CCANZ - Repairs and Remedial

Concrete has excellent durability, and normally requires little or no maintenance, but good performance depends on good designs, details, materials and workmanship.

Why then should repair be necessary? The answer lies in a subjective consideration of the facts concerning any particular concrete unit that has been deemed unsatisfactory in its present condition. The deficiency may be structural, cosmetic or some combination of both.

Unsatisfactory performance in service could arise as a consequence faulty design, the use of unsuitable materials, improper workmanship, undue exposure to abnormally aggressive environments, excessive structural loadings or any combination of such factors.

If or when repair and restoration of concrete becomes necessary, the objective of any remedial work should be to return the concrete to a satisfactory condition of structural adequacy, durability, and/or appearance at a reasonable cost (commensurate with the benefit to be derived).

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A rational repair programme should start with a diagnosis, or evaluation of the damage, and then progress through selection of materials and method to preparation of the deficient area and, finally, to application of the repair. If each of these steps is undertaken correctly, and at the proper time, then a satisfactory repair will be obtained

Selection Guide to Repair Techniques and Materials
Deterioration	Repair Technique	Repair Material
Cavitation	Coating Concrete replacement Jacketing Shotcreting Prepacked concrete	Bituminous coatings Epoxies or other polymers Jacketing materials Latex-modified concrete Polymers Portland cement mortar/concrete
Cracks, active	Caulking Jacketing Stitching Stressing	Elastomeric sealants Jacketing materials
Cracks, dormant	Caulking Coating Convential replacement Dry Packing Grinding Injection Jacketing Shotcreting Thin-bonded or unbonded resurfacing Stressing	Bituminous coatings Dry Pack Elastomeric sealants Epoxies or other polymers Expanding mortar Fast setting materials Jacketing materials Latex-modified concrete Portland cement grout/mortar/concrete
Crazing	Coating Grinding Shotcreting Thin-bonded or unbonded resurfacing	Epoxies or other polymers Fast setting materials Latex-modified concrete Linseed Oil Portland cement grout/mortar/concrete
Dusting	Coating Grinding Jacketing Thin-bonded or unbonded resurfacing Total replacement	Bituminous coatings Epoxies or other polymers Fast setting materials Jacketing materials Latex-modified concrete Linseed Oil Floor hardeners
Erosion	(see Cavitation; Holes, small; Holes, large; and scaling)
Form Scabbing	Coating Convential replacement Dry packing Shotcreting Thin-bonded or unbonded resurfacing Total replacement	Dry Pack Epoxies or other polymers Expanding mortar Fast setting materials Latex-modified concrete Portland cement grout/mortar/concrete
Holes, small	Coating Dry Packing Grinding Shotcreting Thin-bonded or unbonded resurfacing	Dry Pack Epoxies or other polymers Fast setting materials Latex-modified concrete Portland cement grout/mortar
Holes, large	Coating Concrete replacement Shotcreting Prepacked concrete Total replacement	Epoxies or other polymers Expanding mortar Fast setting materials Latex-modified concrete Portland cement mortar/concrete
Honeycombing	Concrete/mortar replacement Dry Packing Prepacked Concrete Total replacement	Epoxies or other polymers Dry Packing Expanding mortar Portland cement mortar/concrete
Permeability	Coating Jacketing Shotcreting Prepacked concrete Total replacement	Bentonite Bituminous coatings Epoxies or other polymers Expanding mortar Jacketing materials Latex-modified concrete Portland cement mortar/concrete Silicones
Popouts	Coating Thin-bonded or unbonded resurfacing Total replacement	Bituminous coatings Epoxies or other polymers Expanding mortar Latex-modified concrete Linseed oil Portland cement grout/mortar
Sand streaking	Concrete/Mortar replacement Prepacked concrete Total replacement	Expanding mortar Portland cement grout/mortar/concrete
Scaling	Coating Grinding Jacketing Shotcreting Thin-bonded or unbonded resurfacing Total replacement	Bentonite Bituminous coatings Epoxies or other polymers Fast setting materials Fibrous concrete Latex-modified concrete Linseed oil Portland cement mortar/concrete Silicones (vertical surfaces only)
Spalling	Coating Concrete replacement Grinding Jacketing Mortar replacement Shotcreting Prepacked concrete Thin-bonded or unbonded resurfacing Total replacement	Bituminous coatings Epoxies or other polymers Expanding mortar Fast setting materials Latex-modified concrete Linseed oil Portland cement mortar/concrete