In this paper, a 3D numerical cement hydration model is used for predicting alkali and hydroxyl concentrations in cement pore water. First, this numerical model is calibrated for Dutch cement employing both chemical shrinkage and calorimetric experiments. Secondly, the strength development of some standard mortars as predicted by the model is found to be in good agreement with performed experiments. Subsequently, alkali release and sorption, as well as the Ca(OH)2 equilibrium are incorporated in the model. Finally, this extended hydration model is used to predict the pH development in cement pore water, which is found to correspond well with experiments reported in the literature.