Recycled carbon fibers in cement-based composites: Influence of epoxide matrix depolymerization degree on interfacial interactions

The use of recycled carbon fibers (rCFs) in cement composites is beneficial regarding strength improvements and environmental aspects. In this paper, we present the addition of carbon fibers recovered from reinforced epoxides using hydrogen peroxide (H2O2) to cement-based composites. Two degrees of depolymerization were investi-gated regarding the physiochemical properties of the fibers and the interfacial interactions. Although regained CFs exhibited a smaller amount of oxygen-containing groups on the surface than virgin CF (vCF), they exhibit better adhesion and pullout resistance, as proved in single-fiber pullout tests from a cementitious matrix. The subsequent incorporation of recovered CFs into cement-based composites resulted in a pronounced increase in flexural and compressive strengths compared with the plain matrices and the cement reinforced with virgin CFs. Furthermore, the rCFs with a higher degree of depolymerization showed a better interfacial interaction toward cement matrices and hence also a better reinforcing effect.

Automated summary

In this paper, the use of recycled carbon fibers (rCFs) in cement composites was investigated. It was found that although the regained CFs had fewer oxygen-containing groups on the surface compared to virgin CFs, they exhibited better adhesion and pullout resistance. The incorporation of rCFs into cement-based composites resulted in a significant increase in flexural and compressive strengths, especially for rCFs with a higher degree of depolymerization.