Chloride binding in Portland composite cements containing metakaolin and silica fume

This paper investigates how the composition of Portland composite cements affects their chloride-binding properties. Hydrated cement pastes prepared with a reference and containing metakaolin and/or silica fume were exposed to NaCl or CaCl2 solutions. Chloride-binding isotherms determined hydrate assemblage was investigated using TGA, XRD, 27Al NMR, 29Si NMR thermodynamic modelling. Compared paste, replacement did not alter capacity. The resulted in highest When combining metakaolin, chloride binding is similar cement. In this study differences linked only changes AFm content, but also alterations Al-uptake chain length C(-A)-S-H.