ABSTRACT
The rainwater is vertically downward infiltrated into the drainage asphalt surface which is the twophase process. The first stage is the external control stage. If the external eater supply rate does not exceed infiltration capacity, then the infiltration rate is equal to the Inflow rate. The second phase is the drainage layer control phase. With the drainage surface saturation degree increasing, the capacity of the surface water conduction is reduced. When it is less than external water supply rate, the rainwater begins forming the runoff to discharge it to the surface of the pavement through the comprehensive slope of the pavement surface. At this time, the infiltration rate is equal to the infiltration capacity of the surface layer. At last, the infiltration capacity reduces to the saturated hydraulic conductivity of the draining-layer.
