Applied Mechanics and Materials Vols. 438-439

Abstract: The pavement performance and extend service of life will be greatly improved by establish pavement sub drainage system to remove excessive water to the edge of highway in time. This paper designed three kinds of asphalt-treated permeable base (ATPB) with different opens grades, and according to the weather characteristics of the north China, their road performances such as water permeability, water stability, anti-cracking, mechanical property have been studied at low temperature by experiment. It is verified that ATPB-25 is more suitable as permeable base in cold area.

Abstract: The recycled asphalt mixture was analyzed by the microstructure, grading variability and agglomerate degree evaluation from the Guaxing road. The results showed that some aggregate was more in quantity and smaller in the variation for the 9.5mm to 0.6mm material of recycled aggregate; the fineness modulus ratio (FMR) was 0.89, so the agglomerate degree of recycled asphalt mixture is relatively small, which had a little effect on the strength of the cold recycled mixtures; the gradation and unconfined compressive strength test of cement stabilized wasted asphalt mixture were made at different blending ratios; the reasonable range of the cold recycled utilization was 20% to 40% for the recycled old materials in Guaxing road.

Abstract: This article studies the low-temperature anti-cracking properties of plain asphalt mixtures and rubber-modified asphalt mixtures at different aging condition. Laboratory flexural test was conducted on the beam specimens of plain asphalt mixtures and rubber-modified asphalt mixtures. Experiment results indicate that rubber-modified asphalt mixtures have superior low-temperature anti-cracking performance than that of plain asphalt mixtures. Compared with the short term oven aging test, the long term oven aging test has more significant effect on the low-temperature anti-cracking of the mixture. In order to better represent the low-temperature anti-cracking of in-service aging asphalt pavement, the long term oven aging test should be used to appraise the low-temperature anti-cracking of asphalt pavements in china.

Abstract: Flame retardants modified asphalt with SBS flame retardant SMA hybrid material was prepared, flame retardant performances of SMA mixture was studied by the cone calorimeter. The results show that adding 12% flame retardant with SBS modified asphalt in preparation of flame retardant SMA mixture, the peak heat release rate values than the non-flame retardant asphalt mixture decreased by 4.02 kW/m2, and the heat release rate values were significantly reduced, the total heat and the amount of smoke of flame retardant asphalt mixture released less than the non-flame retardant asphalt mixture.

Abstract: According to high temperature weak stability of common asphalt mixture, rutting tests of diatomite modified asphalt mixture, modified lake asphalt mixture, modified rock asphalt mixture and common asphalt mixture are carried out. Changes of dynamic stability for common asphalt mixture compared with modified asphalt mixtures are comparatively analysed. The results show that compared with common asphalt mixture, rutting resistances of diatomite modified asphalt mixture, modified lake asphalt mixture and modified rock asphalt mixture are greatly improved. It is proposed that those kinds of modified asphalt mixture are adopted in asphalt pavement of large longitudinal slope section.

Abstract: To study the properties of warm mix flame retardant asphalt mixture, a series tests were put forward, including Marshall Combustion experiments, rut specimen combustion experiment and texture depth experiment. With less mass loss, the warm mix retardant asphalt mixture has a better Marshall Stability, residual stability and freeze-thaw splitting strength ratio after combustion. The composite flame retardant can slow down and stop the burning of asphalt, reduce asphalt aging degree during burning process. The burning amount of warm mix flame retardant asphalt mixture is less than the ordinary hot mix asphalt concrete. To sum up, the warm mix flame retardant asphalt mixture has a good comprehensive performance.

Abstract: Combined with the application of a new tensioning device for prestressed CFRP strengthening concrete structures, in order to ensure the safety and determine the reasonable adhesive length of CFRP on steel plate of the anchorage during prestress exerting of CFRP, the tests were carried out to measure the tensile strength of CFRP and the bond strength of CFRP with steel plate considering the influence of different kinds of adhesive. Based on the results, the behaviors of CFRP under tension are analyzed, and the special CFRP glue is chosen as the adhesive of CFRP bonded on steel plate.

Abstract: According to the intuitive analysis and variance analysis of L₁₆ (4⁵) orthogonal experiment, the activity of slag was investigated on component of compound activator and mixing amount with the compressive strength as evaluation standard of various influencing factors. The results show that the range of anhydrous sodium sulfate (NS) was maximum, clinker (NL) comes second and lime (NH) was minimum, which means that primary and secondary of compound activator to the compressive strength of slag cementations material was NS>NL>NH, and the better activated effects can be obtained as NS=4%, NL=0.6% and NH=0.6%.

Abstract: Based on micropolar fluid theory and micropolar solid elasticity theory, reflection and transmission characteristics of longitudinal displacement wave and two coupled waves are studied when incident longitudinal displacement plane wave propagates through micropolar fluid interlayer in micropolar solid. Theoretical and numerical analytical results reveal that in general the amplitude ratios of various reflected and transmitted waves are functions of the incidence angle, the frequency of the incident wave and the material properties of the medium. At normal incidence, the reflection and transmission of only longitudinal waves take place and no coupled transverse wave is found to reflect or transmit. At grazing incidence, no reflection or transmission phenomena take place and the same wave propagates along the interface. The change rules of the amplitudes varied with incident angle are also discussed.

Abstract: Pure lead titanate (PbTiO₃) and Sn doped PbTiO₃ solid solution were prepared by sol-gel technique. The sol was prepared by mixing stable solutions of Pb-citrate, Sn-and Ti (OC₄H₉)₄ precursors. The structure and particle size and morphology of PbTiO₃ powder were characterized by XRD, and the results shows that the precursors decomposed and forms pure phase after heating at 973 K and 1073 K for 2 h. Influence of different factors on PbTiO₃ gel doped with Sn was discussed. It is found that higher synthesis temperature is needed to prepare Sn doped PbTiO₃ solid solutions.