Enhancing mechanical performance and durability of high strength mortar with incineration bottom ash via Al2O3 micro-powder: An experimental study

The untreated application of municipal solid waste incineration bottom ash (IBA) in cementitious materials can lead to compromised workability, deterioration of mechanical properties, and compromise durability. This paper examines the potential of utilizing Al2O3 micro-powder (ALMP) to enhance the mechanical performance and durability of cementitious materials fabricated with IBA. This paper focuses on the effect of different dosages of ALMP on the workability, mechanical performance and durability of high strength mortar (HSM) prepared by IBA. In addition, effect of ALMP on the ultrasonic pulse velocity (UPV), dynamic modulus of elasticity (DME) and microstructure of HSM was also investigated. Finally, the micro-mechanical performance of HSM paste was determined via nanoindentation experiment. Our study discovered that the integration of ALMP in HSM contrived with IBA notably amplified the flexural and compressive strengths by ranges of 1.12 %∼9.84 % and 3.78 %∼21.26 %, respectively. Simultaneously, the ALMP improved the UPV by an interval of 3.16 %∼9.49 %, and the DME by a parameter of 9.64 %∼18.69 %. Additionally, we observed considerable lowering of drying shrinkage in HSM by 4.96 %∼28.36 % and decline in the chloride migration coefficient by 7.45 %∼38.75 % due to ALMP's presence. Overall, based on the observed impact of ALMP on HSM's workability, mechanical properties, and microstructure, we suggest 10 wt% as the optimal doping amount for ALMP in HSM. Our investigation puts forward that implementing IBA in place of traditional quartz sand in the preparation of HSM could potentially attenuate energy consumption, carbon emissions, and production overheads. The findings of this study may offer instructive significance for improving the resource utilization of IBA in cement-based materials.