bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Neural Network in Urban Land Use Suitability Evaluation
Authors: Zhang Xiao Rui , Chen Gang
Published: April 2011

Urban land use suitability evaluation is the basic work of urban land use planning and management. The evaluation method is a core in urban land use suitability evaluation. Traditional urban land use suitability evaluation methods are GIS-based methods which often can not get satisfactory results for the complex nonlinear urban land use system. Artificial neural network is a frontier theory of complex non-linearity scientific and artificial intelligence science. It is a new method to evaluate urban land use suitability. This paper took the land use suitability evaluation of Hefei city as an example, building a back propagation neural network with 8 neurous of input layer, 5 neurons of hide layer and 3 neurons of output layer. The analysis shows: the high suitability area is 682.27 km2in Hefei city, being about 8.73% of the total study area; the middle suitability area is 5965.76 km2, or about 76.33% of the total area and the low suitability area is 1167.35 km2, or about 14.94% of the total area. The results reflect the actual situation in Hefei city. The study shows that the back propagation neural network model can overcome the shortcomings of traditional evaluation methods. It means that artificial neural network is suitable for urban land use suitability evaluation. This reflects that artificial neural network has great academic value and application prospect in urban land use suitability evaluation. It also reflects that this study can provide a new idea and method for urban land use suitability evaluation.
Investigation on the Sedimentation Behavior of the α-Al2O3 Aqueous Suspension by the Combination of Two Dispersants
Authors: Li Fei Zhou , Han Yu Qiang , Guo Bian
Published: April 2011

The effect of three different types dispersants on the stability behavior of alumina aqueous suspension were investigated by through sedimentation experiment , Zeta potential ,and residual porosity of sintered sample. The results showed that the optimal content and optimal sedimentation pH value of the three different types dispersants were 1.0% and aging at pH9 for PAA-NH4, 0.8% and nearly independent of pH value for Arabic gum , 0.4, 0.2 and aging at pH9 for PAA-NH4 and Arabic gum，respectively. The dispersion effect of the three different type dispersants was PAA-NH4and Arabic gum> PAA-NH4 > Arabic gum. Studies have shown that the combination of PAA-NH4 and Arabic gum has a better effect than one of them on the stability of suspension. Compared with single dispersant, the sedimentation volumes of the two dispersants dispersing suspension is reduced 3%, the dosage of dispersants is reduced 26.7%.
A Software Integration Testing Architecture Based on Contract
Authors: Yu Su Ping , Mao Wei Wei
Published: April 2011

Under the guidance of DBC theory, a new architecture, called Integration Testing Architecture for Contract-Based System (ITACBS) is proposed in this paper. The ITACBS fully considers the characteristics of the component software, using the component interface of the contract document to describe the behavior of the system components.The aim of the ITACBS is to found the error between the components and the paste code and to achieve Integration Testing by monitoring and inspection contract. Compared with traditional method for packaging component,the method which used the ITACBS overcomes the non–state tracking of components caused by the unknown source.Test results show that the component wrapper can provide better testbility than other methods.
Context Perception Mechanism in Virtual Assembly Environment
Authors: Lv Mei Yu , Hou Wen Jun , Jin Yu
Published: April 2011

The structure of virtual assembly environment and the pattern of response message was represented based on the Multi-Agent theory; the context perception mechanism in virtual assembly environment was analyzed, and a perception algorithm was put forward. The result showed that cognitive burden of human had been shared by virtual assembly environment in reason; the efficiency of assembly manipulation in virtual assembly environment had been increased; the level of human-computer interaction had been improved.
The Condition Monitoring of Large Slewing Bearing Based on Oil Analysis Method
Authors: Bai Xiu Qin , Xiao Han Liang , Zhang Lu
Published: April 2011

Large slewing bearing is a special kind of rolling bearing with heavy load and very low rotation speed. It is important to carry out faults monitoring on this kind of rolling bearing. However, it is difficult to carry out vibration monitoring on such large slewing bearing. The running conditions of slewing bearings of ship loader and stacking crane in Qinghuangdao Port were analyzed using ferrography and spectrometric analysis technology. Monitoring results showed that the slewing bearing of SL-Q1 ship loader was under abnormal wear condition. Further inspection indicated that the rolling elements of this bearing underwent severe wear and broke down. This suggested that it was feasible to evaluating the wear conditions of this type of large low-speed heavy-load rolling bearing using ferrography and spectrometric analysis.
The Application of the Projection Pursuit Model of the Particle Swarm Algorithm on the Investment Decision
Authors: Deng Li , Luo Fang Qiong
Published: April 2011

In order to make a good decision in the projection investment, and the application of the projection pursuit model of particle swarm algorithm on the investment decision was studied in depth. Firstly, the development of the projection pursuit model of particle swarm algorithm was introduced, and then the brief introduction of PP and the step of constructing the PPC model were introduced. The basic theory and calculating procession of particle swarm algorithm was analyzed. And then the projection investment decision model was established. Finally a case study was carried out and the results showed that this method was simple and effective.
A Hybrid Model of Cross-Domain Authentication for Password Synchronization
Authors: Zhang Qiu Yu , Cai Zhi Peng , Yuan Zhan Ting , Miao Feng Man
Published: April 2011

Cross-domain authentication is a key technology used in distributed computing, however, it isn’t perfect. In this paper, a new type of hybrid cross-domain authentication model is proposed to make up its shortcoming in safety, scalability and password synchronization. In this model, advantages of Kerberos and SAML in cross-domain authentication process are combined, and it mixed password transport protocols is adopted to achieve password synchronization. Theoretical analysis shows it can enhance the security and scalability of cross-domain authentication, the efficiency of cross-domain authentication is also improved as the attainment of password synchronization.
Low-Cost Condition Monitoring System of Rotating Machinery Based on LabVIEW
Authors: Fan Ya Jun , Guo Yu , Wu Chuan Hui
Published: April 2011

In order to change the current status that machine condition monitoring system is only generally applied to key equipments of large-scaled and high-end business, a low-cost mini condition monitoring system of rotating machinery based on LabVIEW is proposed and designed in this paper. The system is not only of advantages of lower cost, stronger expandability and higher applicability, but also changes the condition that current systems emphasize too much on the comprehensiveness, universality and complexity. It is capable of meeting the wide range of condition monitoring of common rotating machinery, for faults diagnosis and predictive maintenance needs better, then, its potential application can be foreseen.
Stability Bearing Capacity Analysis for High-Strength Angle Steel Members with an Eccentric Load at One End
Authors: Cao Xian Lei , Hao Ji Ping
Published: April 2011

Single-angle compression members with an eccentric load at one end were widely used in transmission towers, analyzing the stability bearing capacity become a very complex issue due to end restraint conditions and the impact of defects. Experiment method and analytical method were used to study the size of the stability capacity on four kinds of members, analytical method use energy relationship, the boundary conditions issue is simplified according to different end restraint capacity, and finally discuss the theoretical ultimate bearing capacity of the test members. Compared with the experimental results show that the elastic theory analytical solution overestimates the capacity of members, using experiment method can obtain more secure mechanical behavior of high-strength angle steel member with an eccentric load at one end.
Research on CO2 EOR Mechanism and Application in Shengli Oilfield
Authors: Lv Guang Zhong , Zhang Jian , Wang Feng , Yan Guang Hong , Zhang Xin Jun
Published: April 2011

As one kind of oil expellant in improving the recovery ration of oil reservoir (EOR), CO2 flooding has merits such as extensive adaptability, low cost, high recoverability, and it will become one main way of EOR in future. In this paper, the EOR mechanism of CO2 flooding has been studied correspond to the geologic conditions in Shengli oil field, which includes three parts: mechanism of expansion, mechanism of reduce oil viscosity and displacement experiment of long core model. Moreover, the detailed process of the test block description of CO2 flooding in Shengli oil field has been set forth. Through the application in Shengli oil field proves that the EOR mechanism of CO2 flooding is right and suits for geologic conditions in Shengli oil field.
Rolling Bearing Finite Element Contact Analysis and Lectotype Design for Lunar Rover Wheel-Legged Mechanism
Authors: Wang Yong Ming , Fan Tong Hua , Yu Xiao Liu
Published: April 2011

Taking the wheel-legged lunar rover based on double-half-revolution mechanism as a research object, this paper has made a dynamics simulation for the simplified virtual prototype model of lunar rover under several typical road conditions, with the purpose of obtaining the load applied on each bearing of lunar rover wheel-legged mechanism. On the basis of simulation analysis, static contact analysis for the wheel-leg rolling bearing was made by the finite element analysis software ANSYS. Through the finite element analysis for the rolling bearing, the maximum contact stress and deformation of the rolling body sustained the maximum force were obtained. The results will provide the new analytical method and basis for the optimization and lectotype design of the lunar rover wheel-leg rolling bearing.
Computer Network Security Several Strategies
Authors: Zhang Kun , Wang Hai Feng , Zhu Jian Feng , Li Zhuang
Published: April 2011

With the continuous development of the Internet, it while brings each kind of beneficial information to the people , the hacker, viral as well as the malicious destruction and so on bad factor also multiplies along with it the spread, the network security and the reliability have become the focal point which various countries pay attention together .
Scheduling Platform of Semiconductor Assembly and Test Producing Line
Authors: Wang Lun , Li Jing Min , Yao Jin
Published: April 2011

With the complexity of new products and devices increasing, the scheduling of semiconductor assembly and test producing line becomes more and more complicated. To deal with the problems of complex operation, low efficiency, high workload and unsatisfactory scheduling results in making plan, we develop a scheduling platform. This paper analyzes the features of the semiconductor assembly and test producing line, and builds the system from function design and database construction. At last, it presents the application of the system. Now the platform has successfully applied in a certain large semiconductor production enterprise. It helps schedulers make the scheduling more accurately and more conveniently; the scheduling results also can be supported for further decision-making clearly.
Removal of Oil from Steel Wastewater by Adsorption onto Organic Modified Sepiolite
Authors: Li Fang Wen , Yang Juan , Ma Song Jiang , Wu Nian Fen , Fu Mei Ling , Jia Hai Wu , Wu Qian
Published: April 2011

The effect of operating conditions, such as adsorption time, adsorbent dosage, influent pH and influent oil concentration, on the performance of organic modified sepiolite used for the treatment of steel rolling oily wastewater was investigated via single factor method, and the adsorption kinetics and thermodynamics were also studied with batch test. Results indicated that oil removal rate reached 96.78% in 45 min which increased by 55.44% compared with crude sepiolite. Reasons for oil removal efficiency rise with organic modified sepiolite included augmentation of interlayer distance (0.007 nm larger than crude sepiolite), increase of specific surface area (from 41.63 to 104.40 m2/g) and stronger hydrophobic. The pseudo second order kinetic model well described experiment data with a perfect correlation coefficient value of 0.9999. Thermodynamic parameters including the Gibbs free energy (△G0), enthalpy (△H0), and entropy (△S0) revealed that adsorption process was a spontaneous, exothermic and physical adsorption process. 
Preparation of the EG/TiO2 Composites in the Method of Impregnation
Authors: Wang Li Qin , Yang Xiang Ni , Zhao Xiu Li , Zhang Rui Jun , Yang Yu Lin
Published: April 2011

The composites of expanded graphite with TiO2(EG/TiO2) were prepared in the method of impregnation, the morphology and crystal structure were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The decolorization performance of the EG/TiO2composites for the methyl orange aqueous solution were studied. The experimental results were shown as follows: the EG/TiO2composites maintained the porous and lamellar structure of EG, and a lot of anatase TiO2particles as a small lumpdistributed on surfaces and in layers of EG. The composites may contain the graphite both oxidized and un-oxidized, and there was no other organic group left in the composites, except for the functional groups of graphite. Moreover, the EG/TiO2composites had excellent decolorization performance for the methyl orange aqueous solution. When reacted for 90 min, the decolorization rate of the methyl orange aqueous solution was at the peak, up to 96.1%. We supposed that it was mainly due to the interaction between the strong adsorptive ability of EG and the degradation property of TiO2particles.
Mechanism Design and Dynamic Analysis of Hybrid Cam-Linkage Mechanical Press
Authors: Ge Zheng Hao , Ma Wen Jing , Zhang Kai Kai , Huang Wei
Published: April 2011

This paper proposes a new structure of hybrid cam-linkage mechanical press. First of all, the design process is introduced and positive movement simulation is done separately for hybrid cam-linkage mechanism and hybrid seven-bar mechanism in Pro/Mechanism. Through comparing the curves of slider’s output displacement, velocity and acceleration, it comes to the conclusion that the slider of hybrid cam-linkage mechanical press has better output motion characteristics. Then power and torque distribution of servo motor and general motor of the hybrid cam-linkage mechanical press is studied in ADAMS based on the simulation results. At last, torque of general motor and servo motor in practical work is analyzed by taking cold extrusion press as an example.
FEA of Stress behavior in the Single-Lap Adhesive Joint
Authors: He Xiao Cong
Published: April 2011

This paper deals with the effects of bending and boundary condition on the stress distribution of a single-lap adhesive joint under tension using the three-dimensional finite element analysis technique. The numerical results obtained from the finite element analysis show that both the left and right hand regions of the adhesive layer are subjected to high stresses. The numerical results also show that most of the extreme stresses occur at interface which is between the adhesive and the upper adherend. It is clear that the stresses are concentrated near the left and right free ends of the adhesive layer while the centre region of the adhesive layer is mostly stress-free. It is also clear that the stress state in this case is mainly dominated by the normal stress components.
Study on Traffic Overload Management for ICIE
Authors: Lu Sheng
Published: April 2011

This paper has an analysis on actions of traffic throughput and traffic overload management based on a new intelligent controller for industrial Ethernet: ICIE (Intelligent Controller for Industrial Ethernet). It proposed a new mechanism to minimize the congestion which is based on the taking an adaptive decision during transferring multicast messages. It also focuses on the actions analysis on traffic throughput to achieve and improve the traffic throughput goal. It has a further discussion on four conditions of traffic management: detection of traffic overload, measures to be taken to avoid traffic overload, traffic overload behavior, traffic overload recovery. It is through the external devices solicitation of join messages that allow the ICIE component to correctly decipher on which ports the downstream listeners are connected.
Experimental Investigation on Transient Process of a New-Type Heat-Pipe Heat-Sink
Authors: Xie Xu Liang
Published: April 2011

In order to verify whether a new kind heat pipe heat sink can meet the requirement of high energy chip cooling or not, an experiment was conducted under heating and cooling process with a constant airflow rate. The transient heat exchange rate and transient temperature response of four thermocouples mounted on the upwind surface of the heat sink condenser were obtained. Results show that heat resistance decreases with increase in heat transfer rate under heating process, and the heat resistance is about 0.22K/W with the airflow rate 40m3/h. The transient temperature response is also analyzed with theory.
Study of TD-LTE Base Station Co-Existence with TD-SCDMA Base Station
Authors: He Hong , Dong Hong , Yang Tong , He Lin , Wu Cong Cong
Published: April 2011

This paper analyzes the reasons which cause the interferences between TD-LTE and TD-SCDMA systems and studies the types of interferences between the two systems in the same area. It gets the additional isolation requirements of coexistence and co-location of TD-LTE/TD-SCDMA base stations with deterministic method which bases on the minimum coupling loss. At last, some proposals for solving the interferences are given.
A Hybrid EMD-Based Time-Frequency Analysis Strategy
Authors: Qian Li , Xu Guo Ping , Yang Ning
Published: April 2011

Empirical mode decomposition (EMD), a new self-adaptive signal processing method, has been recently developed for nonlinear and non-stationary time series analysis. In this paper, EMD method is described and applied in time-frequency analysis. Aiming at the problems of intrinsic mode function (IMF) criterion in the EMD method, neural network (NN) prediction model and wavelet packet transform (WPT) technology are simultaneously introduced into the EMD method to improve the border effect and to enhance the ability of signal analysis, and thus a hybrid EMD-based time-frequency analysis strategy is proposed. The simulated time series are exploited to verify the effectiveness of the proposed hybrid model. Experimental results indicate that the hybrid strategy gives a quite satisfactory performance when both NN prediction model and WPT method are employed.
A Kind of ONS Parse Method Based on Address Aggregation in Internet of Things
Authors: Liang Yu En , Fu Xiang
Published: April 2011

Network services located by Object Name Service (ONS) can associate Electronic Product Code (EPC) of Internet of Things with related Web sites or other Internet resources. Based on depth analysis on ONS parse rules, the paper compared ONS parsing rule based on format string and ONS parsing rule based on Naming Authority Pointer (NAPTR) record and introduced concept of aggregation to improve ONS parsing rules, and then presented a kind of ONS parsing method based on address aggregation. The application example of this method proves its operability.
Surface Matching Technique in Hexahedral Element Mesh Generation with Inside-Out Grid-Based Method
Authors: Sun Lu , Zhao Guo Qun
Published: April 2011

Surface matching technique is a key technique in automatic generation of 3D finite element mesh. In this paper, a surface matching technique including surface-gap filling, boundary match and C-node match, is introduced. Eight types of free facet configurations and their corresponding matching rules are established. Then a combined method of priority nodes and relative position relationships for boundary match is presented, and an effective method for C-node match is given, too. The methods can achieve precise match between mesh boundaries and model boundaries, and establish reasonable geometry and topology connections of matched nodes. Several examples are provided to demonstrate the accuracy and efficiency of the algorithms presented in this paper.
Image Segmentation Method Based on Fisher Criterion and Genetic Algorithm
Authors: Fu Xian Xiang , Chen Zu Jue , Zhao Yong Fu
Published: April 2011

Precise recognition of the weed by computer vision, furthermore raising the weeding efficiency, reducing the use of herbicide, and decreasing the pollution to the environment is one of the key technologies in the field of precision agriculture. To determine the optimal threshold in image automatic segmentation and solve one-dimensional histogram without obvious peak and valley distribution, image segmentation method based on fisher criterion and improved adaptive genetic algorithm is proposed. This method can preserve the multifamily of population and the astringency of the algorithm, and can overcome the problems of poor astringency and premature occurrence. The result shows that the proposed approach has better immunity to Salt and Pepper Noise and greatly shortens the time of image segmentation.
Computer Simulation of Vesicle Fusion
Authors: Wu Shao Gui , Guo Hong Xia
Published: April 2011

A dissipative particle dynamics simulation method is used to get insight into molecular-level details of vesicle fusion in this study. For simplicity, the simulation system contains water and amphiphiles. The fusion mechanism is investigated in detail. It is found that the whole fusion process is in well agreement with the “stalk-pore” hypothesis. The dynamics of vesicle fusion is analyzed by monitoring the time evolutions of morphologies.
Prediction Model of Non-Iterative Least Squares Support Vector Machines Based on Quadratic Renyi-Entropy
Authors: Zhao Guan Hua
Published: April 2011

By comparing and analysing the model of non-iterative least squares support vector machines (LS-SVM) based on quadratic Renyi-entropy, traditional LS-SVM model and standard support vector machines (SVM) model, this paper concludes whether the number of training samples or computing time,non-iterative LS-SVM model based on quadratic Renyi-entropy are significantly better than the model of traditional LS-SVM and standard SVM model and it also proves the effectiveness of applying the concept of quadratic Renyi-entropy on financial distress prediction. At the same time, by the comparison of different point of 3 years of ST which is from 1to 2, the author concludes the forecast accuracy of 1 year ago before ST, the further distance away from the piont of ST, the lower the prediction accuracy is.
Investigation on the Effects of Sheet Thickness and Deformation Temperature on the Forming Limits of Boron Steel 22MnB5
Authors: Li Jia Yue , Min Jun Ying , Qin Kai Yu , Lin Jian Pin , Liu Fu Qiang , Liu Lei Chao
Published: April 2011

To study the effects of temperature and thickness on forming limits of boron steel 22MnB5, Nakajima tests have been performed for the steels with thickness of 1.0mm and 1.4mm at 600°C and 700°C, respectively. The forming limit curve (FLC) of the steel at 700°C is higher than that at 600°C, and the FLC of the steel with 1.4mm is higher than that of the steel with 1.0mm. With increasing the forming temperature, the strain rate sensitive exponent m increases, and it results in a longer Swift’s diffuse instability phase and greater limit strains. The effect of thickness on yield path is different from the case at room temperature, due to the half angle of pointed Vertex, θ0, which increases with increasing of the thickness, and then the limit strains increase.
Performance of Compound Cementitious Material Compounded with Clinker and Limestone Powder and Coal Ash
Authors: Huang Tian Yong , Hou Yun Fen
Published: April 2011

Limestone powder and coal ash are selected to prepare compound cementitious material with clinker. It is found that with the increasing of mixture (including limestone powder and coal ash), the water amount for standard consistency of compound cementitious material increases and the flexural strength and compressive strength at 3 and 28 days decrease. Increasing of limestone powder can reduces the water amount for standard consistency. The compressive strength, flexural strength and cleavage strength decrease with the increasing of mixture. If the mixture dosage is 60%, when the ratio of limestone powder and coal ash is 8:2, the compressive strength is the highest. If the mixture dosage increases to 70%, when the ratio of limestone powder and coal ash is 7:3, the compressive strength is the highest. If the mixture dosage is 80%, the all strengths are very low. The compressive strength increases significantly with time, the compressive strength is greater than 50MPa at 90 days. Although the mortar strength of compound cementitious material is far below for mortar strength required by cement standard, but the middle-low strength grade concrete can be prepared by low water-binder ratio.
Study on the Impact of Sasobit on Asphalt’s Temperature Susceptibility
Authors: Ji Jie , Luo Xiao Hui
Published: April 2011

In order to evaluate the impact of Sasobit on asphalt, the 2%,3%,4% and 5% Sasobit by mass of asphalt are blended into two types of base asphalts (Pen 60/80 and SBS modified asphalt).The mixed asphalt will be called as Sasobit modified asphalt in this study. The 15°C, 25°Cand 30°Cpenetration, the softening point, the 60°C and 135°Cviscosity, the 5°Cductility of Sasobit modified asphalt are tested. The temperature susceptibility of Sasobit modified asphalt is evaluated by using PI, VTS, PVN25-135 and PIR&B. The linear relationships between PI and PIR&B or VTS and PVN25-135 are confirmed. As the addition of Sasobit can differently change the viscosity or rheology of Sasobit modified asphalt under different temperature, it has been shown that the temperature susceptibility of Sasobit modified asphalt become better within the normal temperature range (0°C~50°C) but become higher within the high temperature range (60°C~135°C) as the additive content increases. It has been proved that Sasobit have a different impact of asphalt’s temperature susceptibility at different temperature range. So it is not appropriate to express the temperature susceptibility of Sasobit modified asphalt using a conventional index PI. This study suggests that PI and PVN can be used as indicators of the temperature susceptibility of Sasobit modified asphalt within the normal temperature range and high temperature range respectively.
Experimental Research on Compatibility between Underwater Anti-Washout Admixture and Superplasticizer
Authors: Hu H.M. , Yao Z.X. , Zeng S.Y. , Yu B.B.
Published: April 2011

The compatibility between underwater-washout admixture(AWA) and two different types of superplasticizers, polycarboxylate-type and naphthalene-based, was studied. The results showed that, there were different compatibilities between AWA and different superplasticizer, but the differences were not apparent. Compatibility of AWA with polycarboxylate superplasticizer was better than that of naphthalene superplasticizer. When the solid content is same, the difference of compatibility between AWA and different brand polycarboxylate-type superplasticizer was very slight. The underwater concrete with good anti-washout performance, good fluidity, self-compacting ability and corrosion resistance can be prepared easily through the reasonable compound. However it was difficult to solve the retarding problem and the contradiction between good fluidity and strength of the non-dispersible underwater concrete.
Bislauramide Concrete Foaming Agent: Synthesis and Properties
Authors: Liu Cai Lin , Zhang Yu Rong , Ren Xian Yan , Yang Hai Jun , Yang Jun Xiao
Published: April 2011

A bislauramide concrete foaming agent was prepared in good yield by a simple synthetic route using readily available hexamethylenediamine, dodecanoic acid, and chloroacetic acid. The reaction conditions were optimized by changing reaction temperature, reaction time, and/or molar ratios of reactants. Significantly, the concrete foaming agent has very low surface tension and good foaming properties, and shows evident synergistic effects with commercial concrete foaming agents.
Study on the Curve of Lightweight Aggregate Concrete Compressive Strength by Rebound Method
Authors: Gao Li Xiong , Kong Li Juan , Du Xue Gang
Published: April 2011

Testing strength curve of 1400~1900 density grade lightweight aggregate concrete by rebound method was studied systematically. Results show that, adopting the Chinese national unified testing strength curve, specified by JGJ/T 23-2001 of Technical Specification for Detection of Concrete Compressive Strength by Rebound Method, to detect the lightweight aggregate concrete strength, the strength scaled value obtained is higher, which would reduce the structure assurance coefficient. The special testing strength curve of 1400~1900 density grade and LC15~LC50 strength grade lightweight aggregate concrete were built, and the computed mean relative error and relative standard error are less than 12.0% and 14.0% respectively, meet the error requirement of special curve that specified by JGJ/T 23-2001 of Technical Specification for Detection of Concrete Compressive Strength by Rebound Method.
Mechanical Properties of Fiber Reinforced Lightweight Aggregate Concrete
Authors: Xu Yi , Jiang Lin Hua , Chu Hong Qiang , Chen Lei
Published: April 2011

In this study, the effects of fiber types on the mechanical properties of lightweight aggregate concretes were investigated. Three types of fibers, namely, polypropylene fiber, steel fiber and water hyacinth (Eichhornia crassipes) fiber, and two types of lightweight aggregates, namely, expanded polystyrene and ceramsite were used. The compressive strength and splitting tensile strength of concretes were tested. The results show that both the compressive strength and the splitting tensile strength were improved by adding a reasonable volume of steel fiber and polypropylene fiber into LWAC. The addition of water hyacinth fiber had little effect on the compressive strength of LWAC, while a little increase was observed in the splitting tensile strength.
Research on Mechanical Properties of Crumb Rubber Concrete
Authors: Bian Li Bo , Song Shao Min
Published: April 2011

Considering large number production of the abandoned tyres and the question of the concrete with mixture of crumb rubber，the mainly task of this paper is to study the mechanical properties of different mixing ratio concrete with vary volume of crumb rubber. The results showed that the workability, apparent density, compressive strength, flexural strength and brittleness index decrease as the increase of crumb rubber. While the anti-crack performance and anti-fatigue performance can be improved. The wear-resistance properties are a little lower than common concrete.
Research on Activation and Application of the Fine Powders from Waste Concrete
Authors: Peng Xiao Qin , Huang Tao , Wang Shu Ping
Published: April 2011

Fine powders from crushed waste concretes have high water absorption and their reuse is limited. In this research the fine powders with diameter of less than 4.75mm were activated by using grinding method and hydrothermal synthesis method, and then the specimens were manufactured from these activated fine powders by mechanically compacting at the pressure of 80MPa. The experimental results show that the instant maximum compressive strengths are 9.65MPa and 16.8MPa respectively for the specimens from the ground powders and the hydrothermal synthesis powders. Their apparent densities are low and they can be used as wall materials. The results also show that the optimal grinding time ranges from 80 min to 90 min when using the grinding activation method. When using hydrothermal synthesis method the proportion of lime as an admixture affects the compressive strength and the constant temperature period should be less than 7 hours as the temperature is 120 °Cfor the powder made from gravel concrete.
Effect of Low Temperature on Mechanical Properties of Concrete with Different Strength Grade
Authors: Cai Xiao Ping , Yang Wen Cui , Yuan Jie , Ge Yong , Zhang Bao Sheng
Published: April 2011

The effect of low temperature (-35°C) on the mechanical properties of concrete with different strength grade such as compressive strength, flexural strength, splitting tensile strength and elastic modulus was studied. The results showed that all of the mechanical properties were improved at -35°C. It was also can be found from the tests, as the strength grade increased, the growth ratios at -35°C of compressive strength, flexural strength and splitting tensile strength decreased. But the growth ratio of elastic modulus increased with the increasing of strength grade.
Effect of CaCO3 Whisker and Polypropylene Hybrid Fiber on Mechanical Properties of Concrete
Authors: Wei Jian Qiang , Cao Ming Li , Yao Hang
Published: April 2011

As the composite of materials, fibers compositing, which can give full play to synergism of each fiber’s reinforcement, will become an inevitable trend. Calcium carbonate whisker is a kind of green environment-friendly fibrous powder filler with high strength, high modulus and excellent thermal stability, which has been proven that it has obviously toughening and reinforcing effects on cement-based materials. In this paper, CaCO3 whiskers composite with polypropylene fiber were added into concrete as reinforcement. Effect of different content of whiskers and fibers on the mechanical properties of concrete was investigated. The results shows that the composite of CaCO3 whisker and polypropylene fiber (PP) has better toughening and reinforcing effects than that of single filler. The strength of whiskers/PPF-reinforced concrete can be obviously improved compared with that of pure concrete, whisker concrete and PPF concrete. These increases could be correlated to the synergism of PPF and CaCO3 whisker, which are different in size, aspect ratio, elastic modulus, and reinforcing role in concrete.
Permeability and Corrosion of Reinforced Self-Compacting Concrete
Authors: Li Yue , Du Xiu Li , Sui Chun E
Published: April 2011

Self-compacting Concrete (SCC) has many good properties such as high fluidity, good cohesiveness and resistance to segregation. Therefore, SCC should have higher durability compared to ordinary vibrated concrete in theory. At the same time, the cementitious materials and additives used in SCC are much more than that of used in ordinary concrete, which will cause SCC to generate shrinkage cracks easily and deteriorate its durability. So the durability of SCC should be studied further. In this paper, C30~C60 SCC were prepared, and then the permeability and reinforcing bar corrosion of reinforced self-compacting concrete were conducted. The results show that the permeability of SCC is lower which make sure the embedded reinforcing bars have high resistance to the corrosion.
Fire Resistance of Ultra-High-Strength Concrete: a Review
Authors: Peng Gai Fei , Teng Yan
Published: April 2011

This paper presents a review of advances in research on fire resistance of high-strength concrete (HSC) and ultra-high-strength concrete (UHSC). Further research needs in the near future on UHSC, especially on reactive powder concrete (RPC), are also discussed. It is commonly recognized that HSC suffers strength loss in a manner basically similar to that of normal strength concrete. But the main problem of HSC is explosive spalling under high temperature, which can be solved by employing either polymer fiber or steel fiber. Since RPC200 is a type of RPC which has been successfully prepared in many counties and is to be applied to engineering practice, fire resistance of RPC200 needs a series of investigations urgently. The objectives of such investigations are to restrain explosive spalling and minimizing spalling probability, so as to ensure satisfactory fire resistance of RPC. It is expected that a research will be carried out on explosive spalling behavior, fracture properties, and micro-structure, to establish a mechanism as well as technical measures for improving fire resistance of RPC.
Study on the Delayed Ettringite Formation in Massive Shrinkage Compensating Concrete with U-Type Expansive Agent
Authors: Wang Qian , Ren Zheng Yue , Zhang Zhe
Published: April 2011

This paper introduces the research results of the thermal stability and the delayed formation of ettringite in China and abroad. Aiming at the debate of the ettringite delayed formation condition of the massive shrinkage compensating concrete in the engineering field, the decomposition and delayed formation of ettringite were studied in simulated environments in massive concrete and other controlled curing environment. As UEA is the most applied expansive agent in domestic, the massive shrinkage compensating concrete mixed with UEA is selected as the research object. The test results show that, AFM appears in the research specimens when the inner temperature reach 80°C and the ettringite can reform under the condition of rich water supply after the concrete cooling to an ambient temperature. By comparing the test results of different curing environment, some points for attention during the construction of the UEA massive shrinkage compensating concrete are proposed.
Effect of Curing Condition on Structure and Scaling Resistance of Specified Density Concrete
Authors: Kong Li Juan , Ge Yong , Gao Li Xiong
Published: April 2011

Influence of curing condition on internal relative humidity (IRH) of specified density concrete with different w/b ratios, pore structure of cement paste, hydrated product as well as scaling resistance of concrete were investigated. The results show that, as for concrete with w/b ratio of 0.31, water and standard curing can stop or slow up the migration of internal water, and the structure of cement paste is dense due to good hydrated environment, so the scaling resistance of concrete is best; as for concrete with w/b ratio of 0.47, the IRH of concrete under natural curing condition at 28 days is still 90%, there is sufficient water for the hydration of cement, and internal water content of concrete is lower as compared to concrete under water and standard curing conditions which makes it less easy to saturate, so natural curing concrete has better scaling resistance.
Effects of Controlled Permeability Formwork on Surface Properties and early Age Shrinkage of Concrete
Authors: Lai Jun Ying , Qian Xiao Qian , Zhan Shu Lin , Fang Min Hui
Published: April 2011

Concrete durability is one of the most important considerations in the design of new structures in aggressive environments. It generally depends on the quality of the concrete surface and the cracks of concrete. In this paper, the rebound numbers of concrete cast using controlled permeability formwork (CPF) and ordinary steel formwork were determined. And the early age shrinkages of concrete cured in dry environment of 20±2°C, 75±5% RH, in sealed condition with plastic film and in covered condition with CPF liner were measured. Testing results indicated that CPF could improve the concrete surface hardness and reduce the early age shrinkage of concrete. So CPF can enhance concrete durability and prolong its life-span.
Influence of Mineral Admixtures on the Carbonation Resistance and Chloride Permeability of Steam-Cured HPC
Authors: Wu Jian Hua , Liu Yun Lan
Published: April 2011

This paper studies the influence of different mineral admixtures（fly ash and ground granulated blast furnace slag）on the carbonation resistance and chloride permeability of steam-cured HPC. The test results show that under the condition of steam-cured and standard-cured, incorporating 20-30% of the ground granulated blast furnace slag or 15-20% of fly ash decreased the alkalinity and the carbonation resistance of the concrete; with the increase of the proportion of the mineral admixture in concrete, carbonation resistance of HPC was decreased; incorporating 20-30% of the ground granulated blast furnace slag or 15-20% of fly ash improved the chloride permeability of steam-cured concrete, and the influence of ground granulated blast furnace slag is better than that of the fly ash.
A Study on early Shrinkage of Recycled Concrete
Authors: Shen Chong , Qian Xiao Qian , Qian Kuang Liang
Published: April 2011

The first 3d early shrinkage of recycled concrete from initial setting time with different replacement rates of recycled aggregate was investigated by self-made equipment. The differences between the unimproved recycled concrete and the improved one are observed, in the latter, new mixing method was utilized，that is, R-aggregates is coated with slag and nanoCaCO3, and relevant mechanism is analyzed. The results illustrate that early shrinkage of recycled concrete outweighs natural concrete, but there is not a definite link between the replacement rate of recycled aggregate and the early shrinkage. The treatment can effectively reduce the shrinkage of recycled concrete in 10h, but can not have a sustaining effort. Prewet treatment will generate water loss channels accelerating evaporation speed of water in concrete to accelerate shrinkage of concrete. The treatment can block water loss channel by coating, and slag and nanoCaCO3 can change pore structure and humidity in concrete to reduce the first10h early shrinkage.
Study of the Durability Characteristics of Hydraulic Concrete
Authors: Gu Xin , Ouyang Lin Xiao
Published: April 2011

Hydraulic concrete is a versatile and most popular construction material. Its long-term performance depends on the interactions with the service condition, in which the penetration of deleterious substances is highly significant. Based on the practical application environments of hydraulic concrete, this paper reviews the mechanism and research achievement from the freeze-thaw cycle, concrete carbonization, sea water corrosion, wear abrasion, cavitations damage of hydraulic structure. This is followed by a discussion on various experiments in an attempt to improve the concrete durability, which is relevant to each mechanism of deterioration. Finally, the measures to enhance durability are put forward as a prospect for future hydraulic engineering.
Effect of Saturation Degree on Concrete Deterioration due to Freeze-Thaw Action
Authors: Yang Wen Cui , Ge Yong , Zhang Bao Sheng , Yuan Jie
Published: April 2011

Freezing-thawing durability of cement concrete is extremely important in cold weather, to better understand mechanism of frost damage and air-entraining，saturation degree of pores in concrete and its relation with frost resistance were studied in this paper. Concrete specimens with different saturation degree from 0 to 100% were prepared used a sealed tin with a high water pressure pump. Then these specimens were subjected to six freezing-thawing cycles and the relative dynamic modulus of elasticity was examined. The results showed that critical saturation degree of concrete with water- binder ratio of 0.30 and 0.47, air content of 1%, 4% and 6% were from 0.60 to 0.80. When its saturation degree exceeded the critical value, concrete was deteriorated significantly after only six freeze-thaw cycles. The critical saturation degree was mainly related to the air content of concrete mixture, and it decreased with the increasing of air content. The difference between the saturation degree and the critical value can be used to evaluate potential frost resistance of concrete, and its result was consistent with the result of frost tests very well.
Determination of the Apparent Activation Energy of Concrete by Adiabatic Test
Authors: Wang Jia Chun
Published: April 2011

It is known that apparent activation energy of the binders in concrete characterizes the sensitivity of concrete hydration processes to temperature. In this paper the apparent activation energies of concretes containing different complex binders have been determined through adiabatic temperature rise test. The influence of hydration emission heat on the apparent activation energy of concrete is studied. The study results show that the apparent activation energy is decreasing with the hydration of binder stage development.
Technology and Application Prospect of Tilt-up Construction in China
Authors: Han Qing , Wang Yi Hang , Zhang Guo Wei , Wu Hui
Published: April 2011

Tilt-up is a method for constructing concrete wall rapidly and economically without formwork. A large number of tilt-up structures have been constructed in North America and other developed countries, and it will also be an acceptable term for new rural construction in China. Tilt-up process can reduce the cost of labor and materials in wall construction. With the application of the recycled concrete in tilt-up construction, which is being researched in the Beijing University of Civil Engineering and Architecture, tilt-up building can be has a larger benefit obviously in the suburbs and rural area. With the benefit of both techniques, the paper finally introduces the application prospect in China.
The Experimental Analyses on the Solidified Effect of Heavy Metals in the Ceramsite Calcined by the Composite Materials of Electroplating Sludge and Seabeach Sludge
Authors: Yan Han Dong
Published: April 2011

The electroplating sludge is a kind of solid waste material in the process of handling electroplating waste water, which has indefinite amount of harmful heavy metals hard to dissolute. The electroplating factory must seek economical and valid technology to deal with the sludge harmlessly, along with the reinforcement of the country law administer power to the discharge of the solid wastes. Since the last ten years, the handling technique to electroplating sludge has rapid advance, which mainly include solidification or stabilization technique[1], filling into the sea or pile-up, creature method, recycling heavy metal[2,3], iron-oxygen method, burning brick[8,9] and agriculture function and so on. A key handling technique is the recycling heavy metals from electroplating sludge in recent years, whose research fruits are no mature quietly from an area of technique view[2] and the oddments still need to cope with harmlessly come from recycling heavy metals. This is a kind of technique of low economic yield ratio, low scale benefit and higher production costs from a point of economic view. It is difficult to accept for a mass of small electroplating enterprise in China if there is not encouragement and support from the government. The solidification method is the final handling method for harmful and dangerous waste in west country in recent years[1]. Cementing solidification method is adopted the most effectively at present[6]. It is satisfied with the aim of harmlessly handling electroplating sludge but unsatisfied with the requirement of utilizing electroplating sludge as a resource and disadvantageous to build recycling type economics. Making use of the electroplating sludge to product building materials may be an economical and valid approach to handle it harmlessly as a resource[7]. The solidified effects on heavy metals of electroplating sludge at 1200°C high temperature burnt were analyzed in the paper, at the basis of feasible studies on the technology of burning ceramsite by the composite of electroplating sludge and seabeach sludge.