Chloride Diffusivity of Magnetic Nanometakaolin Mortar in the Presence of Sulfates

Abstract

The purpose of this paper is to investigate the effect of magnetic water (MW) on the chloride diffusivity of mortar exposed to 5% NaCl solution in the presence of various sulfate concentrations (2%–7%). Cement was replaced with 0%–1.5% nanometakaolin (NMK). MW of 1.2 T was used in magnetic specimens. The degradation in mortars was evaluated in terms of compressive strength, mass change, chloride profile and penetration depth, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction analysis after exposure times up to 52 weeks. Using MW rather than tap water resulted in a significant decrease in the degradation level of all tested specimens. When compared to nonmagnetic mortars, the loss of compressive strength and the formation of ettringite in magnetic specimens were retarded by approximately 4 weeks. The chloride content and penetration depth decreased with increasing sulfate concentration. The 1.5% NMK magnetic mortar showed the minimum degradation in the hardened paste matrix.