柔性基层沥青路面结构黏弹性力学响应分析

沥青混合料是典型的黏弹性材料,只有对沥青路面结构进行黏弹性分析,才能得到其实际的力学响应。对一柔性基层沥青路面的各层沥青混合料进行了不同温度、不同频率下的复数模量试验,并利用黏弹性理论关系式,将沥青混合料复数模量试验结果转化为其蠕变柔量的Prony系列表达式,并进而求解在静载和加载、卸载两种荷载模式下路面结构路表弯沉、基层底面拉应变和土基顶面压应变的黏弹性力学响应。研究结果表明,由于沥青混合料的蠕变和松弛特性,各种响应尤其是基层底面的拉应变随时间呈现出较为复杂的变化趋势。随加载或卸载时间的延长,各响应逐渐趋于稳定。本研究也表明进行黏弹性分析可以更科学地描述沥青路面结构的行为特性及破坏原理。

Analysis of viscoelastic responses of asphalt pavements with flexible bases

Asphalt mixtures are typical viscoelastic materials.Realistic responses of asphalt pavements can only be obtained by conducting viscoelastic analysis.In this study complex modulus tests were conducted for asphalt mixtures used in an asphalted expressway with a flexible base,and the test results were then converted to Prony series of creep compliances by using theoretical relationships.Surface deflection,tensile strain at the bottom of the base layer and compressive strain at the top of subgrade were calculated under constant loading and loading/unloading conditions by using viscoelasticity theories.The results indicate that the viscoelastic responses of pavements,especially the tensile strain at the bottom of the base layer,vary significantly with time due to the creep and relaxation characteristics of asphalt mixtures.The responses become stable after long period of loading or unloading.