INVESTIGATION ON EXPANSION OF MORTARS CONTAINING TUFF NATURAL POZZOLAN DUE TO SULFATE ATTACK

Sulfate attack and its effects are important from both scientific and industrial viewpoints. It is perceived that cements containing pozzolan have better performance in sulfate solutions, since the pozzolanic reactions reduce the quantity of Calcium hydroxide and increase Calcium silicate hydrate. This paper investigates the physical/mechanical properties of concretes made by blended cement containing Tuff natural pozzolan, and Portland cement. The microstructure of mortars under sulfate attack is studied using SEM analysis and reaction products are characterized using EDS analysis. The results suggest that, contrary to previous opinions, mortars containing pozzolan show more expansion and unsatisfactory performance in sulfate solution.