Improvement in concrete resistance against water and chloride ingress by adding graphene nanoplatelet

Graphene nanoplatelet (GNP) is a cheap impermeable carbon-based nanoplatelet with large surface-to-volume ratio and has been exploited in polymer materials to improve their transport resistance. Experimental investigation on the transport properties under chloride and water exposure was carried out on concrete containing up to 2.5% of GNP at 0.5% increment. The pore structure was inferred using mercury intrusion porosimetry and significant reduction in pore sizes was measured. Concrete with 1.5% of GNP showed the greatest reduction in transport; water penetration depth, chloride diffusion, and migration coefficients were reduced by 80%, 80%, and 37%, respectively. The barrier effects of GNP were characterized and it was found that more than 50% of the improvement in transport resistance can be attributed to tortuosity while the rest to pore refinement. However, further improvement did not take place at GNP content higher than 1.5% due to limitation in dispersing the nanoplatelet clusters.