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

基本信息

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 /

项目摘要

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.

本研究的目的是开发适用于寒冷地区的自密实高强混凝土，以减轻环境负荷。主要研究成果如下：(1)开发了寒区自密实高强混凝土高效减水剂。研究了不同温度下高效减水剂的化学结构对混凝土流动性、流动性保持性、水化延迟性和高耐久性的影响。结果证实，具有长和短接枝链的异源接枝共聚物表现出高水泥分散性和低水泥水化延迟性，而含有较长接枝链的接枝共聚物满足混凝土在低温下的高流动性和高耐久性。 (2)表明，降低混凝土自收缩对于寒冷地区自密实高强混凝土的防裂具有重要意义。此外，控制混凝土液相离子浓度和掺入大量粉煤灰均能减少自收缩。(3)自密实混凝土配合比预测方法高强混凝土的提出是为了在粉料和骨料质量变化的情况下便于混凝土配合比设计。自密实性的临界状态可以认为是粗骨料的桥结构被粘附砂浆覆盖而牢固，并且受粗骨料浓度和砂浆流动性的强烈影响。在此假设基础上，利用基于蒙特卡罗方法的概率模型可以计算出混凝土满足自密实性时的粗骨料和细骨料的最大值以及单位含水量（水粉比），分别是分形理论。