Investigation on the fracture mechanism of homogenized micro-crack crushing technology for portland cement concrete pavement rehabilitation

Abstract

The homogenized micro-crack crushing technology for concrete pavement maintenance has received increased attention in China. To study the fracture mechanism of the homogenized micro-crack crushing technology, a low-velocity impact test system is developed and experiments using concrete slabs of different thicknesses are conducted with different drop heights and hammer weights. Furthermore, the fracture of concrete slabs under impact loading is simulated using the continuous-discontinuous element method. Finally, the fracture mechanism is investigated in a case study. It is concluded that a cylindrical compression–shear fracture surface appears under the impact head while the fractured blocks are still interlocked with each other. The main cracks in the concrete slabs are initiated and propagate parallel to the longer side of the impact head, whereas branch cracks develop perpendicular to the main cracks. These cracks radiate from the center of the impact head. The cracks inside the concrete develop upward from the bottom of the slabs. Because fractured blocks divided by micro-cracks can interlock with themselves and the crack distributions tend to be uniform, it is beneficial for portland cement concrete pavement rehabilitation to be overlaid by a hot-mix asphalt mixture.