Peng Xu

TL;DR: In this article , a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion.

Abstract: Alkali-activated materials (AAM) are widely applied in the field of building materials and civil engineering to substitute cement materials. This study used two types of municipal solid waste incineration fly ash (MSWI-FA): grate-firing fly ash (GFFA) and fluidized bed fly ash (FBFA) as brick raw materials. Various weight ratio of 20%, 30%, and 40% GFFA and FBFA were added to coal fly ash (CFA), GGBFs (Ground Granulated Blast-Furnace Slag), and an alkali-activating reagent to produce alkali-activated bricks. Microstructure and crystalline phase composition were observed to analyze their compressive strength, and a leaching test was used to prove the material’s safety for the environment. It can be seen from the results of this study that the alkali-activated bricks containing FBFA had higher compressive strength than those containing GFFA in the same amount. Considering the engineering properties, the alkali-activated bricks containing FBFA are more suitable to be used as building materials. The difference in the compressive strength resulted from the large amount of calcium compounds and chloride salts present in the GFFA. From SEM analysis, it was observed that there was a large number of pores in the microstructure. It was also found from the results of XRD that the bricks containing GFFA contained a large amount of chloride salt. From the results of the two leaching tests, it was found that the amounts of six heavy metals detected in the leachates of the bricks in this study met the corresponding regulation standards. This described MSWI-FA is suitable for use as alkali-activated material, and its products have potential to be commercially used in the future.

TL;DR: The results obtained from CEN/TS 14429 verified that the AAMs bricks with the addition of GFFA and FBFA have excellent environmental compatibility and that it provides a comprehensive evaluation on the environmental compatibility of the test materials and products.