Effect of aspect ratio and dosage on the flexural response of FRC with recycled fiber

Recycled fibers (RF) have demonstrated a sustainable solution in the generation of fiber reinforced concrete (FRC), but their flexural performance is still under study. This paper shows the flexural behavior of 15 FRCs specimens with different aspect ratio and dosage of RF (shredded plastic PET bottles), to understand how these parameters affect their performance. In addition, 9 FRCs samples with virgin fibers (commercial Polypropylene) and 2 control samples (without fibers) were used as comparative elements. Workability, three-point bending and residual pull-out tests in combination with a count of fibers in the cracking section were developed. The results show a better flexural behavior of FRC of samples with high dosage and aspect ratio of RF, this combination generated similar or superior flexural performance with a better adherence in the concrete than those with virgin fibers. Data showed three principal problems with FRCs with RF, a reduction of the workability in comparison with concrete without fibers, a lower quantity of fiber than samples with virgin fibers, and a non-uniform tendency in their mechanical performance. (C) 2019 Elsevier Ltd. All rights reserved.