Abstract
The critical issue of the durability of marine concrete lies in the continuous penetration and rapid enrichment of corrosive ions. Here a new ion transfer inhibitor, as TIA, with calcium silicate hydrate (C-S-H) interfacial affinity and hydrophobicity is proposed through insights from molecular dynamics into the percolation behavior of the ion solution in C-S-H nano-channels and combined with molecular design concepts. One side of the TIA can be adsorbed on the surface of the cement matrix and can form clusters of corrosive ions to block the gel pores so as to resist the ion solution percolation process. Its other side is structured as a hydrophobic carbon chain, similar to a door hinge, which can stick to the matrix surface smoothly before the erosion solution is percolated. It can then change into a perpendicular chain shape to reduce the percolation channel’s diameter and thereby inhibit the percolation when ions meet the inhibitor. Therefore, once the erosion solution contacts TIA, it can quickly chelate with calcium ions and erosion ions at the interface to form clusters and compact pores. In addition, the water absorption, chloride migration coefficient, and chloride content of concrete samples decreased significantly after adding TIA, proving that TIA can effectively enhance the durability of cement-based materials. The structure–activity relationship of ion transfer that is proposed can provide new ideas for solving the critical problems of durability of cement-based materials and polymer molecular design.
Highlights
In recent years, marine concrete, as a significant member of marine infrastructure projects, has faced great challenges to its durability with the rise of marine infrastructure projects such as sea-crossing bridges and subsea tunnels [1,2,3,4,5]
Molecular dynamics can simulate the fluid percolation phenomenon in the calcium silicate hydrate (C-S-H) channel [46,47] and adjust the percolation rate of concrete pores by designing a corresponding transport inhibitor agent to prevent erosion ions from entering the concrete through the pores, further improving the durability of concrete and reducing the corrosion maintenance cost. In this investigation, molecular dynamics were first employed to analyze the kinetic behavior of erosion solution percolation in a C-S-H matrix, and an ion transport inhibitor was proposed according to two key technologies, called hydrophobic inhibition and hole blocking
Lammps [60] was employed in molecular dynamics calculations, and periodic boundaries in the x, y and z directions were used for the model
Summary
Marine concrete, as a significant member of marine infrastructure projects, has faced great challenges to its durability with the rise of marine infrastructure projects such as sea-crossing bridges and subsea tunnels [1,2,3,4,5]. Regulating the percolation behavior of corrosive ions in C-S-H gel channels is of great importance for improving the durability of marine concrete structures. Molecular dynamics can simulate the fluid percolation phenomenon in the C-S-H channel [46,47] and adjust the percolation rate of concrete pores by designing a corresponding transport inhibitor agent to prevent erosion ions from entering the concrete through the pores, further improving the durability of concrete and reducing the corrosion maintenance cost In this investigation, molecular dynamics were first employed to analyze the kinetic behavior of erosion solution percolation in a C-S-H matrix, and an ion transport inhibitor was proposed according to two key technologies, called hydrophobic inhibition and hole blocking. Experiments were carried out to verify the effect and micromechanism of the ion transfer inhibitors
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