A.N. FRIED and D.W. LAW Kingston University

This paper examines the relationship between a number of mortar and unit properties and the bond strength of masonry. The water absorption, suction rate, crushing strength and dry density of the units are given. The bond strength between the masonry and mortar was measured by the crossed couplet and bond wrench tests. In addition, the wet density, air content, consistence, setting time and compressive, flexural and tensile strength of the mortars were determined. A designation (iii) mortar was used throughout although some mixes included lime and others were retarded. The findings indicate that the strength properties of the mortar and units do not affect bond strength whilst the suction rate of the unit, some properties of the wet mortar and the addition of a retarder or the use of lime all have some influence.