Multi-Objective experimental optimization of sustainable concrete incorporating incinerator bottom ash and copper mining tailings

Abstract

The construction sector is increasingly evaluating industrial residues as substitutes for conventional cement and aggregate. This study investigates incinerator bottom ash (IBA) as a partial cement replacement and copper mining tailings (CMT) as a fine-aggregate replacement. A two-factor, four-level L16 experimental matrix comprising 16 mixtures was used to evaluate fresh, mechanical, durability-related, and microstructural responses. IBA was the dominant factor in the measured strength response: 28-day compressive strength decreased from 49.53 MPa in the control mixture to approximately 30 MPa at 20% IBA, whereas CMT had a smaller effect and IBA0-CMT20 reached 50.77 MPa. The one-factor ANOVA attributed most of the variation in compressive strength (eta squared = 0.99), density (eta squared = 1.00), slump (eta squared = 0.95), and porosity (eta squared = 0.92) to IBA level. SEM, XRD, and FTIR observations linked the high-IBA response to binder dilution, reduced continuity of hydration products, and greater porosity. Within the tested materials and curing regime, replacing 20% of natural sand with CMT preserved the target compressive strength when IBA was not used. Independent batches, material-specific characterization, leaching assessment, and long-term durability testing are needed before field application.