A novel approach to evaluate the clogging resistance of pervious concrete

Pervious concrete is an important material for permeable pavement, while the clogging phenomenon is deleterious to the service performance of the pervious concrete pavement. In this paper, the pervious concrete is proportioned by introducing a parameter of filling ratio, and the influences of filling ratio and W/C ratio on compressive strength and permeability of pervious concrete are investigated. A novel method using saturated slurry (soil suspension) as clogging media is proposed to evaluate the clogging resistance of pervious concrete. The pore characteristics are analyzed by the image processing to interpret the clogging phenomenon. The results indicate that the filling ratio is an essential parameter in the mix design of pervious concrete, while the only decrease of W/C is not always effective to prepare high performance pervious concrete. The proposed method could evaluate the clogging risk with clogging cycles for pervious concrete with different pore structures. According to image processing analysis, large pores are beneficial to the permeability, but on the contrary, excessive large pores would reduce the permeability due to the increase of pore tortuosity. More importantly, except for porosity and tortuosity, the pore size distribution needs to be sufficiently considered to design an unclogged pervious concrete.