Performance and microstructure of bricks with protective coatings subjected to salt weathering

摘要

Salt crystallization is the crucial damaging mechanism which affects the durability of porous masonry units like bricks. Improper selection of protective treatments and replacement strategies often degrade the situation further and result in frequent future interventions. In this paper, the role of pore size distribution of the bricks in resisting salt crystallization and its effect on the performance of protective coatings has been discussed. Bricks with different microstructural properties were treated with common water repellent coatings - silicone-based and acrylic siloxane-based and were subjected to accelerated salt weathering tests. The performance of the coatings was studied using standard methods, and the coatings were then evaluated for their compatibility with various bricks with varying microporosity, when exposed to sodium sulphate. Bricks highly prone to salt crystallization have been found to be more sensitive to the properties of treatments over them, as breathability assumes a greater significance. (C) 2019 Elsevier Ltd. All rights reserved.