Soluble salts and efflorescence of ceramic bricks and other building materials - review

The deposition of salts on the surface of ceramic materials is called efflorescence. It is resulted from the migration and evaporation of aqueous saline solutions. The efflorescence is basically an aesthetic problem, but due to be a complex phenomenon with economical consequences it worries manufactures and building constructors. Raw materials, building materials, subsoil water, can be the source of soluble salts, which generate the efflorescence. This work is based on studies recently developed at the Federal University of Campina Grande, and has as aim analyze the soluble salts and efflorescence characteristics of ceramic and non-ceramic building materials. Samples of clays, bricks, and other building materials, from several parts from the State of Paraíba, were used in the study. The amount of soluble salts in the materials was determined using the electrical conductivity of its extracts. The efflorescence test was conducted according to the ASTM methodology. Based on the results was not observed a well-defined correlation between the amount of soluble salts of the raw materials and the efflorescence level. The content of 0.025% of soluble salts is a limit that offers a good indication of the materials susceptibility to efflorescence.

efflorescence; bricks; clays; building materials