早期受盐-冻耦合作用下掺玄武岩纤维混凝土耐久性劣化规律  

Durability Deterioration Law of Basalt Fiber Concrete under Early Salt-Freezing Coupling Effect

作　　者：徐存东 李博飞 李准 王海若 曹骏 徐慧 XU Cundong;LI Bofei;LI Zhun;WANG Hairuo;CAO Jun;XU Hui(School of Water Conservancy,North China University of Water Resources and Electric Hydropower,Zhengzhou 450046,China;Key Laboratory for Technology in Rural Water Management of Zhejiang Province,Hangzhou 310018,China;Henan Provincal Hydraulic Structure Safety Engineering Research Center,Zhengzhou 450046,China)

机构地区：[1]华北水利水电大学水利学院,郑州450046 [2]浙江省农村水利水电资源配置与调控关键技术重点试验室,杭州310018 [3]河南省水工结构安全工程技术研究中心,郑州450046

出　　处：《硅酸盐通报》2024年第3期816-824,共9页Bulletin of the Chinese Ceramic Society

基　　金：宁夏回族自治区水利科技项目(GKGX-KY-01);甘肃省水利科技计划项目(22GSLK019)。

摘　　要：针对西北寒旱区早期受冻混凝土在盐-冻耦合作用下耐久性快速降低等问题,本文基于室内快速冻融试验,以3.5%(质量分数,下同)NaCl+5.0%Na_(2)SO_(4)复合盐溶液为冻融介质,研究了不同玄武岩纤维体积掺量下混凝土的耐久性劣化规律,同时采用扫描电子显微镜、超声法缺陷检测和核磁共振孔径检测三种分析手段探究了玄武岩纤维在微观层面上对早期受盐-冻耦合作用下混凝土宏观性能的改善作用。研究结果表明:在早期受冻混凝土中掺加玄武岩纤维能够有效提高抗压强度,减小质量损失;随着纤维掺量的增加,抗压强度、相对动弹性模量呈先增加后降低的趋势;随着冻融循环次数的增加,不同体积掺量玄武岩纤维早期受冻混凝土试块的超声脉冲传播速度逐渐增大,各组试块的总孔隙率与冻融次数呈正相关,且掺加玄武岩纤维能增加无害孔,减少多害孔,从而提高混凝土抗冻耐久性;试验中纤维掺量为0.15%(体积分数)的试块表现最优越。该研究可为寒旱灌区早期受冻混凝土耐久性研究及后期维护提供参考。To address the problem of rapid durability degradation of early freezing plain concrete in the cold and arid regions of northwest China under the action of salt-freezing coupling effect,based on the indoor rapid freezing and thawing test,the durability deterioration law of concrete with different volume content of basalt fibers was studied using a 3.5%(mass fraction,the same below)NaCl+5.0%Na_(2)SO_(4)composite salt solution as a freeze-thaw medium,and scanning electron microscope,ultrasonic defect detection and nuclear magnetic resonance pore size detection were applied to explore the improvement effect of basalt fibers on the macroscopic properties of concrete under the salt-freezing coupling effect at the micro level.The results show that the addition of basalt fibers in the early freezing plain concrete can effectively improve the compressive strength and reduce the mass loss.With the increase of fiber content,the compressive strength and relative dynamic elastic modulus increase first and then decrease.With the increase of freeze-thaw cycle time,the ultrasonic pulse propagation velocity of different volume content of basalt fibers in the early freezing plain concrete gradually increases,and the total porosity of each group specimens is positively correlated with the freeze-thaw cycle time,and the addition of basalt fibers increases the proportion of harmless pores,reduces the proportion of multi-harmful pores,and improves the durability resistance of concrete.In the tests,the fiber of 0.15%(volume fraction)group of test blocks has the most superior performance among all of test blocks.The research results can provide a reference for the study of durability of early freezing plain concrete in cold and arid irrigation areas and later maintenance.

关 键 词：早期受冻 冻融循环 掺玄武岩纤维混凝土 纤维掺量 耐久性 孔隙率 

分 类 号：TV431.3[水利工程—水工结构工程]