酸性环境及干湿循环耦合作用下沥青-集料界面的剪切行为

Shear behavior of asphalt-aggregate interface under acidic environment and dry-wet cycle coupling

为了探究酸性环境及干湿循环耦合作用下沥青-集料界面的剪切力学行为,设置了4类酸性环境及8种干湿循环周期耦合条件,采用直接剪切试验得到应力-位移曲线,并从抗剪强度、界面滑移量、剪切断裂能等角度分析沥青-集料界面在剪切过程中的力学变化过程。结果表明:中性环境下,界面抗剪强度在干湿循环周期下可分为缓慢降低、快速衰退、衰退平衡这3个过程;中酸环境下,第21次干湿循环试验下的界面相对滑移量仍高于0.3 mm;中性环境下,黏附性断裂能主导沥青-集料界面的剪切断裂能,而酸性环境下,黏附性失效消耗的能量与沥青膜内部黏聚性失效消耗的能量相近,黏附性断裂能和黏聚性断裂能共同主导干湿循环作用下的沥青-集料界面的剪切断裂能;随着循环周期的和酸性强度的增加,临界断裂能与相对滑移量不具备良好的相关性。

In order to explore the shear behavior of the asphalt-aggregate interface under the coupling action of acidic environment and dry-wet cycles,four types of acidic environments and eight coupling conditions of dry-wet cycles were set up,and the stress-displacement curve was obtained by direct shear test.The mechanical change process of the asphalt-aggregate interface was analyzed during the shearing process from the perspectives of shear strength,interface slip,and shear fracture energy.Research shows that in the neutral environment the shear strength of the interface under the dry and wet cycle can be divided into three processes of slow decline,rapid decline,and decline balance;In the acidic environment,the relative slip of the interface under the 21 st dry-wet cycle test was still higher than 0.3 mm;In the neutral environment,the adhesive fracture energy dominated the shear fracture energy of the asphalt-aggregate interface.However,in the acidic environment,the energy consumed by adhesive failure was similar to the energy consumed by internal cohesive failure of the asphalt film.Adhesive fracture energy and cohesive fracture energy jointly dominated the shear fracture energy of asphalt-aggregate interface under dry-wet cycles.As the cycle period and acid strength increase,the critical fracture energy did not have a good correlation with the relative slip.