Effect of Quality of Surface Layer of Concrete on Scaling Resistance

(1)冻损机理参考文献对混凝土冻损机理进行了探讨。按6种类型对结垢机理进行了排序。它认为这些机制实际上是复合的，有些机制在某些情况下表现出色，并且形成了缩放。(2)混凝土结构冻损现状采用问卷调查法对东北地区混凝土结构冻损现状进行调查。考虑了冻害的退化症状、面积、构件、时间、原因、修复以及除冰盐的涂抹量。(3)混凝土表面层质量对抗结垢性的影响假设氯化物操作时产生的热冲击影响结垢。在保证孔隙结构和混凝土表面强度达到固定值的同时，可增加抗结垢性。然而，含水量的影响大于孔隙结构和强度的影响。(4)含各种粗骨料混凝土的抗结垢性能含低质量骨料或粉煤灰人工骨料混凝土的抗垢性能在水灰比和空气含量固定的情况下得到提高。但是，单纯从集料的密度和含水率来判断混凝土的结垢损伤是不可能的。(5)蒸汽养护混凝土的抗结垢性当在蒸汽养护混凝土中掺入所需的空气含量时，结垢量减小，即使改变各种制造条件，也无法确定结垢量显著的差异。因此，认为混合所需的空气含量对保证蒸汽养护混凝土的抗结垢性是非常重要的。

(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.