不同养护条件对火灾后混凝土抗压性能的影响  

Effect of curing condition on compressive properties of concrete subjected to fire

作　　者：韦宇硕[1] 胡昱[1] 李庆斌[1] 

机构地区：[1]清华大学水利水电工程系水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《混凝土》2010年第11期10-12,15,共4页Concrete

基　　金：国家"十一五"规划科技支撑项目(2008BAB29B05);清华大学水沙科学与水利水电工程国家重点实验室自主研究课题(2008-TC-2);清华大学骨干人才支持计划

摘　　要：对强度等级为C40掺粉煤灰和C70掺硅灰的两种混凝土进行了模拟火灾的一定时间的高温加热,研究了两种混凝土在高温后不同养护条件下84 d内的强度变化和微观结构的变化。结果表明:C40混凝土高温后强度提高,在养护一段时间后强度会持续下降,之后强度又出现回升,基本上能到达到为加热前的强度水平;C70混凝土高温后强度下降,在养护后强度持续的升高,最后能达到加热前强度的90%以上。外部水进入混凝土内部的速率对混凝土的强度变化有重要的影响,特别是对C40混凝土强度下降的速率以及最低强度影响显著。The strength of normal and high strength concrete which were cured in different ways in 84 days after elevated up to 800 ℃ were tested.The result shows that the strength of C40 containing fly ash was developed after elevated to high temperature,but it would reduce after curing a few days,and then it would develop again untill achive the strength before fire.The strength of C80 containing silica fume was reduced after fire,but it kept developing in days of different ways of curing,and the stength after 84 days curing was about 90% of the strength before fire.The water which permeated into concrete significantly influenced the developing of the strength.Especially when water permeated into the concrete rapidly,the strength of C40 reduces quickly and the minimum value of the strength is low.

关 键 词：混凝土 火灾后 强度 养护 微观 

分 类 号：TU528.064[建筑科学—建筑技术科学]