不同保护层厚度下镁水泥混凝土中钢筋防护试验

Steel bar protection test in magnesium cement concrete with different protective layer thickness

针对镁水泥含有的盐卤成分对钢筋具有轻微腐蚀性的情况,对镁水泥混凝土构件进行耐久性试验,结合不同环境、混凝土保护层厚度和增加钢筋涂层的情况,对试件中钢筋进行电化学测试,并利用SEM形貌和XRD衍射进行微观分析.结果表明:自然干燥环境下,在混凝土保护层厚度分别为25和50 mm时镁水泥构件腐蚀进程大致相同,但是厚度为50 mm时钢筋更易受到腐蚀;在厚度为25 mm时,通过分析镁水泥混凝土构件中钢筋在氯盐和自然干燥环境中的受腐蚀情况,发现涂层的存在有效降低了钢筋腐蚀电流密度,在氯盐条件下对钢筋保护作用更为突出.

To investigate the slight corrosion to steel bars due to the bittern in magnesium cement,a durability test was carried out on magnesium cement concrete components.Combined with different environments,concrete protective layer thickness and increasing steel coating,the electrochemical test of steel in the specimen was carried out,and the specimen was determined by SEM topography and XRD diffraction.The results show that under natural dry environment,the corrosion processes of magnesium cement components with 25 mm and 50 mm concrete protective layer thicknesses are about the same,and the steel bars with 50 mm concrete protective layer thickness are more susceptible to corrosion.Under the condition with 25 mm concrete protective layer thickness,the corrosion of steel bars in magnesium cement concrete components in chloride and natural dry environments shows that the presence of coating can effectively reduce the corrosion current density of steel bars,and the protective effect of steel bars is more prominent under the condition with chloride salts.