Unfired clay bricks: from laboratory to industrial production

This paper reports on the production of unfired clay masonry bricks at both laboratory and industrial scales. The laboratory-scale bricks were produced at the University of Glamorgan while industrial brick production was carried out at Hanson Brick Company in Stewartby, Bedfordshire. Lime-activated ground granulated blast-furnace slag and Portland cement activated slag was used to stabilise Lower Oxford Clay (LOC) for laboratory and industrial brick production. The engineering performance (strength) of the industrial-scale bricks (blended binder content around 7%) at the end of a 90-day moist curing period tends to be higher than that of the laboratory bricks (blended binder content of 13·1%). It was extremely difficult to make a thorough technical comparison of the overall engineering performance of the laboratory and industrial bricks owing to disparities in test methods, brick format (one solid and the other a frog brick) and mixing and compaction methods. However, a comparison of the strength and other properties required for practical application of unfired clay bricks with those of bricks currently used in mainstream construction was carried out. A comparison of the environmental profile was also conducted. The results suggest that there is potential for using unfired clay bricks for low–medium cost housing and energy efficient masonry wall construction within the UK.