Experimental analysis reveals pozzolanic reactivity and pH-dependent heavy metal leaching in bottom-ash-based controlled low-strength material, indicating feasible construction reuse.
Key Points
To investigate the mechanical performance, hydration kinetics, microstructural evolution, and heavy metal leaching behavior of controlled low-strength material (CLSM) prepared with municipal solid waste incineration bottom ash (MSWI-BA) as the sole fine aggregate.
Formulated CLSM utilizing MSWI-BA as the sole fine aggregate alongside varying proportions of cement, fly ash, and water.
Characterized cement hydration heat, compressive strength development, and microstructural densification via ettringite morphology.
Evaluated the leaching mobility of heavy metals under different pH conditions and liquid-to-solid (L/S) ratios.
Cement content of ≥8% activated the pozzolanic reactivity of MSWI-BA, increasing hydration heat by 21.4% to 43.4% and late-age strength by 16.8% to 19.2%.
Fly ash content and water-solid ratio governed microstructural densification by altering ettringite crystal morphology and spatial distribution.
Heavy metal leaching was pH-dependent with higher mobility in acidic conditions, whereas leaching concentrations generally increased then decreased with L/S ratio, except for Ni and Cd which exhibited dilution effects.