Performance characterization and leaching behavior of controlled low-strength material from municipal solid waste incineration bottom ash

To improve the resource utilization rate of municipal solid waste incineration bottom ash (MSWI-BA), this study prepared a controlled low-strength material (CLSM) using MSWI-BA as the sole fine aggregate.Combining microstructural characterization, the effect of MSWI-BA on cement hydration and the effect mechanism of mix design parameters on strength development were revealed. Furthermore, the leaching behavior of heavy metals under different pH conditions and liquid-solid ratios (L/S) was comprehensively evaluated. Results demonstrated that MSWI-BA participated in the hydration process, exhibiting non-inert characteristics. The pozzolanic activity of MSWI-BA was activated with ≥8% cement content, increasing hydration heat by 21.4%-43.4% and late strength by 16.8%-19.2%. Fly ash content and water-solid ratio affected microstructural densification by altering ettringite morphology and distribution, respectively. Heavy metal leaching was pH-dependent, with higher mobility under acidic conditions. Except for Ni and Cd affected by dilution effect, leaching concentrations initially increased then decreased with L/S.