基于修正Neuber方程的沥青路面裂缝形成疲劳寿命预估方法

为预估沥青路面裂缝形成疲劳寿命,根据局部应力-应变理论,通过直接拉伸疲劳试验,建立了沥青混合料的真实应力-应变循环曲线,运用Neuber方程将名义应力、应变转换为局部应力、应变,对循环曲线和Neuber方程进行修正,以符合平面应变问题。通过等应变疲劳试验,建立了沥青混合料的疲劳寿命方程,提出了沥青路面裂缝形成寿命预估方法。根据应变疲劳寿命曲线可合理计算沥青混合料疲劳损伤,由累积损伤可求得沥青路面裂缝形成疲劳寿命。

Estimating method of fatigue life during cracking initiation of asphalt pavement based on modified Neuber equation

To estimate the fatigue life of asphalt mixture during the cracking initiation of asphalt pavement,its true stress and strain loop curve was established by direct tension test based on partial stress and strain theory,its nominal stress and strain were converted into partial stress and strain through Neuber equation,and its loop curve and Neuber equation were modified in order to meet the question of plain stress.The fatigue equation of asphalt mixture was established by isostrain fatigue test,and an estimating method of fatigue life was put forward.It is pointed that the fatigue damage of asphalt mixture can be reasonably calculated by its strain fatigue life curve,and its fatigue life during the cracking initiation of asphalt pavement can be estimated by its cumulation damage.8 tabs,10 refs.