Influence of municipal solid waste incineration bottom ash particle size on the evolution mechanism and distribution characteristics of multiscale pore structures in cement paste

The utilization of municipal solid waste incineration bottom ash (MSWIBA) in cement-based materials has gained attention due to its varying properties across different particle sizes. This study examines the impact of MSWIBA particle size on hydration and pore structure. The results show that incorporating MSWIBA increases micropores (<50 nm) due to hydrogen production from Al metal, reduces mesopores (50-200 nm) via filler effects, and enlarges macropores due to matrix expansion. Smaller MSWIBA particles, rich in Al and CaCO3, enhance early hydration, accelerate carbonation, and affect the C-S-H structure, leading to weaker elastic moduli.