Effects of alkali equivalent and polypropylene fibres on performance of alkali-activated municipal waste incineration bottom ash-slag mortar

Abstract

Slag demonstrate significant potential as an important cementitious material for alkali-activated systems; however, the increase in alkali-activated materials has resulted in a short supply of slag. Therefore, other industrial wastes must be identified urgently to replace slag as an alkali-activated material while considering the alkali equivalent (AE) as an important factor affecting alkali-activated materials and the modification of polypropylene fibre (PPF). Effect. In this study, the effects of the AE and PPF length on the fluidity, consistency, compressive strength, and flexural strength of municipal waste incineration bottom ash-slag mortar are investigated by partially replacing slag with bottom ash (BA) derived from waste incineration as an alkali-activated material. The mechanism is elucidated via X-ray diffraction analysis and scanning electron microscopy. Finally, studies were conducted on the freeze-thaw resistance and dry shrinkage of alkali-activated bottom ash-slag mortar (AABA-SM). The results show that the performance of an AABA-SM can be modified and enhanced by controlling the AE size and the PPF length. Consistency of AABA-SM increased with the AE. The fluidity and mechanical strength of the AABA-SM enhanced significantly when the AE is 6.5%. PPF length of 12 mm were more significant in increasing the flexural strength of AABA-SM. This is attributed to the denser microstructure formed by the appropriate AE and the superior reinforcing effect of the well-coated 12 mm PPFs.In particular, at an AE of 6.5% and a PPF length of 12 mm, the AABA-SM shows a similar change in terms of dry shrinkage as natural mortar and is better resistant to freezing and thawing. This research provides theoretical support to improve the performance of AABA-SM, enhance the utilization of BA, and reduce environmental pollution.