RICHARD GIVENS Buxton Lime Industries Limited

As part of the development work in launching a new type of cement for use with masonry units and following the recommendations of BRE Digest 362, Buxton Lime Industries (BLI) subjected mortars made with the new cement to a series of laboratory durability assessments. These were supported by field trials involving brick panels erected on a severely exposed hilltop in the Peak District of England. Several sets of panels were constructed, some using specially selected sub-standard Fletton bricks containing much higher than normal levels of magnesium and potassium sulfates and others using brick containing lower sulfate levels with different levels of water absorption. Various mortar mixes and binders were used. The panels were periodically inspected for damage and deterioration. Expansion measurements were also made. Four years after the first set of panels was constructed, the benefits can be seen of using the General Purpose Mortar (GPM) recommended in the BRE Digest. The use of the masonry cement formulated to provide this mix design which incorporates a Portland cement having a tricalcium aluminate (C3A) content < 9% is also important.