Development of highly durable concrete products to resist frost and salt damage

高耐久混凝土可长期使用，并具有抗劣化性能。近年来，通过引气剂的发展，生产出了耐久、抗劣化的混凝土产品，使混凝土变得少水、致密。然而，在东北这样寒冷的地区，它们遭受了许多破坏，如结垢和坍塌。尤其是安装了负载物的侧沟开挖设备，由于反复冻融和大量的除冰盐对盐分的破坏，造成了复杂的破坏。本研究采用透水成型的方法制作了一种沟式洞室，并进行了表层强度试验、冻融试验和结垢试验。透水模板法将混凝土中多余的水和气泡排出，使混凝土表面致密。试验结果表明，提高了混凝土的表层强度、抗冻害和抗结垢能力。因此，透水模板法是生产高耐久混凝土的有效方法，可以长期使用。

Highly durable concrete can use for a long time, and have deterioration resistance. In recently year, durable concrete products which have deterioration resistance have been produced to make water less and dense concrete by progress of air entraining agents. Although, in such cold district as Tohoku, them suffer much damage such as scaling and collapse. Especially, a side ditch caver which has installed a load suffers complex deterioration by freeze-thaw repetition and salt damage by a lot of deicing salt. In this study, produced a ditch caver by using permeable form method, and performed surface layer strength test, freeze-thaw test and scaling test. The permeable form method drains excess water and air bubbles at concrete, and makes the concrete surface dense. The result of those test, increased the surface layer strength, frost damage resistance and scaling resistance. Therefore, permeable form method is effective to produce the highly durable concrete and can use for a long time.