Impact of Incorporating Plastic Fibers, Walnut Shells, and Tire Rubber Fibers on the Mechanical Properties of Concrete

Abstract

There are serious environmental issues as a result of the increasing amount of waste generated worldwide, especially from industrial and commercial growth. In order to improve the mechanical characteristics of concrete and address waste management, this study explores the possibility of adding three distinct waste materials—plastic fibers, walnut shells, and tire rubber fibers—as additives. In addition to a reference mixture devoid of waste materials, four concrete mixtures were made, each including 1.0% of the cement weight of waste materials. To assess the mechanical properties, such as compressive, splitting tensile, and flexural strengths, extensive testing was carried out on cubic, cylindrical, and prismatic specimens. The findings showed clear differences in performance between the various waste materials. Notably, in comparison with the reference mix, the compressive strength of tire rubber fibers and walnut shells increased by 4.9% and 8.7%, respectively. Likewise, improvements in flexural strength were observed, with tire rubber fibers improving strength by 8.9% and walnut shells by 11.1%. On the other hand, in every evaluated property, plastic fibers continuously showed decreased mechanical performance. Workability studies revealed that all waste-modified mixtures had decreased slump values; nevertheless, because of its porosity and rough surface, the walnut shell mix had the lowest workability. Across waste-modified mixes, splitting tensile strength dropped consistently, with decreases ranging from 11.5% to 12.4%. By showing the potential of waste materials in concrete production, this study sheds light on the mechanical behavior of concrete that incorporates various waste materials, thereby promoting sustainable construction practices.