Converting municipal solid waste incineration bottom ash into the value-added artificial lightweight aggregates through cold-bonded granulation technology

Abstract

To effective recycle the Municipal solid waste incineration bottom ash (MSWIBA), this study adopts cold consolidation granulation technology to develop eco-friendly artificial lightweight aggregates (ALCBAs), and the materials are over 50 % dosage of MSWIBA, less 50 % fly ash (FA) or ground granulated blast furnace slag (GGBFS), and 10 % ordinary Portland cement (OPC). This study investigated the effects of different binder types and dosages on the properties of ALCBAs, including compressive strength, water absorption rate, bulk density, microstructures, pore development, heavy metal leaching behavior, and sustainability. The feasibility of ALCBAs to design green concrete was also explored. The results show that with higher content of MSWIBA and binders of FA, GGBFS and OPC, the ALCBAs with compressive strength greater than 2.5 MPa, bulk density of about 1000 kg/m3 and water absorption rate greater than 12 % was successfully developed. Increasing the content of FA/GGBFS is beneficial to improve the compressive strength and reduce the water absorption rate and the total porosity and lower the air bubbles percentage of ALCBAs. More importantly, both FA and GGBFS are mixed into ALCBAs, the compressive strength is at 2.5 MPa-3.0 MPa, the water absorption rate is significantly reduced, and the energy consumption, carbon footprint and cost are also significantly reduced. As the content of ALCBAs increases, although the compressive strength and splitting tensile strength are not as good as concrete with natural aggregates, the density of low-carbon concrete with ALCBAs gradually decreases, and the interface transition zone is gradually improved. Overall, ALCBAs can be beneficial to the conservation of natural resources (natural aggregates) and effectively solve the shortage of natural aggregates, and can be used to deal with the accumulation of solid waste in a green way, and it also can open up new channel for solid waste recycling.