Use of CO2 curing to enhance the properties of cold bonded lightweight aggregates (CBLAs) produced with concrete slurry waste (CSW) and fine incineration bottom ash (IBA).

In this study, concrete slurry waste (CSW) obtained from ready-mixed concrete plants was recycled as a fresh cementitious binder and used together with municipal solid waste incineration (MSWI) fine bottom ash (IBA) from waste-to-energy plants to produce cold bonded lightweight aggregates (CBLAs) by using a pelletizing technique. The influence of different curing methods on the properties of the produced CBLAs were experimentally investigated, including moist curing, steam curing, and accelerated CO2 curing at 0.1 bar and flow-through CO2 curing under ambient pressure. The results showed that CBLAs obtained by steam curing at 60 °C had the highest pellet strength, and the CO2 cured samples had the lowest water absorption values. CO2 curing with a pressure of 0.1 bar promoted a better pellet strength. The CO2 curing method can sequestrate 3.5-4.1% (by mass of pellets) of CO2, which can serve as a sustainable CO2 sequestration process to produce CBLAs.