• Title/Summary/Keyword: retarders

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Effects of Sugar and Hydrated Cement Powder on the Reduction in Heat of Hydration (당분과 수화시멘트 분말이 수화열 저감에 미치는 효과)

  • Moon, Hoon;Kim, Ji-Hyun;Cho, Yong-Hun;Lee, Jae-Yong;Chung, Chul-Woo
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.2
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    • pp.135-142
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    • 2014
  • The heat of hydration can be reduced through the use of retarding agents. Typical retarding agents include sugar and glucose. However, these significantly delay the setting of cement paste. For the efficient use of sugar and glucose for mass concrete construction, it is necessary to develop a technique that can provide a setting behavior equivalent to that of plain concrete. In this work, the temperature rise of cement paste was monitored with the addition of various retarders including sugar and glucose. Hydrated cement powder was made with a water to cement ratio of 5 in order to accelerate the retarded cement pastes. It was found that the addition of hydrated cement powder in retarded pastes reduced the maximum temperature of cement paste. The use of hydrated cement powder could also successfully reduce the time to reach the maximum temperature.

Study on Moisture Variation in Light Frame Wall with Different Wall Assemblies (II) - Moister Transfer of Light Frame Wall in Field Test - (벽체구성에 따른 목조벽체 내 수분변화에 대한 연구(II) - 외기에 노출된 목조벽체의 수분이동 -)

  • Kim, Se-Jong;Yeo, Hwan-Myeong;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.1
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    • pp.56-65
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    • 2010
  • The purpose of this study was finding out proper wall assembly to reduce moisture accumulation in light frame wall under outdoor air conditions. For the purpose, moisture transfer and accumulation in a wall were evaluated for five types of wall assembly; typical wall (T), addition of a vapor retarder (P1), addition of two vapor retarders (P2), addition of an open air gap for ventilation behind the siding (P3), and shift of vapor retarder with proposed wall 'P3' (P4). The moisture transfer and accumulation in the all walls were evaluated after applying the typical and proposed walls to the field test house. Performances of the typical and proposed walls were compared according to the season. Rank for effective wall on reducing moisture accumulation in wall was 1) shift of vapor ratarder and addition of open air gap (P4), 2) addition of vapor retarder (P1), 3) typical wall (T), 4) addition of open air gap (P3), and 5) the other (P2).