大粒径沥青混合料基层结构抗裂机理分析

为研究大粒径沥青混合料基层的抗裂机理,采用多层弹性理论程序计算了不同结构类型路面内荷载作用产生的应力应变,基于瞬态传热假设建立了平面有限元模型,计算了降温时路面结构内的温度应力和应变,得到了荷载与温度耦合下各结构层的变形和受力特性。研究发现,当考虑车辆荷载和快速降温共同作用时,快速降温所引起的温度应力远大于标准荷载引起的荷载应力,说明快速降温的温度应力对路面的开裂起主要作用。同时,通过两种结构对比,发现采用ATB 30基层结构的沥青混凝土面层的温度和荷载应力应变均小于传统的半刚性基层沥青混凝土路面。因此认为,设置沥青稳定碎石基层是一种减少沥青混凝土路面开裂的有效方法。

Cracks Resisting Mechanism Analysis of Large Stone Asphalt Mixture Base Structure

In order to study the cracks resisting mechanism of large stone asphalt mixture base,a multi-layer elastic theory program is used to calculate the loading stress and strain in different pavement structures.Then a Finite Element model is established based on a twinkling heat conduct hypothesis to calculate temperature stress and strain of pavement structure when temperature dropped.The stress and strain of all the structural layers are calculated considering the coupling effect of loading and tempetature.It is found that temperature stress which is caused by temperate quick dropped is far more lager than loading stress caused by standard loading,while considering the co-effect of vehicle loading and temperature quickly dropped.Thus it is revealed that cracking in pavement is mainly caused by temperature quickly dropped.By contrast,it is found that pavement stress and strain caused by loading and temperature of the structure with asphalt macadam mixture(ATB30) base are less than that of the conventional semi-rigid pavement.Finally,an asphalt macadam mixture base applied in asphalt concrete pavement structure is believed to be an efficient way in reducing asphalt concrete pavement cracking.