1. REPAIR and FINISHING

2. Learning objective
The importance of proper repair techniques and materials

3. Why Do We Need to Repair Precast Products?
While our Goal is NO REPAIRS it doesn’t always work that way! Repairs are necessary for two main reasons: 1. Manufacturing imperfections 2. Handling damage

4. Repairs
ASTM C76 section 13
“Pipe may be repaired, if necessary, because of imperfections in manufacture or damage during handling and will be acceptable if, in the opinion of the owner, the repaired pipe conforms to the requirements of this specification”

5. Repairs ASTM C1433 & C1577 section 12
“Box sections shall be repaired, if necessary, because of imperfections in manufacture or handling damage and will be acceptable if, in the opinion of the purchaser, the repaired box section conforms to the requirements of this specification.”

6. Concrete is a Unique Construction Material
Almost every imperfection can be repaired if proper techniques and materials are used.

7. We must remember that: Not everything should be repaired!
Basic Guidelines:
Will the product meet all the requirements after the repair?
Not only dimensional, but strength, durability and water-tightness as well.
Painting over reinforcement is not acceptable

8. Classification of Repairs -
Structural
Performance
Cosmetic
Structural needs evaluation

9. Structural Repairs Major defect repair
Compromises structural integrity or designated use of the piece
Needs to be inspected by qualified individual and documented
If it can’t be repaired, then reject it
Have a system in place to communicate to others the status of the piece
Consider the durability of the repair. It should be as good as the original would perform

10. Damaged tongue on the outside – it is not broken past reinforcing or through the wall
Fall-out on the inside –small to medium fall-out
Fall-out on the outside-small to medium fall-out
Damaged bell on the inside -it is not broken past reinforcing or through the bell

11. If manufactured with a thin wall or insufficient steel cover, there is nothing you can do to repair it
Separation cracks and honey combing can be disguised, but not repaired
Note to speaker: Some manufacturers might repair some of the above, but per the spec and for the Quality School, represent these as non-repairable.

12. Performance / Functional Repairs
Fix only what needs fixing – don’t create more problems
Materials – strong, durable, good bond
Appearance is important

15. For confined gaskets (gasket grooves) all three surfaces of the groove are critical.

16. Cosmetic Repairs Appearance is most important
Product appearance can be your:
BEST SALESMAN OR
YOUR WORST SALESMAN

17. Cosmetic Repairs Evaluate Minor defect repair
One that does not impact the functional use or expected service life of the product, routine (e.g. chips, bugholes)
Should have standard repair techniques
Minor = cosmetic, not structural
May wish to document frequency to determine the cause for your repairs

19. Joint Repairs Joint repairs per C443 Section 14
Circumferential length of a single area to be repaired shall not exceed one fourth of the inside diameter or equivalent diameter
Circumferential length of several areas combined shall not exceed one half of the inside diameter or equivalent diameter
Owner may require testing to prove performance

20. Repair Materials

21. Repair Material Selection
Repairs should be made with like materials.
Therefore: Repair concrete with concrete.

22. Basic Repair Materials
Cement – Portland (can blend gray and white)
Sand – screened or Masons
Water
Sand should be screened with a 30 mesh seive

23. Patching Recipe Example
Very large patches – use the same concrete as the product was produced from or a stiff mixture of:
1 part cement, 3 parts sand + water
Smaller, more refined patches – very stiff paste
1 part cement, 2-1/2 to 3 parts sand + water
Water = clean water
Examples given…can use your own recipe with regard to propotions
Parts to be measured in volume, not in weight

24. Patching Recipes Bonding Grout – paintable 1 part cement + water
Cosmetic paint – paintable
Porous bells and spigots – very stiff
1 part cement, 1 part sand + water
More is not better with bonding agents, follow recommended use if used

25. The best for most applications is:
Bonding Agents
The best for most applications is:
Water or cement water slurry
Sika Armatec 110 EpoCem is a great bonding agent

26. Note: water only is the best way to use bonding agent
This graph is based on research by a producer member by cutting cylinders on 45 degrees and re-pouring them to full cylinders
Note: new technologies do exist since this testing was performed and each producer should evaluate the effectiveness of their own materials used.

27. Pre-packaged Materials They have their place, especially in special applications
Very thin overlays,
need for quick setting,
need for high early strength,
special curing requirements,
non-shrink applications,
flowable materials, if specified.
Some are excellent, some are questionable.

28. Pre-packaged Materials
Read and follow ALL labeled directions exactly.
Reasons for failure:
Too much water or re-tempering
Wrong proportions
Improperly mixed
Improperly applied
Improperly cured.
Pre-Packaged Materials should not be re-tempered

29. Air entraining as required Water reducers as needed
Additives
Air entraining as required
Water reducers as needed
Shrinking is a huge problem with patching, use water reducers to reduce shrinking. Ensure sufficient curing (retain the moisture).

30. Repair Methods

31. Structural Repair: Remove unsound concrete from area to be repaired
Check the position of reinforcing and/or add additional reinforcing as necessary
Form as necessary to reconstruct product to original shape
Dampen mating surface with water or apply bonding agent if desired or required

32. Structural Repair:
Make repair with low slump repair mortar consisting of:
Mix used to produce original product or 1 part cement – 3 parts sand, depending on the size of repair and detail required.
Air entrain repair mortar when necessary.
Tarp product or repaired area immediately after repair is completed to allow repair to pre-set.
Steam cure after pre-set is recommended.
Steam curing a repair gives a MUCH better result if possible

33. Performance / Functional Repair
Remove unsound concrete from area to be repaired (if any).
Dampen mating surface with water.
Make repair with very stiff repair mortar consisting of: 1 part cement (1-1/2 to 3) parts sand and water, depending on size or imperfection.
Remove excess material (especially on joint sealing surfaces).
Cure properly to prevent premature drying and shrinkage

34. FINISH THE JOB Check your work
Dimensional Tolerance – Product
Dimensional Tolerance – Joint
Appearance

35. (Sanitary Sewer Only)
Should Go-no gauge repaired joints

36. Defect Review

37. Defect Review Rejection due to cracking ASTM C76
Fractures or cracks passing through the wall, except for a single end crack that does not exceed the depth of the joint
Damaged or cracked ends where such damage would prevent making a satisfactory joint
Any continuous crack having a surface width of 0.01” or more for a length of 12” or more (unloaded)
Highlight the full definition of a proper 0.01” crack. ACPA has gauges for sale for your students.

38. Defect Review Rejection due to cracking ASTM C1433 & C1577
Fractures or cracks passing through the wall, except for a single end crack that does not exceed the depth of the joint 39

39. Defect Review Rejection due to material defects ASTM C76
Defects that indicate proportioning, mixing, and molding not in compliance with 10.1 or surface defects indicating honeycombed or open texture that would adversely affect the function of the pipe.
The ends of the pipe are not normal to the walls and center line of the pipe, within the limits of variations given in 12.3 and 12.4

40. Defect Review Rejection due to material defects ASTM C1433 & C1577
Defects that indicate mixing and molding not in compliance with 9.1, or honeycombed or open texture that would adversely affect the function of the box sections

41. Defect Review Rejection due to material defects ASTM C1433 & C1577
Abnormalities in the ends of the box sections to the walls and center line of the box section, within the limits of variations given in Section 11, except where beveled ends are specified, and
Damaged ends, where such damage would prevent making a satisfactory joint.

42. Repairable or Non Repairable?
Go through the following pics and explain why the pipe is repairable or not repairable.

43. Defect Review You are now the QC Inspector Do the following products:
Meet specifications?
Can they be repaired?
Or should they be rejected?

44. REPAIRS
Note: This piece should not be in a pile of good pile as shown. This pipe should be scraped, non-repairable

45. Minor defect but, been repaired once. Still could be used—repairable
Chain protectors should be used here. Also note, the broken chain link.

46. Recommend not repairing this due to the integrity of the joint has been compromised.

47. Do not repair. Significant shoulder crack, and concrete is delaminating

48. Note: Cracks through the wall of the pipe or greater than 0
Note: Cracks through the wall of the pipe or greater than 0.01” are non repairable and should be rejected
For a hairline crack, less than 0.01”, that does not pass through the wall is acceptable per C76

49. non

53. 54

54. non 55

55. 56

56. QUESTIONS?