Efflorescence and its quantification in ceramic building materials

Abstract

A study of the effect of cement in the formation of efflorescence on the surface of ceramic building materials was conducted. Wicking tests were performed with bricks covered with cement, and a test procedure, where temperature and water pressure applied to the samples could be controlled, has been developed. Salts formed at brick surfaces consist of arcanite (K₂ SO₄ ). Results show that salt deposition kinetics are enhanced by higher test temperature and particularly by imposing water pressure around the brick. A method to quantify efflorescence was developed in order to avoid any subjectivity in the assessment of the test results. Image analysis offers an alternative for quantification of this phenomenon. Study of efflorescence digital images lead to the definition of an efflorescence coefficient. A set of samples with low to high levels of efflorescence was used and the results show a clear distinction between different degrees of efflorescence. It is concluded that this process is a valid one for quantifying the efflorescence phenomenon.