复材加固受损混凝土梁的干湿循环耐久性能研究  

STUDY OF DURABILITY OF DAMAGED REINFORCED CONCRETE BEAMS STRENGTHENED WITH COMPOSITE MATERIALS SUBJECTED TO WET-DRY CYCLES

作　　者：谢燕[1] 邓军[1] 王琪琛 

机构地区：[1]广东工业大学土木与交通工程学院,广州510006

出　　处：《工业建筑》2016年第6期166-169,共4页Industrial Construction

基　　金：新世纪优秀人才支持计划项目(NCET-13-0739);国家自然科学基金项目(51278131);霍英东教育基金会项目(131073);广东省教育厅科研项目(2012LYM_0056)

摘　　要：纤维复材的加固技术正越来越多地被用来修复受损钢筋混凝土(RC)桥梁。而在南方湿热环境下,胶黏剂的性能退化及氯离子对RC梁的侵蚀作用,将对被修复桥梁的耐久性产生不利影响。为此对干湿循环下碳纤维布加固受损RC梁的抗弯承载力及氯离子的扩散情况进行研究。干湿循环加速老化试验包括3个月和6个月两种工况,一次干湿循环为24 h,包括湿环境(3.5%盐水浸泡)10 h和干环境(40℃热风)14 h。试验结果表明:干湿循环略为减小了加固梁的刚度,导致了混凝土与碳纤维布黏结界面的退化;干湿循环前3个月,加固梁的承载能力有明显降低,而后逐步稳定;受损RC梁裂缝附近的氯离子含量远高于其他部分;碳纤维布加固减缓了氯离子由梁底对RC梁的侵蚀,对带裂缝工作的受损梁有较好的保护作用。Fiber reinforced polymer materials are increasingly being used to repair the damaged reinforced concrete（ RC） bridges. The degradation of adhesive bonding in a wet-dry environment,however,may have an adverse effect on the long term durability of the repaired bridges. This paper presented an experimental study on the flexural capacity and diffusion of chlorions of damaged RC T-beams strengthened with carbon fiber sheets subjected to the wetdry cycles. The specimens subjected to wet-dry environment were exposed to a period of 3 months or 6 months. A wet-dry cycle was 24 h including a wet cycle（ salt water） of 10 h and a dry cycle（ hot air at 40 ℃） of 14 h. The experimental results showed that a slight reduction in stiffness was observed for the strengthened beams due to wet-dry exposure. The wet-dry cycles induced degradation to bond at the concrete carbon fiber sheets interface. Only in the first 3 months,however,the wet-dry environmental exposure could obviously reduce the strength of the retrofitted beams. The content of chlorions near the cracks of damaged RC beam was much higher than other sections. Carbon fiber sheets reinforcement could slow down the diffusion of chlorions that caused steel corrosion,which provided a protective effect for the damaged RC beams.

关 键 词：干湿循环 碳纤维布加固 RC梁 抗弯承载力 氯离子分布 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]