Effect of different sulphate carriers on Portland cement hydration in the presence of triethanolamine

Hydration of cements containing different sulphate carriers, namely gypsum, hemihydrate and anhydrite was investigated with and without triethanolamine. It is found that the hydration of different cements is similar without triethanolamine, but differs significantly with it, which is related to the dissolution rate of sulphate carriers. The initial dissolution of the aluminates is increased by triethanolamine, and the comparatively slow dissolution of anhydrite cannot provide sufficient sulphate to compensate for this enhanced dissolution. This results in an increase of the aluminium species in solution and substantial retardation of C3S hydration. Hemihydrate can suppress this impact due to its high dissolution rate.