The influence of outdoor conditions on the strain in brick masonry

One aspect of the investigation into the spacing of movement joints in masonry walls involved the short term and long term deformation of mortar embedded in masonry. In this research the influence of hardening conditions on the physical and mechanical properties of masonry were studied, with a focus on the influence of outdoor conditions. Mortar made in steel moulds (according to European Standards), mortar made in brick moulds, brick-mortar couplets and wallettes have been investigated under constant (20 oC, 60 % RH) and outdoor conditions. During the test period the deformation (for all specimens), the weight (of the small specimens) and the strength (of the mortar prisms) at the end of the period were determined. Outdoors, the weight of the mortar prisms and couplets was always (over the whole year) higher than in the climate room. For mortar prisms shrinkage was the dominant factor, where in couplets and wallettes, due to the bond in clay brick masonry, the shrinkage was restrained and expansion was measured in summertime. The strains due to shrinkage and climate influences, in the clay brick masonry couplets and wallettes were not higher than ¿ 0.17 mm/m.