INFLUENCE OF DIATOMITE ON MORTAR MECHANICAL BEHAVIOR UNDER ACID ATTACK

Abstract

The present work aims to evaluate the influence of a Brazilian calcined diatomite from Bahia on the properties of high-performance mortars exposed to sulfuric acid (H2SO4) attack. The mortars were produced with the replacement of 0 (control), 10, 20 and 30% (by mass) of cement by diatomite. Specimens of the different mixes were kept in saturated lime-water curing for 28 days. Then, the specimens were divided into two equal groups. The first group continued in water for more 63 days and the second group was immersed in 2% H2SO4 solution for the same time. Tests of mass variation and compressive strength were carried out aiming an evaluation of the effect of diatomite over acid attack. The results showed that the cement substitution content by diatomite significantly influenced the compressive strength of mortar. The best mechanical performance was achieved by mixing with higher pozzolan content. After exposure to H2SO4, there was a considerable reduction in mortar resistance. However, no statistically significant differences were observed between the reference mixture and the diatomite mixtures.