Effect of water cement ratio on permeable concrete

Abstract

Permeable concrete is a special type of concrete that permits water to percolate through it. It is also known by the name porous concrete or pervious concrete. The presence of voids in this concrete provides a free path for water to pass through it. This property of permeable concrete helps to reduce the runoff water from the site instantly by percolating it to ground hence acts as a source for ground water recharge. The permeable concrete is prepared by using coarse aggregate with little or no fine aggregete. In case of permeable concrete one can use a water/cement ratio between 0.28 to 0.40. The density of permeable concrete is lesser when compared to conventional concrete. The minimum and the maximum values of densities of permeable concrete are 1600 kg/m3 and 2000 kg/m3 respectievely. Hence the self weight of permeable concrete is lesser when compared to normal concrete. The previous studies on permeable concrete indicate that the compressive strength of permeable concrete is less than that of conventional concrete. This fact limits the use of permeable concrete pavements to light traffic loading only. However the strength properties of permeable concrete can be modified by using different admixtures. Tons of waste glass are produced in a year all over the world which cannot be decomposed hence makes the enviroment unsustainable. So the glass powder when milled down into micro size particles is a better choice to use as replacement to cement because of composition of silica in it. The use of glass powder in concrete increases the compressive strength of concrete and is an important step towards sustainable enviroment. In this paper the effect of varaition in water-cement ratio on compressive strength and permeability has been worked out by variying the water to cement ratio in case of permeable concrete with 10 % glass powder replacement by mass of cement.