碳化混凝土再碱化后钢筋混凝土粘结性能研究

Study on the Bond Strength between Rebar and Concrete after Electrochemical Realkalisation Treatment for Carbonated Concrete

碳化混凝土再碱化过程中,由于物理和化学作用,对钢筋与混凝土的粘结性能有影响。采用拉拔试验,考虑到电流密度、再碱化时间、碳酸钠溶液浓度等因素研究了再碱化后钢筋混凝土的粘结强度。采用扫描电镜(SEM)分析了混凝土的微观结构,结果表明,再碱化后,钢筋混凝土的粘结强度得到明显提高;电流、碳酸钠溶液浓度以及再碱化时间对再碱化后的粘结强度有显著影响;混凝土的微观结构发生了改变,孔隙率减小,有利于粘结强度的增加。

During the electrochemical realkalisation treatment for carbonated concrete, the bond strength between rebar and concrete is changed due to the physical and chemical action. The pull-out test is used to study the effect of current density, realkalisation time, concentration of sodium carbonate solution, realkalisation time on the bond strength between rebar and concrete. The microstructure of the concrete is studied using scanning electron microscope （SEM）. Test results show that after electrochemical realkalisation treatment（ERT）, the bond strength of reinforced concrete is increased. Current density, realkalisation time and concentration of sodium carbonate solution have significant effect on the bond strength after ERT. The microstructure of the concrete is changed after ERT. The porosity is decreased, and it makes for the increase of the bond strength.