IGCC 용융 슬래그로 제조된 지오폴리머의 강도증진에 Pre-curing이 미치는 영향
Effects of pre-curing process on improvement of the compressive strength of IGCC-slag-based-geopolymer
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본 연구에서는 IGCC(Integrated Gasification Combined Cycle; 석탄 가스화 복합 발전)에서 배출된 용융 슬래그(이하 용융 슬래그)를 이용한 지오폴리머의 제조 시 pre-curing 공정이 지오폴리머의 물성에 미치는 영향에 대해 연구하였다. Pre-curing이란 고온양생으로 지오폴리머를 제조하기 전에, 성형체를 상온에서 일정 시간 방치하는 공정으로서, 시편의강도를 높이는 효과가 있다고 알려져 있다. 따라서 본 실험에서는 pre-curing 조건에 따른 지오폴리머의 압축강도 특성을측정하였으며, SEM과 XRD로 미세구조 및 결정상 변화를 관찰하였다. W/S 비율(water/solid ratio)은 사전 실험을 통해, 성형이 가능하면서 최대 지오폴리머 강도를 확보할 수 있는 0.26으로 결정하였으며, 자극제인 알칼리 용액의 농도는 15 M로고정하였다. 상온에서 pre-curing을 0~27일 범위 내에서 실시한 결과, pre-curing 공정을 적용한 지오폴리머의 경우, 그렇지않은 시편에 비해 압축강도가 36~87 % 증가하는 것을 확인하였다. Pre-curing 시킨 시편에서 XRD 측정 결과, C-S-H 겔(calcium silicate hydroxide gel) 상 발현이 촉진되었고 SEM을 이용한 미세구조 관찰 결과, 부정형의 zeolite 상이 더 많이 성장된 것이 관찰되었으며 이러한 상들의 생성이 강도 증진에 영향을 미친 것으로 분석되었다.
Abstract
In this study, the effect of pre-curing process on the enhancement of mechanical properties of IGCC-slag-basedgeopolymer was studied. Pre-curing is a process in which the green geopolymer is left at room temperature for a certain period of time prior to the high-temperature curing, and it is known as increasing the strength of a specimen. Therefore, in this experiment, the compressive strength of the geopolymers was measured according to various pre-curing conditions, and microstructure and crystal phase changes were observed by SEM and XRD, respectively. The W/S ratio was determined to be 0.26, which can offer the maximum geopolymer strength with easy molding ability, and the concentration of the alkali solution was 15 M. Pre-curing was performed at room temperature for 0 to 27 days. Compressive strength of the geopolymer made with pre-curing process increased by 36~87 % compared with the specimens made with no pre-curing process. Those improved compressive strength for the pre-cured geopolymer was confirmed owing to promotion effect of pre-curing process on generation of C-S-H gel and zeolite phases, which were analyzed using by XRD and SEM measurement.
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