Cracks in concrete are inevitable. Whether caused by thermal movement, structural overload, settlement, or shrinkage — cracks provide a direct pathway for water into the structure. Injection grouting is the most effective method to seal cracks permanently and restore structural integrity.
What is Injection Grouting?
Injection grouting involves injecting a repair material — either polyurethane (PU) or epoxy — into cracks, voids, or construction joints under controlled pressure. The material fills the crack from inside and bonds to the concrete faces, sealing the pathway to water and sometimes restoring structural continuity.
Polyurethane (PU) Grouting
Best for: Active water leaks, joints with movement, non-structural cracks. PU grout reacts with water to expand and foam, filling the void and stopping water flow within seconds. Flexible after curing, so it accommodates ongoing movement. Essential for stopping active basement leaks, tunnel seepage, and water tank joints.
Epoxy Grouting
Best for: Dry or dormant structural cracks requiring strength restoration. Epoxy grout cures to a rigid, high-strength material that bonds concrete faces together. Used to restore structural continuity in beams, columns, and slabs. Should not be used in joints that continue to move.
The Injection Process
- Mark and clean the crack
- Drill injection ports at regular intervals along the crack (typically 150–300mm apart)
- Install injection packers in the drilled holes
- Seal the crack surface with fast-setting cement or epoxy paste (not over the ports)
- Inject grout starting from the lowest port, moving upward as each port shows grout
- Allow to cure and remove packers
- Apply surface sealant over cured grout
Common Applications in India
PU injection grouting is widely used in basements, retaining walls, tunnels, metro stations, and water-retaining structures. Epoxy grouting is used for structural crack repair in RCC frames, bridge decks, and industrial floors.
Dhawan Associates provides injection grouting services and supplies Fosroc, Sika, and MC Bauchemie grouting systems across India. Contact us at +91 93109 97953.
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