Cracking due to shear in masonry mortar joints and around the interface between masonry walls and reinforced concrete beams

Cracking occurs frequently in building masonry walls, and are usually located in the joints between the units because they represent generally planes of weakness, in some cases due to their low shear resistance. Sometimes cracks can appear in the interface between masonry blocks and reinforced concrete beams. That cracking has negative implications in building performance, namely, due to the possibility of rain penetration through the cracks and to negative aesthetic aspect. So, the objective of this paper is essentially to achieve a better knowledge of the shear behaviour of joints in masonry, for the particular cases of solid lightweight concrete blocks (blocks of aerated autoclaved concrete and blocks of lightweight concrete with expanded clay aggregates) and solid clay bricks, and to find preventive solutions to minimize those defects.This paper presents the principal results and conclusions of an experimental study that concerned the determination of mortar joints shear behaviour. From the results of the experimental tests, it can be concluded that the properties of the referred joints are significant for the wall overall behaviour, and the inclusion of reinforcing elements in these joints may in some cases serve as a preventive measure and can determine positive implications on that behaviour.