By employing the three-dimensional finite element method

the working mechanism of whiteandblack pavement treated by impact compaction was studied

and then the influence of the overlays' thickness on the mechanical properties of the new asphalt concrete layer (AC) was explored. The simulation results show that a gap will appear between the overlay and the broken existed concrete slab under the wheel load

which is the special working mechanism of the recovered pavement. Under traffic load the potential cracks will rise transversely at the bottom of AC

while the asphalt surface is undestroyed although it is directly suffered from the wheel load. The maximal stress in AC decreases linearly with the increase of the overlays thickness

either AC or the cement treated base (CTB). The pavement cracks would be efficiently decreased with the increase of the overlays' thickness

especially with the increase of CTB's thickness. However

the effect is not evident in improving the rutting resistance of AC by increasing the thickness of the overlays.