自然潮差环境下粉煤灰混凝土微观结构的时变过程  

Time dependent microstructure evolution of fly ash concrete in the natural tidal environment

作　　者：张俊芝[1,2] 方润华 吕萌 章玉容 曹应晖 高延红 ZHANG Junzhi;FANG Runhua;LV Meng;ZHANG Yurong;CAO Yinghui;GAO Yanhong(College of Civil Engineering and Architecture,Zhejiang University of Technology,Hangzhou 310014,China;Key Laboratory of Civil Engineering Structure&Disaster Prevention and Mitigation Technology of Zhejiang Province,Hangzhou 310014,China)

机构地区：[1]浙江工业大学建筑工程学院,浙江杭州310014 [2]浙江省工程结构与防灾减灾技术研究重点实验室,浙江杭州310014

出　　处：《自然灾害学报》2019年第5期9-16,共8页Journal of Natural Disasters

基　　金：国家自然科学基金项目(51279181);浙江省自然科学基金项目(LY19E090006,LQ18G010007,LY17E090007)~~

摘　　要：基于自然潮差环境下在较长时间的暴露试验,获得了混凝土中自由氯离子浓度,并用压汞法测定了不同暴露时间后的不同掺量粉煤灰混凝土的微观结构参数;分析了粉煤灰掺量对混凝土孔隙率、孔径分布及其时变性和自由氯离子浓度的影响;在此基础上,探讨了粉煤灰混凝土中的孔径占比和孔隙率等微观结构参数与其自由氯离子浓度的时变关系。结果表明:粉煤灰可以有效的减少混凝土孔隙率,改善了其孔径分布,增加了10 nm^100 nm的孔径占比,降低了100 nm^1000 nm的孔径占比;随着暴露时间的延长,混凝土中100 nm^1000 nm和1000 nm以上孔径的贡献孔隙率逐渐降低,但对于10 nm以下的贡献孔隙率没有明显的影响;同一暴露时间后,混凝土氯离子峰值浓度随着粉煤灰掺量的增加而逐渐降低,且在暴露后期,粉煤灰对混凝土中自由氯离子浓度分布的影响更加显著。Based on a long-term exposure test in the natural tidal environment,the free chloride concentration in concrete were obtained,and the microstructural parameters of fly ash concrete at different exposure times were measured by the mercury intrusion porosimetry(MIP)method.According to the measured results,the effect of fly ash content on the time-varying porosity,pore size distribution and free chloride ion concentration of concrete has been discussed.Besides,the time-varying relationship between the proportion of different pore diameters as well as porosity and free chloride ion concentration of fly ash concrete was explored.The results show that the fly ash can effectively reduce the porosity of concrete,improve its pore size distribution,increase the proportion of pores size within range of 10 nm^100 nm and reduce the proportion of pores size from 100 nm to 1000 nm.The contributive porosities of pore size from 100 nm to 1000 nm and above 1000 nm decreases gradually with exposure time.However,exposure time has no significant effect on the contributive porosity below 10 nm.After the same exposure time,the peak concentration of chloride ion in concrete gradually decreases with the increasing fly ash content.In addition,the effect of fly ash on the distribution of free chloride concentration in concrete is more significant in the later exposure stage.

关 键 词：粉煤灰 混凝土 潮差环境 氯离子 微观结构参数 

分 类 号：TU528[建筑科学—建筑技术科学] X9[环境科学与工程—安全科学]