冻融循环对混凝土酸雨侵蚀损伤进程的影响

Acid Rain Attack Damage Progress of Concrete in Freezing-thawing Environment

基于混凝土相对表面弹性模量和相对动弹性模量损伤退化曲线的测定,研究了冻融循环对混凝土酸雨侵蚀损伤进程的影响。结果表明:冻融循环使得混凝土在酸雨腐蚀初期的性能上升阶段缩短,提前进入损伤下降阶段,同时使得酸雨对混凝土的损伤速率增大,且随着冻融循环次数和酸雨酸度的增大而不断增大。微观测试分析表明冻融循环加快酸雨对混凝土的损伤进程主要是源于冻融循环引发的冻胀应力可加快混凝土表面腐蚀产物的脱落以及内部新裂缝的产生,并促使已有微裂缝扩展以至贯通,从而为酸雨侵蚀介质的进一步侵入提供快速通道。

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 freezingthawing 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.