基于拉曼光谱实时检测的碳化钢筋混凝土再碱化机理探究

Mechanism Investigations of Realkalization for Carbonated Reinforced Concrete Based on Real Time Raman Spectroscopy Analysis

为了从本质上解释再碱化技术对碳化钢筋混凝土的修复机理,通过1个隔绝外界空气和电解质溶液的模拟混凝土/钢筋界面,利用拉曼光谱技术实现了对碳化钢筋混凝土再碱化修复过程中腐蚀产物成分变化的实时检测.结果表明:经过强加电流式人工加速腐蚀钢筋后,腐蚀产物主要成分为绿锈.在再碱化修复过程中,2个反应同时发生:绿锈被还原为氢氧化亚铁(Fe(OH)_2),并转变为四氧化三铁(Fe_3O_4).酚酞显色试验结果和Fe_3O_4的生成证明了再碱化技术能够有效提高混凝土的碱性.电化学检测结果进一步证明了再碱化技术可以有效减小钢筋的腐蚀概率,降低钢筋的腐蚀活性并使之达到中等程度,但是并没有使钢筋再钝化.

In order to fundamentally explain the repair mechanisms of realkalization technology for carbonated reinforced concrete,a real time Raman study was undertaken,on a simulated concrete/steel rebar interface without direct contact with the air and the electrolyte solution,to observe the evolution of corrosion products during realkalization treatment.The results indicate that the main corrosion product is green rust after artificial corrosion acceleration by impressed current.During the realkalization treatment,two reactions occur simultaneously,green rust is reduced into brucite（Fe（OH）2）and converted into magnetite（Fe3 O4）.The phenolphalein tests and the production of magnetite show that the realkalization technology can effectively increase the concrete alkalinity.The electrochemical measurements further indicate that the realkalization technology can effectively decrease the corrosion probability and corrosion activity of steel rebar to medium level,however,the steel rebars can not be repassivated.