The influence of burnt clay brick waste addition on recycled brick

Abstract

Ceramic materials especially clay soil (CS) have been used in construction for decades now. This CS has been used either unmixed or mixed with several other constituent materials to produce materials with interesting engineering properties. The study in this paper is a contribution to the re-use of broken burnt clay bricks (BCB) by mixing it in various proportions and different grain sizes (0.08 mm to 0.1 mm and 0.25 mm to 0.5 mm) with the initial CS to produce useable bricks. Physical properties (density, porosity and water absorption) and mechanical properties (compressive strength and flexural strength) of the resulting brick are then analyzed. The formulations of these products are done using the following percentages of burnt clay powder (BCP): 0% (reference brick), 20%, 40% and 50%. Whatever the grain size of the samples, the results show a decrease in density (from 1.86 g/cm3 to 1.2 g/cm3) and in the water absorption rate with the burnt clay (BC) content. There is also a decrease in the compressive strength and flexural strength of the bricks with the amount of burnt clay. The loss of mechanical resistance in compression between the reference sample and the highly loaded one (50% burnt clay) is 37.86%, for the flexural strength it is 64.52%. Nevertheless, a small addition of BC (20%) reduces the loss in resistance to 17.4% for compression and 10.7% for flexural strength. Equally, there is an increase in the mechanical strength of the samples with decrease in grain size. The studies carried out shows that a small quantity of burnt clay waste (20%) of the finer grain size can result in bricks with properties similar to those of the reference brick.