Effects of Test Specimens on the Shear Behavior of Mortar Joints in Hollow Concrete Block Masonry

The shear characteristic of mortar joint is the most important factor which decides the behavior of masonry structures subjected to lateral in-plane loading. This article focuses on the experimental study of shear behavior of mortar joint in hollow concrete brickwork. In this experimental program, two types of specimen prepared according to two different standards (RILEM and European standard) were tested in order to study the influence of some formal parameters of test specimens to the shear behavior of mortar joint in hollow concrete brickwork. The test results showed that no matter whether there are horizontal joints in test specimens or not, an important dispersion is highlighted both in shear behavior and in shear failure criterion of mortar joint in hollow concrete block masonry assembly. However, the presence of horizontal joints may cause artifacts which have effect on the redistribution of stress and therefore on the correct transmission of lateral compression to the shear mortar joint. This effect tends to impact the damage and failure mechanism and therefore the failure criteria. In consequence, the Mohr-Coulomb criterion is only verified (with a coefficient 99% regression) for the case of test specimens without horizontal mortar joints although this verification is restrictive in terms of a low number of valid tests.