Pullout Behavior and Interfacial Properties of Cementitious Composites with Graphene Oxide-Treated Polymer Fibers

Poor fiber–matrix interfacial adhesion limits the mechanical performance of synthetic fiber-reinforced cementitious composites. To overcome this limitation, this study investigates the impact of surface-treating polypropylene (PP) macrofibers with graphene oxide (GO) on single-fiber pullout behavior. The thermal and structural response of the treated fibers was characterized using Differential Scanning Calorimetry (DSC), and mechanical performance within the cementitious matrix was quantified. DSC analyses revealed changes in the thermal response of the polymer surface caused by the coating. In pullout tests, surface modification with GO resulted in higher resistance values at specific displacement levels, fR0.5 and fR3.5, showing increases of 20% and 18%, respectively. It is concluded that the GO coating effectively acts as an interfacial anchoring agent, optimizing interfacial shear transfer and enhancing the composite’s energy dissipation capacity in cementitious structures.