受冻融作用钢筋混凝土电化学除氯模型研究  

Study on electrochemical chloride extraction model of reinforced concrete subjected to freezing and thawing effects

作　　者：胡松 屈锋[1] 程火焰[1] 陈峰 石卫华[1] 王功勋[1] 金浩 HU Song;QU Feng;CHENG Huoyan;CHEN Feng;SHI Weihua;WANG Gongxun;JIN Hao(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]湖南科技大学土木工程学院,湖南湘潭411201

出　　处：《自然灾害学报》2024年第5期218-225,共8页Journal of Natural Disasters

基　　金：国家自然科学基金项目(51678234,51808213);湖南省教育厅科研项目(18C0324,19A164,20B214);湖南省自然科学基金项目(2019JJ50185)。

摘　　要：氯盐侵蚀与冻融循环作用下,钢筋混凝土结构遭受严重的耐久性损伤。电化学除氯能有效解决氯盐侵蚀产生的钢筋锈蚀问题,但在盐冻地区其除氯机理受混凝土冻融损伤的影响。对内掺氯盐的冻融损伤混凝土开展电化学除氯试验,基于相对动弹性模量建立混凝土冻融损伤度,研究冻融循环作用后钢筋混凝土电化学除氯机理,建立冻融损伤混凝土电化学除氯效率评价模型。研究结果表明,相较于普通混凝土,冻融环境下粉煤灰混凝土冻融损伤度更大,平均除氯效率更低。随冻融次数和粉煤灰掺量增加,混凝土冻融损伤度增大。随冻融损伤度和除氯时间的增加,混凝土平均除氯效率增加。冻融损伤混凝土平均除氯效率相较于未遭受冻融损伤混凝土,达到钝化目标所需时间更短。基于混凝土损伤度建立了冻融损伤混凝土电化学除氯模型,试验值与模型拟合良好。Reinforced concrete structures suffer severe durability damage due to chloride salt attack and freeze-thaw cycles.Electrochemical chloride extraction can effectively solve the problem of corrosion of reinforcing steel produced by chlorine salt erosion,but its electrochemical chloride extraction mechanism was affected by freeze-thaw damage to concrete in salt-frozen areas.The electrochemical chloride extraction test was carried out on the freeze-thaw damaged concrete mixed with chlorine salt to establish the degree of freeze-thaw damage of concrete based on the relative dynamic elastic modulus,to study the mechanism of electrochemical chloride extraction of reinforced concrete after freeze-thaw cycling,and to establish a model for evaluating the efficiency of electrochemical chloride extraction of freeze-thaw damaged concrete.The results show that fly ash concrete has greater freeze-thaw damage and lower average electrochemical chloride extraction efficiency in the freeze-thaw environment compared to ordinary concrete.Concrete freeze-thaw damage increased with the number of freezes and thaws and with the amount of fly ash added,and the average concrete electrochemical chloride extraction efficiency increased with the increase of freeze-thaw damage and time.The average chlorine extraction efficiency of concrete with freeze-thaw damage is shorter than that of concrete without freeze-thaw damage,and the time required to achieve the passivation target is shorter.A model for electrochemical chlorine extraction of freeze-thaw damaged concrete was developed based on the degree of concrete damage,and the experimental values fitted well with the model.

关 键 词：钢筋混凝土 氯盐侵蚀 粉煤灰 冻融循环 电化学除氯 

分 类 号：TU528[建筑科学—建筑技术科学]