The effect of temperature on the moisture transfer coefficient of cement-based mortars: An experimental investigation

The moisture transfer coefficient (MTC) is an essential parameter utilized in diffusion-convection modeling of ion ingress into cement-based systems, especially in marine environments with variable temperatures. In this study, the MTC of twelve mortar mixtures including six plain mixtures with different water to cement materials ratios and six mixtures containing silica fume or natural zeolite have been examined at temperatures ranging from 20 °C to 60 °C. The MTC values were then estimated for both wetting and drying periods using the combined experimental-numerical procedures. The results indicated that temperature has a significant effect on the MTC during moisture loss in comparison with water absorption. It was found that the average MTC of a drying period increased exponentially up to 40 times when the temperature was elevated from 20 °C to 60 °C. In contrast, a linear decrease in the MTC was observed on average up to 44% during wetting. Moreover, the MTC of mixtures containing silica fume or natural zeolite, in comparison with plain mortars, was less sensitive to temperature during water absorption than during moisture loss.