Effect of Four Iranian Natural Pozzolans on Concrete Durability Against Sulfate Attack

Sulfate attack is one of the most important problems concerning the durability of concrete structures. Natural pozzolans are the natural mineral admixtures which can improve concrete durability against sulfate attack. In this paper, the sulfate resistance of concrete and mortar samples made from ordinary Portland cement containing three different portions of four types of natural pozzolans (Eskandan Pumice, Khash Pumice, Abyek Tuff and Jajrood Trass) was studied. Strength reductions and mass changes of the concrete samples, immersed in sodium sulfate solution, as well as the expansion of mortar prisms, immersed in sodium and magnesium sulfate solutions, were monitored. It was observed that the resistance of mixtures containing natural pozzolans was higher against both sodium sulfate and magnesium sulfate attacks compared to the reference cement.