基于离散元方法的沥青混合料抗裂性能分析

Analysis on the Crack Resistance of Asphalt Mixture with the Discrete Element Method

为了研究沥青结合料性质、集料表面特性和加载条件对沥青混合料抗裂性能的影响,利用离散元方法生成马歇尔数字试件,以伺服控制机理施加荷载,分析了粘结刚度比、粘结强度比、颗粒摩擦系数和加载速率4种细观参数对应力-应变曲线、劈裂强度、配位数和微裂缝的影响,给出了荷载作用后试件内部颗粒的细观响应。模拟结果表明:粘结强度比引起劈裂强度、配位数和微裂缝数的变异性最大,劈裂强度和配位数的变异系数分别为56.9%和5.9%,微裂缝数相差43条,加载速率引起劈裂强度、配位数和微裂缝数的变异性最小,劈裂强度和配位数的变异系数分别为2.3%和1.7%,微裂缝数仅相差1条,从细观角度验证了沥青结合料性质对沥青混合料抗裂性能的贡献率占主导地位。

The influences of asphalt binder properties,aggregate surface properties and loading conditions on the crack resistance of asphalt mixture were studied.Marshall digital specimens were generated with the discrete element method and the specimens were loaded with the servo-control mechanism.The influences of bond stiffness ratios,bond strength ratios,particle friction coefficients and loading velocities on the stress-strain curves,the splitting strengths,the coordination numbers and the micro-cracks were analyzed.And the mesoscopic responses among particles were obtained after loading.The simulated results show that the variabilities of splitting strengths,coordination numbers and micro-cracks caused by the bond strength ratios are the greatest,the variation coefficients of splitting strengths and coordination numbers are 56.9％ and 5.9％,respectively.The difference of the number of micro-cracks is 43.However,the variabilities of splitting strengths,coordination numbers and micro-cracks caused by the loading velocities are the smallest,the coefficients of variation of them are 2.3％ and 1.7％,respectively.The difference of the number of micro-cracks is only 1.And the results verify that the contribution of asphalt binder properties to the crack resistance of asphalt mixture is dominant from the mesoscopic viewpoint.