关键词: 混凝土;酸雨侵蚀;冻融循环;损伤进程;微观机理

Abstract: Based on measuring the damage deterioration curves of the relative surface elastic modulus and relative dynamic elastic modulus of concretes, the influence of freezing-thawing cycles on the damage progress of concretes to acid rain attack were investigated.The results show that freezing-thawing cycles shorten the performance of concrete at the initial stage of acid rain corrosion so that it advanced into the damage reduction stage, and accelerate the damage progress of acid rain attack on concretes.And the damage rate of acid rain to concrete increases with the increases of freezing-thawing cycles and acid rain acidity.Microscopic studies demonstrate that this is due to that the frost heave stress caused by freezing-thawing cycles can accelerate acid rain corrosion products to quickly fall away from concrete surface and increase new internal cracks of concretes, and prompts the expansion of the existing micro cracks until link up, so that provides fast channel for acid rain erosion media into concretes.

Key words: concrete;acid rain attack;freezing-thawing cycle;damage progress;microscopic mechanism