基于动态模量的不同碎石沥青混合料性能分析研究

Research on Performance Analysis of Different Stone Asphalt Mixtures Based on Dynamic Modulus

为了对不同碎石设计的沥青混合料动态特性进行研究,采用简单性能试验机(SPT)在不同温度和荷载频率下分别对铁矿围岩碎石和石灰岩碎石设计的密级配沥青混合料AC20的动态模量和相位角进行测试。其中铁矿围岩碎石设计了两个级配,石灰岩按照传统级配走势进行的设计。对实验得到的结果,分析了荷载频率、实验温度对两种碎石混合料动态特性的影响。依据时–温等效原理,采用西格摩德(Sigmoidal)函数进行拟合经过回归得到了三种级配沥青混合料20℃时的主曲线及位移因子。根据主曲线,对三种混合料在动荷载作用下,表现出的性能进行了对比分析,根据分析在低频荷载作用即长时间荷载作用时,铁矿碎石混合料的高温性能要好于石灰岩碎石,但铁矿碎石两个级配之间的差异很小,说明铁矿碎石混合料在车辆低速行驶即长时间荷载作用时具有很好的性能。

In order to study the dynamic characteristics of the different stone asphalt mixtures, a simple machine performance test (SPT) was used to test dynamic modulus and phase angles of dense-graded AC20 designed by iron surrounding rock gravel and limestone gravel at different temperatures and frequencies. Two gradations were designed by iron surrounding rock gravel, and limestone gravel was designed according to the traditional grading trend. Based on the ex-perimental results, the influence of load frequency and experimental temperature on the dynamic characteristics of the two types of gravel mixtures was analyzed. According to the principle of time-temperature equivalence, the Sigmoidal function was used to fit, and the master curve and displacement factor of three grading asphalt mixtures at 20˚C were obtained through regression. According to the master curve, the performance of the three mixtures under dynamic load was compared and analyzed. According to the analysis, the high temperature performance of the iron surrounding rock gravel mixture is better than the limestone gravel under the low-frequency load acts, that is, the long-term load acts. However, the difference between the two gradations of iron surrounding rock gravel is very small. It showed that the iron surrounding rock gravel mixture has good performance when the vehicle runs at low speed, that is, under long-term load.