Spherical discrete element model for estimating the hydraulic conductivity and pore clogging of pervious concrete

Abstract

Pervious concrete pavements have received increasing interest for stormwater management, especially with record-breaking extreme weather events, including floods. To efficiently direct stormwater, pervious concrete design should provide sufficient hydraulic conductivity that can be maintained over its service life. To study the impact of mixture parameters (aggregate gradation, aggregate-to-paste ratio, and porosity) on hydraulic conductivity and extent of clogging, an approximate model of pervious concrete as sphere packing was generated by the Discrete element method (DEM). The DEM was used in a Pore-scale finite volume (PFV) model to predict the hydraulic properties of pervious concrete. The model was validated with hydraulic conductivity results of seventy pervious concrete cylinders and then used to simulate the clogging of voids with sediments. At a sediment load rate of 0.1 kg/m2 with 0.25–1 mm particle size, the hydraulic conductivity of sphere packings at initial porosity of 20 and 30 % dropped by 66 and 56 %, respectively. The simulations showed that, at the same porosity, larger pore volume (formed by using larger aggregate size) results in a significant drop in permeability due to sediments accumulation.