FUNDAMENTAL STUDIES OF FROST DAMAGE IN CLAY BRICK
Frost damage in brick masonry is one of its most serious and unsightly forms of deterioration and is a risk wherever bricks are exposed to a wet and cold climate. The manufacturers of clay bricks produce a range of brick types which are designated as suitable for all conditions of exposure and which are ‘frost resistant’. Typically, highly vitrified, high strength and thus low porosity bricks (as, for example, those of engineering standard) are regarded as not being liable to frost damage in practice. At the other extreme it is recognised that weaker, more porous bricks generally suffer severe damage if they are frozen and thawed repeatedly in wet conditions. The fascinating observation in practice, however, is that some of the weak, porous bricks are very resistant to damage even under the most severe of conditions. This is recognised by, for example, some handmade bricks (which are relatively porous) being designated frost resistant in the relevant British Standard.