Mechanical characterization of fiber-reinforced rubberized recycled concrete

Abstract

Dumping non-biodegradable wastes, such as construction and demolition waste (CDW) and scrap tires, is causing significant environmental problems. Thus, this study used recycled coarse aggregate (RCA) and crumb rubber (CR) procured from CDW and scrap tires as a partial replacement of natural aggregates. 30% natural coarse aggregate (NCA) was replaced by RCA, and 0, 5, 10 and 15% natural fine aggregate (NFA) was replaced by CR. Besides these, 0.5% polypropylene (PP) fiber was incorporated into the concrete mixtures. Different physical and mechanical properties of rubberized recycled concrete (R2C) and fiber-reinforced rubberized recycled concrete (FR2C) were investigated. Microstructural analysis, chemical analysis, failure modes, and cost-effectiveness were also evaluated. Simplified regression equations have been proposed to predict various mechanical properties of R2C and FR2C mixtures. The inclusion of RCA, CR, and fiber decreased the slump value of the fresh concrete up to 69.7%. The compressive strength decreased with an increase in CR percentage, but it increased by including fiber content. Though all the R2C and FR2C specimens exhibited lower tensile and flexural strength, a marginal reduction was found in FR2C specimens containing up to 5% CR content, which was only 3.3% and 6.8% lesser compared to the control samples. The surface resistivity test revealed that the chloride ion penetrability may be very low for all the combinations of R2C and FR2C specimens. By raising the percentage of CR, the UPV decreased, but the addition of PP fiber slightly increased the value. The cost analysis results pointed out that both the R2C and FR2C combinations saved more energy (up to 2.22 times) and decreased fuel consumption (up to 20.2%). Finally, the present study will aid in advancing sustainable fiber-reinforced rubberized recycled concrete.