Influence of cement constitution and temperature on chloride binding in cement paste

Abstract

This paper describes effects of cement constitution and temperature on chloride binding in cement paste, which is an important subject in relation to lifetime modelling of reinforced concrete structures. The influence of cement constitution on chloride binding is investigated by substituting cement with pure cement clinker. Both theoretical considerations and experimental data for chloride binding in cement pastes are presented. A physicochemical based model to describe the influence of temperature on physical binding of chloride is presented. Solid-state 27Al and 29Si magic-angle spinning nuclear magnetic resonance spectroscopy has been used for quantification of the anhydrous and hydrated aluminate and silicate phases in the chloride-exposed cement pastes. The 27Al isotropic chemical shift and nuclear quadrupole coupling is reported for a synthetic sample of Friedel's salt, Ca2Al(OH)6Cl·2H2O.