混凝土结构工程除盐的研究与应用

基于氯离子腐蚀混凝土的电化学机理,探讨了用电化学方法反其道而行消除混凝土中氯离子的原理、可行性与工程应用前景。通过除盐试验和除盐后混凝土构件受力性能试验,研究了影响电化学方法除盐效果的各种参数(如碱溶液、电极电位、电流密度、金属网腐蚀牺牲等)及其对混凝土结构性能的影响;分析了除盐后钢筋周围混凝土凝胶体孔隙内碱类物质的积聚,及其对钢筋与混凝土之间粘结力的影响。除盐后的拉拔试验和钢筋混凝土板的弯曲试验表明,除盐后钢筋与混凝土之间的粘结性能会受到损伤,但粘结力的损伤不会对混凝土构件的正常使用性能和承载能力造成显著影响。

ON CHLORIDE EXTRACTION FROM CONCRETE STRUCTURES AND ITS APPLICATION

Based on the electrochemical principle of steel corrosion in concrete structures, the principle of chloride ion extraction from concrete is studied. Sixty cylinder specimen and three slab specimen with admixed chloride ion concentration varying from 1.5-3%, by weight of cement, were tested to study the coefficients which affect the efficiency of desalination process, bond strength and mechanical behavior of bending slabs after desalination. It is found that the option of anode mesh, electrolytes and current in desalination is the key to sufficient desalination. The side effect of desalination is impairment of bond strength. It is shown that the impairment of bond strength is up to 30-35% for rod rebars. But part of bond strength can be recovered for a time after desalination. It is also shown that desalination cannot significantly change the load carrying capacity and load-deflection relationship of bending members.