基于GTM的AC-20沥青混合料高温性能试验研究

GTM-based Experimental Study on High Temperature Performance of AC-20 Asphalt Mixture

基于常用中、下面层沥青混合料AC-20,采用3种矿料级配,5种油石比进行GTM旋压试验,并对旋压成型试件进行三轴重复蠕变试验,对蠕变劲度模量和旋转压实曲线的斜率、稳定度指数(GSI)、抗剪强度安全系数(GSF)以及旋转压实次数等进行分析。结果表明:斜率K_1,K_2与蠕变劲度模量的相关性很好;平均斜率K_1与蠕变劲度模量相关性很好,用平均斜率K_1评价AC-20混合料的高温稳定性具有可表征性,推荐采用平均斜率K_1评定AC-20沥青混合料的高温稳定性;随着平均斜率K_1的增大蠕变劲度模量减小,即混合料高温稳定性降低,抗车辙性能变差。

For asphalt mixture AC-20 commonly used in middle or lower layer, GTM test, which is on the condition of 3 values of mineral aggregate gradation and 5 values of bitumen-aggregate ratio, was conducted, and then triaxial repeated creep test conducted on the gyrator forming specimen, by which the creep stiffness modulus, gradient of gyratory compaction curve, gyrator stability index （GSI）, gyratory shear factor （GSF） and the number of gyratory compaction, were analyzed. The result shows that, the K1 and K2 have the good correlation with the creep stiffness modulus; the evaluation of the mixture AC-20’s high temperature stability by the average K1 is of representation, thus to be recommended; the creep stiffness modulus decreases with the increase of average K1, that is to say, the mixture’s high temperature stability is decreased, and the rutting resistance worse.