Analytical Modeling of the Main Characteristics of Crumb Rubber Concrete

In recent years, a very important environmental issue all over the world is the disposal of waste tires. One possibility being explored is to use rubber from waste tires to replace part of the natural aggregates in conventional concrete, resulting in a product called crumb rubber concrete (CRC). Recent research on CRC is focusing on using it in structures subject to seismic loads, due to its higher ductility, damping ratio, and energy dissipation compared to conventional concrete. However CRC can have lower compressive strength ( ƒ' _CRC ), tensile strength ( ƒ' _TRC ), and modulus of elasticity ( E _RC ) when compared with conventional concrete. This paper presents empirical models able to predict the CRC characteristics ( ƒ' _CRC , ƒ' _TRC , and E _RC ). The proposed models are verified through the results of 148 CRC mixes as well as compared with two previous models. The proposed models resulted in predictions of the CRC characteristics with only 10.7%, 12.6%, and 11.3% errors in the predictions of ƒ' _CRC , ƒ' _TRC , and E _RC , respectively. The proposed ƒ' _CRC model reduced the mean, standard deviation and maximum error percentages by 24.6%, 5.8%, and 20.2%, respectively, compared with the nearest best predictions by previous models. The proposed models can aid structural engineers who are considering CRC as an environmentally-friendly alternative to conventional concrete in structural applications.