关键词: 田口方法, 煤矸石, 粉煤灰, 细骨料, 保温性能

Abstract: The recycling of coal gangue and fly ash can reduce the negative impact on ecological environment. In this study, coal gangue and fly ash were used as raw materials. The preheating temperature, preheating time, calcination temperature and calcination time were tested by the Taguchi method. And the crushing index and thermal conductivity coefficient were used as evaluation indexes to optimize the preparation process of fine aggregate. The insulation mechanism of fine aggregates was analyzed in terms of phase composition, micromorphology and pore structure using X-ray diffraction, scanning electron microscopy and mercury intrusion porosimetry. The research findings indicate that the raw materials can be processed under conditions of a preheating temperature of 400 ℃ for 25 min, followed by a calcination temperature of 1 250 ℃ for 25 min, to produce coal gangue-fly ash fine aggregates with a crushing index of 29.1% and a thermal conductivity of 0.138 W/(m·K). Simultaneously, an increase in the calcination temperature contributes to an enhancement in the content of mullite crystals and the compactness of pores. Furthermore, high temperatures can reconstruct the pore structure of porous aggregates, increasing the number of pores with diameters greater than 10 000 nm, which contributes to improving both the strength and thermal insulation performance of the fine aggregates.

Key words: Taguchi method, coal gangue, fly ash, fine aggregate, thermal insulation performance