Evolution of Salt Efflorescence on Clinker Face Walls

Abstract

The lowering of building element aesthetics caused by salt efflorescences can have various characters. It depends mostly on types of wall component types, external environment conditions, and on-going physical and chemical processes. The active salts responsible for efflorescence appearance do not only worsen the wall look. They can also lead to lower durability because of microstructure destruction both in ceramic as well as in mortar. The type of mortar used for face clinker walls in essential way influences the limitation of efflorescences and discolorations which appear. Additionally, the way how wall is formed on the subsoil is a factor determining the character of salts appearing. In this work there is an analysis of the evolution of efflorescences appearing on two exemplary face walls made with various mortars. The walls were built with solid clinker bricks of traditional size 250x120x65mm in connection with two mortars: cement mortar based on portland cement CEM I 42.5, and cement-lime one. Additionally, during the research three different contacts of the wall with subsoil were tested: gravel layer, humus with lawn, and tight concrete band. The analysis lasted for ten years of wall exploitation in external environment. In the tested walls there were made chemical analyses for the quality and quantity of the appearing salts. There is also a raster picture of appearing efflorescence evolution made with AutoCad program during the research time period.