Applied Mechanics and Materials Vols. 174-177

Abstract: Cylindrical welded component is one of the typical components. It is necessary to do aging treatment for keeping stable dimension. Vibratory stress relief (VSR) is a new kind of technology which may eliminate the residual stress in metal component with high efficiency, energy-saving, environment protection and low cost compared with thermal stress relief (TSR). And the effect is greatly impacted by vibration parameter. Vibration modes are tested by modal analysis. Excitation frequency and point, support point and other parameter are determined by stress distribution and the fourth vibration mode of cylindrical welded component. Blind hole method is adopted to measure respectively component residual stress after welding and with 20 minutes of VSR treatment. Result shows that residual stress is reduced by 50% or so after VSR for cylindrical welded component. Therefore, vibratory parameters are determined by component residual stress distribution and its vibration mode. The best effect can be obtained for the technology of VSR.

Abstract: Effects of superfine slag powder, fly ash and ultra-fine CaCO3 on compressive strength of sulphoaluminate cement were investigated. Cement hydration products were analyzed by using scanning electron microscopy (SEM). The results show that different fineness and additions of mineral admixture differ in compressive strength. When the amount of superfine slag powder, fly ash and ultra-fine CaCO3 are added by 10%, 10% and 3% (by weight), the compressive strength of the hardened paste of sulphoaluminate cement is highest, respectively. Meanwhile, it is concluded that the additions of superfine slag powder and ultra-fine CaCO3 facilitates hydration at early ages, while fly ash could accelerate hydration at later ages.

Abstract: This paper makes a study of design of mix proportion of leaf concrete. In the experiment orthogonal design scheme is used to analyze the effect of category of cement, variety and grain size of leaves, variety of superplasticizers, and ratio of water-binder ratio (W/B) on the fluidity (diffusivity index) and the 28-days’ strength of leaf concrete, and had found the primary and secondary order of the influence of the above-mentioned four factors on the index, thus laying a reasonable basis for further development and application of leaves in the field of heat insulating and building materials.

Abstract: Effect of surface applied inhibitor on the durability of high strength reinforced concrete with various chloride content has been investigated in this paper. The C60 concrete specimens contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials were prepared and experienced in months exposure tests after painting with 400 g/m2 inhibitor. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) of the steel rebar in specimens was tested. The results indicate that after surface painting the inhibitor for 28d the bars in concrete specimens with 0.5% NaCl and bar with 25mm cover in specimen with 1% NaCl show the average corrosion rate lower than that of control one (No.0, no painted inhibitor). While the corrosion current of rebar (38mm cover) for No.2 specimen with 1% NaCl and bars for No.3 specimen with 1.5% NaCl are still higher than that of the control one (No.0). The results indicate that the surface painted inhibitor on C60 concrete are effective to inhibit the corrosion of bar concrete at low or middle chloride conditions and not enough to repair the bars in high chloride contaminated concrete. The lower organic nitrogen content in 40-50mm depth also indicates that the inhibitor is harder to penetrate into deeper parts of high strength concrete compared with low or middle grade concrete.

Abstract: In recent years, due to the dual pressures of resources and the environment,the clod recycled technology renovation and expansion of the old road and new road construction process increasingly attention increasingly wide range of applications. In this paper, the water stability of the cold recycled materials in asphalt pavement on cement additives, frozen stability, thermal shrinkage resistance, dry Shrinkage thefour indicators of experiments to evaluate its durability, and compared with the typical semi-rigid material. To verify the feasibility of the cold recycled material as road base material.

Abstract: The temperature and stress fields of reactive powder concrete under high temperature are investigated using finite element analysis software COMSOL MULTIPHYSICS. In this simulation, the influence of variation of thermal parameters with temperature on the temperature and stress distribution is taken into account. The temperature and stress distribution are obtained. And the variation rule of numerical results shows very good agreement with the experimental data.

Abstract: Reinforced concrete segment is the main body of structure in shield tunnel, and its durability has an important effect on shield tunnel. The durability of High Durability Reinforced Concrete Segment (abbr. HDRC Segment) was investigated by impermeability of single segment and chloride diffusion coefficient of core-drilling. HDRC Segment had high compact cover, concrete cover and high strength structural-layer. Permeable height of HDRC Segment was approximately 0.5 mm when Keeping 4 hours in the constant water pressure of 0.8 MPa, and chloride diffusion coefficient of HDRC Segment was only 4.9×10^－13m²/s by NEL method. As for Water impermeability and chloride ion penetration resistance, HDRC Segment is far superior to those of conventional Reinforced Concrete Segment (abbr. conventional RC Segment). It is advantageous to increase durability of HDRC Segment and service life of tunnel engineering.

Abstract: Sheepfold is the important place for the sheep growth and ropagation, its internal environment parameters on the growth of sheep is essential, therefore, to the sheep with a suitable growth and reproduction of the living environment, is our science and one of the key research. The northern cold region sheepfold of sheep breeding fluff construction insulation materials are analyzed and discussed, and the actual construction provides suggestions for sheepfold.

Abstract: The paper chooses a suitable dispersion according to NANO-kaolin characteristics, develops a suitable testing program, also analyzes test results to determine NANO-Kaolin’s impacts to cement, and the mechanism is described, some results were put forward.

Abstract: The heat transfer characteristics of heat storage unit are analyzed by many researchers from both theoretical and experimental in solidification heat release. Most theoretical models define the initial temperature of the phase change materials is equal to the phase transition temperature, in fact, thermal storage unit in the application, its initial temperature is not equal to the phase transition temperature. Many theoretical models have not considered the impact of latent heat of solidification. In this paper, homemade inorganic hydrated salt material is used as heat storage media, packaging with a cylindrical container. The phase change heat transfer process was analyzed both from theoretical and experimental. The effect of initial temperature and the latent heat of the heat transfer material were both considered.