A wide variety of materials influence the properties of ceramic bodies to a considerable degree, and can be used in brickmaking to control various properties. Not all unblended clays are suitable for brick production. For instance, some clays have great plasticity and high shrinkage, which impedes the drying and firing processes. Other clays are not plastic enough, create difficulties for shaping and lead to low mechanical strength. To improve the properties of clay bodies, different raw materials and many industrial, urban and agricultural wastes are used. Additives to brick bodies can be classified in several groups, depending on their effect on processing and properties. They include plasticisers, pore-forming (aerating) agents, colourants and chemical additives. 28 refs.
Primary author(s): Stefanov S
Source: Tile Brick Int.