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.