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

Abstract

In this study concrete samples were made by addition of 0.1wt.% Graphene Oxide (GO) and 50wt.% Ground Granulated Blast Furnace Slag (GGBFS). Tests on mechanical and chloride permeation properties were conducted. Concrete samples exposed to pressurized 3.5% NaCl aqueous solution under time and temperatures. The water pressure was at 0.1, 0.3 and 0.7 MPa. The chloride concentration profiles at different conditions were measured. The results show that the addition of 0.1 wt.% GO and 50wt.% GGBFS increased the compressive strength of concrete sample by 19.9% during 28 days and 17.6% during 90 days compared to ordinary concrete sample. Concrete with a combination of 0.1wt.% graphene oxide and 50wt.% granular slag had an increase in flexural strength of 15% during 28 days and 13.6% during 90 days. A high reduction in electrical conductivity from 4012C to 1200C was observed for 90-days cured concrete containing GGBFS and GO compared to the ordinary concrete. Chloride ion content was substantially enhanced by increase in water pressure and exposure time. The convection-diffusion coupling is the main mechanism of the transfer of chloride ion in concrete in this research. The mix with 0.1wt.% GO and 50wt.% GGBFS was shown considerable performance on chloride penetration in concrete. This admixure reduced the chloride penetration by up to 17.6% in 90 days compared to ordinary concrete. Chloride ion penetration is curtailed when GO and GGBFS are added to ordinary concrete. Pozolanic reaction effects in concrete leading to the filling of the pores are factors in the proposed curtailment mechanism.