Microcracking treatment mechanism of semi-rigid base asphalt pavement with discrete-continuous coupling simulation

The microcracking treatment employs the falling weight to break the semi-rigid base into interlocking blocks to prevent reflective cracks in asphalt pavement. To study the microcracking treatment mechanism, the semi-rigid base microcracking simulation was performed through a discrete-continuous coupling model. After that, the coupling model was verified through a test road in Shaanxi Province, China, and the impact of convex points properties was studied. The results showed the coupling model exhibited a peak compressive stress calculation error of less than 10% and effectively simulated the semi-rigid base cracking. Besides, the properties of convex points significantly impacted cracking. An appropriate area of convex points could effectively reduce upper layer cracks while inducing a more significant number of cracks in the lower layer of the base. The three-convex falling weight produced the most cracks, and the semi-rigid base was microcracked into interlocking blocks. With convex points inner tangent circle radius increasing and length ratio decreasing, the number of upper layer cracks in the base grew while the number of lower layer cracks decreased. However, a bigger length ratio could improve the horizontal extension capability of cracks. These findings contribute to improving the microcracking effect in engineering. After trail impact, if there is no apparent cracking on the semi-rigid base surface, it is recommended to use a three-convex point falling weight, slightly reduce the convex points area, and increase the inner tangent circle radius and length ratio. In the case of severe cracking, it is recommended to increase the number of convex points and their area, decrease the inner tangent circle radius and length ratio, or use a flat-bottomed falling weight.