Effect of cement replacement by fly ash and epoxy on the properties of pervious concrete

Abstract

Permeable concrete has strong drainage and can recharge groundwater, making it a common semi-rigid road base material. Over the last decade, authors have focused on the properties of porous concrete with pozzolanic admixtures. The number of studies on the mechanical properties of pervious concrete made through the replacement of pozzolanic materials with cement is quite limited. Unfortunately, researchers have not focused on utilizing additional admixtures to improve the properties of pervious concrete made with high volumes of pozzolanic replacement. This paper focuses on the effect of using epoxy to partially replace cement on the mechanical properties of permeable concrete made with a significant amount of cement replaced by fly ash. A comparison between the addition and non-addition (15%) of sand as a partial replacement for gravel was investigated and the effect of increased gravel to sand ratios on the properties of porous concrete was also studied. This paper showed a slight decrease in porosity due to epoxy replacement compared to an increase in porosity by other mechanical properties. There was an increase in strength when epoxy replacement reached above 45% as well as a marginal decrease in strength and modulus of elasticity with (50%) fly ash replacement. There was also an increase in strength due to (15%) gravel replacement by sand of above 40%, with a reduction in strength with increased gravel to sand ratios.