Influence of conditioning of clay bricks over shear strength of brick masonry

The physical properties of the units and mortar affect the bond between them, as well as the mechanical performance of the masonry. The initial absorption rate of brick units during the construction process can be influenced by its moisture content. This work aims at understanding the influence of different brick conditioning (without immersion in water, immersed for 1 -2 s, and immersed for 30 min) on the shear bond behavior of the unit-mortar interface and related key mechanical parameters. For this, an experimental campaign of shear tests on triplet specimens was designed by considering three premixed mortars commercially available in Portugal and one lime-cement designed mortar. The results suggest that, regardless of mortar type, shear bond properties generally show higher values when 30-min immersion time brick conditioning was applied. Furthermore, it was observed that the cohesion values of the premixed mortars, whose compressive strengths were similar, tended to be close to each other when the longest immersion time was considered.