This document discusses research into using waste materials like rubber tire chips as a partial replacement for coarse aggregates in concrete. The study aimed to produce M20 grade concrete by replacing coarse aggregates with 0%, 10%, 20%, and 30% rubber chips by volume. 48 concrete cubes were cast and tested for compressive strength at 14 and 28 days. Results showed a 14% increase in compressive strength at 10% replacement but decreases at higher replacements due to poor bonding between rubber and cement. Density also decreased by around 11% with rubber, while workability was reduced for all rubber mixes. The research concludes that partial coarse aggregate replacement with rubber chips in concrete is possible while maintaining strength.