Novel treatment method of coal bottom ash for strain-hardening alkali-activated composite

Abstract

This study explored the viability of using coal bottom ash (CBA), treated as a silicate source for preparing activators, as a filler in strain-hardening alkali-activated composites. The silica content provided by CBA was approximately 30% of that provided by silica fume, and its surface morphology exhibited a rough texture after treatment. The incorporation of CBA led to an improved compressive strength, and the subsequent substitution of treated CBA up to 100% resulted in a 10% increase in the compressive strength. Furthermore, incorporating the treated CBA enhanced the bond strength and pullout energy by up to 70% and 75%, respectively, compared with those of plain composites. The treated CBA also improved the tensile performance, as the replacement rate increased. At a substitution rate of 100%, the tensile strength, strain capacity, and strain energy density increased by 168.64%, 118.3%, and 479.41%, respectively, compared with those of plain composites. Thus, utilizing CBA as an alkaline activator is a promising solution to environmental challenges in the field of construction materials.