Compressive strength and deformation characteristics of concrete block masonry made with different mortars, blocks and mortar beddings types

Concrete hollow block masonry is widely used in North American and Australasian countries because it enables to accommodate grouting and reinforcement to resist higher axial and lateral actions, where it ultimately facilitates to construct high-rise masonry buildings. Subsequently only certain grades of mortars are recommended for the concrete block masonry in the standards mainly due to durability concerns. However, there is a lack of knowledge on the characteristics of concrete masonry with different grades of mortars and significant variations are found among the design standards. Therefore, in this research, an attempt has been made to investigate the compressive strength and deformation characteristics of concrete block masonry using different mortar grades, mortar bedding types and block types. In total, 40 concrete block masonry prisms were constructed and tested with three different types of mortars, two mortar bedding types and two types of concrete blocks. From the experimental results, the failure modes, compressive strength and stress-strain curves are derived and discussed. The experimental results revealed that the lower grade mortared prisms failed by mortar crushing and block splitting, whereas the other mortared prisms mainly failed by tensile splitting in the blocks. The compressive strength of concrete masonry was not significantly compromised for lower grade mortared prisms in comparison to other mortared prism combinations. The deformations and failure phenomenon of the mortar joints, blocks and prisms were investigated in detail using a non-contact digital image correlation (DIC) method. The experimental results were also verified through the finite element analyses and were compared with the predictions of four different masonry design standards. Discrepancies in the prediction of compressive strengths of concrete block masonry between the design standards were noted.