Avaliação do perfil de penetração dos compostos hidratados do aglomerante de argamassas aplicadas sobre bloco cerâmico através de análises químicas, microestruturais, mineralógicas e de resistência de aderência

Abstract

This work is the result of an experimental study that investigated the chemical changes occurring at the interface between a mortar applied over a masonry ceramic block and nearby regions, both within the block and in the interior of the mortar. The analysis of this interface has contributed significantly to better understanding the properties of the materials which make up this interface and the mechanisms of adhesion, as well as the factors that interfere with the performance. This research also sought to develop a practical, reliable and non-destructive methodology capable of identifying the chemical variations occurring in the interface region by means of colorimetric analysis of the elements Ca, Al, S and the pH variation. It was achieved that the interface regions closer to both sides of the ceramic block and the mortar, have very different chemical compositions as compared to the bulk of the materials. This variation was caused by the migration of Ca, Al and S from the mortar to the substrate. The intensity of this migration was inversely related to the mortar water retention property. The adhesion results were directly related to the Ca concentration in the block first layer (200m). The amount of Ca absorbed by the substrate was not influenced by the introduction of lime in the mortar. The chemical change verified, mainly related to the Ca variation, causes the pH change in this region. This variation was easily identified by almost all methods tested. In the case of the mortar, the pH decreases closer to the interface, but the opposite occurs when the pH of the ceramic block is measured. The pH value in the blocks first layer was directly related to the adhesion results obtained.