Investigation on performance of engineered cementitious composites (ECC) based on surface modification of PET fibers using graphene oxide (GO) and polydopamine (PDA)

In order to reduce costs and use local materials to promote the application of Engineered Cementitious Composites (ECC), this paper investigated the performance of ECC reinforced by surface-modified PET fibers. Single fiber pullout, uniaxial tensile test, SEM and XPS were carried out to study the effects of the modification. The modification by coating the PET fibers with graphene oxide (GO) using polydopamine (PDA) as the medium resulted in a significant improvement in the surface roughness of PET fibers. The frictional bond strength between the fibers and cement matrix was increased by 78.8 % due to the bonding of GO with cement hydration products and the secondary functionalization of GO induced by PDA. For the ECCs prepared using 0.5 vol% PVA fibers and 1.5 vol% modified PET fibers, the tensile strength increased from 3.12 MPa to 3.81 MPa (22.1 %), and the tensile strain increased from 1.69 % to 2.85 % (68.7 %) compared to the untreated group. Moreover, with the increase of GO concentration in the secondary functionalization, both the bond strength of the fiber–matrix interface and tensile properties of ECCs were improved.