Leveraging incinerator bottom ash for mitigating early age shrinkage in 3D printed engineered cementitious composites

This study investigates the use of incinerator bottom ash (IBA) as a supplementary cementitious material to mitigate early age shrinkage in 3D printed engineered cementitious composites (3DP-ECC). IBA was processed through milling and thermal treatment before incorporation into 3DP-ECC. The fresh and hardened properties, hydration kinetics and products, early age shrinkage, and microstructural characteristics of 3DP-ECC with IBA were evaluated. Results indicate that pre-treated IBA reduces autogenous shrinkage and plastic shrinkage by 56 % and 30 %, respectively. The substitution of IBA increases the volume fraction of macropores (>1000 nm) of 3DP-ECC at 3 days and 7 days by approximately 300 % and 500 %, respectively, alleviating early age shrinkage. Sustainability analysis reveals that the incorporation of IBA can reduce the normalized embodied energy and carbon footprint of 3DP-ECC by over 17 %. These findings provide a promising approach to utilizing waste materials in mitigating early age shrinkage in 3DP-ECC towards sustainable digital construction.