In the last few years, masonry industry started developing hollow clay units with improved thermal properties and insulating clay blocks, filled with mineral wool. For such precision-ground blocks, bed joints are bonded with thin layer mortar or single-component polyurethane adhesive. These improvements do not significantly affect on the compressive strength of masonry, but could have an effect on the behavior of masonry structures in seismic conditions.
In this thesis we present the results of triplet shear tests, prepared on four types of masonry. Specimens were made from different combinations of hollow clay units produced by Wienerberger Opekarna Ormož (Porotherm 38 IZO Profi and Porotherm 38 S P+E) with general purpose mortar, thin layer mortar and PU adhesive.
According to Slovenian standard SIST EN 1052-3, a characteristic initial shear strength of masonry f_vk0 and characteristic friction coefficient μ_f were determined. In the last part, we discuss experimental test results and compare them with recommended values in the Slovenian standard SIST EN 1996-1-1 (Eurocode 6). A numerical model in SAP2000 was also prepared to show stress distribution and predict failure mechanism.