沥青混合料黏弹性裂纹扩展  

Viscoelastic crack propagation in asphalt mixtures

作　　者：黄晓明[1] 肖益民[1] 张裕卿[1] 

机构地区：[1]东南大学交通学院,南京210096

出　　处：《东南大学学报（自然科学版）》2009年第3期586-591,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家高技术研究发展计划(863计划)资助项目(2006AA11Z110);江苏省普通高校研究生科研创新计划资助项目(CX07B-158Z)

摘　　要：采用Schapery提出的局部衰坏区模型,推导了沥青混合料宏观裂缝稳定扩展阶段开裂速率的简单力学表达式.首先利用裂纹扩展3个基本方程控制裂缝在沥青混合料中的扩展行为,再采用修正Burgers力学模型来准确模拟沥青混合料黏弹性能,通过对黏弹性张开位移和断裂能判据的合理简化,推导出了沥青混合料宏观裂纹稳定扩展的瞬时开裂速率与应力强度因子的关系.然后利用推导出的裂纹扩展速率公式预测了沥青砂浆板拉伸开裂速率,并与试验结果对比.结果显示:理论预测的沥青砂浆开裂速率与试验实测值在裂缝稳定扩展阶段吻合较好;沥青混合料的断裂行为具有时间相关性,其开裂速率随裂缝长度的增加或者应力水平的提高而增大.The failure zone model developed by Schapery is adopted to derive simple mechanical relations for predicting cracking velocity when macro cracks stably propagate in asphalt mixtures. First, three basic viscoelastic crack growth equations are used to control the crack propagation in asphalt mixtures, and a modified Burgers model is employed to accurately simulate the asphalt mixtures＇ viscoelasticity. Then, the relations between instantaneous cracking velocity during stable crack propagation and stress intensity factors are derived based on a rational simplification of viscoelastic opening displacement and energy criterion of failure. The derived theoretical expression is then employed to predict the cracking velocity in thin plate tensile creep tests of asphalt mortar. Results show that theoretical prediction using derived cracking velocity relations shows good agreement with experimental values in stable crack growth stages, and the fracture behavior of asphalt mixtures is time-dependent. The cracking velocity of asphalt mixtures increases with increasing of crack length or stress level.

关 键 词：沥青混合料 黏弹性 裂纹扩展 修正Burgers模型 开裂速率 

分 类 号：U416.2[交通运输工程—道路与铁道工程]