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Title |
Hydration Properties of Ordinary Portland Cement Using Mixture of Limestone and Blast Furnace Slag as Minor Inorganic Additives
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Authors |
이승헌(Seung-Heun Lee) ; 임영진(Young-Jin Lim) ; 조재우(Jae-Woo Cho) |
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DOI |
http://dx.doi.org/10.4334/JKCI.2015.27.1.003 |
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Keywords |
보통 포틀랜드 시멘트 ; 고로슬래그 ; 석회석 ; 수화특성 ; 혼합재 ordinary Portland cement ; blast furnace slag ; limestone ; hydration ; additives |
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Abstract |
In this study, hydration properties of ordinary Portland cement were examined, shown from a limestone and blast furnace slag alone or their mixture up to 10% as a minor mineral additives. As of setting time, it was identified that final setting became faster as the amount of limestone mixture increased, which showed limestone accelerated early hydration faster than blast furnace slag. This is because limestone did accelerate the hydration of alite. At the age of 3 days, limestone 5%-blast furnace slag 5% mixture had the highest compressive strength of mortar. It is because hydration acceleration of alite by limestone, and Ca(OH)2 that was additionally formed by hydration acceleration of alite reacted with blast furnace slag, and as a result, additionally created C-S-H hydrate. Regarding the hydration properties by the age of 7 and 28 days, limestone 3%-blast furnace slag 7% of composited mixture showed the largest compressive strength, and in comparison with the 3 days in curing age. This period is when hydration reaction of blast furnace slag is active and the amount of hydrate depends on the amount of blast furnace slag mixture more than that of the limestone mixture. And in order to vitalize hydration reaction of blast furnace slag the amount of Ca(OH)2 created has to increase, and thus, a small amount of limestone is necessary that can accelerate the hydration of alite. Therefore, after the age of 7 days, the fact that there were a large amount of blast furnace slag mixture and small amount of limestone mixture was effective to the strength development of ordinary Portland cement.
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