Effect of amorphous mineral aggregates on the consolidation of portland cement and geopolymer mortars under alkaline solutions

Efeito de agregados minerais amorfos na consolidação de argamassas de cimento portland e geopoliméricas em soluções alcalinas

Abstract

This article aims to evaluate the AAR products in the Portland cement mortars and metakaolin-based geopolymeric mortars microstructure, and the impact on their physical-mechanical properties. Portland cement and metakaolin mixed and metakaolin-based geopolymer mortars with an innocuous and deleterious mineral aggregate were produced, to characterize their alkali-aggregate reactivity, mechanical properties and microstructure. The results show that, for both geopolymer and Portland cement/metakaolin mixed mortars, the AAR reactive aggregate contributes to the mortar matrix densification and improves their mechanical strength. The microstructure of the samples also indicates that deleterious aggregates contribute to zeolite formation in both produced mortars. In conclusion, mineral phases that are susceptible to alkali-aggregate reaction can also be susceptible to alkaline activation and incorporated into metakaolin-based geopolymers matrices, improving their physical and mechanical properties.

Keywords
Alkali-aggregate reaction; Geopolymer; Metakaolin; Amorphous mineral phases; Mortar