Shear strength variation due to mortar strength variation and the use of a triplet shear test set-up

Abstract Together with a large masonry wall test program control tests to determine the mortar compressive and the masonry shear strength were conducted. It was shown that even for industrially made mortars the mortar compressive strength varied considerably. However, no clear relationship between mortar compressive and masonry shear strength could be established. Therefore a series of tests was performed to investigate the relationship between mortar compressive and masonry shear strength by varying the mortar properties under laboratory conditions. Mortar tests were performed according to EN 1052-11 and shear triplets were made using one type of soft mud bricks to be tested according to EN 1052-3. Some critical features of the used shear test set-up are discussed and suggestions for improvement are given. Results of the tests in which the mortar properties were deliberately varied are discussed. For comparison, the experiences with more than 400 masonry shear tests, performed earlier, are briefly summarized.