Repair of concrete due to corrosion of reinforcement is usually tricky and is usually attended to case by case in order to determine the suitability of any repair method. In the general sense, approaches such as use of coating agents, patch repairs, use of corrosion inhibitors, cathode protection system, or even possible total demolition and reconstruction of the structure. All these require prior corrosion/damage surveys to assess the cause and extent of the deterioration. So, the remedy would vary from structure to structure. I hope this answer gives you an insight on the various approaches that can adopted.

thank you Muzafalu Kayondo , for your Ans.

Replace the old corroded reinforcement and renew the concrete part using shortcreate system. Other option is using fiber reinforcement polymer (frp).