普通ポルトランドセメントおよびエコセメントを用いたコンクリートの打重ね部の付着強度に及ぼす時間間隔の影響に関する実験的研究

概要

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In order to determine the limit of time interval for placing concrete on consolidated fresh concrete to prevent cold joints, which impair water tightness and durability of concrete structures, laboratory experiments were conducted on the bonding strength between lower and upper layers. Concrete mixtures with ordinary portland cement and eco-cement were tested for bonding strength by splitting tensile strength test on specimens with the time intervals up to 6 hours for placing upper concrete on consolidated lower concrete at the ambient temperatures of 20 and 30 ℃. The test results indicated that reduction in bonding strength was smaller for eco-cement at the same time intervals than for ordinary portland cement, indicating significant inter-relation with setting time, duration of bleeding and penetration depth of rodding bar. Allowing 30% reduction in bonding strength between lower and upper layers, allowable time interval were found to be 4 hours for ordinary portland cement and 6 hours for eco-cement at 20℃.
社団法人日本建築学会の論文
2008-03-30