Effects of Crumb Rubber on Concrete Properties When Used as an Aggregate in Concrete Mix Design

This study was performed to show the effects on properties of concrete when incorporating different gradations and different percentages of crumb rubber into a concrete mix. Millions of used tires are disposed of every year in the United States. As a remediation to this negative environmental impact, the environmental engineering community, the materials engineering community, as well as the structural engineering community have been working to use scrap rubber tires in engineering material modification projects to improve their properties and move into a more sustainable direction. In this study the effects of the crumb rubber, obtained from processed used tires, on axial compressive strength and flexural strength of unreinforced concrete was investigated. Different percentages of varying gradations of crumb rubber were used as an aggregate in concrete. The results of this study show that the addition of crumb rubber to concrete as a percent replacement of the fine aggregate is detrimental to the overall strength of the specimen, but not so much that it may not be used in small amounts.