Abstract

This study investigated the effects that recycled buffed rubber fiber mesh from the truck tire retreading process has on fresh and hardened concrete properties. Nine concrete mixtures containing varying amounts of buffed rubber fiber and commercially available polypropylene fiber were produced and compared, based on structural performance. Three concrete mixtures were prepared with polypropylene fibers in the amounts of 0.5%, 1.5%, and 0.5 cubic feet (cf). Five mixtures were tested with buffed rubber in amounts of 0.5%, 1.5%, 0.5 cf, 1.5 cf, and 2.5 cf. In addition, a control mixture containing no fiber mesh was prepared. A direct comparison between the 0.5%, 1.5%, and 0.5 cf mixtures was made and statistically analyzed. The workability increased with the buffed rubber fibers, however, it decreased with polypropylene fibers. The compressive strength decreased and the flexural strength increased with the addition of both types of fibers. The rubber fibers were more beneficial at reducing concrete permeability. The buffed rubber concrete mixtures exhibited exceptional residual strength after ultimate strength was reached. A statistical analysis determined that the recycled rubber fibers produced equal or superior compressive, flexural, and splitting tensile strength at 56 days of age when compared to companion mixtures made with polypropylene fibers. Thus, the potential use of this waste product for use in concrete infrastructure where fibers are utilized is expected.