Effect of the pre-heating conditions on the formation of lightweight aggregates

This study was conducted to evaluate the feasibility of using bottom ash and dredged soil from power plants and electric arc furnace dust as primary materials for the production of artificial lightweight aggregates (ALAs). Preheating treatment was investigated as a means to prevent abnormal pore growth in ALAs, which occurs due to a vigorous bloating process. When the specimens were pre heated at 400 degrees C, absorbed water and interlayer water in the specimen were released before the sintering process, thus preventing cracks and breakage and thereby improving the quality of the ALA. However, when the specimens were preheated at 700 degrees C, more CO2 and CO gases were generated owing to oxidation. As a result, abnormal water absorption drift was suppressed, and the water absorption rate was controlled to be within an acceptable range.