Experimental Study on Workability of Natural Aggregate Concrete Incorporated with Crumb Rubber

This study investigated the effect of crumb rubber on the workability of fresh concrete. Crumb rubber was used to replace fine aggregate at 0%, 5%, 10%, 15% and 25%. Physical properties (particle size gradation, specific gravity, bulk density and aggregate impact value) of the aggregates: sharp sand, Bida natural stone and crumb rubber were determined. Furthermore, the sharp sand and Bida natural stone used for this research were characterized as normal weight aggregates while the crumb rubber was characterized as a light weight aggregate. Workability of the concrete in its fresh state was extensively studied. Generally, the workability of fresh concrete reduced as the crumb rubber increased from 0% to 25%. The reduction in slump values was adduced to the absorbent nature of the crumb rubber. Hence, the research recommended a water-to-cement ratio of 0.55 – 0.60 for use in the production of concrete containing crumb rubber. It was concluded that crumb rubber can be used to produce low workability concrete for use in mass concrete foundations, lightly reinforced concrete elements and roads.