Development of greener lightweight aggregates from industrial waste products for use in construction composites

Lightweight aggregates for construction applications are beneficial in terms of reducing the deadweight of structures coupled with an enhancement in properties such as thermal and acoustic properties. In this study, greener lightweight aggregates are developed from industrial wastes, and the corresponding properties are evaluated. Blast furnace flue dust which is a by-product of steel production was used to replace up to 60% fly ash which is a by-product of coal production in the production of the greener lightweight aggregates. The findings from this study showed that it is possible to produce greener lightweight aggregates with a density as low as 650 kg/m 3 . However, the optimum content of blast furnace flue dust to replace fly ash as the precursor was found to be 40% as there was a decrease in compressive strength and increase in water absorption at higher contents. The compressive strength and water absorption of greener lightweight aggregate composed of 52% fly ash, 40% blast furnace flue dust and 8% semi-plastic clay is 8.3 MPa and 17%, respectively. Microstructural investigation of the aggregates indicated that the porous nature of the developed aggregates is responsible for their corresponding higher water absorption.