Advanced Materials Research Vols. 724-725

Abstract: The gradation of asphalt mixture is a main factor on the asphalt pavement performance, and coarse aggregate skeleton is an effect of distribution in the primary factor. The article analyses the interaction among the particle sizes of coarse aggregate by VCA and CBR double controlling index of aggregate gradually filling test, and identifies the key sizes of coarse aggregate by uniform design and grey system theory, and recommends particles size range content of coarse aggregate. The results show that coarse aggregate skeleton gradation of asphalt mixture by filling test has a good correlation with VCA and CBR.

Abstract: External thermal insulation system of Cast-in-situ concrete exterior wall in high-rise civil building includes with network and without network system, wherein the cast-in-place concrete exterior wall insulation without network system is the most economical and the external thermal insulation system. This system applies to new buildings, can also be applied to energy saving renovation of existing buildings. In this paper, the system technology without steelmesh is synthetically introduced so that more engineers can know and use it better.

Abstract: The research object presented in this paper is coupling effect of porous red sandstone which is more frequently encountered. And this paper use the test system of Split Hopkinson Pressure Bar (SHPB) to survey the impact test action of different porosity red sandstone in different coupling medium in order to obtained the dynamic waveform of fluid-solid coupling red sandstone under impact loading using theoretical analysis and laboratory data. The paper analyzes the impact of porosity, coupling medium on the dynamics characteristics of red sandstone. Based on the experiment study of different coupling medium red sandstone under cyclic impact loading, this paper discussed the dynamic characteristics law of porous sandstone under cyclic impact loading and analyzed theoretically the mechanism of coupling medium under cyclic loading. Porosity has a great influence on dynamic performance of red sandstone. Coupling medium has certain influence on the dynamic characteristics of red sandstone. All those conclusions laid a theoretical foundation for practical application.

Abstract: The working environment of air conditioning system in large-scale building is very complex, and there is no significant linear relationship between factors affecting energy consumption and energy demand of air conditioning system. This study adopts a nonlinear regression model: ANN (artificial neural network) model as energy model of air conditioning system. Take outdoor temperature, categorical day-of-week variable, equipment efficiency and terminal load as input, energy demand as output. Use energy consumption data in 2011 for network training, and energy consumption data in 2012 to verify the reliability of model. Based on energy analysis, the operation condition and the characteristics of energy consumption of air conditioning system for large-scale buildings in Nanjing could be precisely represented.

Abstract: In practical projects, prestressed reinforcement are arranged in concrete slab uniformly. According to the research, a new arrangement method of prestressed concrete slab is provided. This article discussed unbonded prestressed concrete slab system, and gives the theoretical calculation method. It can save more than 50% quantities of reinforcement, and has economic advantages than before.

Abstract: This paper describes a cement concrete bridge deck dedicated interface agent,which can effectively resolve the debonding problem between cement concrete bridge deck pavement and beam body. Then, it focuses on experimental investigation on new and old concrete bonding shear performance, and verification of bonding properties of interface agent. Finally,it puts forward specific requirements and cautions for the construction of interface agent,especially emphasizing that cleaning treatment shall be conducted on beam top and restore its surface structure before spraying interface agent for better bonding with pavement. Keywords: Cement Concrete Bridge Deck; Interface Bond; Interface Agent; Shear Test; Construction Technique

Abstract: In order to control the deformation of large section surrounding rock in 700m level of the main drainage pumping station in the experimental mine, according to the reason for deformation and failure of the main drainage pumping station and material mechanics, fully-closed U-shaped support which used double welding I-steel bottom arch as the main structure was designed and the assembly and principles of support were described in detail, based on theoretical calculation and comparative analysis on the structure and mechanical properties of rectangular I-beam support, U-steel support, single I-beam arch support and double I-beam arch support. Based on the comparative analysis by numerical simulation, the rationality of the high strength support and the detailed support parameters were determined. It gets good effect in field application and ensures the long-term stability of the main drainage pumping station. The results show that: the double-layer I-beam 12^# can increase bending strength by about 7.5 times. Double trough splint device used in shoulder of the support has the advantages of high strength, greater rigidity, good pliability and stable working resistance.

Abstract: A new building material named expanded polystyrene recycled concrete (EPSRC) has been experimental studied not long ago by authors in this paper. Now, numerical analysis was further carried out on hollow EPSRC block and its thermal insulation wall based on thermodynamic principles. The results showed that the average thermal resistance of E45 and E60 EPSRC blocks are 0.616 and 0.823 (m²·K)/W, and the average heat transfer coefficient of E45 and E60 EPCRC masonry wall are 1.473 and 1.280 W/(m²·k). Therefore, the EPSRC blocks can be widely applied to the non load-bearing lightweight insulation masonry by suitable design.

Abstract: This paper presents a possibility of making up a vegetable concrete by using starch and hemp shives. The results obtained by test show that this type of environmental material has a lower density, a lower thermal conductivity, and better acoustic properties. The mechanical performance of the starch-hemp concrete depends on the material density, binder/hemp shive ratio and mix composition. The advantageous of thermal and acoustic properties of the material make it good future in the building construction.

Abstract: On the basis of the national curve of rebounding method, the rebounding non-destruction detecting testing method for concrete compression strength was done by using the engineering example. And the rebounding testing results were compared with the results from the core drilling method for concrete compression strength. It indicated that using the national curve of rebounding method to infer the structure concrete strength of Datong area was feasible, but the inferential strength value was higher than its actual value.