H.R. ROMAN and R.J.K. MENDES Federal University of Santa Catarina, Brazil

Most of the research on structural masonry deals with solid clay bricks or concrete blocks. Very little has been done on hollow clay blocks. This paper describes the physical and mechanical behaviour of both grouted and ungrouted prisms of hollow clay blocks submitted to compressive stresses. Three course stack-bonded prisms were built with full bedding mortar, using one block, two mortars and three grouts. The modulus of elasticity and Poisson ‘s ratio of prisms, grouts and mortars were measured. The main results were: (i) increasing grout strength does not necessarily mean increasing prism strength; (ii) there is an optimum ratio of mortar/grout compressive strength, and possibly of E mortar/E grout, which is around 0.5 and gives maximum prism compressive strength; (iii) this relationship is more important for weaker mortars.