Experimental analysis of pervious concrete with high water reducer and fly ash for strength development

Abstract

Pervious concrete technology is a unique and effective means to meet growing environmental demands. By
capturing rainwater and allowing it to seep into the ground, pervious concrete is instrumental in recharging groundwater,
reducing storm water runoff and meeting Environmental Protection Agency (EPA) storm water regulations. In fact, the
use of pervious concrete is among the best management practices recommended by the EPA and by other agencies and
geotechnical engineers across the world, for the management of storm water runoff on a regional and local basis. Pervious
concrete is a composite material consisting of coarse aggregate, Portland cement, water and chemical admixtures. It is
little bit different from the conventional concrete in that it contains little to no fine aggregates. The coarse aggregate
usually consists of a single size and is bonded together at its points of contact by a paste formed by the cement and water.
The result is a concrete with a high percentage of interconnected voids that, when functioning correctly, permit the rapid
percolation of water through the concrete. The main objective of this project work is to study the strength of pervious
concrete. To determine an appropriate mix design of pervious concrete at which we can get the optimum strength and
permeability characteristics. In this project work, the effect of variation in quantity of a component (sand) in mix design of
pervious concrete on its strength is investigated. The goal is to achieve a maximum strength without inhabiting the
permeability characteristics of the pervious concrete. For the project study, three mixes were prepared i.e. Control Mix,
Mix no 1 and Mix no 2 with varying sand percentage as 2.20 %, 0.0 % and 4.0 % respectively. The mix consisted of ½ inch
down coarse aggregate, ordinary Portland cement, fly ash and water. The mix also included admixtures including a high
range water reducer (HRWR) and hydration stabilizer. Cylinders and beams specimens were casted for this study. Pervious
concrete slab was also casted to perform the infiltration test of pervious concrete pavement. The results of compression
test, flexure test and infiltration rate test of the three mixes were then compared to make conclusions about the research
study. The results of all the tests performed on the specimens casted for this project work study shows that with increasing
the sand percentage in the previous concrete mixes, the strength of the concrete increases but the permeability of the
concrete decreases.