橡胶沥青应力吸收层抗疲劳作用机理研究

Study on fatigue resistance mechanism of AR-SAMI

为研究AR-SAMI的抗反射裂缝与抗疲劳作用机理,通过复合梁三点弯疲劳试验分析了AR-SAMI对加铺层疲劳开裂进程与疲劳寿命的影响;采用有限元数值模拟并结合疲劳断裂力学理论进行疲劳扩展寿命的预估,并与试验结果进行对比;通过计算加铺层底部的最大主应力与裂尖应力强度因子,探讨AR-SAMI的阻裂与抗疲劳作用机理。结果表明:①设AR-SAMI有效抑制了反射裂缝的产生并降低了裂缝扩展速率,使得试件整体疲劳寿命提高了57%;②设AR-SAMI后使得沥青加铺层在开裂后裂尖的应力强度因子大幅降低,也因此降低了裂缝的扩展速率;③应用疲劳断裂力学理论对裂纹扩展疲劳寿命进行预测,结果显示应力吸收层依靠自身较高的疲劳性能使得结构整体疲劳扩展寿命提高了36%。因此,AR-SAMI在长期的使用过程中对抑制裂缝反射并提高加铺层疲劳寿命具有显著的效果。

In order to study the mechanism of AR-SAMI for anti reflection crack and anti fatigue,the three-point bending fatigue test of composite beam is conducted to analyse the effect of AR-SAMI on the fatigue cracking process and fatigue life of the overlay.The finite element numerical simulation and the fatigue fracture mechanics theory are combined to estimate the fatigue crack propagation life,which is compared with the test results.Through calculating the maximum principal stress at the bottom of the overlay and the stress intensity factor at the crack tip,the mechanism of crack resistance and fatigue resistance of AR-SAMI is discussed.The results show that①AR-SAMI can effectively restrain the reflection crack and reduce the crack growth rate,which increases the fatigue life by 57%.②after setting up AR-SAMI,the stress intensity factor of the crack tip is reduced greatly,and the crack propagation rate is also reduced.③prediction of the fatigue crack propagation based on fatigue fracture mechanics theory shows that the stress absorption layer depends on its higher fatigue performance to increase the fatigue crack propagation life of the structure by 36%.Therefore,AR-SAMI has significant effect on reducing the reflection of the cracks and improving the fatigue life of the overlay during the long term use.