复合盐侵蚀环境下聚丙烯纤维混凝土耐久性研究  

Study on durability of polypropylene fiber reinforced concrete under compound salt erosion environment

作　　者：冯晨潞 夏冬桃 李欣怡 FENG Chenlu;XIA Dongtao;LI Xinyi(College of Civil Engineering and Environment,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]湖北工业大学土木建筑与环境学院,湖北武汉430068

出　　处：《混凝土》2023年第12期16-20,共5页Concrete

基　　金：国家自然科学基金(51108164)。

摘　　要：为研究聚丙烯纤维混凝土在复合盐溶液长期侵蚀作用下的耐久性,通过对5组在Na_(2)SO_(4)(5%)、NaCl(0、5%、10%、15%)复合溶液中浸泡不同周期(0 d、30 d、90 d、150 d、210 d、270 d)的聚丙烯纤维混凝土进行动弹性模量测量试验、抗压试验及SEM电镜观察,对比分析聚丙烯纤维混凝土在不同氯离子浓度及不同浸泡周期下的相对动弹性模量评价参数、抗压耐腐蚀系数及微观结构。对相关评价参数进行拟合回归分析从而预测混凝土耐久性寿命,依据抗压耐腐蚀系数建立聚丙烯纤维混凝土的劣化损伤模型。试验结果表明:当复合盐溶液中氯离子浓度为10%时,浸泡210 d的聚丙烯纤维混凝土抗压耐腐蚀系数达到最高值50.01%,聚丙烯纤维在一定程度上增强了混凝土抗盐蚀能力。通过SEM电镜观察复合盐溶液浸泡270 d后的普通混凝土和聚丙烯纤维混凝土微观结构,从微观角度进一步分析印证了宏观抗压耐腐蚀系数变化的原因,并分析了复合盐对混凝土的侵蚀机理及聚丙烯纤维对混凝土的增强机理。In order to study the durability of polypropylene fiber concrete under the long-term erosion of composite salt solutions,five groups of polypropylene fiber concrete immersed in Na_(2)SO_(4)(5%),NaCl(0,5%,10%,15%)composite solutions for different cycles(0 d,30 d,90 d,150 d,210 d,270 d)were subjected to dynamic.The relative dynamic modulus of elasticity,compressive resistance and microstructure of the polypropylene fiber concrete were compared and analyzed at different chloride ion concentrations and different soaking periods.A regression analysis was carried out to predict the durability life of the concrete,and a deterioration damage model for polypropylene fiber concrete was developed based on the compressive and corrosion resistance coefficients.The test results show that the highest value of 50.01%of the compressive corrosion resistance coefficient of polypropylene fiber concrete soaked for 210 d was achieved when the chloride ion concentration in the composite salt solution was 10%,and the polypropylene fiber enhanced the salt corrosion resistance of the concrete to a certain extent.The microstructure of plain concrete and polypropylene fiber concrete after 270 d of immersion in the compound salt solution was observed by SEM electron microscopy,and the reasons for the change in the macroscopic compressive corrosion resistance coefficient were further analyzed from a microscopic point of view,and the erosion mechanism of the compound salt on the concrete and the strengthening mechanism of the polypropylene fiber on the concrete were analyzed.

关 键 词：聚丙烯纤维混凝土 氯盐 硫酸盐 SEM 

分 类 号：TU528.572[建筑科学—建筑技术科学]