Mechanical properties of recycled aggregate concrete containing crumb rubber and polypropylene fiber

Abstract

Scrap tire-derived crumb rubber (CR) in concrete, along with recycled coarse aggregate (RCA) and polypropylene fiber, constitute a way to reusing and recycling waste material and providing green and sustainable concrete structures. This study investigates the effect of substituting recycled constituents such as RCA and CR as a partial replacement of coarse aggregate and fine aggregate, respectively, along with polypropylene fiber addition into the concrete mixture. Fifteen different mixes are considered, with 10% and 30% RCA, 5% and 10% CR, and 1% and 2% fiber content. This study focuses on the experimental investigation of concrete combining RCA, CR, and fiber and evaluates its compressive strength, splitting tensile strength, and flexural strength at different ages. The compressive strength, splitting tensile strength, and flexural strength decrease as the CR content increases, but increase with the increasing fiber content. With regard to toughness and ductility, the effect of fiber is greater than that of RCA and CR, with each being found to increase with the incremental addition of fiber. It is also observed that the beams with fiber show failure in a more gradual manner. Finally, as a general recommendation in the interest of sustainability and environmental concern this paper suggests the use of rubberized concrete with RCA and polypropylene fiber for any structural purpose subjected to further investigations.