Hellenic Natural Zeolite as a Replacement of Sand in Mortar: Mineralogy Monitoring and Evaluation of Its Influence on Mechanical Properties

Abstract

HEU-type zeolite-rich volcaniclastic tuff (Hellenic natural zeolite) is used as a raw material for the production of lighter mortars. The addition of natural zeolite in mortar mixtures of sand and Portland cement leads to a decrease of up to 18.35% unit weight. The increase of the natural zeolite proportions increases the porosity and water absorption of the mortar and, at the same time, decreases the uniaxial compressive strength. These variations in the mortar’s mechanical properties are due to the addition of natural zeolite, which causes incomplete hydration of C2S (2CaO.SiO2) and retardation of the mortar’s hardening.