Experimental study on rainfall-runoff relation for porous pavements

Impervious surfaces have long been implicated in the decline of watershed integrity in urban and urbanizing areas. Porous pavement is one solution to mitigating the problem of stormwater runoff problems. In this research, three available porous pavement systems were investigated to evaluate their infiltration capability of precipitation. Experiments were conducted to simulate different kinds of porous pavements having different sub-base materials in different cells. The discharge volumes were monitored from each cell, and the relationship between rainfall intensity, outflow and outflow duration was analyzed. Results show that these three porous pavements increased infiltration and decreased runoff. The optimum thickness of the porous pavement was 31 cm, which consisted of a 6 cm top layer of porous concrete and a 25 cm sub-base (10 cm concrete without sand and 15 cm aggregate base). Furthermore, under a rainfall rate of 59.36 mm/h, the runoff coefficient of the above porous pavement was zero, while the coefficient of the impervious pavement was 0.85. These results provide a clear indication of the value of porous pavement systems for broad expanses of the human engineered environment.