Stress-Strain behavior of rubberized concrete under compressive and flexural stresses

Scrap tyres are among the most troublesome waste products in the world. Using recycled tyre rubber as a replacement of sand in concrete mixes is an approach to improve the ductility of concrete. The use of rubberized concrete has gained a lot of attention in the past decade to utilize the enhanced ductility in seismic resistance. The properties of the equivalent compressive stress block exposed to combined flexural and compressive stresses are used to design reinforced concrete components. The design parameters of the equivalent compressive stress block for rubberized concrete are not well established. This article presents an experimental investigation of the behavior of rubberized concrete, with the focus on identifying the stress block parameters. Two concrete groups were studied during this investigation with two different design strengths. Four different mixes were prepared for each group, with crumb rubber replacing fine aggregate by 0, 10%, 15%, and 20% of the volume. The mixes properties, such as slump, density, compressive strength, tensile strength, and stress-strain relationship were experimentally assessed and compared. The experimental investigation provided equivalent rectangular stress block characteristics as well as the final compressive strain for those members. The values were compared to those established in key design international codes.