maintenance and rehabilitation of pavements by Roshan .ppt
- 2. Preventive Maintenance Corrective Maintenance Pavement Preservation Pavement Rehabilitation Some Common Terms
- 3. Preventive Maintenance The planned strategy of cost effective treatments to an existing roadway system and its appurtenances that preserves the system, retards future deterioration, and maintains or improves the functional condition of the system (without increasing structural capacity). - AASHTO’s Standing Committee on Highways
- 4. Planned Performed on good pavements Contributes to long- term performance Examples: Fog Seal, Chip Seal, Thin HMA Overlay
- 5. Corrective Maintenance Reactive Performed on failing pavements Does not contribute to long-term performance Examples: Patching, Pothole Repair
- 6. Pavement Preservation The sum of all activities undertaken to provide and maintain serviceable roadways; this includes corrective maintenance and preventive maintenance, as well as minor rehabilitation projects - National Highway Institute
- 8. Pavement Rehabilitation Work undertaken to extend the service life of an existing pavement. This includes the restoration, placing an overlay, and/or other work required to return an existing roadway to a condition of structural and functional adequacy. - National Highway Institute
- 9. Pavement Management Concepts Pavement Life Cycle Pavement Condition Pavement Condition Index (PCI) Pavement Serviceability Index (PSI) Critical “PCI”
- 10. Time or Traffic Pavement Condition Pavement Lifecycle
- 11. Pavement Condition Pavement Condition can be rated using any number rating systems, including: Pavement Condition Index (PCI) PCI = 100 is New/Excellent and PCI = 0 is Failed Present Serviceablity Index (PSI) PSI = 5 is New and PSI = 0 is Failed Used in the AASHTO Design Methodology International Roughness Index (IRI) Rating is Inches/Mile and is automatically recorded
- 12. 100 85 70 55 40 25 10 0 Excellent Very Good Good Fair Poor Very Poor Failed Pavement Condition Index Corps of Engineers (Developed for Airfields) ASTM now has standards for both highways and airfields Analyze Distresses Type Severity Density
- 13. Time or Traffic Pavement Condition Index 100 0 Critical PCI = 65 - 70 Pavement Condition
- 14. Time or Traffic Pavement Condition Index 100 0 Preventive Maintenance Corrective Maint, Rehabilitation, or Reconstruction Critical PCI Critical PCI
- 17. Rehabilitation Time or Traffic Pavement Condition Rehabilitation
- 19. Applying the right treatment . . . To the right pavement . . . At the right time Philosophy of Pavement Preservation
- 20. Improved Pavement Condition Preventive maintenance helps to preserve a pavement and extend its performance Overall condition of network improves Fair, Poor, and Failed Pavements are reconstructed and returned to a high pavement condition Excellent and Good Pavements are kept in high condition
- 21. Cost Savings Most persuasive argument for shifting to preventive maintenance strategies Forms of cost savings Less expensive treatments Longer pavement life Reduction of user delay costs
- 22. Preventive maintenance: (minimum) Rehabilitation: (intermediate) Reconstruction: (maximum) Cost Comparison of Options
- 23. Anticipated benefits Higher customer satisfaction Improved strategies and techniques Improved pavement condition Cost savings Increased safety Stability
- 24. What is Pavement Management ? Systematic method for routinely collecting, storing, and retrieving decision-making data needed to make maximum use of limited amount It also creates a set of steps or computer routines for quickly accessing the data to arrive at educated decisions.
- 26. What pavement characteristics indicate pavement condition? Visible performance indicators Functional indicators Structural indicators Non-Visible defects Environmental effects on materials Load-related damage
- 27. What techniques are used to assess pavement condition? Visual distress surveys Roughness surveys Friction surveys Drainage evaluation Shoulder surveys Deflection testing
- 28. Data Collection Platforms Video – distress, roughness Laser - distress, roughness Friction
- 29. Sample and test (destructive) essential to evaluate causes of distress Test in-place (non-destructive) Important to delineate uniform sections
- 30. Subgrade Support From soils sampling/lab testing In-situ - DCP, Field CBR From deflection testing
- 31. Material Properties Bound layers Thickness Strength Durability - reactive aggregate, stripping Granular base Gradation Quality Subgrade Index properties Resilient modulus
- 33. Why Non-Destructive Pavement Testing? Measure structural condition in place High production rate: more information = better decisions Identify rehabilitation needs Knowledge-based selection of actions
- 34. Successful GPR Applications for Pavements Thickness of Pavement Layers Pavement Rehabilitation studies (identifying changes in structure) Defects in Base (Wet areas) Defects in Hot Mix layers (stripping, trapped moisture) Identifying areas of segregation and poor joint density Deterioration in asphalt covered bridge decks Base wash-outs (<3 ft down) Limited success on concrete pavements
- 35. Findings… Distresses Materials Properties Subgrade, bases, surface Structural Properties Deflection response Layer thickness
- 36. Pavement Distress Categories Load Climate Other Construction
- 37. Load Related Distresses Fatigue Cracking Potholes Rutting Edge Cracking Shoving
- 38. Climate Related Distresses Block Cracking Joint Reflective Cracking Thermal Cracking Weathering/Raveling
- 39. Preservation Candidates Preservation treatments must be applied when: Pavements are in good condition Corrective actions required on only a small area of the total pavement
- 40. Pavements are not candidates for preservation: Pavements in poor condition Substantial repairs required Structural deficiencies
- 41. Time or Traffic Pavement Condition Index 100 0 Preventive Preservation Candidates These Pavements are not Preservation Candidates Critical PCI
- 43. When to Rehabilitate? Rough road, Excessive pavement distress, Loss of skid resistance, Excessive maintenance needs, Inadequate structure for planned use.
- 44. Rehabilitation Alternatives Thick overlay with paving fabric, Thin overlay, Cold in place recycle (CIR), Full depth reclamation.
- 45. Paving Fabrics
- 46. Paving Fabric Basics Keeps water out of the base and subgrade Provides support to retard reflection of existing cracks and distresses Controls evaporation over the long- term, keeping uniform moisture content in the subgrade.
- 47. How does it work? AC Overlay Existing AC Pavement Base or Subgrade Fabric
- 48. Selection Considerations Can provide strength up to equivalent of 1.0 inch of AC (if pavement is stable and fabric is properly installed) Cost of fabric (based on DOT studies) is about the same as 0.5 inches of AC
- 49. Application Considerations Not suitable for severely distressed pavements. Generally not suitable where there is inadequate base/subgrade support. Do not use where free water problems exist.
- 50. Construction Considerations Minimum overlay thickness when using a fabric is 1.5 inches. Major contributor to failure is lack of tack and/or uniformity of tack coat application. Read manufacturer’s literature for detailed instructions.
- 51. 3/8 inch 1/4 inch 1/2 inch Overlay 1.5” What is a “Thin” HMA Overlay?
- 52. Why Thin Hot Mix Overlays? Restores Serviceability Low Initial Cost & Life Cycle Cost Minimal Road User Delays/Impacts Adds Structure Reduces Noise
- 53. Treatment Fog seal Slurry seal Chip seal Thin HMA O’lay Life, years 1 - 2 3 - 5 4 - 7 10 - 15 Cost ($/yd2) 0.25 - 0.35 0.85 - 1.00 0.90 - 1.20 2.50 - 3.50 Cost Comparison of Pavement Treatments
- 54. Thin Overlays: Rules of Thumb Pre-level rutted areas Minimum lift thickness is 1 1/2” Roll while mix is hot (>185ºF) Minimum of 3 passes
- 55. Milling Machine Crusher Mixer-Paver Introduction to Cold In-Place Recycling
- 56. Advantages Reduced cost of construction Conservation of aggregate and binders Preservation of existing pavement geometrics Hauling Costs Minimized Minimal Air Quality Problems Conservation of energy Less user delay
- 57. Significant Structural Improvements Most Pavement Distress Treated Ride Quality Improved Advantages for the Road
- 58. Cold In-Place Recycling Train Milling Machine Paver Emulsion
- 62. Final Considerations Availability of Equipment Availability of Experienced Contractor First cost Life cycle cost CIR?
- 63. Full Depth Reclamation Construction Methods
- 64. Definition Recycling method where all of asphalt pavement section and a predetermined amount of underlying materials are treated to produce a stabilized base course.
- 65. Advantages Pavement structure (especially poor base) improved without significantly affecting pavement geometry, Eliminates ruts, rough areas, and potholes and restores desired profile, Eliminates alligator, transverse, longitudinal and reflection cracking, Provides a uniform pavement structure.
- 66. Advantages (continued) Frost susceptibility may be improved, Low production cost, Conservation of materials and energy, No air quality problems.
- 67. Common Recycling Additives Emulsified Asphalts (MS and SS) Portland Cement Lime Fly Ash Calcium Chloride Foamed Asphalt
- 68. Main Steps Pulverize existing pavement, Introduce additive and mix, Shape the mixed material, Compact, Apply a wearing course.
- 69. Types of Overlays Asphalt overlay over asphalt pavements Asphalt overlays on CC pavements CC overlays on asphalt pavements CC overlays on CC pavements
- 70. Benkelman Deflection Studies (IRC-81:1997) Pavement Benkelman Deflection Studies (IRC-81:1997) Static Load Test Procedure wheel Benkelman Beam Deflection Studies
- 71. Benkelman Beam Evaluation Of Structural Capacity Of Existing Pavement Estimation And Design Of Over Lay For Strengthening Of Weak Pavement
- 72. Need of Evaluation Pavement deteriorate functionally and structurally with time due to traffic loading and the different climatic condition. It is necessary to evaluate the condition of existing pavement in terms of functionally and structurally.
- 73. OVERLAY Pavement that do not have adequate structural strength to carry out the projected future traffic will have to be reinforced by providing additional pavement layer
- 75. Sub Grade Soil Type And Its Moisture Content Compaction Thickness Quality Of Pavement Course Drainage Condition Etc.
- 76. This test procedure covers the determination of the rebound deflection of a pavement under a standard wheel load and tyre pressure.
- 77. Deflected Pavement Structure Bounce Back To Original Shape Deflected Surface Original Position L O A D L O A D Load removed
- 79. 1. Benkelman beam – • Consist of slender beam of length 3.66 m. • Pivoted at 2.44 m from probe. • distance from pivot to dial gauge 1.22 m. • Distance from pivot to front leg 25 cm. • Distance from pivot to rear leg 1.66 m.
- 81. 2. Loaded truck • Weight of truck 12 t • Rear axle load 8170 kg(dual tyre) • Spacing between tyres 30-40 mm. • Inflation pressure 5.6 kg/sq.cm.
- 82. 3. Accessories – • Tyre pressure measuring gauge. • Thermometer(0-100 °c) with 1 ° division. • Measuring tape.etc
- 84. Deflection Survey 1 .Pavement Condition Survey 2.Measurement Of Deflection Done As Per IRC-81:1997
- 85. Deflection Measurement – • Point selection – 1 km road stretch . Minimum 10 points at 50 m interval . • Location Of Point – Lane Width(m) Distance From Lane Edge(cm) Less than 3.5 60 More than 3.5 90
- 87. A B C 2.7 m 9 m
- 89. 1. Select the points and marked. 2. The dual wheel of the truck is centered above the mark. 3. The probe of the benkelman beam is placed between the dual tyres at the marked position.
- 90. 4. Dial gauge is set at 1 cm. 5. Initial reading (s) is recorded when rate of deformation is less than or equal to .025 mm/min.
- 91. 6. Truck is slowly driven (at speed 8-10 m/s appr.) at a distance of 2.7 m. and stopped. 7. Intermediate reading (I) is recorded. 8. Truck is driven forward a further 9 m. 9. Final reading (F) is recorded. 10. Pavement temperature is recorded atleast once in each hour. 11. Tyre pressure is checked at 2-3 hrs interval during a day.
- 93. •Find (S-I) & (S-F) • If deferential Reading ≤ 0.025 mm (2.5 Divisions), then True Rebound Deflection At Temp. T Is XT = 2(S-F) •If deferential reading ≥ 0.025mm, then XT = 2(S-F) + 5.82 (I-F) The pavement rebound deflection at a standard temperature of 20°C shall be calculated
- 95. Standard temp 35 °c. Correction is applied when min thickness of the pavement is 40 mm. No correction for thin bituminous surfacing severe cracking in pavement bituminous layer is striped. Cold and high altitude regions where daily temp. < 20 °c Correction will be positive when temp blow stand. Temperature Correction will be negative when temperature above standard temperature. Correction factor is 0.01mm/ °c variation from standard temp.
- 97. Over Lay Design For A Given Section Is Based Not On Individual Deflection Value But On Statistical Analysis Of All Measurements In The Section 1.Mean Deflection 2.Standard Deviation 3.Charecteristic Deflection DC = M + 2S, For NH & SH DC = M +S, for other roads
- 99. Concept of Over Lay Undulated Surface Cracked Surface Surface Over Lay Surface
Editor's Notes
- #2: 1
- #3: 2
- #4: 3
- #5: 4
- #6: 5
- #7: 6
- #8: 7
- #9: 8
- #10: 9
- #11: 10
- #12: 11
- #13: 12
- #14: 13
- #15: 14
- #16: 15
- #17: 16
- #18: 17
- #19: 18
- #20: 19
- #21: 20
- #22: 21
- #23: 22
- #24: 23
- #25: 24
- #26: 25
- #27: 26
- #28: 27
- #35: GPR is a very useful tool. It is subject to physical limitations resulting from material properties and moisture. We ALWAYS take pavement cores to validate our GPR analyses.
- #43: 42
- #44: 43
- #45: 44
- #46: 45
- #47: 46
- #48: 47
- #49: 48
- #50: 49
- #51: 50
- #52: 51
- #53: 52
- #54: 53
- #55: 54
- #56: 55
- #57: 56
- #58: 57
- #59: 58
- #60: 59
- #61: 60
- #62: 61
- #63: 62
- #64: 63
- #65: 64
- #66: 65
- #67: 66
- #68: 67
- #69: 68