Chloride Ingress into High-Performance Concrete Containing Graphene Oxide Nanoplatelets and Ground Granulated Blast Furnace Slag under Different Conditions of Water Pressure and Temperature

In this study, concrete samples were prepared by adding 0.1 wt. % Graphene Oxide (GO) and 50 wt. % Ground Granulated Blast Furnace Slag (GGBFS). Tests on the mechanical and chloride permeation properties were also conducted. Concrete samples were exposed to pressurized 3.5 % NaCl aqueous solution under a certain time and temperature condition. The water pressures were 0.1, 0.3, and 0.7 MPa, respectively. The chloride concentration profiles under different conditions were measured. The results indicated that addition of 0.1 wt. % GO and 50 wt. % GGBFS would increase the compressive strength of the concrete sample up to 19.9 % during 28 days and 17.6 % during 90 days compared to ordinary concrete sample. Concrete with a combination of 0.1 wt. % graphene oxide and 50 wt. % granular slag witnessed an increase in its flexural strength up to 15 % during 28 days and 13.6 % during 90 days. Compared to the ordinary concrete, 90-day cured concrete containing GGBFS and GO undergone high reduction in Rapid Chloride Permeability (RCP) from 4012 C to 1200 C. Chloride ion content was substantially enhanced upon increasing water pressure and exposure time. In this study, convection-diffusion coupling was the main mechanism of the chloride ion transfer in the concrete. The mix with 0.1 wt. % GO and 50 wt. % GGBFS exhibited acceptable performance in terms of chloride penetration in the concrete. Compared to ordinary concrete, this admixure reduced the chloride penetration by 17.6 % in 90 days. Chloride ion penetration was curtailed while adding GO and GGBFS to the ordinary concrete. The effects of pozolanic reaction in the concrete leading to the filling of the pores were significant factors in the proposed curtailment mechanism.