针对新老混凝土修补界面薄弱过渡区的特点 ,提出改善方法 .即选用适量浓度HCl和时间酸洗老混凝土界面 ,以显著提高老混凝土界面的微细观粗糙度 ,并不过度损伤界面 ;在水泥净浆界面剂中加入粉煤灰和砂 ,以大幅度减少过渡区的收缩和粗大晶体含量 .对比实验结果表明 ,以上两项措施 ,使老混凝土比表面积显著增加 ,过渡区微细观结构显著改善 ,粘结强度显著提高 According to the characteristics of old and new concrete repair interface weak transition zone, the improvement method is put forward, that is, choosing appropriate concentration of HCl and time pickling the old concrete interface to significantly improve the micro-roughness of the interface of the old concrete without excessive damage to the interface; The addition of fly ash and sand into the slurry interface agent can greatly reduce the shrinkage and the coarse crystal content in the transition zone.Comparison results show that the above two measures make the specific surface area of ​​the old concrete increase significantly and the microstructure of the transition zone remarkably improve, Bond strength increased significantly