1) Surface Preparation: Roughen The Surface Of The Existing Concrete By Hacking Or Using A Wire Brush To Expose The Aggregate, Ensuring A Strong Mechanical Bond For The Next Pour.
2) Cleaning: Remove All Loose Debris, Laitance, Oil, And Dust Using Water Jets Or Compressed Air.
3) Bonding Agents: Apply A Bonding Agent Like SBR Latex Or A Cement Slurry/Slush Coat To The Prepared Surface Just Before The New Pour To Improve Adhesion.
4) Waterstops: For Water-Retaining Structures, Install Hydrophilic Swellable Tapes Or Bentonite Strips In The Centre Of The Joint To Create A Watertight Seal.

1) Immediate Remediation: If The Concrete Is Still Soft Enough For A Vibrator To Penetrate, Pour Fresh Concrete Immediately And Vibrate Both Layers Together To Merge Them.
2) Hardened Repair (Injection): For Joints That Have Fully Set And Are Leaking Or Structurally Weak, Use Polyurethane Or Epoxy Injection:
1. Drill & Pack: Drill Holes At Intervals Along The Joint Line And Insert Mechanical Packers.
2. Inject: Use A High-Pressure Pump To Inject Polyurethane Resin (To Stop Water Leaks) Or Low-Viscosity Epoxy (For Structural Bonding).
3. Finish: Once The Resin Cures, Remove The Packers And Patch The Holes With Quick-Set Cement.
3) Surface Sealing: For Minor Non-Structural Cold Joints, Cut A “V” Groove Along The Joint Line And Fill It With A Flexible Sealant Or Non-Shrink Grout.