Development of performance control methods for concrete admixture of using the microcapsule

微胶囊混凝土外加剂性能控制方法的开发

• 批准号: 22656119
• 负责人: MIHASHI Hirozo
• 金额: $ 2.21万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Challenging Exploratory Research
• 财政年份: 2010
• 资助国家: 日本
• 起止时间: 2010 至 2011
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-22656119/
• 关键词: マイクロカプセル; 水和反応; 収縮低減剤; 性能制御; 自己収縮; 徐放性; ポリ乳酸

Recently high-strength concrete and highly-flowable concrete have been developed. In such concrete, autogeneous shrinkage is not negligible and shrinkage-reduction agents are employed for preventing cracks due to the shrinkage. However, a certain amount of the agent needs to be used since a large part of effective components are absorbed by cement hydration products at an early age before the shrinkage starts. In this study, micro capsule technology was applied and surface coating techniques on the shrinkage-reduction agents were employed for controlling the chemical action process of the agents. In the surface coating layer, three different kinds of micro fibers crashed into pieces were mixed. One of the fiber was melt in alkaline water and the others were water-soluble. Experimental results showed that the chemical reaction rate of agents can be controlled by changing the coating thickness together with the type of micro fibers. It was also experimentally proved that autogeneous shrinkage strain in case of early-strength Portland cement was reduced by employing the proposed micro capsule.

近年来，高强混凝土和大流动性混凝土相继问世。在这种混凝土中，自生收缩是不可忽视的，并使用了减缩剂来防止因收缩而产生的裂缝。然而，由于大部分有效成分在收缩开始之前就被水泥水化产物早期吸收，因此需要使用一定量的助凝剂。本研究采用微胶囊技术和表面包覆技术对减缩剂的化学作用过程进行控制。在表面涂层中，三种不同类型的超细纤维混合在一起。其中一种纤维在碱性水中熔化，其他纤维是水溶性的。实验结果表明，通过改变涂层厚度和微纤维的类型，可以控制试剂的化学反应速度。实验还证明，采用所提出的微胶囊可以降低早强硅酸盐水泥的自生收缩应变。