基于海水海砂混凝土真实孔溶液浸泡环境下BFRP筋拉伸性能的退化  

Tensile Properties Deterioration of BFRP Bars in Real Seawater Sea-sand Concrete Pore Solution Immersion Environment

作　　者：朱德举 初开丹[1] 郭帅成 史才军 ZHU Deju;CHU Kaidan;GUO Shuaicheng;SHI Caijun(Key Laboratory for Green&Advanced Civil Engineering Materials and Application Technology of Hunan Province,College of Civil Engineering,Hunan University,Changsha 410082,China;International Science Innovation Collaboration Base for Green&Advanced Civil Engineering Materials of Hunan Province,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,绿色先进土木工程材料及应用技术湖南省重点实验室,长沙410082 [2]湖南大学湖南省绿色先进土木工程材料国际科技创新合作基地,长沙410082

出　　处：《材料导报》2024年第11期136-143,共8页Materials Reports

基　　金：国家自然科学基金山东联合基金项目(U1806225);国家自然科学基金(52208246);长沙市自然科学基金(kq2202160)。

摘　　要：为探究玄武岩纤维增强复合材料(BFRP)筋在海水海砂混凝土环境中的长期力学性能,本工作研究了BFRP筋拉伸性能在海水海砂混凝土真实孔溶液浸泡环境下的演化规律。通过孔溶液压取和离子浓度分析,分别配制了普通海水净浆孔溶液(NA)和低碱度海水净浆孔溶液(LA)的浸泡溶液,同时在加速老化试验中与ACI 440.3R规范建议浸泡溶液(ACI)的测试结果进行了对比。试验所用筋材基体包括环氧树脂基(B/E筋)和乙烯基酯树脂基(B/V筋)两种。在不同温度和浸泡时间加速老化后,通过拉伸试验评估了BFRP筋的拉伸性能变化规律,并采用微观结构表征分析了劣化机理。试验结果表明,相较于降低氯离子浓度,采用降低孔溶液碱度的方法可以更有效地缓解BFRP筋长期力学性能的劣化,同时温度升高对B/V筋力学性能退化的影响比对B/E筋的影响更显著。BFRP筋在腐蚀过程中抗拉强度的劣化程度高于弹性模量,其中B/E筋在三种环境中腐蚀前后的弹性模量差别不大。乙烯基树脂的抗腐蚀能力优于环氧树脂,但其与玄武岩纤维界面性能较弱,导致B/V筋在模拟海水海砂混凝土孔溶液中的耐久性弱于B/E筋。In order to study the long-term mechanical properties of basalt fiber reinforced polymer (BFRP) bars in seawater sea-sand concrete (SSC) environment, this paper investigates the evolution of BFRP bar tensile properties immersed in real SSC pore solution environment. Soaking solutions based on normal seawater cement slurry pore solution (NA) and low alkalinity seawater cement slurry pore solution (LA) were prepared by pore solution extrusion and ion concentration analysis, and the test results were also compared with those in ACI 440.3R specification recommended soaking solution (ACI) through accelerated aging. The BFRP bars prepared with epoxy resin (B/E bars) and vinyl ester resin (B/V bars) were utilized in the tests. The change of tensile mechanical property of BFRP bars was evaluated by tensile tests after accelerated aging at different temperatures and immersion durations, and the degradation mechanism was analyzed by using microstructural characterization. The test results showed that reducing the alkalinity of the pore solution was more effectively than reducing the chloride ion concentration for delaying the degradation of long-term mechanical property of BFRP bars, and the effect of increasing temperature on the mechanical property degradation of B/V bars was more significant than that of B/E bars. The tensile strength degradation of BFRP bars during aging process was higher than their elastic modulus. Meanwhile the difference in elastic modulus of B/E bars before and after accelerated aging in the three environments was not significant. The corrosion resistance of vinyl resin was better than that of epoxy resin, but its weaker interfacial properties with basalt fibers resulted in worse durability of B/V bars than that of B/E bars in the simulated SSC pore solution.

关 键 词：BFRP筋 海水海砂混凝土 孔溶液 拉伸性能 微观结构 

分 类 号：TB332[一般工业技术—材料科学与工程]