bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Constitutive Model Research on Concrete (Uni-Axial or Multi-Axial)
Authors: Yao Jia Wei , Sun Shi Yong , Chen Hao Ran
Published: June 2011

Combined with Jones-Nelson-Morgan model applied to ceramics and graphite successfully, the nonlinear constitutive model of concrete is obtained through large number of tests in this paper. The model takes concrete as nonlinear elastic isotropic material. By using strain energy function, it makes the nonlinear mechanics behavior of concrete as the function of strain energy. According to the mechanics behavior of concrete, a simple model is obtained by increasing stress to realize the model calculation program. The model can be extended to the constitutive model analysis of concrete under biaxial stress. The theoretical model conforms to testing results well.
An Investigation into Mechanical Properties of Self Compacting Concrete Incorporating Fly Ash and Silica Fume at Different Ages of Curing
Authors: Askari Ahmad , Sohrabi Mohammad Reza , Rahmani Yousef
Published: June 2011

In the present study, mechanical properties of self compacting concrete containing fly ash and silica fume as cement replacements are investigated at different ages of curing. Mechanical properties of specimens were examined at 7, 28 and 120 days for compressive strength and 28 days of curing for tensile strength. So as to reach self compatibility, different tests were carried out on fresh concrete such as slump flow test, T50, J-Ring, V-funnel and L-Box test. Self compacting mixtures had a cement replacement of 20, 30 and 40% with class F fly ash and 5, 10 and 15% with silica fume. The results show that normal strength self compacting concrete could be successfully produced using fly ash and silica fume.
Advanced Early Strength Agent Development and Mechanism Analysis
Authors: Shi Yun Zhong , Wang Qi , Song Peng , Jia Li Li
Published: June 2011

Preparation of advanced early strength agent ,the main components including organic A, organic B and calcium nitrate. Then tested advanced early strength agent performance for concrete. Though text, we find, the compressive strength and flexural strength of the specimen, use of the advanced early strength agent is greatly improved than with its much better not to use advanced early strength agent. With the passage of time, advanced early strength agent added does not make the strength of concrete worse, but better.Use SEM and XRD analysis technology text advanced early strength agent by adding performances of concrete, including the degree of cement hydration, the morphology of hydration products and the composition of mineral formation. analysis of the role of advanced early strength agents from the perspective of the mechanism. Identified advanced early strength agent impact on the cement hydration, for the further development of early strength agent to provide a theoretical basis.
Effect of Cement on Compressibility and Microstructure of Tropical Peat
Authors: Kazemian Sina , Prasad Arun , Ghiasi Vahed , Huat Bujang Bin Kim
Published: June 2011

Peats are geotechnically problematic soil due to their high compressibility and low shear strength. Cement is widely used for the stabilization of peat by deep mixing method (DMM). This paper presents the results of the model study of compressibility property of peats stabilized with cement columns formed by DMM. The results of consolidation test, scanning electron micrographs (SEM) and energy dispersive x-ray spectrometer (EDX) showed that the compressibility of peats can be improved significantly by the installation of cement stabilized columns. The amount of cement used to form the column was observed to influence the engineering behaviour of treated tropical peats and it had more influence on sapric peat than on hemic and fibrous peats.
Finite Element Analysis on Moisture Distribution within RAC under Standard Drying Conditions
Authors: Guo Yuan Chen , Wang Xue , Sun Ke Wei
Published: June 2011

With the mass diffusion module of ABAQUS, the moisture diffusion behavior of recycled aggregate concrete material (RAC) was investigated in this work. The simulation was carried out under the standard drying conditions (Ambient humidity: H=60%; Temperature: T=20°C). The results indicate that: with the dry age grows, the water evaporation begins from the RAC’s surface first, and the water concentration reaches the equilibrium value rapidly; then the evaporation process gradually extends to the interior, but the process is quit slowly. In moisture diffusion process, the water concentration takes on gradient distribution. the calculated value of water concentration matches well with the experiment results, and can provide a theoretical base to the caculation of drying shrinkage stress of RAC.
Effect of Fly Ash Content on Properties of Fly Ash-Coal Gangue Foam Concrete
Authors: Wu Che Ping , Yu Xin Gang , Gao Yan Na , Xiao Huaan , Li De Jun , Luo Shi Song
Published: June 2011

The effect of the fly ash content on the properties of the fly ash-coal gangue foam concrete was studied in this paper. Results revealed that: With the increase of the fly ash content, the dry density, the compressive strength and the shrinkage of the fly ash-coal gangue foam concrete decrease; the density of the fly ash - coal gangue foam concrete was influenced greatly by the ratio of water to total dry material. The pore structure and microstructure of the foam concrete was analyzed by scanning electron microscopy, and the results show that most of the pores are fine, closed, and even distributed.
The Research on Performance of Hollow Partition Precast with Recycled Concrete
Authors: Min Zhong , Xie Bin
Published: June 2011

The properties of hollow partition such as compression strength, impact resilience, hanging capability, sound insulation capability are investigated systematically. The results of experiment indicate that if the content of waste concrete was less than 70% the mechanical behavior of the partition is acceptable. When the content of wastes was appropriate the hollow partition precast with recycled concrete have good physical properties.
Study on the Workability of High Strength Concrete with the Grading of Coarse Aggregate Skeleton Structure
Authors: Tian Er Bu , Wang Feng Chao , Zhang Ren Wei , Ji Tao
Published: June 2011

People often use superplasticizer and mineral admixtures (such as steel slag, slag, etc.) to increase the density of concrete and improve concrete strength, but don’t use coarse aggregate gradding. The paper selects the coarse aggregate of skeleton structure from several grading concept, and uses Uniform Design to test high strength concrete workability, and analyses results. It is shown from the results that the method of Uniform Design can significantly reduce the workload, and concrete mixture slump increases linearly with the water-cement ratio and sand percentage, but decreases linearly with steel slag addition, and the water released from the flocculation of cement by superplasticizer can increase the slump, and most of water plays the role of lubricant before it reacts with cement, and the effect of slump that sand extends coarse aggregate skeleton are greater than that sand surface area increases.
Prognostication of Concrete Mix Proportion by ANN Approach
Authors: Gowda Keerthi , Prasad G.L.Easwara
Published: June 2011

An exhaustive literature survey shows, that a very little effort has been done towards Artificial Neural Network (ANN) approach in the area of concrete technology [1, 2, 3]. In the present investigation, development of ANN approach for prognostication of concrete mix proportion in lieu of conventional laboratory approach. The traditional lab approach attracts some drawbacks such as lot of manual involvement, time consuming, chances of creeping of human errors, uncertain prediction and always invasive in nature. Hence to reduce above said drawbacks, this study is undertaken to develop a ANN between concrete mix ingredient properties namely maximum size of aggregate, degree of quality control, degree of workability, type of exposure, characteristic compressive strength required in the field at 28 days and concrete mix proportion. Prognostication of concrete mix proportion is essential for all structural works. The present work deals with collection of huge input data base from literatures, ANN’s training and its testing are adopted to fix the appropriate weighted matrix (Illustrated in Fig [1]) which in turn Prognosticates the appropriate concrete mix proportion. Indian standard code (IS 10262:1982) procedure is also adopted to compare the concrete mix proportions of same samples. The Prognosticated concrete mix proportion from ANN approach yielded very high accuracy results (As shown in fig [2]) compared with IS code method. To account for larger sample data the results of this work will contribute for the prognostication of concrete mix proportions up to a certain degree of level, which will assist a structural engineer in estimation of concrete mix proportion, with minimum effort and non- invasive technique.
Application and Research of High-Strength Steel Fiber Reinforced Concrete in a Project
Authors: Zhu Xiao Fei , Lv Da Wei
Published: June 2011

The application of steel fiber reinforced concrete as a new type of structural material, has unique advantages and wide application prospects. A special structural engineering, the use of high strength steel fiber reinforced concrete, to explore this technology for the construction of a key node in the construction process to elaborate.
Effect of Admixtures on Dynamic Elastic Modulus of Cement Paste at Early Age
Authors: Huang Dong Hui , Wu Sheng Xing , Wang Xiao Jun , Zhao Hai Tao
Published: June 2011

The elastic modulus of cement paste is the key parameter for characterizing the mechanical response of concrete. In modern concrete technology, the admixtures are often used to enhance the performance of concrete. This paper introduces a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of cement paste is investigated, in which three kinds of admixtures are taken into account including Viscosity Modifying Admixture (VMA), Silica Fume (SF), and Shrinkage-Reducing Admixture (SRA). The results from experimental investigation indicate that the dynamic elastic modulus of cement paste increases with decreasing water-cement ratio. The addition of SF increases the dynamic elastic modulus, however, the overdosage of VMA causes its reduction. SRA reduces the elastic modulus at early age without affecting the elastic modulus at later period.
Approach to the Load Resistance in Two Kinds of Bamboo Reinforced Concrete Slab
Authors: Flores Bastidas Camilo , Flores Bastidas Constanza Lucia , Tsutsumi Jun Ichiro Giorgos , Takeuchi Caori Patricia
Published: June 2011

Steel reinforced concrete is generally used in houses structure elements. However bamboo strength properties similarly to the wood, make it an alternative concrete composite material. Load test were performed in two kinds of bamboo guadua concrete reinforced composite slabs. During the tests the slabs functioned as domestic roofing-flooring in standing houses, the slab systems tested were bamboo stem covered slab and stem free slab. Two different tests were designed to measure the deflection in the middle of the composite slab and along a single bamboo stem. In three different slab sizes and after replications, no deflection under the applied load was recorded. Therefore, bamboo composite slabs without steel reinforcing seem likely to be used in long lasting houses for middle and high class dwellings in Colombia.
Investigation of Properties of Low Thermal Conductivity Pozzolanics Soil Bricks Towards Sustainable Development
Authors: Namboonruang Weerapol , Rawangkul Rattanakorn , Yodsudjai Wanchai , Khedari Joseph
Published: June 2011

The development of new alternative type of pozzolanics soil bricks using the locally available clay from Ratchaburi province were mixed with fly ash from Kanchanaburi province, where both source in western of Thailand, is the main purpose of this study. These are compared to the local clay cement bricks without the mixing of flyash in different proportions. In the present work, the physical properties of the specimens are presented namely, compressive strength, modulus of rupture, thermal conductivity and unit weight. Tests were also conducted to study the influence of time of curing on the increase in physical properties of the bricks. It was concluded that the addition of fly ash reduces the thermal conductivity and unit weight, while increases the water adsorption property of the specimen. The compressive and flexural strength are decreased when the ratio of fly ash is more than 30 percentages. However, when considering the various factors it can be said that, appropriately ingredient toward produce to commercial of the good pozzolanics soil bricks is portland cement constant was 5 percentages and 30 percentages of fly ash by weight basis of soil at water per total powder, W/P 0.3525. The compositions of fly ash more than 25 percentages by weight basis of soil and since up to 14 days of curing time proved to be economical mixtures for load bearing panels or brick type structural elements according to the Thai Industrial Standard(TIS) for structural clay load-bearing tile. Therefore, commercial development is highly promising.
Preliminary Exploration of On-Line Measuring Layer Moisture Content with Electrical Resistance Method during Wood Drying
Authors: Zhou Qiao Fang , Cai Ying Chun , Xu Yan , Zhang Xiang Ling
Published: June 2011

Electrical resistance method was used to detect layer moisture content across the thickness of Larch (Larix gmelinii) specimen during drying, and the temperature of the same layers and the environment were also measured by remote temperature scanner. During the drying process, layer moisture content was obtained from other Larch specimens with slicing method. Layer moisture content measured with electrical method was compared with that acquired with slicing method. Results showed that the wood center temperature was more suitable than the environment temperature as compensated temperature to amend moisture content measuring with electrical resistance method; variation of layer moisture content of Larch specimen could be more or less measured with electrical resistance method, and had a relatively good agreement with that acquired with slicing method except that u15 was 3% higher than U1 and u3 was 4% higher than U3 in the middle stage of drying.
The Effect of Silica Nanoparticles and Cellulosic Fibers on the Compressive, Tensile and Flexural Properties of Ordinary Concrete
Authors: Foroughi Mohammad , Kadivar Marzieh , Nabavi Mohammad Mehdi , Kadivar Mohammad Reza
Published: June 2011

The present paper is a laboratory study on the effect of using silica nanoparticles with cellulose fibers in increasing compressive, flexural and tensile strength of concrete and the results has been compared with ordinary concrete made of cement alone. Evaluation is conducted based on a 28-day long period, and a 7-day short period; the results showed that the concrete containing a small percentage of nanoparticles, with a determined ratio of water and cement, in comparison with ordinary concrete with the same water and cement ratio, has improved considerably. For comparison, compressive, flexural and tensile strength of plain concrete and the concrete containing cellulose fibers is also measured. The results show that by each of these three criteria, strength of concrete containing nano-materials and the cellulosic fibers has been increased considerably. Finally, the relationship between compressive, flexural and tensile strength of concrete shows that the tensile and flexural strength of the concrete containing nanoparticles increases by increasing compressive strength.
Application of Nanotechnology in Civil Engineering
Authors: Nabizadeh Rafsanjani Hamed , Kadivar Mehdi
Published: June 2011

Nanotechnology is a science concerned with the design, construction and utilization of functional structures with at least one characteristic dimension measured in nanometres. Nanotechnology initially developed in the fields of physics and chemistry, and most fundamental developments still occur in these fields. Nanotechnology also needs to be applied in areas such as the engineering field. Obviously, the application of nanotechnology to science and engineering has increased in other fields over the years. One area which is one of the most active research areas in the field of nanotechnology is civil engineering. This paper presents a broad overview of the application of nanotechnology in the civil engineering.
Nanotechnology in Geotechnical Engineering
Authors: Kadivar Marzieh , Barkhordari Kazem , Kadivar Mehdi
Published: June 2011

The present paper reviews the application of nanotechnology in geotechnical engineering, in which the concept of nanotechnology as well as the new concept of nanosol is explained. We have also given explanation for nanometer additives used in the introduced soil, different forms of nanoparticles, their specific properties, and effects of these nanoparticles on engineering properties of soil including index properties and strength, and analyzed the reasons through which these effects are caused. Furthermore, influence of recent advances in nanoinstruments and electron microscopes as well as their application in geotechnical studies.
Experimental Study to Calibrate Monotonic Micromechanics-Based Fracture Models of Q345 Steel
Authors: Liao Fang Fang , Wang Wei , Chen Yi Yi
Published: June 2011

Micromechanics-based facture models have been proved to predict ductile fracture in steel structures with good accuracy. The stress modified critical strain (SMCS) model and the void growth model (VGM) are suitable to predict fracture initiation under monotonic loading. In order to calibrate the parameters in these models for the largely used Q345 steel in China, material tests, scanning electron microscope tests and finite element analyses were conducted. The test specimens were made from base metal, deposit metal and heat affected zone of Q345 steel to investigate crack initiation in welded connections. The results of this paper can be applied to predict ductile fracture in welded steel connections under monotonic loading.
Research on Model of Comprehensive Fuzzy Assessment of Projects Post Evaluation
Authors: Zhu Hong Zhang , Hu Ji Bo
Published: June 2011

We generally use methods of statistical forecasting and antithesis in projects post evaluation, but they can only be used as a qualitative evaluation but as a quantitative evaluation. Based on the fuzzy mathematics, this text presents a better quantitative mathematical analysis-fuzzy comprehensive evaluation method. And then, it established a model of comprehensive fuzzy assessment of projects post evaluation. At last, it illustrate that the model of comprehensive fuzzy assessment can evaluate projects post evaluation accurately and quantitatively.
Comparing Hysteretic Behavior of Flexible Piers with Different Stirrup Ratio and Slenderness Ratio
Authors: Yuan Xiao Jing , Liu Fan
Published: June 2011

Flexible piers have been widely used in bridge engineering due to its superior ductility. The stirrup ratio and slenderness ratio were deemed to have a most important impact on hysteretic behavior of them. Five flexible piers were made under static vertical loads and low cyclic horizontal reversed loads. The process of test was introduced and failure mechanism, hysteretic behavior, skeleton curve, ductility, energy dissipation capacity, and stiffness degeneration of flexible piers were analyzed. Experimental studies show that (1) Failure mode of specimen is bending failure and their ductility factor falls between 4.15 and 6.30; (2) displacement ductility factor improves with increasing of the stirrup ratio. Stirrup could greatly improve the capacity on ductility and energy dissipation, while it has little impact on the bearing capacity; (3) ultimate bearing capacity decline with the increase of slenderness ratio, however, when the slenderness ratio member is larger, the hysteresis curve is fuller and energy-dissipation is better.
Experimental Investigation on Residual Strength of Plain Concrete under Fatigue Biaxial Compression with Constant Confined Stress
Authors: Meng X.H. , Wang W.W. , Zhou J.H. , Song Yu Pu
Published: June 2011

A model of attenuation of residual strength with number of cycles has been founded .In this model the constant confined stress and maximum stress of fatigue loading are both considered. 55 specimens of plain concrete are tested under biaxial compressive fatigue loading with constant confined stress. Based on the data of experiment, the coefficients of the model are determined. The residual strength attenuating curves are shown in the paper. The model can be used to predict the residual life of specimen under biaxial compressive loading with constant confined stress. The results of prediction show that the suggested method is better than the Miner rule.
Microstructural Investigation of Carbonation of Calcium Silicate Hydrate in Hydrated Cement Paste
Authors: Chen Wei , Xu Wen Bing , Li Yuan
Published: June 2011

Carbonation is one of the most common degradation reactions of concrete which greatly shortens the service life of steel-reinforced concrete structure. The carbonation of synthetic calcium silicate hydration derived from hydrated cement paste is investigated with microstructural characterization method including scanning electron microscopy, X-ray diffraction analysis, coupled TG-DSC analysis and Fourier transform infrared spectroscopy. The changes in the morphology, mineral composition and polymerization degree of the calcium silicate gel before and after the carbonation are investigated. The major finding of the research includes that the C-S-H collapses during the carbonation reaction, which actually densifies the microstructure. The major hydration product is calcite. The carbonation resistance of C-S-H is enhanced with increasing C/S ratio. The polymerization degree of C-S-H is increased by the carbonation reaction.
The Influence of Annealing Temperatures on the Crystalline and Photocatalytic Abilities of Anodized TiO2 Nanotube Arrays
Authors: Lee Jyh Wei , Chang Yu Jie , Weng Guo Jie , Lee Chi Kang , Huang Yi Chu
Published: June 2011

The TiO2 nanotube array thin films were fabricated on pure Ti plates by anodization process and annealed at 450oC, 500oC and 550oC for 30 minutes, respectively. The methylene blue (MB) degradation test was further conducted to evaluate the effects of annealing on the photocatalytic ability of TiO2 nanotube array. It was observed that better photocatalytic ability was found for the thin film annealed at 450oC, which was mainly the anatase phase. On the other hand, the anatase/rutile mixed phases were discovered on thin films annealed at 500oC and 550oC, respectively. In this work, the photocatalytic ability of TiO2 nanotube array with mixed anatase/rutile phases was not comparable to that reported in literature. It was suggested that the MB degradation ability was not only related to the crystallinity structure, but also strongly influenced by the surface characteristics of TiO2 nanotube array thin film.
New Waterproof Insulation Roof Building Materials and the Construction
Authors: Zhang Jie
Published: June 2011

In this paper, Portland cement was used as cementitious material and expanded perlite was used as insulation material. Fatty acid salt water repellent was also added to make this new thermal insulation, waterproof and light weight roof building material. It can be cast onto flat roof during construction or made into tiles and laid onto sloping roofs. This new roof building material had short construction period and can be completed in a one-time process. It may replace conventional construction method of applying insulation and waterproof materials separately.
Serpentine Flat Plate Collector Thermal Performance Testing
Authors: Tang Qian Yu , Wang Hua , Wang Hui Tao , Qing Shan
Published: June 2011

Due to the conventional flat plate solar collector has low efficient, it is necessary to make some improvements in the structure of conventional flat solar collector. This research improved the structure of conventional flat solar collector and conducted thermal performance testing for the improved structure which is serpentine heat pipe flat plate solar collector. The test results indicate that serpentine heat pipe flat plate solar collector has higher efficient than conventional solar collector. Thus, serpentine has better economic and environmental benefit than conventional solar collector.
Approach for Quantitative Express of Tire’s Foot Print
Authors: Li Hong Tao , Shao Yu Li , Wang Bao Liang
Published: June 2011

With special design and manufacture instruments, foot print of used truck tires under different combinations of vehicle load was studied in this paper. The load factor is studied in terms of wheel load and tire inflation pressure. Based on the experimental data, approach for quantitative expression of foot print is also researched. Thus, the behavior of tire-pavement contact can be quantitatively expressed The area of the tire’s footprint should be calculated with different equations varying with the kinds of pavement, and critical change point of the tire’s footprint shape should be decided with load factor varying with the kinds of pavements.
Electromagnetic Properties of Bearing Cement-Based Materials
Authors: Guo Ai Li , Gao Ri , Ba Heng Jing
Published: June 2011

For studying absorption/bearing integration of building materials, high-strength cement-based materials were prepared by using active fly ash, silica fume and quartz, etc. Electromagnetic parameters of the cement-based materials were measured through coaxial method, and then by means of these parameters, the reflectivity of electromagnetic waves of the cement-based materials were simulated under variable electromagnetic wave incident angle (θ), frequency (f) and thickness of the material(d).The reflectivity of electromagnetic waves with 8~18GHz frequency range vertically transmitting into the cement-based materials was obtained through far field radar scattered cross-section measurement, and was compared with simulated reflectance under the same incident conditions. The results show that the high-strength cement-based materials with imaginary part of dielectric constant can consume energy of the incident electromagnetic wave. Incident angle less than 15° has little effect on the reflectivity of the cement-based materials in 2~18GHz frequency range. While the thickness of the cement-based materials is 15mm or 25mm, simulation results of the reflectivity are in good agreement with measured ones. Measured absorption peak and -10dB bandwidth increase with the increasing of thickness of the cement-based materials with compressive strength of 120.7MPa. This suggests that the cement-based materials studied in this paper have the characteristics of absorption/bearing integration.
Research on Mechanical Behaviour of Cement Mortar with High-Volume Coal Gangue
Authors: Qiu Yu Liang , Zhang Xiao Xu , Liu Kai Ping , Hu Xiao Yong , Guan Bo Wen
Published: June 2011

With the fast development of modern industry, the fact that coal dominates the main energy structure will not change for a long time. While the output of coal gangue has accounted for 15%~20% in that of coal. Therefore, coal gangue has become one of the greatest contributions to industrially discharged solid waste in China currently. Nowadays the comprehensive utilization ratio is less than 20%, so there is so much room for the activity and comprehensive utilization of coal gangue. In this article, coal gangue in Tongchuan stimulated by thermal, mechanical and chemical activation has been used as supplementary gelatinize material in cement. The optimal activated ways and technological parameter have been selected by the test of strength, fluidity, water requirement for normal consistency of cement paste, and stability. Also XRD and SEM are used to discuss the change of microstructure which has taken place in activated coal gangue preliminarily.
Study on the Influence of Form Factor of Abrasion Particles on Concrete
Authors: Gao Xin Xin , Cai Yue Bo , Ding Jian Tong
Published: June 2011

The form factor of abrasion particles is one of the most important Influencing factors of abrasion resistance of concrete. In order to evaluate the serves life of concrete, a relationship about the form factor of abrasion particles and the wear degree of abrasion resistance of concrete should be established. In this paper, wear process of basalt on concrete was studied under the flow velocity form 1.7m/s to2.4m/s by a improved under water method test equipment. Meanwhile, an image acquisition method was used to get the form factor of basalt to measure the influence of form factor of basalt on wear degree of concrete. The result shows: the abrasion rate of concrete is higher when the flow velocity is faster and the particle form is sharper, and there is an exponential function relationship between particle forms and abrasion rate.
Stress Strain Analysis of Steel Specimens Not Wholly Quenched
Authors: Wang Rui Jie , Cheng He Ming , Shao Bao Dong , Li Jian Yun
Published: June 2011

A finite element model of not wholly quenched steel fatigue specimen is established. Hardness value of some distance to work piece surface are assumed different and cyclic strength coefficients of different zones are different, both is assumed to be proportional to hardness value. Elasto-plastic finite element analysis was carried out for this model. According to the stress-strain distribution on transverse section, the effect of not wholly quenched on fatigue crack initiation life is analyzed.
The Grain Refining and Strengthening Mechanism of C-Mn Steel by CSP
Authors: Zhang Chao , Wu Run , Song Chang , Zhang Yong Fu , Li Shu Li , Tan Jia Mei
Published: June 2011

The grain refining of C-Mn steel on CSP line was investigated in this paper. The grain size was about 100μm after rolling by stand F1 and then decreased all the way of the rolling process(stands F2-F6) to 15μm. The strengthening mechanisms, grain refinement strengthening, solution strengthening, precipitation strengthening and dislocation strengthening, were figured out to develop a physical metallurgy model for prediction of the properties. It was noted that there is an agreement between the predicted properties and the measured ones of the steel.
Corrosion Behaviors of Ultrapure Ferritic Stainless Steels in Simulated Urban Refuse Leachate
Authors: Qin Li Yan , Fan Guang Wei , Xu Fang Hong
Published: June 2011

The corrosion behaviors of ultrapure ferritic stainless steels in simulated urban refuse leachate were investigated by means of different measurement methods including steady-state polarization curves, potentiostatic open-circuit relaxation curves and scanning electronic microscope. The results show that the ultrapure ferritic stainless steel 443, 444 and the austentic stainless steel 304 maintained good passive state after being immersed in the simulated leachate for 720h. The descending order of pitting resistance is 444>443>304. According to the passive film equivalent resistance Rp and the interface capacitance Cd obtained by fitting the potentiostatic open-circuit relaxation curves, the descending order of passive film stability is also 444>443>304.
Study on the Performances of Phosphate Repair Material Modified by Fly Ash
Authors: Tang Chun Ping , Wu Li Gun
Published: June 2011

Aiming at the characteristics of phosphate repair material, by mixing fly ash in it, its properties can be improved effectively. The experiment has studied the effects of fly ash on the setting time, strength and air shrinkage property of phosphate repair material.the result shows that mixing appropriate fly ash can prolong the setting time, and on the condition of maintain constant fluidity, the strength of phosphate repair material can be enhanced, but with the increase of fly ash admixture, its strength will be reduced, the fly ash admixture within 10% can reduce the air shrinkage of repair material.
Experimental Study on Producing Concrete Hollow Block with Mining Slag
Authors: Tian Yu Ze
Published: June 2011

The experiments of compressive strength about maix proportion of concrete are repeatedly done, adopting orthogonal experimental method. In this experiment, dry separation waste rocks and mine tailings in mining slag of Qidashan Iron Mine which is subsidiary company of Anshan Iron and Steel Corporation are used instead of traditional fine and coarse aggregate concretes. Then the optimized mix proportion is determined to make the concrete small hollow blocks. Sample test shows that it is feasible to make load bearing concrete small hollow blocks which can meet national standards.
Experiment on Making Autoclaved Sludge Bricks with the Dewatered Sludge from Water-Supply Plant
Authors: Zhou Sai Jun , Qu Jun Tong
Published: June 2011

How to efficiently dispose of the urban water-supply plant sludge has become an urgent task of controlling pollution caused by municipal solid waste. This paper is an experiment on autoclaved sludge brick, which is mainly made of sludge from the water-supply plants, fly ash, lime, sand and cement, integrated with the manufacturing process of autoclaved fly ash brick. By orthogonal optimal process, we get the optimal parameters for making sludge bricks as follows: W sludge : W ash : W lime = 15%: 45%: 15%, stirring intensity being 1400r/min, forming and curing condition being the constant temperature and humidity Curing Box (60 °C, humidity 95%), and autoclave curing condition being 1.2Mpa (time 10h). With the optimal parameters, the compressive strength of the produced bricks reaches 20.8Mpa, and its flexural strength reaches 5.4 Mpa. Besides, stirring conditions, forming and curing conditions together with the influence of curing conditions on autoclaved sludge bricks’ mechanical properties are discussed.
Green's Function Solution of the Semi-Cylindrical Gap with Multiple Shallow-Buried Inclusions
Authors: Li Hong Liang
Published: June 2011

In mechanical engineering, earthquake engineering and modern municipal construction, semi-cylindrical gap and shallow-buried inclusion structure are used widely. In this paper, Green's Function is studied, which is the solution of displacement field for elastic semi-space with semi-cylindrical gap and multiple shallow-buried inclusions while bearing anti-plane harmonic line source force at any point. In the complex plane, considering the symmetry of SH-wave scattering , the displacement field aroused by the anti-plane harmonic line source force and the scattering displacement field impacted by semi-cylindrical gap and multiple cylindrical inclusions comprised of Fourier-Bessel series with undetermined coefficients which satisfies the stress-free condition on the ground surface are constructed. Through applying the method of multi-polar coordinate system, the equations with unknown coefficients can be obtained by using the displacement and stress condition of the cylindrical inclusion in the radial direction. According to orthogonality condition for trigonometric function, these equations can be reduced to a series of algebraic equations. Then the value of the unknown coefficients can be obtained by solving these algebraic equations. Green's function, that is, the total wave displacement field is the superposition of the displacement field aroused by the anti-plane harmonic line source force and the scattering displacement field. By using the expressions, an example is provided to show the effect of the change of relative location of semi-cylindrical gap , the cylindrical inclusions and the location of the line source force. Based on this solution, the problem of interaction of semi-cylindrical gap , multiple cylindrical inclusions and a linear crack in semi-space can be investigated further.
A Modified High-Order Moment Method Based on the Normal Transformation Polynomial
Authors: Li Wei
Published: June 2011

Normal transformation technique is often used in practical probabilistic analysis in structural or civil engineering especially when multivariate random variables with the probabilistic characteristics expressed using only statistical moments are involved. In this paper, a modified high-order moment method(MHOM) is given based on the polynomial coefficients of a third-order normal transformation polynomial (NTP) using the first four central moments of random variables having unknown distributions. The present high-order moment method is introduced into several typical test problems having unknown distributions are available. Since it needs neither the computation of derivatives nor iteration, and since it is unnecessary to know the probability distribution of the basic random variables, the present method should be practical in actual reliability problems. Applications to several typical examples have helped to elucidate the successful working of the present MHOM.
A New Conception of Free Torsion Rigidity in Constraint Torsion Theory for Members with Open Thin-Walled Cross-Section
Authors: Xiong Xiao Li , Jin Li Bing , Li Kai Xi
Published: June 2011

In calculating the internal force and deformation of a thin-walled member, the influence of the free torsion rigidity must be considered and it makes the study complicated. Actually, from the analogy relations between the equilibrium equation in the constraint torsion theory of a thin-walled member and that in the plane bending theory of a tension-bending solid bar, the action of the free torsion rigidity can be regarded as a tension effect on a thin-walled member with torsion, i.e. the action can be described as a second-order effect like the tension action in the plane bending theory. Taking cantilever bars for example, the simple calculation method of the internal force and deformation of thin-walled members are deduced by the Taylor series in mathematics, and then verified by ANSYS.
Evaluating the Two-Point Probability Function of Capillary Pores by Computer Simulation
Authors: Zheng Jian Jun , Huang Yao Jun , Zhou Xin Zhu
Published: June 2011

To more exactly predict the chloride diffusivity of cement paste, it is essential to determine the two-point probability function of capillary pores. The intention of the paper is to present a computer simulation method for evaluating the two-point probability function of capillary pores. By introducing three physical quantities to quantify the mutual interference between neighboring cement particles, the microstructure evolution of cement paste is simulated. Based on the simulated microstructure of cement paste, a numerical method is developed for evaluating the two-point probability function of capillary pores. After verifying the numerical method with the experimental results obtained from the literature, the effect of the hydration time and water/cement ratio on the two-point probability function is assessed in a quantitative manner. It is found that the two-point probability function decreases with the increase of the hydration time for a given water/cement ratio, but increases with an increase in water/cement ratio for a given hydration time.
Analysis on the Embankment Settlements Induced by Slurry Shield Under-Tunnelling
Authors: Zhang Zhong Miao , Lin Cun Gang , Wu Shi Ming
Published: June 2011

Based on field settlement monitoring data in construction of Hangzhou Qiantang River tunnel, the settlements of the embankment induced by two shields respectively were compared. The study shows that: 1.The settlements of the embankment induced by the west shield are larger, which are accounted for sustained rainfall, severe fluctuation of the chamber pressure, lack of construction experience and worse control of shield driving parameters. 2. Peck equation is applicable to settlement fitting in this case history. Trough back-analysis, the traverse tough-width parameter and ground volume loss range from 0.33 to 0.47, 0.99% to 1.57% respectively for the embankment settlements above the west tunnel, and from 0.24 to 0.34, 0.25% to 0.52% for the east tunnel. 3. Good control of shield driving parameters contributes to small disturbance to surrounding soils, thereby decreasing the induced settlements of the embankment.
Investigation on Compaction Characteristics of Reinforced Soil
Authors: Chegenizadeh Amin , Nikraz Hamid
Published: June 2011

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on compaction characteristic of composite soil (i.e. clay composite). A series of laboratory tests carried out to evaluate fiber effect on optimum water content and maximum dry unit weight of composite soils. Clay was selected as soil part of the composite and plastic fiber was used as reinforcement. The fiber parameters differed from one test to another, as fiber length varied from 10 mm to 35mm and fiber content were selected as 0.1% and 0.4%. For each test, compaction curved derived and the results were compared. The results proved that inclusion of fiber affected compaction behaviour of samples so that increasing in fiber content and length caused increasing in Optimum Moisture Content (OMC) and slightly decreased maximum dry unit weight.
Test Research on Health Criterion of Cavities Behind the Lining
Authors: Li Ming , Chen Hong Kai
Published: June 2011

It’s very common that there are cavities after the lining and seriously affects the health of the tunnels. According to the status that the health standard is not uniform at present, the health levels can be divided into four parts: health, sub-health, disease and sick into death. For studying the single index criterion of lining cavities, and introducing lab large-scale model test combining the engineering example, analyzing the variety of structure bearing capacity, disease producing shapes and varying rule and so on where are different dimension cavities after lining. The results show that the carrying capacity curve expresses reverse S characteristic, it can be divided into slow, fast and complete degradation basis on the variety of velocity, and it is uniform to the sub-health, disease and sick into death, finding out the single health criterion of cavity: it is health where no cavities after the lining, it’s sub-health when the dimension is less than 100mm, disease when the dimension is between 100mm and 550mm, it’s sick to death if the dimension were more than 550mm.
Bearing Capacity Characteristic of Unsaturated Granular Soils
Authors: Uchaipichat Anuchit , Man Koksung Ekachai
Published: June 2011

An experimental program of laboratory bearing tests was performed to characterize the bearing capacity of foundation on unsaturated granular soils. All tests were performed by pushing a circular rod on the surface of compacted sand specimens with different values of matric suction until failure. The test results show an increase in ultimate bearing capacity with increasing matric suction at low suction value but a decrease in that at high level of suction. The comparisons between the test results and simulations using the expressions proposed in this paper are presented and discussed. Good agreements are achieved for all testing values of suction.
Rapid Manufacturing of Cellular Structures of Steel or Titaniumalumide
Authors: Löber Lukas , Klemm Denis , Kühn Uta , Eckert Jürgen
Published: June 2011

The Selective Laser Melting (SLM) technique is used to produce different cellular structures. Regular unit cells are placed in tensile bars to determine the mechanical performance of different lattice structures. The mechanical properties of the tensile bars with lattice structures are compared to fully dense tensile bars. Tensile bars are produced by conventional casting to compare the mechanical properties between SLM and casting. To exclude other influences, the whole process chain starting from the powder to the finished part is characterized. The different powders, namely 1.4404 steel powder and a titaniumaluminde (Ti-48Al-2Cr-2Nb [TiAl]) powder are characterized via scanning electron microscopy (SEM), energy disperse x-ray spectroscopy (EDS), chemical analysis and light microscopy (LM). In addition measurements of the particle size distribution are conducted. Detailed experimental conditions of the SLM-process are given.
Composites Fabrication via Friction Stir Processing
Authors: Sun Ning , Apelian Diran
Published: June 2011

Friction stir processing (FSP) is a post-processing method that locally manipulates the microstructure by imparting a high level of energy in the solid state giving rise to improved mechanical properties. Additionally, FSP has emerged as an advanced tool to produce surface composites and synthesize the second phase into the matrix. In the current study, FSP was investigated for the manufacture of localized zones of composite materials made by the emplacement of a second phase into cast A206 Al alloy matrix. Both the discontinuously reinforced aluminum (DRA) and some encapsulated powders (nano-sized SiC or Ta) were used for the second phase emplacement. Through SEM and EDS mapping, the morphology and distribution of second phase particles have been studied. The work shows that friction stir processing is a viable means of producing localized composite zones in Al components.
A New Technology for Treating Liquid Metals with Intensive Melt Shearing
Authors: Fan Zhong Yun , Zuo Yu Bo , Jiang Bo
Published: June 2011

Melt quality is crucial for both continuous and shape casting of light alloys. Gas, oxides and other inclusions in the melt usually deteriorate the quality of the casting products. Conventional refining techniques, such as filtration and rotary degassing, can refine the melt by removing the inclusions although they are costly and time-consuming. A new technology for liquid metal treatment through intensive melt shearing was developed recently to improve the melt quality prior to metal casting. The new technology uses a simple rotor-stator unit to provide intensive melt shearing, which disperses effectively the harmful inclusions into fine particles to enhance nucleation during the subsequent solidification processing. Experimental results have demonstrated that the high shear unit can be used for general melt treatment, physical grain refinement, degassing and preparation of metal matrix composites and semisolid slurries. In this paper we offer an overview of the high shear device and its application in processing light alloys.
Processing of Functionally Graded Aluminium Matrix Composites by Centrifugal Casting Technique
Authors: Rajan T.P.D. , Pai B.C.
Published: June 2011

Functionally graded materials (FGM) possess a gradual transition in the composition or microstructure within a component inducing gradual changes in the functions and properties of the material with varying location. The present investigation is to form functionally graded aluminum composites with varying microstructural features and properties gradation using centrifugal casting by varying the material and process parameters. The ex-situ Al-SiC FGM has shown graded distribution of SiC towards the outer periphery and Al-SiC-Graphite has shown both particle gradations of SiC and Graphite towards inner periphery due to hindered settling phenomena. In in-situ Al-Si and Al-Si-Mg2Si system the particles are distributed towards the inner periphery of the casting. The paper also emphasizes on selected engineering components and tailoring their graded structures and properties by utilization of suitable reinforcement combinations and process parameters are discussed.
Metal Injection Moulding of Titanium
Authors: Ebel Thomas
Published: June 2011

A route to handle titanium specific challenges as oxygen and carbon sensitivity when applying Metal Injection Moulding is presented. It is shown that by appropriate processing components with excellent mechanical properties can be manufactured from Ti-6Al-4V alloy powder. In addition, alloy modification by simple powder metallurgical methods is performed in order to optimise the fatigue properties by changing the microstructure of the sintered part.