Feasibility study on using incineration fly ash from municipal solid waste to develop high ductile alkali-activated composites

Abstract Incineration fly ash (IFA) is a by-product generated along the incineration process of municipal solid waste, which can pose great danger to human health and environment if not properly addressed. With the intention to use IFA in a cleaner and more sustainable manner, the current work focuses on exploring the possibility of utilizing IFA for civil engineering applications. The idea is to prepare high ductile engineering materials using IFA, i.e. alkali-activated fiber reinforced composites or IFA-AAFRCs. The results showed that excellent mechanical properties can be obtained with the IFA replacement ratio even up to 40%. The maximum tensile strength, tensile strain capacity and compressive strength at 28 days can reach 2.78 MPa, 5.19% and 73.78 MPa, respectively. The meso-scale studies, including three-point bending test, single-crack tensile test and single fiber pullout test, revealed that the IFA replacement (10% and 40% IFA) can improve the micromechanical properties which are responsible for high ductility. Microstructural analyses using SEM and EDS demonstrated that the IFA replacement is beneficial in generating more amorphous gel products, leading to a dense and compacted microstructure. In addition, a preliminary study was conducted to evaluate the leaching behavior of heavy metals from the composites. The results showed that the prepared composites are rather effective in immobilizing toxic heavy metals. Based on all the obtained results, it can be concluded that the composites are promising for civil engineering applications, especially for cases where high ductility is demanded.