Influence of Waste Crumb Rubber as a Partial Replacement for Fine Aggregates on Concrete Properties

This study investigated the effect of using waste crumb rubber as a partial replacement for the fine aggregates on the fresh and hardened properties of normal mix concrete. Waste crumb rubber with particles sizes of 2 mm–4 mm was supplanted in the mix design of the concrete as part of the fine aggregates. Three different percentages of waste crumb rubber were considered to replace the fine aggregate which are 5%, 10%, and 15% by volume. The properties of fresh concrete were evaluated through standard slump test, while the hardened properties were examined through compressive, splitting tensile, and flexural strength tests after curing at 7 days and 28 days. Furthermore, ultrasonic pulse velocity (UPV) tests were also carried out to evaluate the integrity and quality of the crumb rubber concrete. The test results revealed that the partial replacement of the fine aggregate with waste crumb rubber significantly decreased the workability and mechanical properties of the concrete. In addition, the concrete workability decreased with the increasing substitution of the waste crumb rubber replacement to that of the fine aggregate. Similarly, by increasing substitution of the waste crumb content, the compressive strength, splitting tensile strength, and flexural strength showed a decreasing trend from the control mixture at 7 days and 28 days.