Preparation and High-Strength Micro-Expansion Mechanism of CFB Fly Ash Compaction Slurry

Abstract

Abstract: The activity and expansibility of circulating fluidized bed coal-fired sulfur-fixed ash (CFB fly ash) were utilized to prepare compaction slurry. The effects of CFB fly ash content and water-binder ratio on the workability, strength and expansion rate of the compaction slurry were investigated.CFB fly ash and mineral powder were mixed in different ratios, and the high-strength and micro-expansion characteristics of CFB fly ash compaction slurry were studied and verified by XRD and SEM analyses. The results show that, with the increase of CFB fly ash replacing cement content, the water demand of the compaction slurry increases and the compressive strength decreases. The 28 d compressive strength of the specimen with 20% (mass fraction) CFB fly ash is close to that of the base sample, up to 85.8 MPa, while the flexural strength rises first and then decreases, and the expansion rate rises sequentially. With the increase of water consumption, the expansion rate decreases but is positive. With the increase of the rate of CFB fly ash replacing mineral powder, the workability decreases, and the 28 d compressive strength rises first and then decreases. The specimen with 20% (mass fraction) CFB fly ash and 10% (mass fraction) mineral powder has the highest 28 d compressive strength, which is 99.8 MPa, and the expansion rate has been increasing. The various properties of compression slurry with CFB fly ash and mineral powder meet the requirements of the iron standard. CFB fly ash not only expands by its own hydration, but also can activate the activity of mineral powder, resulting in a composite enhancement effect.

Key words: CFB fly ash, ettringite, compaction slurry, mineral powder, micro-expansion, high-strength, fluidity, water-binder ratio

CLC Number:

TU528

ZHOU Mingkai, RAO Ke, MENG Xiuyuan, WANG Yuqiang. Preparation and High-Strength Micro-Expansion Mechanism of CFB Fly Ash Compaction Slurry[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(6): 2157-2167.

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