Procedure Involved in the Process of Concrete Repair Works – Civil Engineering are described below:
1. Scope:
This Work instruction is developed to define the procedure involved in the process of concrete repair works.
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2. Relevant Process/Specification:
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As per Customer’s specification
3. Tools/Equipment Required:
1. Grinder with disc, (Pneumatic Electrical)
2. Compressor
3. Jack hammer – Light/Medium duty
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4. Blasting pot, hose & hood
5. Slow speed heavy duty drilling machine with paddle
4. Procedure /Method:
Obtain approval for concrete structure to be repaired and arrange work permits.
Ensure protection for the equipments, which are near to the work area and/or provide temporary supports for those equipments supported by the structure to be repaired.
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Line marks the limit of repair as appropriately to cover all visible cracks.
Grind cut along the line with pneumatic/electrical grinder to a depth of 10-20 mm by taking precautions to avoid any feather edges or further crack development during breaking.
Break out concrete by using light or medium duty jack hammer to a depth of minimum 50mm behind rebar or up to sound substrate such that minimum 100 mm clean, uncorroded steel.
Replace the old steel with new one if the reduction in section (because of corrosion) is more than 15% of its original section. New steel shall be lapped with existing steel.
If sufficient lap is not available, drill a hole near to the existing steel, of size proximately twice the diameter and of depth specified by the manufacturer/client shall be made. Fix the steel inside the hole with the Chemical grout.
Grit/Sand blasts the rebar. Apply approved protective coating, in compliance with the material manufacturer’s recommendation.
The exposed concrete shall be soaked for 12 hrs. (Or as per customer’s specification) before concreting apply approved bonding agent.
The repairing material shall be selected on the basis of the type of the structure to be repaired.
For placing concrete or flow able repair material, watertight formwork shall be made true to plumb and line.
Approved concrete mix flow able repairing material shall be mixed as per design/manufacturer recommendations. It shall be poured and compacted (if necessary) to obtain hard, dense, impermeable and durable concrete.
Approved plaster type repair material shall be mixed and applied over the surface in layers to get smooth, durable surface.
The repaired surface shall be cured for a minimum period of 7 days (or as per customer’s specification) before coating.
Type of protective coating system over the surface of the structure depends upon the surrounding environment. Approved protective coating shall be applied.
Remove rubbish promptly to keep the site tidy and clean.