bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Test of the Influence of Moisture Content on Creep Property of Sandy Slate Coarse-Grained Soil
Authors: Liu Qun , Wang Xiang , Song Xiao Dong
Published: September 2013

Coarse-grained soil is widely used in subgrade engineering, creep property of which is the important factor that affects long-term settlement of fill embankment. The creep property of sandy slate coarse-grained soil under different moisture conditions is analyzed through uniaxial compression creep test on influence rule of moisture content on creep of coarse-grained soil. Relations between moisture contents and creep parameters are studied on the basis of H-K Creep Model. It turns out that moisture content is the important factor that affects creep property of sandy slate coarse-grained soil and using dry or saturated coarse-grained soil is able to decrease long-term settlement of embankment.
Dynamic Response of Asphalt Pavement on Semi-Rigid Base due to Heavy Load
Authors: Zhang Li Juan
Published: September 2013

The purpose of this paper is to study dynamic-characteristics of asphalt-pavement on semi-rigid base loaded with moving, heavy-load. Based on transient-dynamics theory, three-dimensional finite-element (FE) model was developed for structural dynamic-responses analysis using ANSYS software. The heavy-duty axle-load model was established according to Belgium-Design Code, and the dynamic-load was simplified as sinusoidal-wave load. For the pavement mechanics indexes (road-surface deflection, the vertical and lateral stress, the shear stress and the strain), the time-history curves and distribution conditions in the structure were presented. Expect tensile-strain at surface-layer, the relationship between axle-load weight and mechanic-indexes are almost linearly proportional. The calculation shows that under moving heavy-load, the surface-layer suffers from rather high vertical compressive-stress and shear-stress, the base and subbase are loaded with high tensile-stress and the subgrade top undergoes large vertical-strain . For asphalt-pavement on semi-rigid loaded with moving, heavy-load, besides the conventional indexes (including road-surface deflection and tensile-stress at the bottom of base or subbase), the design indexes should also include the shear-stress on road surface, the vertical-strain on the top of subgrade and the vertical compressive-stress on road surface.
Laboratory and Field Studies on Construction Opportunity of Porous Concrete Overlay in Tunnel
Authors: Yang Qun , Li Xu
Published: September 2013

The double-layer pavement design with a combination of normal concrete layer and porous concrete overlay is the promising way towards tunnel pavement. This paper is aimed to confirm the optimal construction opportunity of porous concrete overlay based on the mechanical behavior of tunnel pavement. Parameters like compressive strength, shearing strength and tensile splitting strength were examined in laboratory and field experiment respectively. It is observed that the strength of the pavement gradually decreases with the increase of the construction time interval between the two layers. The results have revealed that the reasonable construction opportunity of porous concrete overlay should be controlled between the initial setting time and the final setting time of normal concrete layer.
Simulation Analysis on Tension and Deformation of Composite Soil Nailing
Authors: Zhao Yan Lin , Zhang Hao Bin , Zhu Qing Pan , Chen Dong
Published: September 2013

For studying the mechanism of the composite soil nailing, this paper applies FLAC-3D to simulate pure soil nailing, soil nailing-soil anchor, soil nailing-micro pile-soil anchor. The analytical results as follows: (1)Because of the anchoring of the anchor, the axial tension of soil nailing in each row is much smaller than the one in the pure soil nailing supporting, and the tension of soil nailing which are closed to soil anchor decreases obviously. (2)The extrusion action of prestressed anchor makes the potential slip surface backward shifts and the sliding radius increases, which is better for the stability of foundation pit side (3)Micro-pile increases the strength of the soil in a certain range and improves the initial stress field before the excavation. (4)The inner force of the whole soil nailing and the prestress anchor declines but the drop is not large after the establishment of the micro-pile support in advance. (5)Prestressed anchor and micropile play a very important role in controlling the deformation of foundation pit.
Experiment Study of High-Temperature Stability of SMA
Authors: Shi Fu Zhou , Nie Man Yi , Wang Xuan Cang , Guo Rui
Published: September 2013

The high temperature stability of SMA is affected by many factors. Some factors that may affect the high temperature stability of SMA (stone mastic asphalt) analyzed by the way of Marshall and rutting testing, in the laboratory. The results show that the high temperature stability of SMA is closely related to its gradation,asphalt content,testing temperature,the number of rolling. This paper will only discuss the above factors. Study results indicated that adding proper coarse aggregate (diameter4.75mm ) and mine dust contents would play occluding and wedging role in aggregate mixture. The rolling times of SMA asphalt mixture should be Strictly controled, in order to improve the compaction density. When the experiment temperature was increased up to 67°C, high-temperature stability of SMA can not meet the requirement of standards. The optimal dosage of asphalt in rutting test is 5.0%, which is more 0.3%~0.4% than that in marshell-test. Key words: road engineering; SMA; rutting testing; Marshell test; high temperature stability
Study on Volcanic Rock Chemical Composition and Physical Properties in Hainan Province
Authors: Yao Yong Sheng , Zheng Jian Long , Tang Bo Ming , Zhu Hong Zhou
Published: September 2013

In order to study the chemical composition of volcanic rock and physical properties in Hainan province, used the method of X-ray fluorescence, analysises on its chemical composition, and researched the physical properties of volcanic rocks including density test, porosity test, acoustic test, resistance test. The results showed that: the volcanic rock is tholeiitic at the cavity of lava area in Hainan province, P-wave velocity and S-wave velocity would change with the changing of porosity.
Research of Asphalt Mixtures High Temperature Stability
Authors: Luo Gen Chuan
Published: September 2013

Rutting is one of the most hazardous damage form of asphalt pavement.But,owing to itself inherent in the viscoelastic characteristics of asphalt mixture,the diversity of factors influencing the high temperature of asphalt pavement anti-rutting performance and the complexity of rut formation,this three reasons make ruts become a worldwide problem.Starting from the mixture.This article analyzed the influence factors of the rutting resistance of asphalt mixture at high temperature.For asphalt mixture, through the experimental data, the research status at home and abroad, from the type of asphalt, asphalt content, grading of aggregates and air voids four aspects analysis and study the influence factors of the stability of asphalt mixture at high temperature.
Research on New Type of Cracking Resistant Water-Proof Layer as a Treatment Method of Pavement Crack
Authors: Xie Li , Zhu Bao Lin , Bian Li , Wang Tong
Published: September 2013

This article proposes a new type of cracking resistant water-proof pavement structure by building mechanical model and performing lab tests. This cracking resistant water-proof layer is a composite material formed by using high performance emulsified asphalt that makes two or more kinds of crushed stone with different particle size interlocking and binding with each other. In addition to this, this article preliminary determinates three field testing indexes, which are asphalt distribution measurement, pullout strength test and shear strength test of modified emulsified asphalt. At last, it is proved that the cracking resistant water-proof layer have a favorable effect on the experimental road.
Permanent Deformation Characteristics of Concrete Face Rockfill Dams on Alluvium Deposit Subjected to Different Strong Seismic Excitations
Authors: Cen Wei Jun , Zhou Tao , Xiong Kun
Published: September 2013

Using seismic analysis theory of CFRD, the numerical calculation of dynamic response of a high CFRD on alluvium deposit in strong earthquake zone subjected to strong seismic excitations of different transcendental probabilities was carried out, with emphasis on the seismic safety evaluation by permanent deformation. The influence of dynamic mechanical properties of the alluvium deposit on the dam's permanent deformation was also analyzed. The results show that permanent deformation will increase gradually with the increasing of peak value of seismic acceleration. The seismic safety of dam is in a normal range under the earthquake with transcendental probability of 2% in 100 years. The alluvium deposit has significant influence on the dam's dynamic response.
Experimental Study on Dynamic Shear Modulus and Damping Ratio of Soft Soils in Binhu New District of Hefei
Authors: Wan Xin Lin , Yang Dao Lin
Published: September 2013

The article through to free vibration column experiment research to soft soil of Binhu new district of Hefei, The data and curves are given for four types of soil dynamic shear modulus and damping ratio with shear strain and draw rules of different size of confining pressure on the dynamic shear modulus and damping ratio of soil. For hefei binhu new area soft soil of the physical and mechanical characteristics, select the optimal soft foundation treatment scheme, practical design calculation model is set up, and perfect the construction technology measures, the article has some reference value.
Several Issues on Structural Dynamics of Aqueduct Bridges
Authors: Li Yu Chun , Zhang Hao
Published: September 2013

This paper reports several issues on structural dynamics of aqueduct bridges. These issues include the modeling of sloshing water, dynamic characteristics of aqueduct bridges with fluid-structure interaction, seismic responses of aqueduct bridges, wind-induced buffeting responses of aqueduct bridges, equivalent wind load on aqueduct bridges. The results mentioned in this paper can be referred for the investigation and design of the wind and seismic resistance of the aqueduct bridges.
Model Reduction and Seismic Active Control of an Multi-Spanned Highway Bridge
Authors: Ning Jing
Published: September 2013

The Eigen mode reduction method and active control and passive base isolation strategies are exerted on one continuous isolated prestressed concrete bridge. The goal of this study is to check the applicability of the eigen mode reduction method and LQR control law on the isolated continuous or rigid-connection type bridge, to find a more effective control strategy when nonlinearity is introduced. A spaced frame finite-element model is developed by a MATLAB program coded by the author, its validity is checked through comparisons with a sap2000 model. In this program, the nonlinearities of 3 different columns and 5 isolators are considered with their bilinear force-deformation relationship. the factors such as the control devices, sensors, and the corresponding noises and time delay are all considered in the model. Eigen mode reduction method was applied to set up the controllers. The seismic response measurements and regulated outputs are adjusted to optimize control effects.
Experimental Study of LRB Energy Dissipation Walls and its Engineering Example Study
Authors: Zhou Chun Li , Chen Wei , Sun Jin Kun
Published: September 2013

LRB energy dissipation wall is a type of energy dissipation device for building structures. According to the results of an quasi-static test, structure with LRB energy dissipation wall shows a stronger energy dissipation capacity and a better seismic performance than the normal frame-shear wall structure. This paper also introduces the applications technology of LRB energy dissipation wall in High-level framework structure. According to the dynamic property analysis of a three-dimensional finite element model which was built by the finite element analysis software ETABS, LRB energy dissipation wall can effectively prolong the natural vibration period of high-rise frame structure and significantly reduce the maximum acceleration, shearing force and horizontal displacement in different floors to make the variation more smooth which is important the to the energy dissipation and earthquake mitigation.
Recent Changes of Water Discharge and Sediment Load in the Buyuan River Basin, China
Authors: Zhong Rong Hua , He Xiu Bin , Fu Kai Dao
Published: September 2013

Changes in stream flow and sediment load in the Buyuan River Basin is a focus due to its vital ecological niche in supply feeding and spawning habitats for upstream migrant fish species of Mekong River. Based on the precipitation and water discharge series data (19592008), and sediment load series data (19932008), the runoff and sediment discharge variation and its response to precipitation has been analyzed. The results shown that, during the study period of 19592008 at the Manan gauging station, annual runoff of Buyuan River has generally decreased, but not significant at the 95% confidence level. However, the decline trend of sediment load was obvious for gauged period from 1993 to 2008. The seasonal runoff distribution in the Buyuan River was uneven and demonstrated an observably unimodal distribution. Both water discharge and sediment load are largely derived from wet season (from Jun to Nov), especially in flood season from July to September. During the study period 1993-2008, both annual and monthly observed value of water discharge and sediment load had coincident changing processes. Double mass curves indicated decreasing precipitation was the main reason for runoff reduction in the Buyuan River Basin; declining rainfall and water discharge were two key factors for sediment load reduction. In 2002, however, sediment discharge undergone abrupt change due to huge peak discharge and two consecutive years strong precipitation in the Buyuan River Basin.
The Research and Development of the Constitutive Model of Soil
Authors: Xu Zhi Hua , Sun Da Wei , Sun Qian Cheng
Published: September 2013

This article introduced the development of the constitutive model of soil briefly, and analysed several classic constitutive models. On this basis, the paper reviewed the development trend of the constitutive model of soil, and expressed the urgency of perfecting the constitutive model of soil, which considered coarse soil particle breakage.
Hydraulic Conductivity and Scale Effects Investigation in Basalt in the Dam Area of Xiluodu Hydroelectric Station, Jinshajiang River, China
Authors: Li Yuan Yao , Sun Rong Lin , Chen Ren Quan
Published: September 2013

Hydraulic conductivity (K) and scale effects in basalt in the dam area of Xiluodu hydroelectric station were investigated by three kinds of field hydraulic tests with different test scale, 2608 water pressure tests in single borehole, 54 water seepage tests in adit and groundwater tracer test. Statistical results show the high heterogeneity of fractured rock and K difference between two neighboring test intervals are often more than two orders of magnitude. However, there is a strong decreasing trend of hydraulic conductivity with the increase of vertical depth. Moreover, these three kinds of hydraulic test results demonstrate that hydraulic conductivity increases with the increase of test scale in heterogeneous basalt and the heterogeneous degree of K decreases with the increase of test scale. K from water seepage test in adit, with the test scale of 1-2 m, is dispersed from 0.00024 m/d to 3.46 m/d. K from water pressure test in single borehole, with the test scale of 4-7 m, is 0.0002-1.04 m/d. K from groundwater tracer test, with the test scale of 70-145 m, is concentrated between 0.46 m/d and 2.1 m/d. High heterogeneity of fractured rock and multi-level of fractures are thought as the major reason resulted in scale effects of hydraulic conductivity.
Simulation of the Changes of Flow Fields by Ecological Islands in Wohushan Reservoir
Authors: Niu Ming Hui , Xu Zheng He , Kong Ke
Published: September 2013

Based on the MIKE21 software, the water quality model to simulate flow field, velocity, and proliferation of pollutants before and after ecological islands is established in Wohushan Reservoir. It consists of mass equations and momentum equations. The results indicate ecological islands can ease the phenomenon of reservoir circulation and speed up the water exchange rate in the vertical direction that shortens the recovery time of water. The study provides a strong guarantee for water resources regulation, management and protection of Wohushan Reservoir.
A Zonal Watershed Hydrological Model Considering Land use and Land Cover Change and its Application
Authors: Li Xi Nan , Xie Ping , Zhu Yong
Published: September 2013

In order to evaluate quantitatively the hydrology and water resources effects of land use and land cover change (LUCC), a zonal watershed hydrological model considering land use and land cover change (ZWHM-LUCC) was developed. According to the daily rainfall, evaporation and discharge data of Wuding River Basin during 1980~2000, the parameters of the model were calibrated and verified. The results show that coefficient of water balance (R) is 1.004 and the qualified rate of annual runoff depth (DR) is86.67% during calibration period 1986~2000 and the R is 0.938 and the DR is 66.67% during calibration verification 1980~1985. The calculated results indicate that this model has good adaptability in Wuding River Basin. The different scenarios of land use/land cover were analyzed by the model, with 2000 year as base year, 13 scenarios were designed, which be helpful to study water-economy-ecology interactions and natural-social dualistic, and provide the scientific basis for Wuding river basin water and soil conservation planning and water resources planning.
Evaluation of Seismic Landslide Runout Distance Based on the Fuzzy Mathematics and Range Analysis
Authors: Zeng Yao Xun , Fan Xiao Yi
Published: September 2013

The Runout Distance is One of the most Important Factors of Landslide Hazard. it Not only Controls the Hazard Area but also Influences on the Landslide Hazard Assessment. Based on the Data of Landslides Induced by the Wenchuan Earthquake, the Six Slope Structures, Including Rock and Soil Mass, Slope Type, Gradient (α), Slope Height ( h), Azimuth Difference between Slope-Aspect and Strata Trend(θ1), Difference between Slope Gradient and Obliquity of Rock Layer (θ2), and Seismic Intensity were Selected to Evaluate the Landslide Runout Distances. the Evaluation Model of Landslide Runout Distance was Proposed by the Combination of Fuzzy Mathematics and Range Analysis. the Results Indicated that it was Different that the Slope Structures Influenced on the Runout Distance in the Different Volume Scale. According to the Evaluation Model, the Typical Landslide Runout Distances were Studied, and the Evaluation Results Accord with the Actual Runout Distances.
Slope Cracks in the Safety Assessment of the Rainfall Period
Authors: Chang Te Hsing , Lin Chi Li , Huang Fu Kuo
Published: September 2013

Unsaturated cracked slopes are easily to be affected by rainfall in the soil. Actually, some of the rainfall becomes the surface runoff and the rest permeates the crack under the ground in water cycle system. The infiltration makes the groundwater level rise. It also increases the pore water pressure and slide stress of the soil and decreases the anti-shear strength of soil. That makes the slope fracture or deform. However, most of the slope stability analyses set the physical properties of the soil as constant values but neglect the influence of the crack and infiltration. Those analyses underestimate the influence of the crack and the change of water content to the anti-shear strength of the soil. Therefore, it was unable to predict the possible damage time point by these evaluation results. The knowledge and methodology of the rainfall combine infiltration and slope stability analysis in this research. Simulations of the moisture content of the soil and the groundwater level are performed by FEMWATER numerical model. The simulating conditions are based on the different cracked positions and rainfall durations. The data of moisture content changes of the soil will be transformed into the parameters of safety factors fitted by STEDWIN numerical model. The influence of the slope stability with different cracked positions was gained from the simulations.
Slope Stability Forecast of LS-SVM Based on Chaos Genetic Algorithm Optimization
Authors: Cai Zheng Long , Meng Yong Dong , Wang Rui Yao , Lu Wei Ping
Published: September 2013

As the relationship between geotechnical slope stability and influencing factors is complex and nonlinear, the least squares support vector machines (LS-SVM) is used to establish the nonlinear relation between slope stability and influencing factors. And in consideration of that parameters selection of LS-SVM exerts a major influence on modeling results, the parameters of LS-SVM are optimized by chaos genetic algorithm (CGA). Thus the CGA LSSVM is proposed for forecasting slope stability. Through the comparison between the method and the simple genetic algorithm (SGA) parameters optimization. The result shows that parameters optimization of the CGA has better faster convergence speed, higher prediction precision. And the model is applied to predict the safety factor of the actual slope engineering and the results are well consistent with the actual situation. It is shown that the model is reasonable and feasible.
Research on Liquefaction Characteristics of Saturated Undisturbed Loess under Different Level of Liquefaction
Authors: Wang Qian , Wang Lan Min , Liu Hong Mei , Wang Jun , Dong Lin
Published: September 2013

On the basis of the dynamic triaxial liquefaction test of the loess samples which were taken from the Shibei tableland, Guyuan city, and evaluating the liquefaction potential of the loess through laboratory experiment and response analysis. Then the liquefaction characteristics of saturated undisturbed loess under different level of liquefaction are analyzed based on the evaluation results. The results are shown that: when the saturated undisturbed loess liquefaction is light, dynamic stress is decayed barely, weak dynamic residual deformation is generated, pore water pressure begins to grow, the dynamic stress dynamic strain stagnant curves have not marked change, and the deformation of the soil is at viscoelastic stage. When the loess liquefaction is middling, attenuation of dynamic stress is not obviously, dynamic strain is increasing, amount of pore water pressure much higher than stage one, the long axis slope of hysteresis curves is reduced significantly, the sizes and shapes difference of adjacent hysteresis loop is obvious, and the deformation of the soil is at viscoelastic-plastic stage. When the loess is liquefied completely, dynamic stress is decayed evidently, dynamic strain increased dramatically, and its crest value could exceed 10%, the peak value of pore water pressure is sustainable increasing, and emerge the apparent fluctuation under the action of a drastic dynamic strain, the form of the stagnant curves tend to be irregular, the loess is in elastic-plastic stage.
Development and Application of Monitoring and early Warning System for Geological Disasters in Highway High Slope
Authors: Lei Ting , Tan Zhuo Yin , Lin Chuan Xiang
Published: September 2013

According to the characteristics of geological disasters in highway high slope, rainfall and fissure deformation of rock mass are determined as major monitoring objects. Meanwhile, based on wireless communication technology, a hardware system for monitoring geological disasters in highway high slope, composed of rain gauge, displacement meter, data collection and transmission equipment and wireless early warning device, is established. Finally, based on network-based programming technology and SQL Server2005 database platform, a monitoring and early warning software for geological disasters in highway high slope, integrating all functions of sensing, transmitting, realizing and applying, is developed to achieve remote real-time monitoring, visualization management, data analysis and remote early warning.
Damage Identification for Masonry Materials Based on Bayesian Inference
Authors: Fu Xiang Ping , Peng Bin , Ji Zheng
Published: September 2013

The basic frequency of masonry specimens can be obtained by dynamic tests with ambient or artificial excitation. The elastic modulus of masonry structures, as well as the damage factors, can then be determined by training their finite element models and make the calculated frequencies agree with the measured ones. Using 530 groups of dynamic test data, the damage factors of four masonry specimens were identified. The Bayesian inferences of the highly diverse measured results were conducted through a Markov Chain Monte Carlo (MCMC) sampling method, and the location of the damage was identified. The methodology was applicable, and can be used in the damage identification for other materials or structures.
Effect of the Hydration Heat on Creep
Authors: Rao Rui , Huang Yong Hui , Liu Ai Rong
Published: September 2013

A method for the box girders creep calculation considering the hydration heat is proposed and the effect of the hydration on the creep is discussed. The box girder is divided into several components and the average hydration temperature of the component is defined to represent the general condition resulted in the hydration. The formulae of the average hydration temperature have been recommended based on the discussion with respect to the formulae accuracy. The effect of the hydration on the creep is changed into that of the variable age of loading and the relationship between them is also given. It has been found that the hydration decreases the creep stress obviously.
Digital Image Correlation Test System with Automatic Transmission for Quasi-Brittle Material
Authors: Yue Hong Liang , Zhang Chun Hui , Wang Yan
Published: September 2013

To realize the automatic transmission for present digital image capture test system, a new system which consists of laptop computer, camera, fixing device and mechanical testing machine was presented and designed. The Monitor software, which was developed using MATLAB to realize automatic transmission function for the system, includes slow and high speed. The general stage and key stage for quasi-brittle materials can be effectively captured by the software. With MATLAB, the digital image correlation software (DIC) was developed. In DIC the first image is used as the base image. The images are sorted by photographing time (or file name), and the listing file is generated. The grid is drawn on the base image to divide the area into ‘facets’, the size of which can be adjusted between 1pixel and 100 pixels. Based on fast Fourier transform and convolution algorithm, the image comparison is realized and the deformation of the material is calculated. The designed system is applied to the compression test of a concrete specimen, and the results show that the system realizes automatic transmission image capture, and calculates accurate displacement. The displacement distribution is uniform in linear elastic stage, and varies in yielding stage. This is mostly due to localized failure and displacement discontinuity.
Deepwater Pile Foundation Construction Technology of Xiaoyi Reservoir Bridge
Authors: Li Zhong Mei
Published: September 2013

Construction of deepwater pile foundation is difficult and complex. By the example of Xiaoyi reservoir bridge, this paper introduces the construction scheme of the pier in the water, which is building temporary bridge and drilling platform. Field-operation platform and steel sheet pile cofferdam. Engineering practice proves that this construction scheme can speed up construction schedule, and can ensure the quality of construction, which offers mirrors and references for similar engineering.
Experimental Study on the Shear Behavior of Recycled Concrete with Artificial Sand
Authors: Lan Wen Wu , Yao Zhi Peng , An Yi , Chen Li
Published: September 2013

This study examines the shear behaviors of concrete structure with recycled concrete and artificial sand (AS). Thirty-six beams were prepared with two strength grades (C35, C45) and different artificial sand replacement rates (0%, 30%, 50%, 70%, and 100%). They were submitted to four-point static stress test in order to distinguish the shear behaviors of ASCRC (AS-containing recycled concrete) and of natural concrete that is fabricated using original coarse aggregate and natural sand. Experimental results found the shear strengths values of the ASCRC were lower than the nature ones, with decreasing extents less than 20%. When AS-containing level ranged from 30% to 70%, the cube compressive and shear strengths were more lower than other replacement ratios. Shear force-shear strain curve of the ASCRC was found similar to that of the nature concrete. The peak strain of the ASCRC rose with the increase of the shear strength, but the slope of the curves was lower.
Buckling Behaviors of Steel-Concrete Composite Plate
Authors: Li Fa Xiong , Liu Qian , Huang Hou Qing
Published: September 2013

The flexibility of connection between the steel plate and concrete slab gives rise to interface slip and additional deflection. A method of analysis for steel-concrete composite plate with slip effect resulting from studs is presented. The basic idea is to place a hypothetical thin shear-layer between steel and concrete slab, where all the shear deformation is concentrated in the thin layer. Analytical solutions for elastic critical buckling load of composite plate considering slip effect under axial compressive and pure shear are derived. The theory model and the solutions are then validated by means of three-dimensional finite element analysis.
Researches on Cement Cold-Recycled Base
Authors: Wang Tan , Wang Wei , Liu Tao
Published: September 2013

This article presents the recent advances in cold-recycled waste pavement materials with cement. It introduces various factors of influence on pavement performance, including cement content, gradation, reclaimed asphalt pavement (RAP), optimum moisture content (OMC), compaction density and curing conditions; explores main pavement performance, such as mechanical properties, shrinkage properties, fatigue properties and water stability properties of the cement cold-recycled mixture; summarizes the application experience of the cement cold-recycled mixture; pointes out the research topic of cement cold-recycled base at present, which includes properties of old pavement materials, the application of additives, the establishment of pavement performance evaluation indexes and systems, etc.
Influences of Fly Ash Level on Cementitious System Performance of Concrete Based on the Quantization Parameter Analysis
Authors: Shi Liang , Wu Ye , Liu Jian Zhong
Published: September 2013

In order to achieve a scientific selection of fly ash used in concrete, the influences of fly ash level on cementitious system rheological parameters, hydration degree and capillary adsorption properties were quantitative analyzed. The results show that Class I fly ash reduces the yield stress and plastic viscosity of cementitious system. The yield stress of system increases dramatically and the plastic viscosity of system reduces when Class III fly ash added. Rheological parameters of cementitious system change little when Class II fly ash added. The higher level fly ash uses the more CSH gel generates and the less Ca(OH)2 crystals generates in cementitious system at early age (3d to 7d). High level fly ash increases the cement paste initial capillary adsorption amount but reduces the capillary absorption rate.
Experimental Study of Slag Powder Fineness Effect on Concrete Performance
Authors: Li Bin , Hang Mei Yan , Dong Su Fen
Published: September 2013

Slag powder can improve concrete compression strength and durability owing to the activity of volcano ash and powder filling effect when replacing cement as active mineral admixture. Test results show that the 28-day strength can reach to 74MPa if slag powder with the fineness 810 m2/kg is used to replace 60% cement when making C40 concrete. And at 4.0MPa water pressure, the seepage height can be only 12mm, the electric flux in 6 hours can drop by 72% than that didn't use slag powder, the ability of freeze-thaw cycle can reach F350. But attention should be paid to the grinding process impact on the economy of the massive practical application process.
Fly-Ash Concretes of 50% of the Replacement Ratio to Reduce the Cracking in Concrete Structures
Authors: Mao Ming Jie , Yang Qiu Ning , Zhang Wen Bo , Yoshitake Isamu
Published: September 2013

Fly-ash concrete used in massive concrete structure has superior advantages to reduce hydration heat. On the other hand, the fly-ash concrete has negative property of low strength development at early age because pozzolanic reaction of fly-ash activates at mature age, such as after 28 days. To investigate these characteristics of fly-ash used in concrete, the present study discusses thermal cracking possibility of fly-ash concrete by using FE analysis software. The present study employs prediction formulae proposed by Zhang and Japanese design code in the simulations. The objects in this study are normal strength concrete mixed of fly-ash up to 50% of replacement ratio to cement. The comparative investigations show that temperature effect is more significant than strength development at early age. Based on the analytical study, high volume fly-ash concretes of 30-50% of the replacement ratio can be concluded as effective and useful materials to reduce the cracking possibility in massive concrete structures. Keywords-Fly-ash concrete; Early Age, Prediction Formulae for Strength; Thermal Stress Analysis
Research on the Mixture Ratio Design of Ultra-High Strength Concrete
Authors: Xu Li Bin , Feng Nai Qian , Tew Kia Hui
Published: September 2013

Ultra-high strength concrete (including the coarse aggregate of over 5mm), with high compressive strength and strong durability, is regarded as a new-type building material that could economize on raw materials, land and energy and the development trend of concrete technology both at home and abroad. However, the large consumption of binding materials, low water-binder ratio and the viscous mixture are prone to give rise to the inferior pumping capacity, pipe blockage and pipe break, thus preventing its massive application in the real projects. Therefore, through the design of reasonable mixture ratio, this paper makes up and produces the pumping ultra-high strength concrete of over 100MPa that contains coarse aggregate by adopting the compound design of mineral admixtures, such as slag powder, fly ash and ganister sand so as to optimize the relevant parameter of the mixture ratio. Finally it comes to the conclusion that while making up the ultra-high strength concrete of over 100MPa, it is much more reasonable to appropriately add the mixing amount of the mineral admixtures, increase the water-cement ratio and decrease the water-binder ratio.
Mineral Lightweight Renders of Modified Composition for Final Facade Surface Treatment
Authors: Melichar Tomáš , Bydžovský Jiří
Published: September 2013

The intention of the research presented in this article was to study the basic physico-mechanical parameters of mineral lightweight renders. Both alternative and primary raw materials were used to modify the filling agent; namely utilized quartz sand, diatomite and hydrophobised perlite. Determining and evaluating the basic parameters of plasters with the modified composition enabled to assess the effect of substituting the filling agent within the particular designed formulas. Emphasis was placed on the parameters in the fresh and hardened conditions of the plasters – workability, water volume, density, compressive and flexural strength. It was found that by appropriately adjusting the water dosage then better parameters could be obtained than in the reference formula – commonly commercially produced renders.
Dynamic Response and Damage Mechanism of Two-Core Composite Sandwich Panels under Low-Velocity Impact
Authors: Li Chang Liang , Jiang Da Zhi , Zeng Jing Cheng , Xing Su Li
Published: September 2013

Dynamic response and damage mechanism of two-core sandwich panels with foam and honeycomb cores and glass fiber/epoxy composite sheets under low-velocity transverse impact are investigated. The emphasis is focused on the contact force response and crash mechanism of the two-core sandwich panels. Effects of configurations, impact energy levels and types of the cores on the dynamic response are investigated. A modified drop-test experiment is carried out to obtain contact force history of the two-core sandwich structures under different impact energies. The experimental results show that the 10:10 configurations for both honeycomb and foam core sandwich structures under lower impact energy absorb more impact energy than the other two structures. However, under higher impact energy, the honeycomb core sandwich structures of 15:5 configuration absorbs a little more impact energy than the other two, while for the foam core sandwich structures the 5:15 configuration shows a little better impact resistance. Results also show that when impact energy is low foam core sandwich structures do better in absorbing impact energy than the honeycomb ones.
Undrained Shear Strength Characteristics of Natural Silty Clay
Authors: Yin Jie , Miao Yong Hong
Published: September 2013

Triaxial consolidation undrained shear tests were carried out on both undisturbed and reconstituted samples of natural silty clay to investigate their undrained shear strength characteristics. Test results suggest that the strength envelope of the undisturbed sample is composed by two straight lines, which is different from that of the strength envelopes of reconstituted samples showing a straight line through the origin. Undrained shear strength of undisturbed samples are larger than corresponding reconstituted samples due to the resistance of soil structure in the pre-yield stress state. In the post-yield stress state, however, strength envelope of the undisturbed sample lies among the reconstituted samples with different initial water contents. Undrained shear strength for undisturbed samples in the post-yield stress state and reconstituted samples can be well correlated with the water content under different confining stress, which implies that undrained shear strength mainly depends on the current water content.
Exploration into Anticorrosive Property of Antirust Compound-Admixture
Authors: Yang Xiao Cao , Zhan Shu Lin , Lai Jun Ying
Published: September 2013

This paper studied the influence on corrosion resistant performance through the rust resistance performance tests and the resistance to chloride ion penetration tests. In the tests, four test specimens were prepared: (a) blank sample without corrosion inhibitors or composite admixture; (b) mix 20% composite admixture replacing the cement; (c) mix 2% organic inhibitor replacing the cement; (d) combine 20% composite admixture and 2% organic inhibitor replacing the cement. The results showed that both of the composite admixture and the organic inhibitors had the ability to prevent steel corrosion in concrete structures and had their own advantages respectively. Mixing mineral admixture and inhibitor together had synergy effect and had more obvious anticorrosion effect, which helped the specialized production of antirust compound-admixture to ensure homogeneity of concrete.
Influence of Mineral Admixtures on Chloride Diffusion Coefficient of Self-Compacting Concrete
Authors: Xiong Jian Bo , Li Peng Ping , Wang Sheng Nian
Published: September 2013

The influence of mineral admixtures on workability of fresh concrete and chloride ion permeability resistance of hardened concrete for C50 self-compacting concrete was investigated by means of the Natural Immersion Test. The results showed that the chloride diffusion coefficient in fly ash concrete decreased first and then increased with increasing fly ash content in cementitious materials, when fly ash content was 30% or 40%, it got the lowest value at 28 days or 90 days, respectively. The chloride diffusion coefficient in specimens decreased with increasing the ground granulated blast furnace slag content in cementitious materials, but it changed little when the replacement was in ranges of 50% to 60%. Furthermore, for the specimens which replaced by fly ash and ground granulated blast furnace slag, the chloride diffusion coefficient decreased first and then increased with increasing the fly ash content in complex cementitious, and when fly ash content was 10% or 20%, it got the lowest value at 28 days or 90 days, respectively.
Effect of Fly Ash and nanoCaCO3 on the Setting Time of Cement Paste
Authors: Zhao Zhi Qin , Ge Zhi , Sun Ren Juan , Xin Gong Feng , Huang Da Wei
Published: September 2013

This paper presents an experimental study to evaluate the effects of fly ash and nanoCaCO3 on setting time of cement paste. The test group included the contents of fly ash was 30%, 40%, 50%, 60% and content of nanoCaCO3 was 2.5%, 5%, 10%, 20%. Results indicate that setting time was increased with the incorporation of fly ash, shortened with the incorporation of nanoCaCO3. The incorporation of 5% nanoCaCO3 by mass of cementitious materials reduced initial and final setting times by 60 and 70 min, respectively. In comparison to the referenced paste with 40% fly ash. The best fly ash content appear to be 40% when nanoCaCO3 was added.
Mechanical Properties and Applications of Engineered Cementitious Composites (ECC)
Authors: Zhao Zhi Qin , Sun Ren Juan , Feng Zi Qiang , Wei Shan Shan , Huang Da Wei
Published: September 2013

Engineered Cementitious Composite (ECC) is a fiber reinforced cement based composite material, which systematically designed on the basis of micromechanics and engineered to achieve high ductility under tensile and shear load. The article introduced the development of ECC as advanced construction material, shown different mechanical properties of ECC, tensile strength, compressive strength, bending strength, shear strength. And in light of recent and future full-scale field applications of ECC were also summarized.
Predicting the Shear Strength of High-Strength Steel Fiber Reinforced Concrete Beams without Stirrups
Authors: Wang Zi Guo , Sun Yu Yan , Mao Jian Feng
Published: September 2013

This paper predicts the shear strength of high-strength steel fiber reinforced concrete (SFRC) beams without stirrups based on existing experimental test results from 5 previous studies. A suitable model was developed by performing linear regression analysis on the database. The adequacy of the model was examined from statistical point of view.
Energy Saving Analysis on the Recovery Fresh Air Heat Pump Units of a Public Building
Authors: Chen Ao Xue , Liu Hai Long
Published: September 2013

In this paper,the recovery fresh air heat pump units were used to heating in winter for a public building in the city of Jilin China,compared the original design of the engineering with the new design,analyzed the economy,energy saving and emission reduction of the new design scheme.The new design scheme can save standard coal consumption about 33.74 tons, operating cost saved about 28000 yuan, operation power less than the original scheme, it saved 83600 kWh and electricity 43900 million yuan.It reduced the pollutant emissions and saved the administrative costs. Using the new design scheme, system recovery period was 1.07 years.
A Comprehensive Analysis of Soft Soil Foundation Pit Accident
Authors: Hu Hui , Tang Lian Sheng , Lin Xing Li , Kuang Fei
Published: September 2013

Factors affecting the supporting structure in a soft soil foundation pit are analyzed in this paper. Based on the information obtained from accident investigation, design factors and construction factors, such as insufficient embedded depth of pile and insufficient anchor pullout resistance, are discussed in detail. The analysis and conclusions can serve as a good reference for similar projects design and construction.
Internal Wave Real Time Measurement System
Authors: Zheng Pei Nan , Li Xiao Ting , Miao Jing Jun
Published: September 2013

This paper introduced the significance of marine internal wave detecting, analyzed the status situation of internal wave measurement technique in the world, and then put forward a kind of measurement system for detecting ocean internal wave. The system can measure all kinds of environment data (temperature, salinity, depth, turbulence and so on) on a perpendicularly profile by the under-water rising-sinking platform, and it can also transmit investigation data to shore workstation by the satellite in real time or a setting time. The system is made up of rising-sinking float platform, moorage platform, callback equipment, stowing system in ship or on land and so on. The data gained can be transmitted to shore by satellite. The system can continuously work about 3 months, internal wave can be realized measured between 0-300m, the extend system can be reached to 4000m maximal depth. The system can detect internal wave effectively in long time, it has an important military and social sense.
A Study on Node Connection Technology of Wood Structure
Authors: Bian Zhi Hui , Wang Tie Cheng , Zhao Shi Yong , Li Xu Guang
Published: September 2013

As an important component of modern wood frame system, the design and construction of node are also constantly developing. By taking Sino-Canadian Exchange Center for Low-carbon & Building Energy-saving housing project for example, this paper is to introduce the node connection technology of the wooden structure in three aspects:new joint connection technology of Wood components , connection of Wood - concrete structures and node details processing in the wood structure, which plays a positive reference role in the development and promotion of modern wooden architecture node technology.
Nodal Collocation for the P-Convergent Scheme in Boundary Element Technique
Authors: Woo Kwang Sung , Jang Won Seok , Kwon Yoo Mi , Jo Jun Hyung
Published: September 2013

The concept of the p-convergent boundary element modeling has been presented to analyze the potential problem with L-shaped domain. The details of the p-convergent boundary element formulation are discussed. These include the equations of nodal collocation for the p-convergent scheme, selection of higher order hierarchical shape functions, techniques for integrating the product of the kernel functions and corresponding shape functions, strategies for selecting collocation points used in approximating the unknowns associated with the higher order shape functions, and program organizations. A numerical example that demonstrates the performance of the p-convergent boundary element formulation is shown with respect to different arrangement of collocation points including both symmetric non-hierarchical pattern and non-symmetric hierarchical pattern.
The Collapse Load of Plates by Hierarchical C0-Plate Element
Authors: Woo Kwang Sung , Yeo Yong Hwan , Lee Dong Woo , Yang Seung Ho
Published: September 2013

Although a structural analysis of plates based on the linear elastic theory yields good results for deformations and stresses produced by working loads, it fails to assess the real load-carrying capacities of plates on the verge of yielding. In the case of a limit analysis of plates, the yield line theory is widely used on the basis of the upper bound theorem and theoretically it overestimates the strength of plates. That is why the p-version of the finite element method has been proposed for determining the accurate limit load of plates causing collapse. In this method, the hierarchical Co -plate element for bending of elastic-plastic plates accounting for transverse shear effects has been formulated, and is based on the incremental theory of plasticity and the Reissner-Mindlin plate theory. The numerical results are presented for a variety of rectangular plate problems and are compared to the results obtained by the h-version software ADINA, as well as with the available analytical solutions in literature.