非均匀碱-硅酸反应下RC梁长期膨胀特征研究  

Long-term expansion characteristics of reinforced concrete beams under non-uniform alkali-silica reaction

作　　者：李鹏飞[1] 刘微 蒋正施 LI Pengfei;LIU Wei;JIANG Zhengshi(College of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Yongchuan Water Conservanvy Bureau of Chongqing City,Chengqing 402160,China;Planning and Research Institute,China Railway Changjiang Traffic Design Group Co.,Ltd.,Chongqing,400074,China)

机构地区：[1]重庆交通大学河海学院,重庆400074 [2]重庆市永川区水利局,重庆402160 [3]中铁长江交通设计集团有限公司规划研究院,重庆400074

出　　处：《人民长江》2023年第10期203-208,220,共7页Yangtze River

基　　金：重庆市自然科学基金项目(cstb 2022 nscq-msx 0509);重庆市研究生科研创新项目(CYS22407)。

摘　　要：碱-硅酸反应(ASR)能够产生膨胀应力,引起混凝土膨胀、开裂甚至破坏,而钢筋会对碱-硅酸反应引起的膨胀产生抑制作用,但目前仅用材料试验无法对钢筋的约束作用进行评估。围绕钢筋的约束作用,以钢筋混凝土(RC)梁为研究对象,采用加速ASR反应试验,研究了34个月内不同碱溶液浸泡区域和深度下RC梁的膨胀特性。进一步分析了钢筋对混凝土碱-硅酸反应膨胀的约束机理。结果表明:当浸泡位置和浸泡深度不同时,RC梁结构表现出不同的膨胀特征,直接浸入碱溶液的部位膨胀率较大,钢筋周围的膨胀率明显降低。钢筋能够对膨胀产生直接和间接两种约束作用。研究成果可为ASR反应损伤后钢筋混凝土的结构力学性能评估提供参考。Alkali-silica reaction(ASR)can produce expansion stress,causing concrete expansion,cracking and even damage,while steel bars can inhibit the expansion caused by ASR reaction.However,at present single material tests cannot evaluate the restraint effect of steel bars.Based on the restraint effect of steel bars,the expansion characteristics of reinforced concrete(RC)beams under different alkali solution immersion areas and immersion depths within 34 months were studied by an accelerated ASR reaction experiment.The results showed that when the immersion position and immersion depth were different,the RC beam structure exhibited different expansion characteristics.The expansion rate of the part directly immersed in the alkali solution was larger,and the expansion rate around the steel bar was significantly reduced.Furthermore,the constraint mechanism of steel bars on the expansion of concrete ASR reaction was analyzed.The results showed that steel bars can produce direct and indirect constraints on expansion.The research results can provide reference for the evaluation of structural mechanical properties of reinforced concrete after ASR reaction damage.

关 键 词：膨胀特征 RC梁 约束机制 长期监测试验 ASR反应 

分 类 号：TU375[建筑科学—结构工程]