模拟车辆荷载的沥青混合料应力松弛试验研究

Simulated Vehicle Loads of Asphalt Stress Relaxation Testing Research

路面的服役过程实际上是单向瞬时车辆荷载反复作用下路面材料应力松弛不断累积和遗传的过程，在这个过程中材料内部出现的松弛应力会影响路用材料的性能变化。为了研究车辆荷载作用下沥青混合料应力松弛特性，以某高速公路车辆随机荷载的模拟结果为基础研究了代表性沥青混合料的应力松弛试验特性；采用MTS设备综合考虑高速公路货车随机车辆荷载模拟表达式设计了模拟车辆荷载作用的沥青混合料应力松弛试验方法。试验结果表明，在模拟车辆荷载作用下沥青混合料的应力松弛试验可以分为两个阶段：第1阶段应力下降迅速即松弛速度较快，第2阶段曲线趋于平缓即松弛速度减慢。

During the service period of pavement, the stress relaxation of pavement material is cumulated, stacked and inherited under the one-way instantaneous cyclical load. In this process, the mechanical performances of the material, such as modulus and strength, are as affected by the stress relaxation. In order to study the characteristics of asphalt stress relaxation in the case of vehicle loads, the simulation results obtained from the random vehicle loading of a sampled highway as the basis contributing to the investigation on the representative asphalt; by means of MTS equipment and the testing method to simulate asphalt stress relaxation under this case has been designed taking into consideration the analog of vehicle loadings. Experimental results show that the asphalt stress relaxation can be divided into two phases in the case of simulated vehicle loadings： that is, at first the stress decreased rapidly, i.e. that relaxation velocity is faster; then, the curve tends to be flat, namely, relaxation rate slows down.