基层层间状态对沥青路面荷载应力与疲劳性能的影响

Effects of Base Course's Interfacial Bond on Load Stress and Fatigue of Asphalt Pavement

基层间接触不良是导致半刚性基层路面早期损坏的重要原因之一。为分析半刚性基层间粘结状态对沥青路面疲劳性能的影响,从弹性层状体系理论出发,利用BISAR3.0程序中剪切弹性柔量AK表征双层半刚性基层的层间粘结状态,分析沥青路面弯沉、层底拉应力和剪应力随AK的变化规律;研究半刚性基层层间粘结状态对路面结构疲劳性能的影响。结果表明:不良的基层间接触状态会使接触状态迅速恶化,并降低基层的疲劳寿命。水稳基层间状态良好时,上面层不会首先疲劳开裂,而疲劳破坏会从下基层向上发展传递;但是水稳基层间状态很差时,疲劳破坏首先发生在上基层。与基层层间完全光滑状态相比,完全连续状态下上基层底最大拉应力增大5.7倍,上基层底最大剪应力增幅最大为31%。

The poor base course＇s interfacial bond is an important reason causing damage to the road early. In order to analyze the influence of semi- rigid base interlayer bonding state on the fatigue performance of asphalt pavement,starting from the theory of elastic layered system,the shear elastic compliance AK from BISAR3. 0 program is used to characterize the bonding state of double semi- rigid base layers,and the change law of the asphalt pavement deflection,the bottom layer of tensile stress and the shear stress with AK is analyzed. The influence of semi- rigid base interlayer bonding state on fatigue performance of asphalt pavement structure is also studied. The results shows that poor contact condition between the semi- rigid base interlayer will rapidly deteriorate the contact state,and reduce the fatigue life of semi- rigid base. When the base course＇s interfacial bond is good,the upper layer will not be the first fatigue crack,and fatigue failure will develop from the bottom to the upper base,but when the base course is very poor,fatigue failure will occur on the bottom of upper base. Compared with completely smooth interlayer state,the maximum tensile stress on the bottom of upper base increases by 570%,the maximum shear stress on the bottom of upper base increases by 31%.