This document summarizes research on using crumb rubber from waste tires as a partial replacement for fine aggregate in concrete. It discusses how tire production is increasing waste, and using crumb rubber in concrete can provide environmental benefits while potentially maintaining structural properties. The study aims to determine the effects on compressive strength of replacing sand at various percentages with crumb rubber, and adding glass fibers to the cement to potentially improve strength. Previous research found strength generally decreased as rubber content increased but toughness improved. The document reviews literature on this topic and describes the materials and methods to be used in the study.