of embankment with depth between 3.0m ~7.0m is higher than that one of embankment with depth between 0.0m ~3.0m. According to the compactness test, the density of Douposi heavily weathered material embankment is no less than 93.0% when the blow count of heavy dynamic penetration is above 5.8.(4) on the condition of the DCM construction of main tamp with 1 time and inter-grid of different construction layers along depth, the density of lower layer of embankment is increased obviously, and the density of upper layer of embankment is also increased when the DCM construction is continued. It is suggested that after the DCM construction of main tamp with 1 time is completed, the DCM in the lower energy level and full tamp with 1 time or the bumping vibration compaction is adopted, the density of Douposi heavily weathered material embankment will be increased.(5)there is the same result and the suggestion for Douposi weak-middlely weathered material embankment. The test result can be provided as the reference for the consolidation of karst funnel in Kunming new airport and similar engineering.
Model Development and Application for Saline Water Irrigation in Arid Area in Inner Mongolia
Authors: Yang Shu Qing , Jia Jin Feng , Ye Zhi Gang
Published: December 2010

Taken Hongwei test field in the He Tao irrigation area of Inner Mongolia for research example, soil water and salt movement model system in regional unsaturated zone is established and tested, through the method of regional zoning. Detection results indicate that the calculated results from the model system agree well with the measured data. It is concluded that simulating and forecasting soil water and salt movement in regional unsaturated zone with this model system is feasible and authentic.
Application of the Complex Variable Differential Method in the Back Analysis of Geotechnical Engineering
Authors: Liu Ming Wei , Zheng Ying Ren
Published: December 2010

On the stability analysis of complex slope, the determination of rock-soil masses shear strength parameters is very important. It’s very necessary to use the back analysis method to verify experiment result of rock-soil masses parameters for the important slope engineering. Because the sensitivity of shear strength parameters to displacement parameters is very poor, so that we couldn’t get the satisfactory shear strength parameters result by traditional back analysis method. Aiming at the problems of traditional back analysis method, this paper puts forward a totally new method of back analysis, which is applicable to the shear strength parameters of rock-soil masses through the integration of complex variable differentiation method, optimization method and elastic-plasticity finite-element method. The method mathematically back calculates shear strength parameters of rock-soil masses on the basis of displacement of measuring point. The sample calculation result indicates that the method possesses high accuracy and searching efficiency, and is a method of back analysis of displacement deserving popularizing.
Test Study and Design on the Bearing Capacity of Long Column of Steel Reinforced High-Strength Concrete
Authors: Han Zhuo , Sun Zhi Ping , Yu Bo
Published: December 2010

On the basis of the experiment，the following problems are discussed，including coordinate work of the steel skeleton and concrete，the failure state of the long column，mechanical properties of the steel skeleton，the loaded behavior of concrete in compressive zone，distribution law of the load and the deflection，etc. the calculation formula of the bearing capacity based on the reference[3] is discussed finally，investigation showed the calculation is safe and reliable. At the same time, proposed a method about how to fabricate the test specimen.
Research on Low Voltage Power Line Narrow-Band Communication Simulation Platform
Authors: Tian Hai Ting , Yuan Rui Ming , Huang Zhi Gang , Wang Si Tong , Li Shun Xin , Zhong Kan , Lu Guan Na , Yang Xiao Bo
Published: December 2010

Power line communication is popular at indoor communication and smart home applications, which face a harsh using condition that is of bad impedance match, large signal attenuation, unexpectable noise and channel high time variation. These difficulties set a high threshold for power line communication technology and improve the communication channel simulation to an important place. To predetermine the performance of power line communication productions, a narrow-band communication simulation platform was developed. This platform is based on low voltage communication channel model, and can update the system parameters using on site measured data, which could get a match with the real application environment. Main channel characteristics, such as noise, signal attenuation and frequency respond could be simulated on this platform. Noise generation frequency range of this platform is 0~120MHz, attenuation frequency range is 0~4GHz and attenuation range is 0~120dB. All performance indexes can well cover the measurement boundary of power line communication.
Experimental Study on Microcosmic and Microscopic Properties of C100 High-Strength Concrete
Authors: Yue Zhong Wen , Zhang Hui , Dou Bo Yang , Han Peng Fei
Published: December 2010

In order to study high strength and other characteristics of high strength concrete, scanning electron microscopy and mercury pressure method were used to analysis the surface morphology, organization, structure, composition and fractal features of C100 high strength concrete materials in terms of the microscopic mechanism, and the material strengthen mechanism and the causes of failure were revealed. The results shows that, as the adequate hydration and particle hydrates increase in C100 concrete, more gel-like mesh or wrinkles are generated, and there is a strong bonding effect between fine particles. As the use of mixing composites material in C100 high strength concrete, the density of the material is improved and the proportion of harmful hole is lowed, and its mechanical properties and durability are all improved. When concrete is damaged, cracks increase and coalescence show an increase of fractal value.
Study of Ultimately Loading of Pile Foundation by Strength Reduction Method of No-Linear Limit Analysis of FEM
Authors: Dong Tian Wen , Zheng Ying Ren , Huang Lian Zhuang , Chen Gang
Published: December 2010

For judging the security of pile foundation, the loading static test is popularly used in engineering. Some conditions could confine this method to estimate the ultimately loading according with objectivity, for example the high loading bearing pile foundation, the especial condition of static test, over length pile, etc.. So the strength reduction method (SRM) is put research this question in the basis of the ultimate loading capacity theory of pile foundation and the limit analysis of FEM. The judging condition and the safety storage factor (SSF) of SRM were built. The judging condition have three item, (1) the inflexion lies on F-s curve, and the bottom of F-s curve is parallel to the s axis; (2) the point of V type appear on F-Qu curve, so the previous reduction factor of this inflexion of F-s curve and the point of V type of F-Qu curve is SSF on the loading condition of pile head; (3) the equivalent plastic strain connected in soils around pile shaft and pile end. This method was used to analyze and estimate the ultimately loading of the large diameter pile, and its error of SRM to the static loading test and the increment loading method of FEM (ILM) are less 5%. So it shown that SRM may be used to attempt in engineering for judging the security of pile foundation and computing the ultimately loading.
Adsorption of Methylene Blue onto Secondary Expanded Graphite
Authors: Chang Yan Hong , Wang Bin , Luo Hui , Zhi Lin Jie
Published: December 2010

A secondary oxidation and expansion of graphite process resulted in a specific surface area enhanced material, which could be used in methylene blue (MB) adsorption in industry, due to the low running cost and mass production. The morphology of the samples was investigated using scanning electron microscopy, and the structures vary from the expansion level. It was found that with a pH value about 9, the sample exhibited better adsorption property toward MB after re-expansion. The adsorption capability of MB adsorbed on unit mass of the secondary expanded graphite turned out to be 120mg/g. The considerable adsorption capability could be further enhanced through a multiple expansion process.
Analyzing the Influence of Pile - Soil - Structure Interaction on Seismic Response of Cable-Stayed Bridge Tower
Authors: Tian Shi Zhu , Zhang Chang Ming , Luo Wei Bing
Published: December 2010

This paper instancing of Harbin Sifangtai Cable-Stayed Bridge, simulates two kinds of non-linear bridge tower model considering the pile - soil - structure interaction and not considering using ABAQUS6.8 software. By comparing the frequency, modal, displacement of the tower top, acceleration of the bridge tower and stress of the tower bottom under two circumstances, analyzing and obtaining the conclusion that the seismic response results will be very different to a long-span Cable-Stayed Bridge, whether considering the pile - soil - structure interaction or not.
Cement Hydration Kinetics Research Based on the Multi-Phase Hydration Model
Authors: Lei Bin , Wu Lang , Song Gu Quan
Published: December 2010

Based on the multi-phase hydration dynamic model, taking into account the factors such as chemical composition of cement, curing temperature, water-cement ratio, the final hydration degree and fineness of cement, a theoretical hydration kinetics equation is established in this paper. It can be used to predict the hydration rate increases with the change of hydration degree. The results showed that: water-cement ratio will accelerate the phase boundary reaction, while not influence the early crystallization of nucleation and crystal growth; temperature can accelerate the hydration process, while it can not change the ultimate hydration degree.
Experimental Research on Wet-Chemical Property of Highly Weathered Rock
Authors: Hou Chao Qun , Wang Xiao Mou , Yang Ling Yun
Published: December 2010

Based on analyses on mineral composition, mechanical property and hydrology property, three kind of samples are made in both drying state and saturated state respectively. Large-scale triaxial shear test, compression test and vibration test are applied on these samples. Through comparative analysis of test data, wet-chemical property of the samples is studied. Studies show that three samples have wet-chemical property in saturated state, which appears as decreasing of strengthen and increasing of deformation. Mechanism of wet-chemical property is also studied in two ways. On the one hand, filling particles is lubricated by water and re-construction of structure takes place between particles. On the other hand, soften and wet-chemical properties of mineral component are the internal factor causing the deformation. At last, some suggestions are given on construction of roadbed filled with this highly weathered rock.
Glass Phase Structure of Blast Furnace Slag
Authors: Li Chao , Sun Heng Hu , Li Long Tu
Published: December 2010

This paper studies the blast furnace slag glass phase structure by a series of analysis methods. In glass phase, both Si and Al ions are confirmed to occupy only tetrahedral sites, while the [SiO4]4- and [AlO4]5- are separated by Ca and Mg. Furthermore, the glass structure corresponds to micro-crystal model, which means it contains some nano-scaled micro-crystals in the glass phase. In addition, the slag glass may separate into two phases: a calcium rich phase and a silica rich phase. According to devitrification experiment, it has been inferred that the chemical composition and structure of silica rich phase are close to that of akermanite,which means most of Si is distribute around Mg.
The Spring Rigidity Values Analysis in Incremental Method of Deep Excavation with Considering Interaction among Soil Springs
Authors: Chen Cun En , He Chun Bao
Published: December 2010

Based on the theory of interaction between deep excavation support structure and subsoil, the influencing coefficient is presented in this paper in the condition of different foundation model. The calculation result shows that the foundation deformation considering interaction among soil springs is large than those not considering the interaction, and also larger than engineering practical condition. Theoretical analysis indicates the stiffness change of soil spring is related to spring rigidity in both active region and passive region when it is calculated by incremental method. The example proves that the method presented in this paper has good preciseness comparing with the results of engineering practical condition. So the theory of incremental method of deep excavation considering interaction is consummated.
Experimental Research on Dynamic Response for RC Column Subjected to Impact Loading
Authors: Su He , Zhang Yu Min , Su You Po
Published: December 2010

In order to analyze the influences of axial compression ratio and loading speed to the dynamic response and failure mode of RC columns subjected to blast loading, the collapse test for 6 reinforced concrete column models were conducted. Results show that there are three kinds of failure types: shear failure, flexural failure, flexural-shear failure. It tends to failure in shear mode when compression ratio is 0, and tends to failure in flexural or in flexural-shear mode when compression ratio is 0.5 and 0.25 respectively. The peak value of the exerted load and end moment will increase with the increasing of axial compression ratio in the first stage (approximately when compression ratio is less than 0.25) and then will decrease. The peak value of extra axial forces will decrease with the increasing of axial compression ratio.
Influence of Different Ways of Foundation Treatment on the Differential Settlement of Road- Tunnel Composite Structure
Authors: Liu Zhen , Zhou Cui Ying , Huang Wei
Published: December 2010

In order to insure the safe and reliable road-tunnel composite structure, it is important to consider the influence of different foundation treatment ways on the differential settlement of the composite structure. Based on the nonlinear FEM, connecting with the western corridor connecting project from Shenzhen to Hong Kong in China, a numerical model has been established to estimate the settlement of the road- tunnel composite structure under three different foundation treatment ways, such as pressure grouting, PHC piles (prestressed high-strength concrete piles) and foundation in natural state. This study shows that the influence of the different foundation treatment ways on the transverse and longitudinal differential settlement of the composite structure of road-tunnel is strong. The results from this study provide a useful guideline for settlement control of other similar projects composed of tunnel and road structure.
Study on Bi-Stable Behaviors of Isotropic Shell Structures and Numerical Simulation
Authors: Wu Yao Peng
Published: December 2010

Bi-stable structure can be stable in both its extended and coiled forms. For the elastic isotropic shell, a theoretical model in terms of only two parameters is proposed. Based on the principle of minimum potential energy, the conditions for bi-stability of isotropic shell are derived. The results indicate that, a pre-stressed shell will have its two stable states if the acting pre-stress satisfies some confined conditions. Further, the bi-stable model is improved taking into account boundary effect of the shell. The results show the rolled-up radius for the second stable state becomes larger. Meanwhile, using shell element in ABAQUS code, numerical simulation on bi-stable process is carried out. The numerical results of rolled-up radius characterizing the bi-stability agree well with the predicted results.
Research on Compressive Stress - Strain Relationship of Fiber Reinforced Concrete
Authors: Wang Tie Cheng , Zhao Hai Long , Hao Jin Jin , Zu Jian Quan
Published: December 2010

The marked brittleness of concrete could be overcome by the addition of fibers. This paper experimentally investigated the mechanical properties and constitutive relationship of different fiber reinforced concrete. It is shown from the results that the compressive strength and peak strain of concrete with fiber have little improvement, but the ultimate strain, deformation capacity, toughness and energy dissipation capacity are improved greatly. The damage constitutive model recommended by the emendatory code for design of concrete structure (appendix C) (GB50010-2002) is applied for calculations and analyses according to the test results. The damage constitutive model and non-elastic constitutive model of different fiber reinforced concrete are established based on the test results. It is indicated from the analyses that the constitutive models established in this paper are in accordance with the characteristic of the fiber reinforced concrete in loading process. The damage constitutive model in appendix C in code could be applied directly in some low precision calculation and engineering application.
Analysis and Comparison on Mechanical Properties between Full-Graded and Wet-Screened Concretes
Authors: Zhou Shi Hua , Yang Hua Quan , Dong Yun
Published: December 2010

Based on typical hydraulic engineering, difference of performances between full-graded and wet-screened concrete was studied. Results showed that owing to the gradation effect and skeleton effect of coarse aggregate and the size effect of specimen, full-graded concrete was 105%, 75%, 65% and 115% in compressive strength, splitting tensile strength, ultimate tension and compressive elastic modulus respectively, compared with wet-screened concrete. Under the same curing condition, compressive strength of wet-screened standard concrete specimen can represent the actual compressive strength of full-graded concrete.
Comparison of FT-IR, Thermal Analysis and XRD for Determination of Products of Cement Hydration
Authors: Ou Zhi Hua , Ma Bao Guo , Jian Shou Wei
Published: December 2010

Fourier Transform Infrared Spectroscopy (FT-IR), thermal analysis and X-Ray Diffraction (XRD) are commonly performed to study the hydration products in cement pastes. The three methods were compared in this frame to detect products of cement hydration at different ages, especially at early ages (before 24h ages). The results indicate from the present experiment that CH (Calcium hydroxide) can be detected by three methods at all ages; C-S-H can be distinguished by FT-IR at all ages; ettringite may be detected by FT-IR before 24h ages and by XRD at all ages; and monosulphate can be detected by FT-IR before 24h ages. The process of cement hydration, characterized by formation and development of some hydration products, can be clearly observed by three methods. FT-IR is suggested for detecting the major hydration products before 24h ages, FT-IR and XRD are suggested for detecting the major hydration products after 24h ages, and thermal analysis is suggested for analyzing the degree of hydration quantitatively.
Micromechanical-Rheology Model for Predicting the Complex Shear Modulus of Asphalt Mastic
Authors: Zhang Jiu Peng , Pei Jian Zhong , Wang Bing Gang
Published: December 2010

The dynamic shear rheometer (DSR) was used to measure viscoelastic properties of asphalt mastic. Mechanical volume filling effects and additional interacting mechanisms within mastic systems are discussed on the basis of micromechanical-rheology model to predict the complex shear modulus of asphalt mastic from the measured mastic data. The Einstein coefficient is 3.761, and the maximum volumetric packing fraction is 0.562 for the measured asphalt mastic. The predicted G* of asphalt mastics is very close to the actual value, and the relative error is not exceeding 10%. The micromechanical-rheology model can predict the complex shear modulus of the asphalt mastic from the viscoelastic property of neat asphalt, the volumetric filler effect and an interactive effect between the filler and the asphalt.
The Seismic Investigations on Active Stone Structure Buildings (Concept and Principles)
Authors: Shi Yang Hang , Yu De Hai
Published: December 2010

Based on the study results of stone-performance and on-site observation for years,this paper introduces the main points in earthquake-proof reviewing for multi-storey stone structure housing,which are served for decision-making on the engineering practice and management. It is in the background of large-scale stone production areas,in order to push the very little Chinese stone building culture to all around of the world,in the premise of scientific planning, rational design,elaborated construction and proper use. The main contents include the seismic investigations on multi-storey and the first framed storey in active stone buildings, by means of general investigation on spot. After the study, the keys and ways in seismic fortification were advanced first. Also the study will be beneficial to design, construction, rebuild, reinforce, administer, decision and protect on the worthy buildings in active and build-waiting stone structure.
Deterioration of Mechanical Properties of High-Strength Pumpcrete after Exposure to High Temperatures
Authors: Yuan Guang Lin , Zhang Jing Wei , Chen Jian Wen , Zhu Dan Yu
Published: December 2010

This paper makes an experimental study of mechanical properties of high-strength pumpcrete under fire, and the effects of heating rate, heating temperature and cooling mode on the residual compressive strength(RCS) of high-strength pumpcrete are investigated. The results show that under air cooling, the strength deterioration speed of high-strength concrete after high temperature increases with the increase of concrete strength grade. Also, the higher heating temperature is, the lower residual compressive strength value is. At the same heating rate (10°C/min), the residual compressive strength of C45 concrete after water cooling is a little higher than that after air cooling; but the test results are just the opposite for C55 and C65 concrete. The strength deterioration speed of high-strength concrete after high temperature increases with the increase of heating rate, but not in proportion. And when the heating temperature rises up between 200°C and 500°C, heating rate has the most remarkable effect on the residual compressive strength of concrete. These test results provide scientific proofs for further evaluation and analysis of mechanical properties of reinforced-concrete after exposure to high temperatures.
Adiabatic Temperature Rise of Pulverized Fuel Ash (PFA) Concrete
Authors: Ng P.L. , Ng I.Y.T. , Fung Wilson Wai Sin , Chen Jia Jian , Kwan A.K.H.
Published: December 2010

Owing to the less exothermic pozzolanic reaction of pulverized fuel ash (PFA) compared to cement hydration, the addition of PFA can reduce the heat generation of concrete during its hardening. However, as the water to binder (W/B) ratio would affect the proportions of cement and PFA that could react with water, the conventional practice of determining concrete temperature rise solely based on the cement and PFA contents may not yield accurate estimations. An experimental programme was launched to investigate the adiabatic temperature rise of PFA concrete mixes. Seven concrete mixes without PFA added and 14 concrete mixes with PFA dosages at 20% and 40% were tested with the recently developed semi-adiabatic curing test method. The adiabatic temperature rise was obtained by applying heat loss compensation to the test results. It was found that the incorporation of PFA could suppress the adiabatic temperature rise by 4°C to 14°C. The test results revealed the dependence of adiabatic temperature rise on both PFA dosage and W/B ratio, whose combined effects can be accurately addressed via the prediction formula and design chart developed herein.
The Study of the Chemical Modifier for Matrix Asphalt-Crumb Rubber System
Authors: Quan Xu Dong , Feng Wei Min , Liao Guo Sheng
Published: December 2010

This paper studied the compound modified asphalt which was made of crumb rubber modified asphalt, and some chemical modifier were added.The experimental shows the performance of this kind of modified asphalt .The proper parameters and ratios can be used to improve level of the using of crumb rubber modified asphalt.
Properties and Mechanism of Soil Consolidator for Highway Slopes
Authors: Tang Hua
Published: December 2010

The unconfined compressive strength, deformability and water stability of clay soil consolidator were investigated; the results were compared with those of cement and lime. The results indicated that the strength, water stability and resistant to deformability of stabilized soil containing the consolidator were prior to those of cement and lime. Moreover, the stabilization mechanism of the consolidator was descried.
Investigation on Hydration Characteristics of Zinc-Doped Portland Cement Pastes
Authors: Li Xiang Guo , Yin Xiao Bo , Ma Bao Guo , Wu Bei , Chen Quanbin , Lv Yang
Published: December 2010

Compressive strength, setting time, hydration heat and hydration product were investigated to evaluate the effects of Zn2+ ion concentrations and the anion of zinc salts on the hydration characteristics of Portland cement paste. The results show that the hydration characteristics of zinc-doped cement pastes depend on Zn2+ ion concentrations and the anion of salts. With the incorporation of ZnCl2, the hydration heat, exothermic rate and the early-age strength of cement pastes were reduced, the arrival time of the highest temperature was delayed, and little negative influences on the compressive strength at 28 days were observed. The total hydration did not decrease incorporating ZnSO4; the hydration exothermic process was delayed. There were little negative influences on the compressive strength of the samples at 3 days and 28 days. Moreover, for the samples with the same Zn concentration, the retardation effect of ZnCl2 samples was stronger than that of ZnSO4 samples.
Experimental Research on Fire Response and Post-Fire Bearing Capacity of Profiled Sheet-Ceramsite Concrete Composite Floor
Authors: Wang Xin Tang , Wang Hai Jiang , Zhou Ming
Published: December 2010

Compared with ordinary concrete composite floor, profiled sheet-ceramsite concrete composite floor(PSCCF) has the advantages of lighter weight and higher strength, and its resistant fire characteristics is better than ordinary concrete composite floor for stability of characteristics of ceramsite under high temperature. For study of the characteristics of the floor after fire, the experimental research on bearing capacity of the profiled sheet-ceramsite concrete composite floor after fire and the floor not subjected to fire load are further carried out at indoor temperature here. Based on the experimental results, effect of the fire on post-fire bearing capacity of the profiled sheet-ceramsite concrete composite floor is discussed, and the failure phenomenon and mechanism are analyzed. It is shown that he failure form of the profiled sheet-ceramsite concrete composite floor after fire has great change compared with the floor not subjected to fire load, but the bearing capacity of it is still higher.
Crack Resistance Evaluating of HSC Based on Thermal Stress Testing
Authors: Chen Bo , Cai Yue Bo , Ding Jian Tong , Jian Yao
Published: December 2010

In order to evaluate the crack resistance of high strength fly ash concrete, concretes with different contents of silica fume and fly ash were compared with same strength grade by adjusting water to binder ratio. Compared with the concrete with 5% silica fume plus 35% fly ash，concrete with 40% fly ash has same mechanical properties and tensile strain as well as lower drying shrinkage. Complex crack resistance of high strength fly ash concretes were evaluated by Temperature Stress Testing Machine (TSTM). The results show that fly ash concretes have outstanding crack resistance because of higher allowable temperature differential and lower cracking temperature.
Representation Based Classification of Strength Theories of Concrete
Authors: Zhang Ji , Zhang Zhong Xian , Huang Cai Ping
Published: December 2010

This paper proposes a new classification of strength theories of concrete based on mathematical representation. First, stress invariants in strength criteria are classified according to their geometrical meanings in the stress space. Then, strength criteria of concrete are classified according to the categories of stress invariants employed in their representations and subclassified according to the nonlinear terms involved. By this formal classification, the mathematical properties of strength theories of concrete can be analyzed more clearly for constitutive formulation.