Advanced Materials Research Vols. 791-793

Abstract: In modern society, the development of urbanization process makes the increasing waste concrete and natural aggregate resource increasingly drying up. Recycled concrete research has become the inevitable development of society. This paper briefly introduces the research status of waste concrete recycling, and points out the current waste engineering application research status and existing problems of the concrete utilization. The industrialization of recycled concrete is in accordance with the needs of environmental protection and sustainable development strategy.

Abstract: The tensile properties of alloy steel 35CrMoA were measured by dynamic tension experimental apparatus, and the stress-strain curves of the material at strain rate range from 10^-2/s to 10³/s were obtained. The fracture appearance and metallurgical structure were observed for the recovered specimens. The influence of strain rates on mechanical properties and microstructure of the 35CrMoA steel was analyzed. Based on the experimental data of mechanical properties, the JC constitutive parameters were fitted for 35CrMoA.

Abstract: With the expansion of the security market, the demand of the anti-counterfeiting technology is becoming more and more big, and the requirement of the anti-counterfeiting technology is becoming more and more is also high. In this paper, a simple summary of the application of fluorescent material in the anti-counterfeiting field is finished. And analysis of the current situation and development tendency of fluorescent material at home and abroad is given in this paper.

Abstract: It is important for the design engineer to realize that scatter and variability of materials properties are inevitable and must be dealt with appropriately. On occasion, data must be subjected to statistical treatments and probabilities determined. The fracture toughness of pipe steel has great effect on the safety of welded pressure pipe. The fracture toughness test of circumferential welded joint was carried out in this paper for X65 pressure pipe steel. The fracture toughness experimental results were analyzed by using computer program developed by ourselves. The distribution of weld fracture toughness of X65 pressure pipe steel which may accord with normal distribution, lognormal distribution or weibull distribution can be determined by calculating the results only one time. The program, which plays an important role in structure reliability analysis, can be used to determine the probability statistic distribution of the mechanical properties. The calculated results indicate that the weld fracture toughness of the X65 pressure pipe steel can either accord with normal distribution, lognormal distribution or weibull distribution, but the optimum fitting distribution of the fracture toughness is weibull distribution.

Abstract: Installing, seismic affections cost and complexity of maintenance are different due to the different mechanical of dampers. With the data collected from experts, this paper calculates the weight of indexes by the method of Delphi firstly, and then evaluates dampers of cables by fuzzy comprehensive method. Conclusions are drawn as follows :(1) Reliability is the most important factor to evaluates dampers;(2) Oil damper and MR damper are weak in reliability, economics and complexity of maintenance compare with other dampers;(3) High damping rubber, viscous damper and friction damper lead the top three of all the dampers. Meaningful references are provided for engineers to select dampers for cables according the character of cable stayed bridges.

Abstract: Cantilever construction has been commonly used in construction of continuous rigid frame bridge and construction control plays an important role in ensuring the line-type and the forced state. Because of long construction period, it tends to construct across the winter possibly. Considering that the impact of winter intermission on construction control of pre-camber is a problem which the constructors and control staff must pay attention to, this paper takes the impact of winter intermission on construction stage into consideration. The research has guiding significance for the construction of the similar bridge to a certain degree.

Abstract: Most bridges show different degrees of disease in the operations many years later. Combing the bridge disease investigation, materials inspection and load test done on the background of the interchanges over Yicheng-Houma expressway, this paper will make assessment of the frequently-used box-girder bridges' bearing capacity in the expressway to provide a reference for bearing capacity assessment of the old expressway bridges.

Abstract: Thermal cycling of a unit Sn0.7Cu solder was studied based on the steady-state creep constitutive equation and Matlab software. The results show that there is a steady-state cycle for the thermal cycling of unit Sn0.7Cu eutectic solder. In steady-state thermal cycling, the shear stress is increased with the increase of temperature. There is a stage of stress relaxation during high temperature. A liner relationship between maximum shear stress and maximum shear strain is observed during thermal cycling. The metastable cycle number is declined greatly with the increase of maximum shear strain.

Abstract: Two kinds of welding methods, including SMAW and GTAW, were employed to connect 16MnR steel and 2205 steel. OM and TEM was used to observe the microstructure. EDX line scan was used to analyze elements in special areas of the joint. The results show that the degree of carbon migration in the side of 16MnR of the seam welded by GTAW is larger than that by SMAW. Particle and chain-island are two main form of Fe₃C in micro-area of carbon migration. The grain size of seam material in GTAW section is larger than that of SMAW and the content of austenitic of seam material in GTAW section is more than that of SMAW. The tongues in the side of 16MnR appear in both two seams welded by SMAW and GTAW and they are parts from base metal.

Abstract: In order to solve the problem of traditional buffeting analysis method is complex, the paper summarizes a calculation method of simplifying the suspension bridge buffeting response spectrum which considers the background response by simplifying the vibration mode function. Examples calculation shows that this function is efficient and accurate. With this method the paper analyzes the impact of parameters including structural damping ratio, aerodynamic admittance function, pneumatic self-excited forces, the main beam span and so on on the suspension bridge buffeting response. Results show that: First, the impact of the background response on concrete bridges with larger damping ratio cannot be ignored. Second, when aerodynamic admittance takes Sears function, the buffeting response analysis results may be partial dangerous. Third, the role of the background response on large long-span bridges of more than 2000 m can be ignored.