Effect of Graphene Oxide and Fly Ash on Frost Resistance of the Steel Fiber Reinforced Concrete

The addition of graphene oxide (GO) and fly ash (FA) to SFRC (steel fiber reinforced concrete) increases frost resistance. Based on the analysis of the amelioration of GO on the frost resistance of SFRC, the improvement mechanism and the effects of GO and FA on the durability of SFRC were studied in depth. The test blocks' compressive strength, relative dynamic modulus of elasticity, and mass-loss rate were tested through experiments. The pore distribution and morphological characteristics of concrete were captured by industrial CT scanning technology. The effects of GO and FA on the pore distribution and morphology of the SFRC are discussed. The results show that the compressive strength of GO-SFRC(graphene oxide and steel fiber reinforced concrete)with GO proportion of 0.03% is 28.20% higher than that of ordinary SFRC without freezing and thawing; after 100 freeze-thaw cycles, the compressive strength of the G(0.03)S(25) increased by 31.70% compared with the compressive strength of the G(0.00)S(25), and pore shape of G(0.03)S(25) presents a spherical shape and an elliptical spherical shape; based on the data analysis of the strength loss, relative dynamic elastic modulus loss and mass-loss rate, it is considered that the properties of ordinary SFRC are the worst under freezing and thawing; as FA admixture increases, the porosity decreases; with FA of 30% and GO of 0.03%, the GO-FA-SFRC has the best frost resistance, as well as most of the pores are closed which resemble spheres and ellipsoids.