Title |
Setting Time, Compressive Strength and Drying Shrinkage of Mortar with Alpha-Calcium Sulfate Hemihydrate
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Authors |
이계혁(Kye-Hyouk Lee) ; 김규용(Gyu-Yong Kim) ; 이보경(Bo-Kyeong Lee) ; 신경수(Kyoung-Su Shin) ; 남정수(Jeong-Soo Nam) |
DOI |
https://doi.org/10.11112/jksmi.2017.21.5.117 |
Keywords |
α형 반수석고 ; 모르타르 ; 응결시간 ; 압축강도 ; 건조수축 Alpha-calcium sulfate hemihydrate ; Mortar ; Setting time ; Compressive strength ; Drying shrinkage |
Abstract |
In this study, to evaluate the setting time, compressive strength and drying shrinkage of ordinary Portland cement and Portland blast-furnace slag cement mortar with 0, 10, 20, 30 wt.% alpha-calcium sulfate hemihydrate. As a results, as the replacement ratio of alpha-calcium sulfate hemihydrate increased, the initial setting time of ordinary Portland cement and Portland blast-furnace slag cement mortar was faster. In addition, the compressive strength decreased with increasing replacement ratio of alpha-calcium sulfate hemihydrate in both ordinary Portland cement mortar and Portland blast-furnace slag cement mortar. The strength development of Portland blast-furnace slag cement mortar with alpha-calcium sulfate hemihydrate was effective than that of ordinary Portland cement mortar. On the other hand, in the case of the mortar with alpha-calcium sulfate hemihydrate, it was confirmed that shrinkage deformation was reduced at the early age by growth pressure of needle-shaped ettringite crystals produced by incorporation of alpha-calcium sulfate hemihydrate. However, the effect of inhibiting shrinkage deformation of mortar with alpha-calcium sulfate hemihydrate was not significant as the age passed. Therefore, it is considered that the alpha-calcium sulfate hemihydrate is useful as a construction material.
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