Applied Mechanics and Materials Vols. 744-746

Abstract: When using Rock Quality Designation (RQD) method to evaluate rock mass integrity, the premises are often neglected and there are some limitations in RQD method. This study proposes a hole section statistical method and a rock block coefficient to supplement and improve the limitations of RQD method. The accuracy is verified by applying it to a reservoir.

Abstract: A nonlinear multifunctional polyamine N,N,N’,N’-tetra (3-aminopropyl)-1,6-diamino-hexane (TADH), was prepared and employed as a novel hardener for diglycidyl ether of bisphenol A (DGEBA). Nonisothermal reactions of DGEBA/TADH were systematically investigated with differential scanning calorimetry (DSC). In addition, analysis of thermal stability of the cured DGEBA/TADH with thermogravimetric analysis (TGA) revealed that it possessed quite good thermal stability and increased residual char content at 600◦C in nitrogen. Furthermore, dynamic mechanical analysis (DMA) of the DGEBA/TADH network showed its relaxations were characterized by localized motions of hydroxyl ether segments and cooperative motions of whole network chains (glass relaxation) at different temperature regions.

Abstract: The rapidly development of highway needs the related research. For the lack of design method of mixture asphalt which based on performance and component, the related design method is needed urgently. This can be very important to the heavy traffic highway in construction in our country. This paper analyses the influence on the performance of ATB mixture in the view of asphalt film thickness. We consider the change law of the performance of ATB mixture in different thickness of asphalt film, and the various technical indicators to determine a reasonable range of thickness of asphalt film and provide a reference for the design of mixture asphalt.Key word: asphalt film thickness, bituminous stabilized macadam, comprehensive property

Abstract: The evolution of the microstructure of a typical nickel-based superalloy GH4169 is investigated by the hot compression tests. The microstructural parameters such as fraction of recrystallization and grain size were analysed quantitatively. The results show that the effects of deforming temperature and strain rate on the dynamic recrystallized grain size are significant. With the deformed temperature increase and the strain rate decrease, the dynamic recrystallized grain size increases.

Abstract: A novel cementitious microfiltration membrane was fabricated for water permeation. The membrane wasproduced using low-cost cement and quartz particles under ambient conditions, rather than a sintering process as was generally applied. By the analysis of SEM, pore size distribution and water permeation tests, the effect of water-to-cement ratio (w/c) on membrane structure was studied. The membranes havebimodal pore size distributions, with varying mean pore sizes of 6.5-8.7 μm. With the increase of w/c from 0.3 to 0.8, membrane pore sizes and porosities show a similar trend of first increase and then decrease. Moreover, membrane structure tends to dense in this process, which results in an obviously decrease ofmembrane water flux from 53 to 1 m³·m^-2·h^-1·bar^-1.

Abstract: A numerical simulation has been conducted for concrete pavement on atmospheric thermal environment adjacent to ground under solar radiation. By computational fluent dynamics software Fluent, the finite volume method was used, and the solar radiation was described by the non-gray radiation transfer model and was solved by the Discrete Ordinate Method (DOM). The concept of constant temperature layer was introduced in order to determine the real temperature on pavement. Computed results indicate that the temperature on concrete pavement is impacted by the solar radiation significantly, and the atmospheric temperature falls down in geometric series with the increasing distance to ground. However, the effects of pavement on the temperature of ambient air beyond the near-ground region become much gentle. In comparison to the measured values, it shows that the current numerical method can simulate the interaction between pavement and ambient atmosphere effectively and can be extended to urban microclimate simulation.

Abstract: In this study, the mixtures between benzoxazine monomer and electrically conductive carbon black (CB) were radiated with gamma ray at different doses, i.e. 0, 25, 50, 75, and 100 kGy before polymerization. The contents of carbon black filler were varied i.e. 0, 5, and 30wt%. The thermal properties such as curing temperatures and glass transition temperatures were determined using differential scanning calorimeter (DSC), while the decomposition temperature and char yields were analyzed using thermogravimetric analyzer (TGA).The results reveal that the radiation could decrease the curing temperature of pure polybenzoxazine. In addition, the decomposition temperature and char yield were increased with the increase of CB content. At the same CB content, the radiation dose could decrease the decomposition temperature and char yield.

Abstract: Taking a six-story glass bead thermal insulation concrete frame structure building in Kangding, Sichuan as model, to design filler wall composing of fly ash autoclaved aerated concrete block. Utilizing energy dissipation theory analyzes the building energy consumption. Conclusion: The glass bead thermal insulation concrete frame structure of fly ash autoclaved aerated concrete block filler wall meets the requirement of Sichuan residential building energy-saving code.

Abstract: According to the characteristics of high altitude and strong ultraviolet radiation in Tibet, this paper do ultraviolet irradiation experiment research to different strength grades of concrete blocks in a closed laboratory, it is found that ultraviolet rays has promoting effect to early strength growth of test block, but the growth became slow along with the time.

Abstract: Through magnetite concrete beam under the action of gravity drop hammer impact dynamic bending test, reasonable testing program was designed to realize the whole process of dynamic test data acquisition, beam load and impulse, time history curves of displacement and force dynamic force - displacement curve and dynamic strain of fracture zone curve. By observing the destruction of the different strain rate，the constitutive relation of dynamic strength changing with the loading rate and input energy was studied. At the same time, the strain rate，the fracture process of different rate of damage and the destruction form need to be found.