水泥基材料裂缝对钢筋锈蚀过程的影响

裂缝的存在对混凝土中钢筋的锈蚀过程有重大影响,目前关于裂缝对钢筋锈蚀过程的影响程度有很多不同的观点.针对该问题,在实验室条件下利用模拟的海水氯盐环境对带裂缝的圆饼试验中铁丝的锈蚀过程进行了研究.研究首先将铁丝预埋入圆饼形砂浆试件,待试件具有一定强度后,利用机械方法在圆饼表面制造不同宽度的贯穿与非贯穿裂缝;然后通过比较裂缝底部暴露的铁丝表面和未暴露表面随时间的不同腐蚀程度来确定裂缝的存在对锈蚀过程的影响.研究表明:当贯穿裂纹的表面宽度为0.5mm时,锈蚀位置与裂缝位置的相关性大于60%;裂纹宽度为0.2mm时,两者的相关程度低于20%.

Influence of crack on steel corrosion in cement-based materials

Cracks make serious impact on concrete durability, in particular on the corrosion process of steel bars embedded in concrete. As for the working cracks of reinforced concrete, their impact on the corrosion process of steel in concrete is still highly debated. The corrosion process of embedded iron wires in mortar disk specimens subject to laboratory artificial chloride environment were studied. The i-ron wire frames were cast into the mortar specimens then cracks are created in disk specimens by mechanical loads. After exposure to the chloride water environment, the iron wires were extracted from specimens and the corrosion extents of exposed zone and covered zones were compared. The results show that the correlation between the corrosion position and the crack position is greater than 60% if the crack width approaches 0. 5 mm while this correlation is lower than 20% for crack width of 0. 2 mm.