摘要
将聚丙烯纤维(PP纤维)以不同体积掺量(0、0.1%、0.2%、0.3%)掺入混凝土中,以纤维掺量、复合盐溶液浓度、干湿循环次数为变量,开展PP纤维混凝土试件在不同浓度复合盐溶液(MgSO_(4)+NaCl)浸泡与烘干耦合作用下的宏-微观腐蚀劣化试验,探究PP纤维混凝土在新疆南疆盐渍土环境下的抗腐蚀性能变化规律。结果表明:(1)PP纤维在混凝土内部的“桥接”作用延缓了试件表面砂浆层的剥蚀速率,抑制了试件表层及内部微裂缝的产生与扩展,减少了有害孔隙的生成数量。(2)PP纤维的掺入提高了混凝土抵抗复合盐侵蚀的能力,随着复合盐溶液浓度的增大,纤维掺量为0.2%试件的相对动弹性模量波动幅度和质量损失率均比其他掺量试件的小,其宏观耐久性能表现最好。(3)复合盐溶液侵蚀下,PP纤维混凝土发生物理结晶腐蚀和化学腐蚀破坏,膨胀性腐蚀产物主要是钙矾石(AFt)和石膏,合理掺量的PP纤维减小了腐蚀产物的生成空间,减轻了混凝土的腐蚀劣化程度,这与试件宏观耐久性能评价指标的变化规律一致。研究成果可为PP纤维混凝土在南疆盐渍土地区实际工程中的应用提供参考依据。
The polypropylene(PP)fiber were added to concrete with different volume content(0,0.1%,0.2%,0.3%).To explore the corrosion resistance of PP fiber concrete in the saline soil environment of southern Xinjiang,the macro-micro corrosion degradation tests of PP fiber concrete were carried out under the linked reaction of the composite salt solution(MgSO_(4)+NaCl)with different concentrations drying-wetting cycle,while taking the fiber content,the compound salt solution concentration and the drying-wetting cycle number as variable.The results show that(1)The bridging effect of PP fiber in concrete delayed the denudation rate of the mortar layer on the specimen surface,inhibited the generation and expansion of micro-cracks on the specimen surface and inside,and reduced the formation of harmful pores.(2)The addition of PP fiber improves the resistance of concrete to compound salt erosion.With the increase of compound salt solution concentration,the fluctuation range of the relative dynamic elastic modulus and the mass loss rate of the specimen with the fiber content of 0.2%are smaller than those of other samples,so the macroscopic durability performance is the best.(3)Under the erosion of compound salt solution,physical crystallization corrosion and chemical corrosion damage occurred in PP fiber concrete,and the main expansive corrosion products were ettringite(AFt)and gypsum.Reasonable PP fiber content can reduce the generation space of corrosion products and the concrete corrosion degradation degree,which is consistent with the rule of the evaluation index of the macroscopic durability of specimens.The research results could provide references for the practical engineering application of PP fiber concrete in the saline soil environment of southern Xinjiang.
作者
王成
李桢怡
葛广华
李曦彤
戎泽斌
薛山
WANG Cheng;LI Zhenyi;GE Guanghua;LI Xitong;RONG Zebin;XUE Shan(College of Water Resources and Architectural Engineering,Tarim University,Alar 843300,China;South Xinjiang Geotechnical Engineering Research Center,Tarim University,Alar 843300,China)
出处
《混凝土》
CAS
北大核心
2023年第4期29-35,39,共8页
Concrete
基金
国家自然科学基金(52168035)
新疆生产建设兵团区域创新引导计划项目(2018BB045)
新疆生产建设兵团重点领域科技攻关计划项目(2019AB016)。
关键词
聚丙烯纤维混凝土
复合盐溶液
干湿循环
耐久性能
微观特征
polypropylene fiber concrete
composite salt solution
drying-wetting cycle
durability performance
microscopic feature
