감수제의 사용이 micro-POFA 혼입 시멘트 페이스트의 초기 수화 특성에 미치는 영향에 관한 실험적 연구

초록

Palm Oil Fuel Ash(POFA) has been widely used to replace Portland cement to enhance the mechanical properties and durability of concrete. However, it reduces the workability of concrete due to the high content of unburnt carbon and its angular shape requiring the usage of superplasticizer to ensure a proper flowability. In this study, effects of different types and dosage of superplasticizer on the early mechanical and hydration properties of cement paste containing micro-POFA were evaluated using mini-slump test, early compressive strength, TGA, XRD, and SEM. The results indicated that the flowability of cement paste containing micro-POFA reduced as the replacement ratio of micro-POFA increased. As the dosage of superplasticizer increased, the flowability was also increased. In addition, the usage of superplasticizer reduced the early compressive strength, and the strength decreased with an increase in the dosage of superplasticizer. It was confirmed that superplasticizer hindered the formation of C-S-H leading to a relative increase in the formation of Ca(OH)2.

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