JAUE2024-057: Study on the Applicability as Concrete admixture for Combustion Ash of Different Fuel Types

Abstract

Woody biomass combustion ash generated form woody biomass power plants can be mixed into concrete as an admixture, thereby contributing to the reduction of environmental impact. In this study, experiments were conducted to compare woody biomass exclusively burned ash with two types of ash, mixed ash of coal and wood, and JIS Class Ⅱ certified ash, in order to clarify the strength development of the hardened body, image analysis of hydrates, and  composition of the mortar interior. In terms of C-S-H production, the cement paste mixed with woody biomass ash showed the same amount of C-S-H production as other ashes, confirming the progress of the pozzolanic reaction. In terms of compressive strength , W/B=40(%) was the highest and W/B=60(%) the lowest value for both ashes. At W/B=40(%), the cement paste mixed with mixed ash showed the highest value. This is thought to be due to the high content of the glass phase. The SEM/EDS analysis results showed the progression of a pozzolanic reaction that produced a low-Ca type C-S-H phase in all ashes.