为模拟再碱化钢筋混凝土结构的耐久性,对再碱化后的钢筋-砂浆试件进行加速碳化试验,碳化的时间采用试件进行再碱化前第1次碳化所用的时间.采用交流阻抗谱、极化曲线和pH测试等测试方法研究再碳化过程中钢筋电化学和水泥砂浆碱性的变化.试验结果表明:在本试验条件下,再碳化后试件的pH值仍然大于10.00;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.
A re-carbonation test of re-alkalized steel-mortar was carried out for the simulation on the durability of realkalisated reinforced concrete.The re-carbonation time was the same as the first carbonation time before re-alkalisation.The electrochemistry 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 10.00 after re-carbonation;after re-carbonation,the corrosion current density of steel increases,which is less than that before re-alkalisation;the corrosion potential of steel decreases,which is more than that before re-alkalisation.