Comparison of the Mechanical Behavior of Concrete Containing Recycled CFRP Fibers and Polypropylene Fibers

Abstract

The incorporation of natural or recycled fibers in concrete represents a field for improvement in this structural material and a step towards sustainability. The objective of this research is to determine whether the addition of recycled carbon fibers (CFRP), which have been hardened using epoxy resin, improves the behavior of concrete and whether its performance is comparable to that achieved by adding polypropylene fibers, which would result in a viable recycling alternative for this type of fiber. In order to explore this objective, 120 specimens were produced, on which compression, flexural, and impact tests were performed, and into which recycled CFRP fibers or polypropylene fibers were incorporated. By comparing the results obtained, it may be concluded that the addition of fibers substantially improves the ductility of the concrete and reduces the spalling effect when compared to concretes without added fibers. The concretes containing recycled CFRP fibers in quantities of 3 kg/m3 and 6 kg/m3 obtain better flexural and impact behaviors than concretes featuring the same amounts of polypropylene fibers, making this recycling alternative viable for CFRP fibers as well as reducing the amount of energy and raw materials that would be used to manufacture the fibers.