Studies on mechanical properties and durability of steel fiber reinforced concrete incorporating graphene oxide

Abstract

Steel fiber reinforced concrete (SFRC) is a kind of modified concrete that has attracted much attention at present. Compared with ordinary concrete, SFRC has superior physical and mechanical properties, so it is widely used in railway sleeper prefabricated, highway pavement, and tunnel lining. However, the compressive strength, impermeability, and frost resistance of SFRC are not prominent compared with ordinary concrete. To optimize the performance of SFRC, different amounts of graphene oxide (GO) were added in this study. The results showed that the excellent properties of GO have a significant improvement effect on the mechanical and durability of SFRC. Among them, the compressive strength, flexural strength, and splitting tensile strength of the specimens were increased by 20.1%, 29.5%, and 26.2% compared with the reference group after 28 days of curing. At the same time, the penetration depth of chloride ion is reduced by 56.8% at most compared with the benchmark after adding GO, the mass loss and relative dynamic modulus loss were 4.5% and 32.6% after 100 freeze-thaw cycles respectively, which were much lower than those of the reference group. To explain this phenomenon, different microstructure characterization techniques including XRD, MIP, and SEM were used to study the composition, pore size distribution, and microstructure of concrete. The results showed that the main role of GO is to promote the early hydration reaction, repair the micro defects of the matrix, improve the density of the matrix and strengthen the bonding between steel fiber and the matrix. In this work, the strengthening mechanism of GO on the SFRC matrix has been discussed in detail.