Pervious concrete using fly ash, silica fumes, GGBFS and metakaolin : A review

Abstract

Pervious concrete is a special type of concrete which consist of cement, coarse aggregate, water and if required admixtures and other cementitious materials. As there is no fine aggregate present in the matrix, the void content is more which allows the water to flow through it. Therefore, the pervious concrete is called as permeable concrete or porous concrete. Considering the high porosity and high permeability of pervious concrete, it is capable of various environmental benefits such as reduction in stormwater runoff, reduction in urban heat island effect and recharge of ground water. Cement being one of the major source of CO2 emission, it is replaced by some proportion of SCMs. This study shows the effects of replacement of SCMs such as Silica fumes, fly ash, ggbfs and metakaolin with Cement. By adding 5-10% silica fumes, void ratio is decreased to 25% and compressive strength increased significantly.Highest compressive strength was achieved at 50% replacement of cement, upto 17% more than normal pervious concrete. When the cement is replaced by 2% of metakaolin porosity decreased and density increased significantly. Optimum level of replacement for cement with fly ash was seen to be 5-15%. While fly ash's replacement with cement shows the similar behavior as that of metakaolin. KEYWORDS: Pervious concrete, porous concrete, permeable concrete, silica fumes, fly ash, ggbfs, metakaolin