Surface-treated polypropylene fiber for reinforced repair mortar cementitious composites

The effects of surface treatment of polypropylene (PP) fiber on the mechanical and microstructure of fiber-reinforced cementitious (FRC) composites are investigated. Surface treatment of the PP fiber was performed with 3-aminopropyltrimethoxy silane (APS) and methyltriethoxy silane (MTES) in order to improve interaction between PP fiber and matrix. The effects of APS and MTES on the surface of PP fiber are studied by scanning electron microscopy, energy dispersive spectrometer, and Fourier transform infrared spectroscopy. The experiment results indicated that the treatment of PP fiber with APS and MTES can effectively increase the adhesion between fiber and matrix, and an improvement in the flexure and compressive strength of the cementitious composites was found in the samples containing treated PP fiber compared to the samples containing untreated PP fiber. The optimized mechanical properties could be obtained using 1.0% APS (by weight) and 1.0% MTES (by weight)-treated PP fiber at studied conditions, respectively.