Enhancing the shrinkage resistance and impermeability of cement-based materials using carbon fiber modified by in situ-grown nano-SiO2 and carbon nanotubes

Abstract

To improve the shrinkage resistance and impermeability of carbon fiber reinforced cement-based composites (CFRC), the surface of carbon fiber (CF) must be modified to strengthen the bond between the CF and cement matrix. Therefore, a novel method for modifying CF using in situ-grown hybrid nano-SiO2 (NS) and carbon nanotubes (CNTs) is proposed herein to enhance its reinforcing effect. The results suggest that in situ-grown hybrid NS and CNTs can function synergistically and outperform in situ-grown single NS and CNTs in enhancing the reinforcing effect of CF. In situ-grown NS strengthens the chemical bonding between the CF and cement matrix via its seeding effect and pozzolanic activity. Meanwhile, in situ-grown CNTs enhances the physical bonding between the CF and cement matrix via its physical friction effect. More interestingly, the in situ-grown hybrid NS and CNTs function synergistically to enhance the reinforcing effect of the CF by strengthening the chemical and physical bonding between the CF and cement matrix. Hence, the in situ-grown hybrid NS and CNTs improve the shrinkage resistance and impermeability of CFRC more effectively compared with the in situ-grown single NS and CNTs.