Effects of existing asphalt pavement on loading stress of ultra-thin-whitetopping pavement

Ultra-thin-whitetopping(UTW) is a recently developed rehabilitation technique of distressed asphalt concrete pavement. For quantitatively analyzing the influence degree of the existing asphalt pavement to UTW pavement, UTW slab is regarded as surface layer, the existing asphalt layer is regarded as base course, and the layers under the base of existing asphalt pavement are regarded as the compositive ground. Using the three-dimensional isoparametric element, according to elastic three-layer model, loading stresses of UTW are calculated. On the basis of these results, the effects of asphalt thickness, thickness of slab, and general modules of ground(E c) on the stress are analyzed. The results indicate that loading stress of slab bottom varies linearly with thickness of asphalt, and the slope is relate to the modules of the ground(E s). The thickness of asphalt exceed 6 cm was favorable for serving of UTW while the slab was thin. Elastic modules of asphalt layer exceeding certain value little influenced to stress of slab bottom of pavement, and this value can be utilized to evaluate quality of existing asphalt layer.With decreasing of the elastic modules of asphalt, thickness of asphalt layer bring minus effect to the stress of slab bottom.