Influence of mineral additives on the properties of pervious concrete

Pervious concrete is a permeable concrete which presents a lower strength than conventional concrete due to its high porosity. The strength of pervious concrete can be improved by using a low w/c paste with additives or admixtures. This study focused on the addition of mineral additives (diatomite, fly ash, limestone dust, and fine sand) in a low water to cement ratio (w/c) paste to improve the strength and other properties of pervious concrete. The strength, total void content, density, thermal conductivity, and abrasion resistance of pervious concrete were investigated. The results show that these additives increase the paste volume and improve the mechanical properties of pervious concrete. The improvement from addition of diatomite or fly ash is due to both chemical and filler effects, while that from addition of inert limestone dust or fine sand is only due to filler effect. Pervious concrete with mineral additives show increase in strength and abrasion resistance with a slight increase in density and thermal conductivity. The incorporation of 10% fine sand is highly desirable in this study as it gives high strength and high permeability. The high permeability is probably due to the use of large particle sand with little or no fine particles which led to an improved continuous void.