中文摘要：

通过试验研究了混凝土经历不同高温作用后的抗冻性能,并探讨了高温对混凝土冻融破坏的影响机理.研究结果表明：随温度升高,混凝土中的凝胶体不断分解,孔隙结构不断破坏,使得遭受高温后混凝土抗冻性能降低;未受高温作用混凝土的抗冻等级远高于F150,经历300℃高温混凝土的抗冻等级略高于F150,分别经历600℃和800℃高温混凝土的抗冻等级均低于F50.

英文摘要：

The resistance performances to freezing-thawing of concrete after different high temperatures were tested,and the effect mechanisms of high temperature on freezing-thawing failure of concrete were discussed.With the increase of the temperature,the gel in concrete was decomposed and the pore structure was destroyed gradually,which made the resistance performance to freezing-thawing of concrete after high temperature was obviously decreased.The resistance class to freezing-thawing of concrete in normal temperature was far higher than F150,and the resistance class to freezing-thawing of concrete after 300 ℃ was a little higher than F150.But the resistance class to freezing-thawing of concrete after 600 ℃ and 800 ℃ were all both less than F5O.