碳化和氯离子对海砂钢筋混凝土的协同劣化机理及其治理方法研究

本项目以海砂混凝土耐久性为研究主题，结合前沿的电化学与微观分析方法，探讨碳化和氯离子对海砂钢筋混凝土的协同劣化机理及其治理方法。揭示碳化和氯离子的协同互作用对混凝土碳化速率、氯离子结合及介质传输等性能的影响规律；分析钢筋钝化膜与pH值和氯离子浓度等因素的相互依存性，结合钝化膜的形成与破坏过程，提出碳化和氯离子协同作用下海砂混凝土中钢筋腐蚀脱钝机制；通过量化碳化和氯离子协同作用下钢筋腐蚀反应的动力学参数，建立海砂混凝土中钢筋腐蚀的速率模型；结合混凝土碳化过程、钢筋脱钝条件及钢筋腐蚀发展过程，构建基于碳化和氯离子协同作用的钢筋腐蚀劣化模型；最后基于腐蚀劣化机制探讨海砂混凝土中钢筋腐蚀的治理方法。通过项目研究可规范和推动海砂的资源化利用，并为保障海砂混凝土结构的合理使用寿命提供科学依据。

This project intends to explore the deterioration mechanisms and prevention methods for the reinforced concrete with sea sand under the synergetic action of carbonation and chloride. Based on the electrochemical and micro-analysis methods, the durability of sea sand concrete will be investigated, and the mechanisms and prevention methods against synergetic deterioration by carbonation and chloride in reinforced concrete be examined. The influence of synergetic action by carbonation and chloride on carbonation rate, chloride binding, and ions transport will be disclosed. The inter-dependency of passive film on pH value and chloride concentration will be analyzed, and depassivation mechanisms of reinforcement steel in sea sand concrete under the synergetic action of carbonation and chloride will be proposed. From the quantification of dynamic parameters of corrosion reaction of steel bars by synergetic deterioration of carbonation and chloride, the model of reinforcement corrosion rate can be established. Combined with carbonation process, depassivation condition, and corrosion development process, the deterioration model of reinforcement corrosion by synergetic action of carbonation and chloride can then be formed. Consequently the prevention methods against synergetic deterioration by carbonation and chloride in reinforced concrete made with sea sand can finally be proposed. Based on the research findings, the comprehensive utilization of sea sand can be motivated, and the scientific evidence for service life assurance of sea sand reinforced concrete can then be provided.