MAINTAMNANCE

1. MAINTENANCE
AND
REHABILITATION
OF
PAVEMENTS

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

7. Pavement
Preservation
Preventive
Maintenance
Corrective
Maintenance =
+

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

15. Time or Traffic
Pavement
Condition
Preventive
Maintenance
Preventive Maintenance

16. Corrective
Maintenance/Repair
Time or Traffic
Pavement
Condition
Corrective Repairs

17. Rehabilitation
Time or Traffic
Pavement
Condition Rehabilitation

18. Reconstruction
Time or Traffic
Pavement
Condition
Reconstruction

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.

25. Distress
Identification

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

32. HWD
GPR
Non-Destructive Testing

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

42. Rehabilitation
Alternatives

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

59. Emulsion Tanker
Recycler
Single Machine

60. View before Recycling

61. View after Recycling

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