Modified Concrete for Impeding Chloride Diffusion from Sea Water in the Marine Environment

The application of nanomaterials to concrete is an innovative approach to enhance mechanical properties and durability performances. In this work, the addition of a combination of Graphene Oxide Nano-Platelets (GONP) and Ground Granulated Blast Furnace Slag (GGBFS) was studied as admixture in concrete. Tests on mechanical and chloride permeation properties were conducted. The results showed that the mix with 0.05 % GONP and the mix with 30 % GGBFS obtained better mechanical strength than the rest of the mixes. The highest electrical resistivity was achieved for the 90-day cured sample with 50 % GGBFS in CONP-free concrete and the 0.01 % GONP in GGBFS-free concrete, which was found to be the most effective in increasing concrete resistance to chloride permeation. The mix with 0.1 w % GONP and 50 w % GGBFS exhibited considerable performance even with other mechanical and durability performances. The addition of 0.1 % graphene oxide and 50 % granular slag increased the compressive strength of the concrete sample by 19.9 % during 28 days and 17.6 % during 90 days compared to the conventional concrete sample. Concrete with a combination of 0.1 % graphene oxide and 50 % granular slag experienced an increase in flexural strength by 15 % during 28 days and 13.6 % during 90 days. A significant reduction in electrical conductivity from 4012C to 1200C was observed for 90-day cured samples containing 0.1 wt % GO and 50 wt % GGBFS compared to the conventional sample. Response Surface Method (RSM) applied to the test data presented an optimized concrete mix containing 0.08 w % GONP and 50 w % GGBFS, the outcome of which was in close agreement with the experimental results.