Archive of Applied Mechanics ( IF 2.8 ) Pub Date : 2021-07-21 , DOI: 10.1007/s00419-021-02020-1 Xia Zhang 1 , Enli Chen 1 , Pengyong Gao 1 , Chundi Si 1
Microcrack propagation in asphalt mixtures leads to macroscopic cracks in pavement. It is necessary to study crack evolution from the perspective of micromechanics to precisely predict structural damage. This paper developed a micromechanical model of three-point bending under a bending fatigue load for a bitumen specimen that was a three-phase asphalt mixture composed of coarse aggregate, asphalt mortar and air voids. A three-point bending test was carried out to verify the correctness of the micromechanical model. The microscopic parameters of bitumen were calibrated by fitting the stress–strain curve of the laboratory test data. Microdynamic simulations demonstrated that the growth of microcracks included an initial transition period, a rapid growth period and a stable period. The microcrack propagated from the bottom edge to the center of the specimen under the bending load, mainly within the asphalt mortar or asphalt–aggregate interface. Compared with a static load, the longitudinal stress at the microcracks was much larger, and the number of microcracks increased more rapidly, under the dynamic load. The width of the microcrack increased instantaneously when the internal stress state of the specimen reached its material strength, then changed almost periodically with sinusoidal loading and finally stabilized. The micromechanical modeling method can potentially be used to predict the position and width of macroscopic cracks in asphalt pavement.
中文翻译:
三点弯曲载荷作用下沥青混合料裂纹演化的微观动力学模拟
沥青混合料中的微裂纹扩展导致路面出现宏观裂纹。有必要从微观力学的角度研究裂纹演化,以精确预测结构损伤。本文为沥青试样开发了一种在弯曲疲劳载荷下三点弯曲的微观力学模型,该沥青试样是由粗骨料、沥青砂浆和空隙组成的三相沥青混合物。进行了三点弯曲试验以验证微机械模型的正确性。通过拟合实验室测试数据的应力-应变曲线来校准沥青的微观参数。微动力学模拟表明,微裂纹的生长包括初始过渡期、快速增长期和稳定期。微裂纹在弯曲载荷作用下从试样底部边缘向中心扩展,主要在沥青砂浆或沥青-集料界面内。与静载荷相比,在动载荷作用下,微裂纹处的纵向应力要大得多,微裂纹的数量增加得更快。当试样的内应力状态达到其材料强度时,微裂纹的宽度瞬间增加,然后随着正弦加载几乎呈周期性变化,最终稳定。微观力学建模方法可用于预测沥青路面宏观裂缝的位置和宽度。在动态载荷作用下,微裂纹处的纵向应力更大,微裂纹数量增加更快。当试样的内应力状态达到其材料强度时,微裂纹的宽度瞬间增加,然后随着正弦加载几乎呈周期性变化,最终稳定。微观力学建模方法可用于预测沥青路面宏观裂缝的位置和宽度。在动态载荷作用下,微裂纹处的纵向应力更大,微裂纹数量增加更快。当试件的内应力状态达到其材料强度时,微裂纹的宽度瞬间增加,然后随着正弦加载几乎呈周期性变化,最终趋于稳定。微观力学建模方法可用于预测沥青路面宏观裂缝的位置和宽度。