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Effect of Quality of Surface Layer of Concrete on Scaling Resistance

混凝土表层质量对抗结垢性能的影响

基本信息

批准号：
11650593
负责人：
TSUKINAGA Yoichi
金额：
$ 1.86万
依托单位：
Hachinohe Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650593/
关键词：
Concrete Freezing and thawing action Deicer salt Scaling Moisture content Thermal shock Pull-off test Air-void character 微小硬度プルオフ法透過性

项目摘要

(1) Mechanism of frost damageThe mechanism of frost damage of concrete was investigated from the reference. The mechanism of the scaling was put in order by 6 types. It thought that these mechanisms were compound actually, and that some of the mechanisms excelled in some case and that the scaling developed.(2) Actual state of frost damage at the concrete structuresThe actual state of frost damage of concrete at the Tohoku district was investigated by the questionnaire. Deterioration symptom, area, members, time, causes, and repair of the frost damage, and the spreading amount of deicer salts were considered.(3) Effect of quality of surface layer of concrete on scaling resistanceIt supposed that the thermal shock which occurs in case of the chloride operation influenced a scaling. Scaling resistance can be increased in securing to fixed value in the pore structure and the strength of the concrete surface. However, the fact that the influence of the water content is larger than the pore structure and the strength was confirmed.(4) Scaling resistance of concrete containing various coarse aggregatesThe scaling resistance of the concrete containing low-quality aggregates or fly ash artificial aggregates was improved when securing fixed water cement ratio and air content. However, scaling damage of concrete could not be estimated solely from the density and the moisture content of aggregates.(5) Scaling resistance of steam-cured concreteWhen mixing required air content in steam-cured concrete, the scaling amount decreased and even if various manufacturing conditions were changed, differences with remarkable scaling amount were not confirmed. Therefore, it supposed that to mix required air content was very important to secure the scaling resistance of steam-cured concrete.

(1)冻害机理在文献[1]的基础上，对混凝土的冻害机理进行了研究。按6种类型对结垢机理进行了整理。认为这些机制实际上是复合的，有些机制在某些情况下更好，而且结垢也在发展。(2)混凝土结构的冻害实际情况通过问卷调查，调查了东北地区混凝土的冻害情况。考虑了冻害的劣化症状、面积、构件、时间、原因和修复，以及除冰盐的铺展量。(3)混凝土表层质量对抗结垢性能的影响假设了氯离子作用下发生的热冲击影响结垢。在确保孔结构和混凝土表面强度达到固定值的情况下，可以增加抗结垢能力。不同粗集料混凝土的抗垢性能在保证水灰比和含气量不变的情况下，劣质集料和粉煤灰人工集料混凝土的抗结垢性能得到了提高。但不能仅从骨料的密度和含水率来判断混凝土的结垢损伤。(5)蒸养混凝土的抗结垢性能当蒸养混凝土中掺入所需含气量时，结垢量减少，即使改变不同的生产条件，也不能证实结垢量显著的差异。因此，认为掺入所需的含气量对保证蒸养混凝土的抗结垢性能是非常重要的。