Modified Asphalt By Polymer Blends For Highway Pavement

Asphalt is an important low-cost thermo-plastic material which is widely used for construction, in particular as road-paving. Therefore it is exposed to a wide range of load and weather conditions. Increasing traffic factors, such as heavier loads, higher traffic volume and higher tire pressure demand higher performance pavements. However, this kind of materials does not have good mechanical properties because it is hard and brittle in cold weather, and soft and fluid in a hot environment.In order to solve these problems, We modified asphalt in this paper by powdered Styrene Butadiene Rubber(SBR) blend with organic acids soaps, asphltite, reinfocer, plasticizer and waste automobile tyres powder. The best ratio was obtained through orthogonal design. Softening point, ductility, penetration degree and these properties after Rotary Thin Film Oven Test(RTFOT) aging of modified asphalt have been determined. The qualification test also did by Transportation Department of China and Institute of Highway of Shandong Province. The results show that the polymer blends less susceptible to temperature and increasing substantially its all-round performance. The properties of modified asphalt are higher than original asphalt and meet the Specification for Construction of Highway Modified Asphalt Pavement(JTJ 036-98) of China, so that it can be used as highway pavements.The sample also measured according to Strategic Highway Research Program (SHRP) of USA such as PAY, DSR and BBR. The performance grade of modified asphalt was increased.The microstrcture of the modified asphalt was characterized by SEM, FT-IR, TG-DTG, DSC and microscopy, and then, we discussed the possible mechanism of the modification.Three parts are included in this paper:Part one: The review of asphalt and modified asphalt of highway asphalt binders.Part two: The material and instrument employed in this paper.Part three: The results of our research and the mechanism discussion.In this paper, powdered SBR and asphltite were firstly used to modify asphalt for highway pavements in China. We got satisfied results.This work was supported by the Science and Technology Commission of Gansu Province and the NWNU-KJCXGC-03 of Northwest Normal University.