Development of the self-compacted and high-strength concrete for cold region

寒地自密实高强混凝土的研制

• 批准号: 12450216
• 负责人: NAWA Toyoharu
• 金额: $ 4.8万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450216/
• 关键词: Self-compacted and high-strength concrete for cold region; Graft Copolymer; Autogenous shrinkage; Fly ash; Ionic concentration; Mix design of concrete; Monte Carlo method; Fractal theory; 高強度コンクリート; 高性能AE減水剤; 温度; 初期高温養生; 強度発現; 硫酸アルカリ; 粒度分布 /

This purpose of this study is to develop the self-compacting and high-strength concrete for the cold region to reduce an environmental load. Most important results are summarized as follwos :(1) We developed the superplasticizer for the self-compacting and high-strength concrete in cold region. The effect of the chemical structure of superplasticizer on the fluidity, fluidity retention, retardation of hydration, and high durability of concrete was examined when the temperature was varied. As a result, it was confirmed that the heterologous graft copolymer having a long and short graft chains shows highly cement dispersed and low retardation of cement hydration, and the graft copolymer containing longer graft chains satisfied both high fluidity and high durability of concrete at low temperature.(2) It was indicated that the reduction of autogenous shrinkage of concrete is very important to prevent cracking the self-compacting and high-strength concrete for the cold region. Moreover, it was imposed that both to control the ionic concentration of liquid phase in concrete and to containing a large amount of fly ash were able to decrease the autogenous shrinkage.(3) The prediction method of the mix proportion for the self-compacted and high-strength concrete was proposed in order to make concrete mix design easily when the quality of powder and aggregate were varied. The critical state of self-compactability could be asumed that the bridge structure of the coarse aggregate covered with adherent mortar firms and was influenced strongly by the concentration of coarse aggregate and the fluidity of mortar. Based on this assumption, the maximum values of both coarse aggregate and fine aggregate and the unit water content (water-powder ratio) when concrete was satisfied of the self-compactability could be calculated by using the probability model based on the Monte Carlo method and the fractal theory respectively.

这项研究的目的是为冷区域开发自我压缩和高强度混凝土，以减少环境负荷。最重要的结果总结为follwos：（1）我们开发了用于冷区域中自我压缩和高强度混凝土的超塑料。当温度变化时，检查了超塑料化学结构对流动性，流动性保留，水合的延迟和高耐用性的影响。结果，证实具有长长和短移植链的异源移植共聚物显示出高度的水泥分散和较低的水泥水泥水泥水分的延迟，以及含有更长的移植链的移植物共聚物满足了高度的高流动性和高温下的高温下的高温。冷区域的高强度混凝土。此外，强加于控制混凝土中液相的离子浓度和包含大量的粉煤灰能够减少自动收缩的量。自我压缩性的临界状态可能会令人震惊，即粗骨料的桥梁结构被粘附的迫击炮公司覆盖，并受到粗骨料的浓度和砂浆的流动性的强烈影响。基于此假设，当可以使用基于蒙特卡洛方法和分形理论的概率模型来计算混凝土满足混凝土时，粗骨料和细骨料的最大值以及单位水含量（水蒸比）。