Applied Mechanics and Materials Vols. 190-191

Abstract: The compaction can directly affect the performance of asphalt pavement, while the mixing temperature, the molding temperature, the temperature of aggregates and the rolling times can all affect the compaction performance. The L9(34) orthogonal tests and indoor tests were used to analyze the influence of the main factors on the examination indicators. The results show that molding temperature have a significant effect on the physical and mechanical properties of SMA13 asphalt mixtures when the confidence level α is 0.10. Finally, quantitative analysis is performed to study the optimal compaction technology of molding temperature and rolling times.

Abstract: Taking OGFC-13.2 (target porosity: 16%) as an example, this paper analyzes the shortages of current specifications on OGFC gradation design, and proposes an optimized design method for OGFC mixture. Then the Bailey method was used to detect whether the target mix can make the mixture constitute a skeleton structure. Finally, the rationality of new design method is verified through several conventional experiments with recommended gradation. New design method with clear thinking and good operability, can better guide the OGFC gradation design.

Abstract: The compressive creep behavior of Mg-4Al-1RE-1Ca-0.2Sr (AECJ411002) alloy was investigated at temperatures in the range of 125~175°C and different compressive stress in the range of 88~112MPa with special apparatus. The results show that the creep deformation increases with the increasing of temperature and compressive stress. There is linear logarithmic relationship between the steady creep rate and all the temperature and stress used. The steady creep rate obeys an empirical equation. The stress exponents are similar at different temperatures and the appearance activation energies are not greatly different under different stresses. Their average value is respectively 6.19 and 39.05kJ/mol. Material constant A is 4.18×10-14. The steady creep rate is controlled by a dislocation climb led by grain boundary sliding. The creep resistance enhances because of the heat-resistant phases Al2Ca and Al4Sr distributing at grain boundary.

Abstract: Thermal-mechanical controlled process (TMCP) has been used to develop new high strength low alloy (HSLA) steels with excellent corrosion resistant property for oil ship construction. Experiment results shown that the microstructure of the steel, which consisted of only ferrite including bainite ferrite, exhibited expected corrosion resistant performance. Higher Mo content led to better corrosion resistance.

Abstract: Overlay new cement concrete pavement on the old cement concrete pavement following different treatment schemes, survey pavement cracking phenomenon after the opening of the new pavement , analysis the crack resistance of the various programs, accumulate experience for the cement concrete pavement repair technical solutions.

Abstract: In order to reduce welding stress, decreased welding crack and improve coating performance, a set of complete computer control system was designed and applied to prepare TiCN cermet composite coating by process. The system, which consists of PC, SCM (AT89C52), sensor, interface circuit, pneumatic rammer, corresponding mechanism and valves, can peen the welded seam by a pneumatic rammer which is controlled by the signal from data acquisition card. The system can easily adjust the peening frequency, force, distance, and angle able. The result show that the system can make coatings more inseparable and compacter, less weld defect, and the coatings have an excellent mechanical property.

Abstract: Aims at the safety problems caused by corrosion under coating for it can not easily be observed, specimen of corrosion damage under coating was made for the research of detection by applying infrared thermal wave technology. The surface temperature distribution infrared thermal images were captured, also the surface temperature history of corrosion area, non-corrosion area and their difference. Analysis of test results show that the infrared thermal wave technology is an effective tool in detecting corrosion damage under coating, there has a fine detection time used to estimate the coating thickness, and the position and sizes of defects can be found out directly by the hot spots in the infrared images. The damages can be quantitatively recognized by images processing, but surface uniformity of the specimen has great impact on the damage identification.

Abstract: A sensitive and selectivity fluoroimmunoassay was established for the determination of bisphenol A, on the basis of being labeled quantum dots. Anti-rabbit IgG conjugated by quantum dots were regarded as a probe in this system. The presented method produced a widely linear range from 0.0001 to 100.0 ng mL-1, with detection limit of 0.078 pg mL-1. The method was applied to determine bisphenol A in plastic leach liquor, with the recoveries from 99.8% to 102.5%. The results were similar to those obtained from a high performance liquid chromatography method, while this method is simple, rapid, sensitive and accurate.

Abstract: The effect of Ca and rare earths on compressive creep behavior of Mg-4Al alloy was investigated with a special apparatus. The microstructures were analyzed by OM, XRD, SEM and EDS before and after compressive creep test. The results reveal that a small amount of Ca was added into AE41 alloy in order to refine the crystalline structure and improve the creep resistance. Comparing with NdPr rare earths alloy, the creep resistance of LPC rare earths alloy decreases, but is still better than AE41 alloy. The as-cast microstructure of AE41 alloy is mainly composed of α-Mg matrix and Al11Nd3 phase. The acicular Al11Nd3 phase is prone to decompose at high temperature, which leads to the poor creep resistance of AE41 alloy. The acicular Al11RE3 phase is gradually replaced by Al2Ca and Al2RE with Ca addition into AE41. LPC rare-earth mixture is in cluster at grain boundaries so that the creep resistance is worse than that of alloy containing NdPr rare-earth mixture.

Abstract: After autoclaved flyash-lime brick masonry was compressed, in the masonry makes pull stress,bend stress, cut stress and complex stress state. The effect of mortar joint thickness on the compressive strength of masonry is the extend of improving under the complex stress state in the masonry. In the domestic and foreign brick construction teaching materials, they are all value the influence and make some describe and comments, but it was limited to the general qualitative analysis. Still not a series study was conduct on the impact, now in order to explore the influence on it, combining with domestic and foreign relevant theory, test statistics and author’s study.