Assessment of Crumb Rubber Concrete for Flexural Structural Members

Abstract

To address the ever-increasing quantity of scrap tires produced in the United States, a study is conducted on the use of crumb rubber in concrete for enhancement of structures against blast effects. Crumb-rubber concrete (CRC) is produced by replacing a volume percentage of the traditional coarse and/or fine aggregate with crumb-rubber particles. Crumb rubber is produced in various gradations from used vehicle tires. The research program characterizes the mechanical properties of CRC and provides an assessment of the capability of CRC in providing flexural resistance for structural applications. The experimental and analytical investigation found the following four results: (1) crumb rubber replacement of coarse and fine aggregate is done at a cost premium of approximately 0.75 times the replacement percentage; (2) the addition of crumb rubber results in a decrease in unit weight, compression strength, splitting tensile strength, and elastic modulus, which are linearly related to the addition of rubber; (3) the modulus of rupture was not sensitive to replacement of up to 40% rubber aggregate; and (4) flexural failure modes occur at lower demand levels due to the use of rubber replacement. The reductions are consistent with the material property conclusions previously discussed.