Study on the anti-corrosion and barrier ability of modified sulfoaluminate cement mortar cutoff wall against sulfate

Abstract

Calcined layered double hydroxide (CLDH) was used to modify sulfoaluminate cement (SAC) mortar to develop a new sulfate-resistant barrier material. Through investigations into mechanical properties, permeability, microstructure, and migration characteristics, the results demonstrated that the addition of CLDH improved the mechanical properties and pore structure of SAC mortar and inhibited the diffusion of SO42-. Based on its anti-corrosion and barrier ability, the optimal CLDH dosage in SAC mortar was determined to be 2 % of the cement mass. Service life calculations and Visual MODFLOW simulations demonstrated that the SAC-CLDH cutoff wall has significant durability and barrier effect on sulfate. Compared to the site without the SAC-CLDH cutoff wall, the effective dispersion distance and area of sulfate decreased by 88.79 % and 93.43 % during 4000 days. This finding provides a new reference for the containment and management of high-concentration sulfate-contaminated sites.