冷却方式及静置时间对高温后HFCC抗压强度影响  

Effect of cooling method and standing time on the HFCC compressive strength after high temperature

作　　者：贾福萍 张鑫 侯昕明 郭鹏 杨柯红 JIA Fuping;ZHANG Xin;HOU Xinming;GUO Peng;YANG Kehong(School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China;Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering,Xuzhou 221116,China;School of Engineering,Zhengzhou Technology and Business University,Zhengzhou 451400,China)

机构地区：[1]中国矿业大学力学与土木工程学院,江苏徐州221116 [2]江苏省土木工程环境灾变与结构可靠性重点实验室,江苏徐州221116 [3]郑州工商学院工学院,河南郑州451400

出　　处：《混凝土》2022年第3期10-13,19,共5页Concrete

基　　金：国家青年自然科学基金(51408594);中央高校基本科研业务费专项资金资助(2011QNB20)。

摘　　要：标准养护的大掺量粉煤灰混凝土(High Fly-ash Content Concrete,简称HFCC)试块,经历250、450、650℃及自然冷却或喷淋冷却后,于不同静置时间(1、3、7、14、28、56 d)进行抗压强度测试,以研究高温后HFCC抗压强度随冷却方式与静置时间的变化规律。结果表明:250、450℃后,采用不同冷却方式试块的抗压强度相较于常温情况下均有不同程度降低,且随静置时间趋于稳定;650℃后,采取自然冷却的HFCC其抗压强度会大幅降低,且在静置期间难以恢复,但采取喷淋冷却的HFCC在静置期间其抗压强度却有很强的“自我修复能力”。同时,通过XRD与SEM分别研究了HFCC常温与高温静置1 d后的物相组成和形貌特征变化,从微观层面对高温前后HFCC的抗压强度变化作出解释。Standard cured high fly-ash content concrete(HFCC),after being exposed to the high temperature of 250,450,650℃and natural cooling or spray cooling,were accepted in this study to investigate the compressive strength of the HFCC.Meanwhile,different standing time(1,3,7,14,28,56 d)were taken into consideration on the compressive strength.The test results demonstrated that the compressive strength of the specimens suffered from 250℃and 450℃through different cooling methods decreased to some extent,and tend to be stable with the extension of standing time,in comparison to that of specimens in normal condition.After the exposure of 650℃and then being experienced natural cooling,the compressive strength of the HFCC decreased significantly and was difficult to recover with the standing time increases.The compressive strength of the HFCC after spray cooling under the same case compared to natural cooling,however,possesssed a strong“self-repairing ability”during the standing time.Simultaneously,from the microscopical perspective,the XRD and SEM techniques,respectively,were used to better present the phase composition and morphology characteristics of specimens exposed to normal and high temperature after standing time of 1 d.

关 键 词：粉煤灰混凝土 抗压强度比 温度 自然冷却 喷淋冷却 静置时间 

分 类 号：TU528.01[建筑科学—建筑技术科学]