Applied Mechanics and Materials Vols. 193-194

Abstract: The article analyzed the filling and repairing effect of ultra-fine fly ash about recycled concrete under different gradations. And obtained something by analyzing test data: ultra-fine fly ash could improve the recycled concrete workability and strength to some extent, but different gradations of the recycled concrete have different effects on strengthen. Recycled concrete strength increased by an average of about 15% after incorporation of ultra-fine fly ash. These conclusions could provide a certain reference value for the recycled concrete research and application of enhanced technology.

Abstract: The influence of heat stability of wood-plastic composites (WPC) was researched effectively by adding the heat stabilizer composites of lead sulfate tribasic and dibasic lead phosphate, pure lanthanide, composites of zinc stearate and lanthanide and single BHT. The mechanism and factors of stability for different heat stabilizers were revealed by means of analyzing fourier transform infrared spectroscopy (FTIR). The result indicated that the rank of effective heat stability from high to low was composites stabilizer of lead, pure BHT, lanthanide added zinc stearate and pure lanthanide in sequence.

Abstract: Fatty acid phase change materials(PCMs) and composite diatomite PCMs were prepared in this study, the phase change temperature of different mole ratio lauric acid(LA) and capric acid(CA) PCMs were tested by step cooling curve method, thermal physical performance of the prepared PCMs were tested by differential scanning calorimeter (DSC). A new type of lightweight phase change gypsum wallboard incorporated with LA-CA/diatomite composite PCMs was prepared, and the thermal performance of this material was studied. The results showed that the LA and CA could form an eutectic mixture. DSC results indicated that the phase change temperature of the PCMs and composite diatomite PCMs are both 26.7°C, the latent heat of the PCMs are 142.2J/g and 73.5J/g, respectively. Thermal performance test of the gypsum wallboard indicated that the temperature difference of the phase change gypsum wallboard at different moment is lower than the blank gypsum wallboard, which showed a better energy storage function of the phase change gypsum wallboard.

Abstract: The influence of nitrite concentration on the corrosion of steel immersed in three simulated pH environments that really exist on the surface of steel in concrete has been investigated by comparing and analyzing the change of threshold level of Cl^- and NO₂^-/Cl^- mole ratio. The results indicate that with the presence of nitrite, the corrosion of steel can be inhibited effectively. Chloride threshold level increases with the increasing of nitrite concentration and highly alkaline environment plays an important role in assisting nitrite to inhibit corrosion. The use of NO₂^-/Cl^- mole ratio as the parameter to guarantee the inhibition efficiency is suitable in highly alkaline environment, but not appropriate in weakly alkaline and neutral environments.

Abstract: Planting Orychophragmus violaceus in light-weight green concrete is feasible by drilling method. O. violaceus roots can fit the plant-growing concrete and surrounding perlite. Compared with O. violaceus roots growing in soil, the number of lateral and fibrous roots around the taproot growing in light-weight green concrete is much more. O. violaceus can be selected as a plant species growing in greening concrete.

Abstract: The roots can significantly increase the soil reinforcement of vegetation, and the fractal theory provides a new perspective for vegetation roots studies. This article applied the Fractal Fox software to calculate the fractal dimension of medicago sativa and cynodon dactylon roots in different growth periods and proved that the two species show fractal characteristics. The conclusions from the analysis are as follows: ①The fractal dimensions of the two plant roots tend to be stable with the increase of growth period; ②The fractal characteristic value of cynodon dactylon root is more significant than medicago sativa root; ③Compared with medicago sativa root, cynodon dactylon root is more effective in increasing the shear strength of soil.

Abstract: In this paper, the basalt fiber/polylactic acid composites were prepared by laying-up hot-pressing process, using PLA sheet as the matrix material and basalt fiber fabrics as the reinforced material, besides, the mechanical properties were studied and the parameters of hot-pressing were optimized. PLA mass fraction, heat pressing temperature, heat pressing pressure and heat pressing time were selected as the four main influence factors and tensile strength and bending strength were taken as the test indexes, the best processing conditions: PLA mass fraction 63%, Heat pressing temperature 195 °C, Heat pressing pressure 7MPa, Heat pressing time 10min were optimized through orthogonal experiment and range analysis. The significance of the study was providing theoretical guidance for the further development of high-performance basalt fiber composites.

Abstract: Aim: To strengthen management cost of construction projects, reduce procurement cost of materials, guarantee materials quality and to promote the profitability of the project. Approach:Adopt scientific centralized procurement implemented by construction enterprise headquarter.Result: It not only reduces materials procurement cost, but also improves the quality of procurement, which, guarantee the project quality and promote the profitability of both the project and the enterprise that carries it out. Conclusion: The centralized procurement mode of construction project materials can effectively reduce construction cost and promote the profitability of both the project and the enterprise that carries it out.

Abstract: This paper presents the results of testing performed to evaluate the influence of steel fiber on the performance of concrete materials. The performance of concrete materials was studied through frost resistance, carbonation testing and restraint cracking testing. Experimental results show that the steel fibers can improve the frost resistance and carbonation of concrete, compared with plain concrete. Steel fibers can also reduce cracking, and improve the cracking resistance of concrete materials.

Abstract: The impact of the construction industry on the consumption of natural resource and environment cannot be ignored. There is no doubt that green building will be a trend in the international construction industry. It is crucial to choose the appropriate green building materials, because it acts as key factor to the development of green building. With the brief introduction of two mainstream assessment tools of green building materials in the world and two main evaluation tools that are used in China as well as their advantages and disadvantages, this article is expected to serve as the reference for development of green building materials and the assessment tools in China.