CALCINED SOILED WASTE: PERFORMANCE, COST AND ENERGY EFFICIENT POZZOLAN IN CEMENTITIOUS BUILDING MATERIAL

Abstract

This study investigates the suitability of converting unwanted Singapore marine clay and waste bentonite slurry into a sustainable substitution of cement through calcination while examining salient factors (effect of percentage substitution, calcination temperature, particle size and storage conditions). The estimated cost of incorporation this technology into industrial scales will be assessed and compared to OPC production and commercially produced clay minerals. Lastly, a novel approach of using vacuum technology to reduce calcination temperatures is simultaneously examined. Results indicate that both calcined Singapore marine clay and calcined waste bentonite can optimally replace cement up till 20% replacement level. This is maintained while achieving strength higher than pure mortar, with lower energy requirement and carbon emission. The production of calcined waste clays requires an activation temperature of only 700°C. Using the proposed novel method vacuum calcination at 450℃ shows similar effects as that of atmospheric thermal treatment at 700°C.