Pavement Desing Methods

1. PAVEMENT DESIGN
USING CLIL METHODS
CATHOLIC UNIVERSITY OF COLOMBIA
1

2. OBJECTIVES
• UNDERSTAND AND COMPLETE THICKNESS CALCULATION BASED ON
PREVIOUS CONCEPTS
• KNOW VARIABLES INVOLVED IN AND BE ABLE TO CALCULATE REQUIRED
THICKNESS OF RIGID AND FLEXIBLE PAVEMENTS
2

3. AASHTO PAVEMENT DESIGN
METHOD CONSIDERATIONS
• PAVEMENT PERFORMANCE
• TRAFFIC
• ROADBED SOIL
• MATERIALS OF CONSTRUCTION
• ENVIRONMENT
• DRAINAGE
• RELIABILITY
• LIFE-CYCLE COSTS
• SHOULDER DESIGN
3

4. TWO CATEGORIES OF ROADWAY PAVEMENTS
• RIGID PAVEMENT
• FLEXIBLE PAVEMENT
RIGID PAVEMENT TYPICAL APPLICATIONS
• HIGH VOLUME TRAFFIC LANES
• FREEWAY TO FREEWAY CONNECTIONS
• EXIT RAMPS WITH HEAVY TRAFFIC
4

5. ADVANTAGES OF RIGID PAVEMENT
• GOOD DURABILITY
• LONG SERVICE LIFE
• WITHSTAND REPEATED FLOODING AND SUBSURFACE WATER
WITHOUT DETERIORATION
5

6. DISADVANTAGES OF RIGID PAVEMENT
• MAY LOSE NON-SKID SURFACE WITH TIME
• NEEDS EVEN SUB-GRADE WITH UNIFORM SETTLING
• MAY FAULT AT TRANSVERSE JOINTS
6

7. FLEXIBLE PAVEMENT TYPICAL
APPLICATIONS
• TRAFFIC LANES
• AUXILIARY LANES
• RAMPS
• PARKING AREAS
• FRONTAGE ROADS
• SHOULDERS
7

8. ADVANTAGES TO FLEXIBLE PAVEMENT
• ADJUSTS TO LIMITED DIFFERENTIAL SETTLEMENT
• EASILY REPAIRED
• ADDITIONAL THICKNESS ADDED ANY TIME
• NON-SKID PROPERTIES DO NOT DETERIORATE
• QUIETER AND SMOOTHER
• TOLERATES A GREATER RANGE OF TEMPERATURES
8

9. DISADVANTAGES OF FLEXIBLE PAVEMENT
• LOSES SOME FLEXIBILITY AND COHESION WITH TIME
• NEEDS RESURFACING SOONER THAN PC CONCRETE
• NOT NORMALLY CHOSEN WHERE WATER IS EXPECTED
9

10. BASIC AASHTO FLEXIBLE
PAVEMENT DESIGN METHOD
• DETERMINE THE DESIRED TERMINAL
SERVICEABILITY, PT
• CONVERT TRAFFIC VOLUMES TO NUMBER OF
EQUIVALENT 18-KIP SINGLE AXLE LOADS
(ESAL)
• DETERMINE THE STRUCTURAL NUMBER, SN
• DETERMINE THE LAYER COEFFICIENTS, AI
• SOLVE LAYER THICKNESS EQUATIONS FOR
INDIVIDUAL LAYER THICKNESS
10

11. BASIC AASHTO RIGID PAVEMENT
DESIGN METHOD
• SELECT TERMINAL SERVICEABILITY
• DETERMINE NUMBER OF ESALS
• DETERMINE THE MODULUS OF SUB-GRADE REACTION
• DETERMINE THE SLAB THICKNESS
11

12. VARIABLES INCLUDED IN
NOMOGRAPHS
• RELIABILITY, R
• INCORPORATES A DEGREE OF CERTAINTY INTO DESIGN
PROCESS
• ENSURES VARIOUS DESIGN ALTERNATIVES WILL LAST THE
ANALYSIS PERIOD
• RESILIENT MODULUS FOR ROADBED SOIL, MR
• GENERALLY OBTAINED FROM LABORATORY TESTING
12

13. VARIABLES INCLUDED IN
NOMOGRAPHS
 EFFECTIVE MODULUS OF SUB-GRADE
REACTION, K
•CONSIDERS:
1.SUB-BASE TYPE
2.SUB-BASE THICKNESS
3.LOSS OF SUPPORT
4.DEPTH TO RIGID FOUNDATION
 DRAINAGE COEFFICIENT, MI
•USE IN LAYER THICKNESS DETERMINATION
•APPLIES ONLY TO BASE AND SUB-BASE
•SEE TABLES 20.15 (FLEXIBLE) AND 21.9 (RIGID)
13

14. 14

15. 15

16. 16

17. 17

18. 18

19. 19

20. 20

21. 21

22. 22

23. 23

24. 24

25. 25

26. FLEXIBLE PAVEMENT DESIGN
• PAVEMENT STRUCTURE IS A MULTI-LAYERED
ELASTIC SYSTEM, MATERIAL IS CHARACTERIZED
BY CERTAIN PROPERTIES
• MODULUS OF ELASTICITY
• RESILIENT MODULUS
• POISSON RATIO
• WHEEL LOAD CAUSES STRESS DISTRIBUTION (FIG
20.2)
• HORIZONTAL: TENSILE OR COMPRESSIVE
• VERTICAL: MAXIMUM ARE COMPRESSIVE, DECREASE
WITH DEPTH
• TEMPERATURE DISTRIBUTION: AFFECTS MAGNITUDE OF
STRESSES
26

27. COMPONENTS
27
Sub-grade (roadbed) course: natural material that serves as the
foundation of the pavement structure
Sub-base course: above the sub-grade, superior to sub-grade course
Base course: above the sub base, granular materials such as crushed
stone, crushed or uncrushed slag, gravel, and sand
Surface course: upper course of the road pavement, should withstand
tire pressures, resistant to abrasive forces of traffic, provide skid-
resistant driving surface, prevent penetration of surface water
3 inches to > 6 inches

28. ECONOMIC ANALYSIS
• DIFFERENT TREATMENTS RESULTS IN DIFFERENT DESIGNS
• EVALUATE COST OF DIFFERENT ALTERNATIVES
28

29. SENSITIVITY ANALYSIS
• INPUT DIFFERENT VALUES OF TRAFFIC VOLUME
• COMPARE RESULTING DIFFERENCES IN PAVEMENT
• FAIRLY SIGNIFICANT DIFFERENCES IN ADT DO NOT YIELD
EQUALLY SIGNIFICANT DIFFERENCES IN PAVEMENT
THICKNESS
29

30. OTHER ISSUES
• DRAINAGE
• JOINTS
• GROOVING (NOISE VS. HYDROPLANING)
• RUMBLE STRIPS
• CLIMATE
• LEVEL AND TYPE OF USAGE
30

31. FAILURE EXAMPLES
• PRIMARILY RELATED TO DESIGN OR LIFE-CYCLE, NOT
CONSTRUCTION
• ALL IMAGES FROM DISTRESS IDENTIFICATION MANUAL FOR
THE LONG-TERM PAVEMENT PERFORMANCE PROGRAM,
PUBLICATION NO. FHWA-RD-03-031, JUNE 2003
31

32. FATIGUE CRACKING
32

33. RUTTING
33

34. SHOVING
34

35. PUMPING
35