EXPLORING CRUSHED CONCRETE WASTE AS RECYCLED FINE AGGREGATE IN CONCRETE PRODUCTION

Abstract

Concrete waste is generally a challenge that is left to accumulate in illegal dumping areas and landfills. This research focused on how structural concrete waste could be crushed and used as recycled fine aggregate in the production of concrete. Experiments were carried out to establish the performance of this 0.6 water-cement ratio concrete containing partially recycled fine aggregate. Concrete fluidity and compressive strength tests were carried out at 7 days and 28 days only because the study was exploratory in nature. Results indicated that replacement of 20% natural fine aggregate with recycled fine aggregate resulted in the increase of concrete compressive strength by 8% from 28 MPa to 30 MPa at 28 days. 40% replacement of natural fine aggregate resulted in a drop of compressive strength by 11% yet retaining compressive strength at 25 MPa. 20% and 40% replacement of natural aggregate resulted in the concrete fluidity reduction of 5% and 17%, respectively. The average theoretical density was 2538 kg/m3. The study concluded that normal grade structural concrete can be attained using crushed concrete waste resulting in taking out the concrete waste from landfills and illegal dumping sites. These results established an environmentally friendly mode of handling concrete waste sustainably. Further, this solution would result in slowing down the depletion of natural fine aggregate bodies.