Performance investigation of the artificial aggregate by integrally recycling incineration bottom ash and fly ash

The potential expansion risks caused by the reaction of metallic aluminum and glass particles in incineration bottom ash (IBA) in high-alkalinity environments limit its use as an aggregate in concrete applications. This study aims to develop artificial aggregates (AAs) by integrating IBA with a low-alkalinity binder comprising incineration fly ash (IFA) and blast furnace slag (GGBS). The synergetic effects of using IBA with IFA-GGBS binders in AAs are investigated and compared to integrating IBA with IFA-OPC binders. The impacts of IFA and IBA contents on physico-mechanical properties and mineralogical characteristics of AAs are also assessed. The results show that AAs achieve a loose bulk density ranging from 890 to 1072 kg/m(3), with the highest strength of 5.7 MPa recorded for GGBS-based aggregates with 40 % IBA. The pozzolanic reaction of GGBS-IFA contributes to a robust binder that facilitates interlocking within the system. The relatively low alkalinity associated with the pozzolanic reaction between GGBS and IFA suppresses the potential expansion reaction, ensuring the safe application of AAs in concrete. Moreover, the internal curing of GGBS-based AAs and their interaction with the cement matrix densify the microstructure of the interface transition zone, resulting in excellent compressive strength of AAs-contained concrete (>45 MPa), which surpasses that of conventional concrete.