Investigation of Flexural Properties of Cement Reinforced with Recycled Carbon Fiber-Reinforced Polymer Composite Additives

The use of fiber-reinforced polymer (FRP) composites has significantly increased across various industries, due to their exceptional physical and mechanical characteristics. However, the sustainability of composite parts remains a considerable challenge. Typically, end-of-life (EOL) composite parts are disposed of in landfills due to the high costs of recycling and the limited application of recycled composites. This article introduces a preliminary study that investigates the application of mechanically recycled composite materials for construction purposes. Carbon fiber-reinforced composite laminates, with an average thickness of 3.175 mm, were pelletized to create additives. The size of these mechanically recycled composite additives was standardized at 25.4 mm x 25.4 mm. These pelletized additives were then blended with cement to produce cement beam test specimens, which were evaluated for their flexural properties. The study considered two key variables: the surface condition of the additives and the additive content. To assess the impact of the surface condition on enhancement, one group of additives underwent surface treatment through sandblasting, while another group remained untreated. Additionally, different additive concentrations, specifically 2% and 5%, were used to fabricate cement flexural test specimens, with the aim of investigating the effect of additive content on structural performance. The test results showed that the inclusion of recycled composite additives led to a significant improvement in the maximum load and modulus of rupture (between 21% and 39% increase) as well as bending stiffness (between 12% and 27% increase) of the cement beams, in comparison to non-reinforced cement beams.