基于结构层寿命递增的耐久性沥青路面设计新思想

New Structure Design of Durable Asphalt Pavement Based on Life Increment

为了建立科学的耐久性沥青路面设计新思想,通过力学分析探究了沥青路面近表面的应力分布特征,论证了以路表荷载作用区边缘作为沥青路面破坏源的合理性。针对中国现行沥青路面疲劳设计方法的缺陷,开展了沥青混合料疲劳试验,在考虑加载速度影响的基础上,建立了以真实应力比表征的沥青混合料疲劳方程。结合中国沥青路面各结构层设计寿命相等所诱发的问题以及实际沥青路面结构的破坏特征,提出了各结构层自上而下设计寿命递增的沥青路面结构设计新思想和耐久性沥青路面结构设计新理念。结果表明:沥青面层近表面是其真正的破坏源;基于真实应力比的疲劳方程反映了材料的本质特征;耐久性沥青路面的各结构层应采用疲劳寿命递增的方法进行设计。

In order to establish a new scientific structure design of durable asphalt pavement, the stress distribution characteristics near the asphalt pavement surface were explored by mechanical analysis. It was proved that taking the boundary of the loading action area on the surface as the source of damage was reasonable. Aimed at the defects of current fatigue design method for asphalt pavement in China, fatigue tests on asphalt mixture were carried out and fatigue equation characterized by real stress ratio was established with the influence of loading speed considered. A new structure design of durable asphalt pavement was proposed,according to which the design life of each structural layer, from surface layer to subbase course, would be increased to solve the problems in equal design life of each layer in China with asphalt pavement structure damage considered. The results indicate that the area near the surface of asphalt layer is the real damage source~ the fatigue equation characterized by real stress ratio can reflect the essential features of the material~ the method of fatigue life increment should be adopted in structure design of eachlayer for the durable asphalt pavement.