Applied Mechanics and Materials Vols. 174-177

Abstract: Based on durability of fly ash concrete, the freezing and thawing, impermeability and cracking resistance of fly ash concrete were researched. The results show that the frost resistance of concrete was reduced, impermeability and crack resistance were improved with increasing the fly ash content.

Abstract: Accurate in apparatus, complex in operation, expensive in fund and plentiful in time, test of unsaturated soil is difficult. Influence of status of dry and wet and degree of compacting was not considered generally when Duncan-Chang model was be used to unsaturated soil. With parameters of model served as constants, it was not consistent with the practice that parameters would be changed with saturation and water content and its application would be limited. General triaxial tests of drainage and consolidation about dry density and water content combined are carried out, influence of relation between stress and strain about clay is discussed, mathematical equations of parameters of Duncan-Chang model are established, thus modified Duncan-Chang E-B model of unsaturated clay is carried out that influence of dry density and saturation can be considered. From study we can see, on the one hand, characteristics of stress and strain about unsaturated clay are influenced obviously by saturation and dry density, the main parameters of E-B model keep close correction with dry density and saturation, and the both mutual effect can be expressed by multiplication. On the other hand, status of compacting and process of gradual change from dry to wet can be described with modified E-B model. Thus it will be more complete in factors considered, inosculate in practice, and convenient for use.

Abstract: Steel fiber has a fine nature in reinforcing concrete. This essay aims to find out the influence of physical forms of steel fiber on its nature of reinforcement. By comparing two types of cement mortar reinforced by steel fibers, it is found that spiral steel fibers have a better bond strength with matrix than straight ones. Therefore, a conclusion could be drawn that physical forms of the steel fiber play a significant role in steel fiber reinforced concrete, and the experiment also serves a rewarding reference to the application of spiral steel fibers.

Abstract: A series of Cr/H-ZSM-5 with different chromium contents were prepared by impregnation method. The samples were characterized by XRD, BET, NH3-TPD, FT-IR and SEM. The samples have the larger surface areas and sufficient acidity sites by characterization, also Cr species have existed in the catalyst surface.

Abstract: The unconfined compressive strength is used to be the valuation index, the mechanical performance of three kinds of new road base material, which are fly ash stabilized steel slag sand (FA-SS for short), lime and fly ash stabilized steel slag sand (L-FA-SS for short), cement and fly ash stabilized steel slag sand(C-FA-SS for short), are studied in this paper. The results show that the unconfined compressive strength performance of FA-SS is similar to L-FA-SS, and it can meet the highest strength when the ratio of steel slag to fly ash is 1:1~2:1. When the ratio of fly ash to the steel slag is 10:90, it is good to use cement stabilizing. Comparing the new road base materials with the traditional road base material, the former has better strength performance and economy function advantage.

Abstract: Polylactide(PLA)-based wood plastic composites (WPCs) toughened with LLDPE were manufactured by extrusion blending followed by injection molding. The fracture surfaces created from the impact test were recorded with SEM. Fractal analysis has been used to calculate the fractal dimension of the fracture surfaces with four different techniques. Then, the relationship between the fractal dimension of the fracture surfaces and its impact strength of the PLA-based WPCs was investigated with the linear regression. The results show that there is a positive correlation between the impact strength and the fractal dimension for each calculation method.

Abstract: Abstract. Based on an extensive experimental program, the paper studies the behavior of High Performance Fiber Reinforced Cement Composite (HPFRCC) under Uniaxial compression. The experimental parameters are: PVA fiber content by volume, fly ash and silica fume content. The compressive strength, peak strain as well as compressive stress-strain curves are obtained. The test results reveal that PVA fibers can greatly improve plastic deformation ability of HPFRCC, especially have significant impact on ductility after the peak stress, though fiber content has small influence on compressive strength. With the increase of fly ash content, peak stress of HPFRCC decreases, but toughness increases. 10% silica fume content has not obvious effect on compressive strength for HPFRCC with large quantities of fly ash , but leads to less ductile behavior.

Abstract: Heterocyclic monomers based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over four steps from readily available starting materials. The new dificient acceptor has good solubility in organic aolvents to permit an appropriate coating process. Two soluble donor-acceptor π-conjugated oligomers comprising electron-rich thiophenes the electron-deficient EDOBT have been carefully investigated.

Abstract: Preparation, properties of autoclaved bricks from waste foundry sand and their strength formation mechanism were investigated in this article. Autoclaved bricks were prepared using waste foundry sand, crashed stone, fly ash, activators such as slaked lime, and special composite as starting materials, accompanying preparation process of wheel-rolling blending, molding with high pressure, and autoclaved curing process. Prepared autoclaved bricks have been authoritatively tested. The results show that strength reaches the standard of 15C, radium activity concentrations are lower than the limit in main building materials, coefficient of carbonization and data of drying shrinkage can be in consistent with Chinese fly ash brick standard. Leaching toxicity is lower than the standard. The strength formation mechanism was investigated by XRD and SEM techniques. The results show that under the conditions of high-temperature, high-pressure steam a mesh structure will be generated and assembly connected, thus forming the strength of autoclaved bricks.

Abstract: Low frequency cyclic horizontal load experiments have been carried out on the sandwich insulation (ECW-8) and ordinary (ECW-1) multi-ribbed composite wallboard. Mechanical properties of two specimens such as bearing capacity, energy dissipation and failure modes were studied. Two specimens are both shear failure. The cracking load of insulation wallboard increases by 29.1% than ordinary wallboard. The initial stiffness of insulation wallboard is 1.38 times of ordinary wallboard. The ultimate bearing capacity and energy dissipation performance has little difference between them.