INCORPORATION OF TANNERY WASTE AND SUGARCANE BAGASSE ASH IN SOIL–CEMENT BRICKS

Abstract

Seeking to use wastes disposed in the environment by incorporating them into low environmental impact materials, the study aimed to analyze the effect of using sugarcane bagasse ash and leather dust generated in tanneries in soil–cement brick mixtures. The experiment involved the characterization of used soil mixtures in various ratios, brick molding, and the analysis of performance parameters after an assessment of the material microstructure and heavy metal leaching (chromium). The comprehensive strength against compression decreased with an increasing ratio of waste in the mixtures, where mixtures containing 5.56% ash ratio reached a maximum of 2.52 MPa, and those with leather dust reached 3.69 MPa for the same ratio. Microscopically generated images with a scanning electron microscope indicated differences in the internal structure of the bricks, where ash joined the soil–cement structure whereas the leather dust remained inert and separated from the soil cement composite. Leached hexavalent chromium values were below 0.06 mg.L -1 for up to 20% waste, which, according to the NBR 10005 standard, does not pose any health risks. Following the acceptable standards, up to 7.14% by volume of sugarcane bagasse ash can be incorporated into bricks without any harm in relation to the standards. Leather dust indicated usage potential of up to 14.29% in the analyzed mixtures.