Porosity analysis of polymer‐modified drymix mortars using multi‐cycle Mercury Intrusion Porosimetry

Abstract

This paper presents the pore structure of a Portland cement‐based tile adhesive mortar modified with cellulose ether and EVA (vinyl acetate–ethylene) redispersible polymer powder, investigated by means of Mercury Intrusion Porosimetry (MIP). To address the instrumental issue of ink‐bottle porosity, we apply a multi‐cycle MIP variant. We also discuss interpretation challenges specific to polymer‐modified systems, namely the influence of substrate and presence of large air voids stabilized by organic admixtures. To this end, we compare results from real‐life application samples with those from air‐evacuated specimens stored in plastic containers.

The obtained results allow us to describe porosity changes in tile adhesive mortar induced by water attack. With a refined interpretation approach, we distinguish transport‐relevant cement matrix porosity from larger air voids introduced by organic additives. We further relate the microstructural findings to mechanical behaviour.