Torsion shear test for mortar joints in masonry: preliminary experimental results

The paper describes a new experimental testing procedure for characterising the shear behaviour of mortar joints under combined shear and compression loading. The test apparatus subjects a single joint specimen of annular circular cross section to normal compressive force combined with torsion. The choice of annular cross section results in predictable distributions of normal and shear stresses across the mortar joint, allowing shear behaviour at a material point to be characterised. The latter has been a widely reported shortcoming of existing mortar joint shear tests which all result, to varying degrees, in complex, non-uniform distributions of shear and normal stresses across the mortar joint. The paper describes the test methodology and details the results of a preliminary series of tests conducted using the apparatus.