Lec 09 Pavement Design (Transportation Engineering)

1. Pavement Engineering
What is a Pavement?
A structure built on existing ground to facilitate
rapid, safe, reliable & comfortable traffic movement
Pavement engineering involve the study of:
• Pavement Materials
• Pavement Structural Analysis
• Pavement Design
• Pavement Maintenance and Rehabilitation
• Pavement Management Systems

2. Pavements are designed based on
“serviceability”
Serviceability is an indication of how
good a ride the traveling public gets!

3. Pavement Structure

4. Types of Pavements
 Flexible Pavements
 Rigid Pavements

5. Flexible Pavement Surfaces

6. Hot Mix Asphalt Surface
Hot Mix Asphalt Binder Course
Stabilized Base
Granular Subbase
Natural Subgrade
Prime Coat
Prime Coat
Tack Coat
Typical Flexible Pavement Configuration
- High Traffic Volume

7. Hot Mix Asphalt Surface
Granular Base
Natural Subgrade
Prime Coat
Typical Flexible Pavement Configuration
- Low Traffic Volume

8. Typical Hot Mix Asphalt Concrete
(HMAC) Paving Operation

9. Asphalt Concrete Paving

10. Seal Coat Pavement
(a.k.a. Chip Seal, Surface Treatment)

11. Surface Treatment (or Seal Coat or Chip Seal)
Granular Base
Natural Subgrade
Typical Flexible Pavement Configuration
- Low Traffic Volume

12. Seal Coat Construction – Asphalt Spray

13. Seal Coat Construction – Aggregate Spread

14. Seal Coat Construction – Rolling

15. Rigid Pavement Surfaces

16. Portland Cement Concrete Surface Slab
Stabilized Base
Granular Subbase
Natural Subgrade
Prime Coat
Prime Coat
Typical Rigid Pavement Configuration
- High Traffic Volume

17. Portland Cement Concrete Surface Slab
Granular Base
Natural Subgrade
Prime Coat
Typical Rigid Pavement Configuration
- Low Traffic Volume

18. Paving of a Concrete Pavement

19. Types of Rigid Pavements
 Jointed Plain Concrete Pavement (JPCP)
 Jointed Reinforced Concrete Pavement (JRCP)
 Continuously Reinforced Concrete Pavement (CRCP)
 Pre-stressed Concrete Pavements (PCP)

20. Types of Rigid Pavements
Jointed Plain Concrete Pavement (JPCP)

21. Types of Rigid Pavements
Jointed Reinforced Concrete Pavement (JRCP)

22. Types of Rigid Pavements
Continuously Reinforced Concrete Pavement (CRCP)

23. Types of Rigid Pavements
Prestressed Concrete Pavement (PCP)

24. Use of Aggregates in
Pavement Construction
Hot Mix Asphalt Concrete (HMAC)
Portland Cement Concrete (PCC)
Granular Base and Subbase Layers
Seal Coats

25. Classification of Aggregates
 Based on Origin (Natural & Artificial)
 Based on Density of Particles
– Normal Weight (SG 2.5-2.8); Lightweight (SG 1.5-2.0)
 Based on Method of Processing (Crushed/uncrushed)
 Based on Affinity to Water
– Hydrophilic (siliceous); Hydrophobic (Carbonaceous)
 Based on Particle Size
– Coarse Aggregate (Larger than #4 sieve)
– Fine Aggregate: #4(4.75mm) to #200 sieves (75 m)
– Mineral filler (finer than #200 sieve)

26. Natural & Artificial Aggregate Types
Natural aggregates from:
 Igneous Rocks (Granite)
 Metamorphic Rocks (Marble, Gneiss, Quartzite)
 Sedimentary Rocks (Limestone, Dolomite,
Sandstone, Caliche)
Artificial aggregates from:
 Byproducts of Industrial Processes (Blast-furnace
slag; Iron-ore gravel)
 Manufactured Aggregates (Lightweight aggregate,
Hydrated fly ash)

27. Coarse & Fine Crystals - Igneous Rocks

28. Microstructure of Limestone & Marble
- Sedimentary vs. Metamorphic

29. Excavation

30. Crushing

31. Transportation

32. Sizing
Stockpiling

33. Some Distinct Aggregates
Concrete
Sand
Screenings
¾” Crushed
Limestone
1” Crushed
Gravel
3/8” Pea Gravel
3/8” Crushed
Trap Rock

34. Criteria for Selection of Aggregates
Stabilized (Bound) Materials
 Compatibility with binder
 Durability -Resistance to freeze-thaw,
degradation
 Stability (or strength) of the Mix
Unstabilized Materials
 Strength
 Durability
 Drainability
 Low frost susceptibility

35. Important Aggregate Properties
 Gradation (ASTM C-33)
 Specific Gravity & Absorption (ASTM C-127, C-128)
 Hardness or Resistance to Wear (ASTM C-131)
 Durability (Resistance to wet-dry, freeze-thaw, heat-cool)
 Shape and Surface Texture
 Deleterious Substances (ASTM C-40, C-142)
 Surface Chemistry
 Particle Crushing Strength
Standard Tests by ASTM, AASHTO, State DOTs

36. Los Angeles Abrasion Test
Before
After

37. Soundness Test
Before After
5 Cycles of Soaking and Oven Drying
Magnesium Sulfate or Sodium Sulfate Solution

38. Aggregate Gradations
Continuous GapUniform

39. * Uniformly graded
- Few points of contact
- Poor interlock (shape dependent)
- High permeability
* Well graded
- Good interlock
- Low permeability
* Gap graded
- Only limited sizes
- Good interlock
- Low permeability
Types of Gradations

40. Aggregate Size Definitions
Nominal Maximum Aggregate
Size
– one size larger than the first sieve to
retain more than 10%
Maximum Aggregate Size
– one size larger than nominal
maximum size
100
100
90
72
65
48
36
22
15
9
4
100
99
89
72
65
48
36
22
15
9
4

41. Aggregate Moisture States

42. Asphalt Concrete Mixes

43. Asphalt Concrete
 3-phase system (aggregate, asphalt cement, air)
 Mix design to achieve maximum stability
– Aggregate type & gradation
– Asphalt content (% by weight of total mix)
– % Air voids
 Mix design methods
– Marshall Method
– Hveem Method
– Superpave Method

44. Marshall Mix Design
Method
Compaction
Testing

45. SHRP (Superpave®) Gyratory
Compactor

46. Design Parameters
Six Mix Design Parameters
– Stability
– Flow
– Unit weight of compacted mix
– Voids in mineral aggregate (VMA)
– Percent voids in mix
– Voids filled with asphalt (VFA)
Mix Design Method
– Calculate asphalt content for maximum
stability, maximum unit weight and median air
voids (4%)

47. Asphalt Concrete Phase
Diagram
Aggregate Solids
Absorbed Asphalt
Effective(free) Asphalt
Air VoidsVAV
VEA
VAGG
VT
MAGG
MAA
MEA
MT
MTA

48. Distresses in Flexible Pavements

49. Pothole

50. Rutting

51. Alligator Cracking

52. Longitudinal Cracking

53. Transverse Cracking

54. Block Cracking & Edge Cracking

55. Flushing & Bleeding

56. Raveling in HMAC & Seal Coats

57. Failures

58. Airfield Pavement Failure

59. Airfield Pavement Failure

60. Distresses in Rigid Pavements

61. Longitudinal & Transverse Cracking

62. Corner Crack & Diagonal Crack

63. Spalling

64. Faulting

65. Punchout

66. Failures

67. Failed Crack

68. Shattered Slab

69. Pumping from Slab Edge

70. Polished Aggregate & Scaling

71. Blow-Ups (Buckling & Shattering)

72. Condition
Assesement

74. PhotoLog Van

75. CT Photolog

76. Pavement Profiling
Laser
and
Acceler-
ometer
in here

77. Pavement Profile

78. US24 Pavement Profile
WB High Freq.
The high frequency roughness
does not have a significant
affect on truck dynamics

79. US24 Pavement Profile
WB Low Freq.
Low frequency variations
are long bumps that can
get trucks bouncing

80. US24 Pavement Profile
EB Low Freq.