工作裂缝对GFRP筋混凝土梁粘结耐久性的影响  

Bond durability of glass fiber-reinforced polymer bars embedded concrete beams with work crack

作　　者：杨文瑞[1] 何雄君[1] 代力[1] YANG Wen-rui HE Xiong-jun DAI Li(School of Transportation, Wuhan University of Technology, Wuhan 430063, Hubei, Chin)

机构地区：[1]武汉理工大学交通学院,湖北武汉430063

出　　处：《长安大学学报（自然科学版）》2016年第5期52-59,共8页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51178361)

摘　　要：为了提供更准确的关于GFRP筋混凝土梁长期粘结耐久性影响规律的试验数据及设计理论指导,基于实际混凝土梁带工作裂缝持续受载的工作状态,通过对带工作裂缝GFRP筋混凝土梁加速老化后进行三点偏载试验,研究分析了工作裂缝对GFRP筋混凝土梁受室外环境、水溶液、60℃的碱性溶液等3种不同环境侵蚀90、180、270d后的粘结耐久性影响,并提出关于不同滑移量计算粘结应力的理论计算方法;还依据试验数据及计算理论确定了环境作用270d后各工况下的最大粘结应力。研究结果表明:带工作裂缝GFRP筋混凝土梁在碱性环境作用270d后,滑移荷载损失高达38.5%,挠度值增加46.3%,最大粘结应力损失高达59.4%;未带工作裂缝GFRP筋混凝土梁在任何侵蚀环境条件下,其滑移荷载及挠度值变化比例均小于带工作裂缝的GFRP筋混凝土梁;最大粘结应力值均大于带工作裂缝GFRP筋混凝土梁,且损失比例均小于带工作裂缝的GFRP筋混凝土梁;室外环境、水溶液、碱性溶液这3种环境中,碱性溶液对GFRP筋混凝土梁的粘结耐久性能影响最为明显,且工作裂缝较大程度地加大了各种环境对GFRP筋混凝土梁粘结性能的劣化影响。To provide the more accurate experimental data and theory to guide the design of GFRP reinforced concrete beams for the long-term bond durability, based on the sustained load working state of the actual concrete beam with work crack, experimental and analytical investigations of bond performance of glass fiber-reinforced polymer （GFRP） bars embedded in concrete beams with crack was presented. Beams were conditioned with sustained flexural loads in outdoor, tap water and 60℃ alkaline solution for 90, 180, 270 d, after which they were subjected to eccentric three-point flexure tests to evaluate bond performance, a theory calculation method of bond stress with different slip values was proposed, and the maximum bond stresses under various conditionsafter 270 d were determined according to the test data and theoretical calculation. The results show that the slip load loss, deflection values and the maximum bond stress reach to 38.5% and 59.4% respectively, and the deflection values increase 46.3% when beams are conditioned with alkaline environment for 270 d. The changing range of slip loads and deflection values of GFRP reinforced concrete beams without work crack is less than that of beams with work crack under any erosion environment condition. The maximum bond stress for GFRP reinforced concrete beams without work crack is bigger than that of beams with work crack, and the loss ratio is less than beams with work crack. Among the three environments, alkaline environment can obviously deteriorate the bond performance of GFRP reinforced concrete beam, and the environmental impact is largely intensified by work crack on the bond performance of GFRP reinforced concrete beams in the worse way.

关 键 词：结构工程 GFRP筋 混凝土梁 耐久性 粘结性能 工作裂缝 

分 类 号：TU528[建筑科学—建筑技术科学]