J. F. GOODWIN British Ceramic Research Limited

The mechanism of sulphate attack in brickwork is reviewed and the occurrence and concentration of sulphates in soils and groundwater is considered. Calcium silicate bricks are shown to be resistant to attack by sodium sulphate solutions of various strengths, as are specimens of designation (iii) cement:lime:sand mortars prepared with sulphate resisting Portland cement. Similar strength mortars prepared with ordinary Portland cement, on the other hand, exhibit varying degrees of attack. The acid soluble sulphate content of typical calcium silicate bricks was found to be negligible and unlikely to contribute to sulphate attack of brickwork built with them.