University of Technology and Life Sciences Bydgoszcz, Department of Civil Engineering and Building Physics
Kazimierz Wielki University, Department of Mathematics, Physics and Technology

Durability of masonry structures compatible with their long term integrity is mostly predicted based on properties of their components: masonry units and mortar, disregarding the properties of the masonry composite which in fact will need to be resistant to stresses and against the penetration of moisture. Susceptibility to water penetration of the mortar-unit interface is a critical factor for the masonry system. This paper presents results of comparative studies of gas permeability of components of masonry (bricks and mortars) with permeability of masonry composites. The systems including the same type of bricks and two groups of masonry mortars (conventional and modified) were tested using the laboratory transient gas reservoir method. The microstructural properties of mortar samples selected from joints at the interface with masonry unit and in the center of joints between the units were determined by mercury porosimetry. The results show significant variability of permeability of composite materials with different type of mortars and independence of permeability of the system from the permeability of mortar. The difference may be related to the structural difference of mortar cured within joints – particularly at the contact zone with masonry units. The discussion of compatibility of masonry components with respect to the desired properties of the system is performed.

Key words
Compatibility, gas permeability, structure, masonry composite, mortar, bricks