Effect of Salt Contamination on Water Vapour Sorption Hysteresis of Ceramic Bricks

摘要

An effect of the presence of sodium chloride on water vapour adsorption/desorption loop was quantified for two types of commonly used ceramic bricks with different hygroscopic ability. The measurements were carried out for salt free materials and saline materials contaminated with sodium chloride solutions of two different concentrations. It was found out that at relative humidity higher than deliquescence point, the hysteretic effects of the saline bricks were similar or less significant as the ones of the salt free bricks. In this range of relative humidity the desorption moisture contents did not exceed the values predicted using the simply additive model. However, for the relative humidity lower than deliquescence point the hysteretic effects of the saline bricks were more significant than the ones of the salt free bricks. The effect was of importance in the case of hygroscopic ceramic brick where obtained desorption moisture contents of the saline bricks were noticeably higher than for the salt free brick.