High-temperature effect on mechanical properties of fiber reinforced concretes including waste tire rubber

Abstract

In this paper, concretes including three different fiber types (carbon steel fiber [CSF], forta ferro fiber [FFF], and polypropylene fiber [PPF]) with different percentages by volume (0.5%, 1%, and 1.5%) and crumb rubber (CR) as a replacement of fine aggregate by volume (5%, 10%, and 15%) are mechanically investigated. Compressive strength, flexural tensile strength, pull out strength, and elevated heat resistance tests are conducted 28 days after casting on the prepared concrete specimens. For the elevated heat resistance test, samples are exposed to 200, 400, and 600 degrees C heat for 2 h and then compressive strength test is applied. According to the test results, fiber reinforcement limits compressive strength decrease and improves flexural tensile strength properties of the rubberized concretes. The positive effect of the fiber reinforcement is also observed on the samples conducted to pull out strength and elevated temperature resistance tests. CSF and PPF reinforced rubberized concretes perform better pull-out resistance then the FFF reinforced rubberized concretes. Elevated heat resistance test is as expected since with elevation of the temperature strength of the concrete decreases. But according to the test results of the present study, the strength decrease seems to be limited with fiber reinforcement. As a result, incorporation of the fiber and CR could help to utilize more waste tire (CR) in concrete to produce sustainable eco-friendly concrete.