This study explores the mechanical properties, microstructure, and environmental performance of ECC incorporating municipal solid waste incinerator bottom ash (BA) and rubber powder as sustainable fine aggregates. Six ECC mixtures were designed with varying BA-to-rubber ratios to evaluate the synergistic effects of rigid and viscoelastic waste particles. Experimental results revealed a distinct hybridization effect: while complete replacement of natural sand generally reduced mechanical strength, the mixture incorporating 75% BA and 25% rubber achieved the best balance among the waste-based mixtures, with a tensile strength of 3.23 MPa and an ultimate strain of 1.95%. This hybrid mix outperformed both the pure rubber and pure bottom ash waste systems in terms of tensile capacity. Microstructural analyses indicate that this enhancement is associated with a dual mechanism: (1) physical synergistic packing, where finer BA particles fill interstitial voids between rubber aggregates, resulting in the lowest porosity (20.47%) among waste-based mixes; and (2) chemical densification, where the pozzolanic reaction of BA consumes calcium hydroxide and strengthens the ITZ. Life cycle assessment showed that the natural-sand control achieved the lowest strength-normalized environmental impacts because of its high compressive strength, while B75C25F20 exhibited the best environmental efficiency among the waste-based mixtures (0.027 kg CO 2 -eq/MPa and 0.190 MJ/MPa). These findings demonstrate that combining reactive BA with limited rubber content enables high-performance and lower-impact ECC, offering a viable pathway for sustainable infrastructure.
Cheng et al. (Fri,) studied this question.