Chloride binding and mobility in sodium carbonate-activated slag pastes and mortars

Mater Struct. 2017;50(6):252. doi: 10.1617/s11527-017-1121-8. Epub 2017 Dec 1.

Abstract

This study evaluates the chloride binding capacity and the migration of chloride in sodium carbonate-activated slag cements and mortars. The effect on chloride mobility and binding of adding a calcined layered double hydroxide (CLDH) to the binder mix was also assessed. Significantly improved durability characteristics can be achieved for sodium carbonate-activated slag mortars by the addition of small fractions of CLDH, as a consequence of a higher degree of reaction, higher chloride binding capacity, and the refined pore structures present in these modified materials, in comparison with alkali-activated cements produced without CLDH. The addition of CLDH enables the production of sodium carbonate-activated slag cements with notably reduced chloride ingress compared to silicate activated slag cements.

Keywords: Chloride; Durability; Layered double hydroxide; Microstructure; Sodium carbonate-activated slag.