Modeling the coupled hydration–porosity–moisture transfers in mortars with organic admixtures

•A model for the coupled hydration-moisture transfers in mortar with CE is presented.•It's based on mass balance equations and cement compound hydration rates.•The hydration degree of the mortar was validated by TGA tests.•This hydration degree is affected by the cellulose ether added to the mortar mix design•The CE effect must be taken into account for accurate results especially for porosity.

A model of the coupled evolution of hydration–moisture transfer processes and their influence on porosity is suggested for polymer-modified-mortars (PMM) with cellulose ether addition. This model is based on mass balance equations of each phase of the material (solid, liquid and gas), and hydration rates of cement compounds. It takes into account the effect of the cellulose ether, used as a polymer admixture, on the hydration kinetics. The model allows describing the time evolution of the water content, the porosity and the amount of anhydrous and hydrated products, which are the main input data characterizing the material properties in most durability predictive models. Simulation results were compared to the experimental ones obtained by thermogravimetric analysis (TGA) and water porosity measurements.