페로니켈 슬래그 미분말의 시멘트 페이스트 내 수화특성과 공극 분석

초록

Ferronickel slag is a byproduct of the steel alloy which is gaining attention nowadays utilizing it as supplementary cementitious material in concrete mix. In this study, the hydration characteristics of ferronickel slag grain were investigated by analyzing scanning electron microscopy images, X-ray diffraction peak, and porosimetry of ferronickel slag blended cement paste. Especially, the degree of hydration was calculated by mapping grayscale images of ferronickel slag in back-scattered electron mode. Ferronickel slag with blain of 4,660 cm2/g were replaced by 0 %, 10 %, 30 % and 50 % of total amount of binder using ordinary Portland cement to figure out the microstructure of ferronickel slag paste. In the image analysis, MgO-based hydrate and unreacted ferronickel particles were observed where calcium silicate hydrates were present. The high MgO and SiO2 content of ferronickel slag lead to latent hydration in the cement matrix therefore the reactivity (degree of hydration) of ferronickel slag is much lower than ordinary Portland cement. In the BSE image analysis, higher replacement of ferronickel slag was found to lead to 1.7 more unhydrated area. Pore distribution in the ferronickel slag paste was mostly concentrated in small capillary pores as replacement ratio increased, resulting in a denser pore structure. © 2019 by Korea Concrete Institute.

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