Interfacial properties of nanosilica-treated structural polymer fibres in cement matrix composites

In this study, silica nanoparticles formed on the surface of structural polymer fibres improved bonding with the cement matrix and provided a self-healing function when cracking occurred in the composite. Silica nanoparticles were formed via a sol-gel process on fibre surfaces; these treated fibres were dried at room temperature and 50 °C. Observation of the fibre surfaces by digital microscopy confirmed the formation of silica nanoparticles on the fibre surfaces. The amount of silica nanoparticles produced on the surface was quantitatively determined by the change in mass before and after the surface treatment. Measurements of the water absorption and amount of soluble matter lost confirmed that the surface of the hydrophobic structural polymer fibres had been modified. The interaction between the nanosilica-treated structural polymer fibres and cement matrices was evaluated using a single-fibre bond test. This test showed that the nanosilica-treated fibres had a maximum pull-out strength and interfacial toughness that were 104.1-113.4% and up to 120% higher, respectively, than those of the untreated fibres.