Activation of Blast Furnace Slag with CFB Fly Ash as a Supplementary Binder Material: Hydration Products and Effects of Sulfate Attack

Guan Yu Chen, Wei Hsing Huang

研究成果: 雜誌貢獻期刊論文同行評審

摘要

Circulating Fluidized Bed (CFB) combustion is a clean technology for burning, with advantages of adapting to a large variety of fuel, high combustion efficiency, lower NOx emissions, and stable operation. The residue collected from the ash-hoppers of the electrostatic precipitator of the CFB boiler is called CFB fly ash. This paper presents the hydration development on the application of CFB fly ash to activating blast furnace slag (BFS) as a supplementary binder material (SBM) for replacement of Portland cement in making concrete. Investigation of the hydration products of cement pastes prepared with combinations of BFS and CFB fly ash were conducted by means of X-ray diffraction, thermal gravimetric analysis, and scanning electronic microscope. Test results show that the main hydration products of the CFB fly ash-BFS blended pastes were found to be hydrated calcium silicate (C-S-H), ettringite, gypsum, and some portlandite. Considering that CFB fly ash produced from the combustion of high-sulfur coke has high SO3 contents, the volume stability of mortar made from CFB fly ash-activated BFS was subjected to tests in accordance with ASTM C1012 and ASTM C1038 for evaluating the internal and external sulfate attack, respectively. The results indicate that, due to the high sulfur (SO3) content of CFB fly ash, the expansion caused by internal sulfate attack (ISA) increased with increasing proportion of CFB fly ash in the mixture. In contrast, no significant expansion was observed in the external sulfate attack (ESA) test, regardless of the proportion of CFB fly ash in the mixture. In order for the CFB fly ash to serve as a supplementary binder material and to maintain adequate volume stability, the amount of CFB fly ash used for the activation of BFS is recommended to be no more than 20% of the SBM.

原文???core.languages.en_GB???
文章編號41
期刊Crystals
12
發行號1
DOIs
出版狀態已出版 - 1月 2022

指紋

深入研究「Activation of Blast Furnace Slag with CFB Fly Ash as a Supplementary Binder Material: Hydration Products and Effects of Sulfate Attack」主題。共同形成了獨特的指紋。

引用此