Overcoming chloride ions-induced deterioration in compressive strength of mortar by graphene oxide: Experimental study and molecular dynamics simulation

Using seawater to make concrete structures saves freshwater resources and reduces transport costs in offshore construction. However, the presence of chloride ions in mortar causes the formation of Friedel's salt, which changes the microstructure of cement hydration products. As a result, the compressive strength of the mortar significantly deteriorates due to excessive chloride ions. Graphene oxide (GO) is used to overcome chloride ions-induced deterioration in the compressive strength of mortar in this study. The compressive strength of mortar mixed with chloride ions is increased from 38 +/- 5.2 MPa to 44.5 +/- 0.2 MPa with the addition of GO. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis show the decrease of porosity in mortar with GO and adsorption of chloride ions on GO. Molecular dynamics simulations show that GO yields constraints on the mobility of chloride ions and the improvement of interfacial strength between calcium silicate hydrates.