| 摘要 |
PURPOSE:To provide an underwater unseparable concrete blend composition for underwater execution hardly causing separation of materials in water, capable of readily controlling an air amount and using a defoaming agent having low handling cost and a defoaming agent for such concrete blend composition. CONSTITUTION:The concrete blend composition is obtained by adding one or two kinds of water-soluble cellulose ethers selected from a group consisting of hydroxyalkyl celluloses and hydroxyalkylalkyl celluloses and an acetylene glycol derivative as the defoaming agent to a concrete blend containing a cement binder, an aggregate and a water-reducing agent. As the acetylene glycol derivative, a nonionic surfactant obtained by adding ethylene oxide to 2,4,7,9-tetramethyl-5-decyne-4,7-diol and having 1-20 ethylene oxide-added mol number is preferably used. |
