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Chapter 7 Isolated Partial Depth Concrete Repair

Chapter 7 Isolated Partial Depth Concrete Repair. From… Maintenance Technical Advisory Guide (MTAG). Partial-Depth Repairs. 3-4. 2. Learning Objectives. List benefits of partial-depth repairs Describe the advantages and disadvantages of different available repair materials

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Chapter 7 Isolated Partial Depth Concrete Repair

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  1. Chapter 7Isolated Partial Depth Concrete Repair From… Maintenance Technical Advisory Guide (MTAG)

  2. Partial-Depth Repairs 3-4.2

  3. Learning Objectives • List benefits of partial-depth repairs • Describe the advantages and disadvantages of different available repair materials • Describe recommended construction procedures • List important quality control activities • Describe potential unexpected adjustments or construction quality problems • Identify troubleshooting solutions

  4. Presentation Outline • Introduction • Design considerations • Construction • Quality control • Troubleshooting

  5. Introduction • Definition Removal and replacement of small, shallow areas of deteriorated PCC at spalled or distressed joints. • Distress limited to upper 1/3 of slab • Existing load transfer devices are functional

  6. Benefits • Restores structural integrity • Improves ride quality • Extends the service life • Restores a well-defined uniform joint sealant reservoir

  7. Good Candidate Projects • Spalling associated with joint inserts • Spalling caused by intrusion of incompressibles • Spalling associated with localized areas of scaling, weak concrete, clay balls, or high steel

  8. Poor Candidate Projects • Joint spalling associated with dowel bar misalignment or lockup • Spalled cracks • Spalling associated with durability problems or reactive aggregate

  9. Good candidate?

  10. Good candidate?

  11. Good candidate?

  12. Good candidate?

  13. Good candidate?

  14. Presentation Outline • Introduction • Design considerations • Construction • Quality control • Troubleshooting 

  15. Module 7-1 Design, Materials & Specifications From… Maintenance Technical Advisory Guide (MTAG)

  16. Design Considerations • Selecting repair boundaries • Material selection • Curing • Opening to traffic

  17. DULL SHARP Unsound-Delaminated Solid Selecting Repair BoundariesDetecting Deteriorated Concrete Sounding the pavement: • Hammer • Steel rod • Steel chain

  18. Selecting Repair BoundariesSounding

  19. Selecting Repair Boundaries Repair Dimension Recommendations • Minimum dimensions • Length: 300 mm (12 in) • Width: 100 mm (4 in) • Depth: 50 mm (2 in) • Extend repair 75 to 100 mm (3 to 4 in) beyond visible deterioration • Combine close patches (<0.6 m [2 ft]) • Repair entire joint if > 2 patches

  20. Cementitious PCC-based Gypsum-based Magnesium phosphate High alumina Material SelectionRepair Material Types • Polymeric • Epoxy • Methyl methacrylate • Polyester-styrene • Polyurethane • Bituminous

  21. Material SelectionBonding Agents • Enhances repair to pavement bond • Sand-cement grouts used with PCC repair materials • Epoxy bonding agents used with both PCC and proprietary materials

  22. Material Selection Factors • Allowable lane closure time • Ambient temperature • Cost • Size of repair • Estimated performance

  23. Curing • Cure to avoid shrinkage cracks • Hot-weather curing—curing compound, moist burlap, or polyethylene • Cold-weather curing—insulating blanket or tarp • Follow recommendations for proprietary materials

  24. Opening to Traffic • Opening criteria • Minimum strength (20.7 MPa [3,000 psi]) • Minimum time • Opening based on actual PCC strength is preferred

  25. Typical Item Codes http://i80.dot.ca.gov/hq/esc/oe/awards/#item_code

  26. Module 7-2 Construction and Inspection From… Maintenance Technical Advisory Guide (MTAG)

  27. Presentation Outline  • Introduction • Material selection • Construction • Quality control • Troubleshooting 

  28. Construction Steps • Marking repair boundaries • Concrete removal • Repair area cleaning • Joint preparation • Bonding agent application • Patch material placement • Curing • Joint sealing

  29. Marking Repair Boundaries

  30. Concrete Removal • Saw-and-patch (recommended) • Chip-and-patch • Mill-and-patch • Hydrodemolition

  31. Concrete RemovalSaw-and-Patch Method

  32. Concrete RemovalChip-and-Patch Method

  33. Concrete RemovalMill-and-Patch Method

  34. Concrete RemovalMill-and-Patch Method

  35. Concrete RemovalHydrodemolition

  36. Repair Area CleaningSandblasting

  37. Repair Area CleaningAir Blowing

  38. Joint Preparation

  39. Joint Joint Preparation 75 mm (3 in) Bond breaker 75 mm (3 in) Patch Plan View Scoring Pavement 25 mm (1 in) Profile View

  40. Bonding Agent Application • Patch area must be clean • Application techniques • Coat horizontal and vertical surfaces • Apply uniformly

  41. Bonding Agent Application

  42. Patch Material PlacementGeneral Guidelines • Batch small quantities • Temperature recommendations • Some epoxy materials placed in lifts • Overfill patch area by ~3 mm (1/8 in) • Consolidate material • Screed and hand trowel

  43. Patch Material PlacementGrout Mixer

  44. Patch Material PlacementAdding Admixture

  45. Patch Material PlacementMixing an Epoxy Patching Material

  46. Patch Material PlacementConsolidation

  47. Patch Material PlacementFinishing

  48. Curing

  49. Joint Sealing

  50. Finished Patch

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