再碳化后再碱化钢筋混凝土（水泥砂浆）的电化学研究

The electrochemical study of realkalisated reinforced concrete (cement mortar) after re-carbonation

摘要:

对再碱化后的钢筋混凝土（水泥砂浆）试件进行加速再碳化试验，再碳化的时间采用试件进行再碱化前第一次碳化所用的时间。采用电化学阻抗谱、极化曲线和pH测试等测试方法，研究再碳化过程中钢筋表面状态和水泥砂浆碱性的变化。试验结果表明：在本试验条件下，再碳化后，水泥砂浆试件的pH值仍然大于10；再碳化后，钢筋的腐蚀电流虽然有所增大，但仍小于再碱化前的腐蚀电流密度，钢筋的腐蚀电位负移，但仍大于再碱化前的腐蚀电位。研究结果表明，再碱化后的混凝土结构对CO2具有较好的抵抗侵蚀的作用。

Abstract:

A re-carbonation test of Realkalisated reinforced concrete (cement mortar) was carried out. The re-carbonation time was the same as the first carbonation time before realkalisation. The surface state of steel and the alkaline of the cement mortar was studied with electrochemical impedance spectroscopy (EIS), polarization curve and the measurement of pH. The test results show that under the experimental conditions, the pH of cement mortar is above 10 after re-carbonation; after re-carbonation, the corrosion current density of steel increases and is less than before realkalisation; the corrosion potential of steel decreases, but is more than before realkalisation.