Applied Mechanics and Materials Vols. 670-671

Abstract: This paper conducted all kinds of performance testing of different rubber particle size and different dosage of silica fume rubber modified cement concrete under the condition of 10% the silicon ash content, such as: analysis research of compressive strength, splitting tensile strength, flexural strength, and pull off the pressure ratio and pressure ratio. Experimental results show that silica fume can improve rubber concrete compressive strength, splitting, bending strength, the folding ratio, adding silica fume concrete fracture pressure ratio and compression ratio are improved; the silica fume can effectively improve large brittleness and lack toughness of concrete, and improve the compactness of concrete.

Abstract: Through the conventional triaxial test about plain reactive powder concrete under different confining pressures at 0Mpa, 25 Mpa,50 Mpa and 75 Mpa, this paper obtained the stress-strain curves in axial direction and radial direction of plain reactive powder concrete under different confining pressures, compared and analyzed the effects of confining pressures on peak strength, peak strain, Elastic modulus, Poisson ratio and failure modes of plain reactive power concrete also. The results showed that peak strength increases with the increase of confining pressure, when confining pressure increases from 0Mpa to 25Mpa, the peak strength increases most rapidly. The results also showed that peak strain increases linearly with the increase of confining pressure, when confining pressure increase from 0Mpa to 75Mpa gradually, the peak strain increases from 0.2 percent to 0.93 percent, meanwhile Poisson ratio increase with the increase of confining pressures, yet Elastic modulus changes slight at different confining pressures, failure modes of plain reactive powder concrete at different confining pressures exhibit different modes, when confining pressure is 0Mpa, failure mode presents as splitting failure, shear failure mode at 25Mpa, while shear failure merge local crushing at 50MPa and 75MPa.

Abstract: In order to clarify the adaptability of sulphoaluminate cement (SAC) and to improve the quality of SAC construction, several common calcareous compounds including calcium chloride, calcium sulphate and calcium hydroxide in designed content were introduced to SAC paste, respectively, following by the investigations of the corresponding fluidity degree and setting time. The experimental results show that calcium chloride in relative high content (no less than 1%) accelerates the cement setting, along with an enlarged degree of fluidity. As a comparison, the involvement of calcium sulphate in SAC paste does simply play a role of setting retarder by prolonging the setting time and enlarging the fluidity degree simultaneously. On the other hand, the presence of calcium hydroxide in SAC paste results in a state of being “neither setting nor flowable”, since the corresponding SAC paste shows a prolonged setting time and a remarkably lowered degree of the initial fluidity degree. All the phenomena can be explained from the viewpoints of hydration mechanism of dehydrated calcium sulphoaluminate.

Abstract: Presented article is of interest to specialists in the field of building materials. The provided information describes nanostructured binders (NB) that are promising in the production of building materials for various purposes. As a result of conducted researches the character of hardening kinetics of NB with different composition was identified, which is similar to the classic representative of binding system – Portland cement. The importance of keeping the technological and temporal parameters of NB receipt by comparing it with a quartz suspension was substantiated. Also a system for monitoring the grinding process allowing to control and manage the technology was provided.

Abstract: At junction of Heng dong Count Shi Ji Road and Zang Qing Road, its subgrade soil is almost miscellaneous fill. Based on the analysis of the basic characteristics of miscellaneous fill subgrade and the local climate and traffic load, we apply the Dynamic compaction method consolidate to the Miscellaneous fill foundation and replace the conventional road with continuous reinforced concrete pavement (CRCP). This paper provides the Continuous reinforced pavement design method and a reference for similar projects.

Abstract: Adding the glass will make the cohesion property of HMA (Hot Mix Asphalt) worse. we often improve the antistrip performance of conventional HMA by the means of adding hydrated lime. In this article, we compare the effect of two different patterns of adding hydrated lime. The test reveals that: replacing the mineral power with hydrated lime can improve the overall performance of mix; With respect to mixing the hydrated lime with asphalt in advance, the water stability of concrete increase more, if the mineral power is replaced by equivalent; Although it can’t do a favor to the mix’s low temperature performance, mixing the hydrated lime with asphalt in advance can significantly improve the high temperature performance, it can be used in high temperature region while it rains rarely.

Abstract: Depth study of deformation characteristics of concrete can reveal failure mechanism of concrete materials based on strain. This paper studies the deformation characteristics of concrete under uniaxial compression, and draw conclusions that deformation can cause the expansion of internal micro cracks, in accordance with the expansion of micro cracks, the law of cracks development of concrete under uniaxial loads is divided into three stages, micro-cracks relatively stable, stable crack development period and unstable crack development period. The research results can provide valuable reference for future research work.

Abstract: Based on continuum damage mechanics, by defining the initial and critical damage value, because of the plastic volumetric strain of the specimen, we established the calculation methods of the rock specimen’s damage value. Through the conventional triaxial compression test of the shale, we find that damage value D changes as axial strain changes during compression, and summarizes its variation.

Abstract: With the improvement of concrete materials and the emergence of new materials, adding silica fume to high-performance concrete (HPC) has been one of the important ways in concrete technology. In this paper, through experimental study on the mechanical performance of HPC with 5%, 10%, 15% and 20% silica fume replacing cement for different water-binder ratio, along with polycarboxylates high performance water-reducing admixture, silica fume has large effects on 28d compressive strength, split tensile strength and flexural strength of the HPC. Meanwhile, due to the different level of water-binder ratio, the relationship between split tensile strength, flexural strength and compressive strength is also obvious linear.

Abstract: Under sustained loads with a fixed value, the deformation of concrete will continue to increase as time increases; this phenomenon is called creep of concrete. Currently, there are several theories to explain the phenomenon of concrete creep, viscoelasticity theory, seepage theory, viscous flow theory, plastic flow theory, micro-fractures theory and internal forces balance theory. Above models mostly studied linear creep of concrete under low stress status. This paper mainly research on concrete creep mechanism, and pointed out the advantages and limitations of the various theories, which has a guiding significance for theoretical research.