Unraveling the microstructural properties of cement-slag composite pastes incorporated with smart polymer-based corrosion inhibitors: From experiment to molecular dynamics

Incorporation of corrosion inhibitor into the cement-slag composite pastes can effectively improve the resistance to seawater erosion. However, corrosion inhibitor inevitably affects the microstructures and transport properties of cement-slag composite pastes, which poses a great challenge for the engineering application prospects of the composite pastes modified by corrosion inhibitor. In this paper, a smart organic polymer with hydrophilic and hydrophobic components is designed as corrosion inhibitors, and a combination of experiments and molecular dynamics (MD) simulations is employed to investigate the effect of this smart polymer-based corrosion inhibitor on cement-slag composite pastes under seawater erosion. Experiments show that this smart polymer-based corrosion inhibitor has profound effect on the hydration properties, pore structures and ions resistance of cement-slag composite pastes, with an optimum content of approximately 6%. MD simulations reveal the nanomechanism by which this smart polymer-based corrosion inhibitor hinders water and ion transport in the calcium aluminate-silicate hydrate (CASH) nanopores. Analysis suggests that strong electrostatic interactions, originating from the CaCASH-Oinhibitor pairs and the H-bond networks, are the primary sources of the corrosion inhibitorCASH bonding mechanism. Besides, the migration rates of water and ions are reduced as the large cluster structures formed among the corrosion inhibitor molecules, water molecules and erosive ions.