Applied Mechanics and Materials Vols. 357-360

Abstract: The lunar soil simulants using for vehicle-terramechanics research on the ground need to expose in air containing water molecules for a very long time. The influence of the engineering properties of lunar soil simulant caused by air moisture should be determined. This paper has obtained the moisture absorption of JLU-1, JLU-2 and SNJ-4 using weighing method. The result indicates that the hydroscopicity of three lunar soil simulant are: SNJ-4>JLU-2>JLU-1, all less than 2%. It shows that even in saturation state, the moisture content of three specimens is very little. The length of storage time of lunar soil simulant in natural environment has little effect on its engineering properties. Lunar soil simulant after be made can be storaged well for a long time in the natural environment, and used for ground foundation test. The results can supply the reference to evaluate the engineering properties and formulate the suitability standards of lunar soil simulant.

Abstract: The article by using the coating apparatus of fluidized bed, the surface coating method of the spherical particles of pre-expanded polystyrene (EPS), processing of EPS surface modified; different volatile solvents, as well as an acrylic resin, epoxy, modified polyurethane coating material selection, the EPS particle surface coating processing experiments. The test results show that after the modified material after foaming and mold filling repression through modified EPS material has a lot of improvement in its inter-particle adhesion, impact resistance and strength, the process can be EPS material of high value-added processing to provide a new way.

Abstract: In order to study the mechanical properties of recycled concrete with the same strength, three kinds of recycled concrete have been made which their intensities reached C25, C30, C35 at the recycled coarse aggregate replacement ratios (0%, 50%, 100%), and severally completed the stress-strain curve test on the same strength of recycled concrete, separately analyzed the variance about failure pattern and peak strain, elastic modulus that all belonged to recycled concrete under the condition of the same strength. Studies have shown that the overall shape of recycled concretes stress-strain curves is similar to normal concretes under the same strength, and the difference is small, modulus of elasticity decreases with the increase of recycled coarse aggregate replacement ratio, while the peak strain basicly remains unchanged. Their curves can be used two stages respectively and also be represented by three fitting polynomial and rational expression, their descent stages steepened gradually with the increase of recycled coarse aggregate replacement rate.

Abstract: For the purpose of studying the difference between recycled concrete and ordinary concrete on shearing property under the circumstance of equal strength, nine recycled concrete beams, which have equal altitude and varying width, have been produced by using different replacement rates of 0%, 50% and 100% respectively to test their shear performance. The differences between recycled concrete and ordinary concrete on shearing strength, shearing strain and constitutive relation were analyzed in this paper. The study indicates that with the same compressive strength, there is only a slight difference between recycled concrete and ordinary concrete on shearing strength. The shearing strength of the recycled concrete is similar to the tensile strength of the ordinary concrete. Recycled concretes peak value increases as shearing strength increases. The stress-strain curve of recycled concrete is similar to that of the ordinary concrete. Its shear modulus increases when shearing strength increases.

Abstract: The concept of powder volume equivalent coefficient is presented to study the reasonable powder volume and solve the problem that the cohesiveness and bleeding of low strength manufactured sand concrete is poor. With the way of laboratory experiment, water requirement of normal consistency of different powder is tested to determine the powder volume. The impact of powder volume on the low strength manufactured sand concrete workability under same sand ratio is analyzed with improved Mehta method. The experimental result shows that freshly mixed low strength manufactured sand concrete workability can be evaluated with powder volume equivalent coefficient and the reasonable powder equivalent volume is 156~160L/m3.

Abstract: Primary concrete of pebble coarse aggregate were used as the source of recycled aggregate concrete for pebble recycled coarse aggregate. Replacement rate of recycled aggregate for change parameter, 99 specimens were designed. The prism compressive strength, cube compressive strength and flexural strength were tested and achieved. The test results show that damage process and form of pebble coarse aggregate concrete are similar to those of normal concrete. It is gel adhesive failure between coarse aggregate and cement. Comparing with natural aggregate concrete, the strength indexes of recycled aggregate concrete of pebble coarse Aggregate slightly increase.

Abstract: The methods to define the material parameters related to the super-elasticity of shape memory alloy in the software of ANSYS are introduced. The mechanical behaviors with super-elasticity occurring in the shape memory alloy are numerically simulated by the software ANSYS. The stress field near crack-tip of mode I in the material of shape memory alloy with super-elasticity are numerically simulated by the software ANSYS. Results of numerical simulation show that the software ANSYS is able to simulate the fracture behaviors occurring in the shape memory alloy structures effectively.

Abstract: The synthesis of a novel class of diamine-based polyols derivatives and the potentials and the limitations of these polyols were reported. This class of diamine-based polyols with high hydroxyl values and no acid values can be used in rigid polyurethane foams. The prepared rigid foams show the properties of low density, high closed cell content, low thermal conductivity, and high compressive strength.

Abstract: The effects of YRS addition on the characteristics of ceramsite were investigated. Chemical components, especially ratios of SiO₂ + Al₂O₃/Flux (defined as SA/F ratios), were used to explain physical properties and pores distribution of ceramsite. Results showed that the maximum addition of YRS for making ultra-lightweight ceramsite (ULWC) was 35%.Larger pores inside the ceramsite bodies could be obtained as YRS additions ranged from 10% to 30%. Ceramsite with higher YRS additions (40%) became denser and have lower porosity.

Abstract: Slate has high alkali activity.When broken as aggregate, it produce high content of slate powder.In order to study the effect of slate powder on fly ash in suppressing alkali activity of slate aggregate and the possibility of making full use of the powder,we carried the experiment on rapid mortar bar method.The experimental results show that:1. When the content of slate powder is less than 15% , it has no adverse effect on fly ash in suppressing alkali activity of slate aggregate. When the content of slate powder is greater than 15%,it can increase the effect of suppression.2. For alkali-silica reaction,what really suppress it is the active SiO2 that comes from slate powder or fly ash.As long as the mineral admixture containing active SiO2 grinds fine to the fineness of cement particle, it can increase the effect of suppression on fly ash in suppressing alkali activity of slate aggregate, rather than reduces the suppressive effect.