Anna Kaczmarek1
1)  Faculty of Civil and Environmental Engineering,
University of Technology and Life Sciences in Bydgoszcz, Poland

Keywords: Mortar, Face wall, Tightness, Efflorescence.

Abstract. In historic buildings the wall integrity was provided intuitively which resulted in maintenance of continuity and resistance to secondary efflorescence until now. Contemporary facial walls show particular susceptibility to efflorescence. This phenomenon is common and appears during the first year of building functioning, with special intensity in a spring season. With proper choice of mortars and technological regime the deposit should be dissolved during next months until it disappears completely. However, when it changes into a crust which recurrently transmutes into deposit and additionally maintains high wall humidity then it becomes a signal that a mistake was made. One of the most often common errors is usage of incorrect mortar which is a consequence of flaws in construction regulations and some stereotypes functioning in executive environment. The aim of this article is indication of mortar types which create joints characterized with low susceptibility to water penetration into face wall interior. The evaluated value is joint quality defined as number of specimens showing total joint permeability during tests and pressurized water penetration range in complex tests. The tests were performed in aggregated sets which consisted of two clinker bricks connected with supporting joint. Five mortar types were selected to tests: pure cement based on portland cement CEM I 42.5, cement with addition of 5 and 15% of hydrated lime, and cement with addition of 5 and 15% of truss. The basic test were performed on the set elements and microstructure parameters were defined. The obtained results let us indicate the joint which limits humidity migration into a face wall interior.