Final year project ppt - The Future of Pavement Design

Investigation into the use of the mechanistic empirical pavement design methodology for the design of a roadway pavement in Vergenoegen.

1. UNIVERSITY OF GUYANA Faculty of Technology Department of Civil Engineering NAME: RIAZ ZALIL REG.NO: 10/0933/0102 INTERNAL SUPERVISOR: DR. CHARLES GARRETT

2. TITLE Pilot Study into the Use of Mechanistic-Empirical Design Technology for the Design of a Roadway Pavement in Vergenoegen

3. PRESENTATION OUTLINE Introduction Background Problem Statement Objectives Scope of project Methodology Pavement Design Approach Pavement Response Modeling Pavement Alternatives AASHTO 1993 Design AASHTO 2002 Evaluation Economic Evaluation Pavement Type Selection Pavement Structure Conclusion Recommendations

4. INTRODUCTION Purpose of Access Road: Facilitate the movement of farmers to and from the backlands Access route to arable farm lands for cultivation Low volume roadway Geometric Configuration: Length = 3 miles ( km) Width = 22 ft ( m)

5. BACKGROUND The Access Road in Vergenoegen Look at this road…I ain’t going deh !

6. BACKGROUND Location (6 52’24.9’’N and 58 21’51.30’’W) Main Road Access Road Access Road

7. BACKGROUND Condition (Wet Seasons)

8. BACKGROUND Condition (Dry Seasons)

9. PROBLEM STATEMENT The statement of problem is to design a new pavement structure for the access road in Vergenoegen that could fulfill all the traffic and environmental conditions while at the same time being an economically viable structure.

10. OBJECTIVES Quantify and characterize the loadings of the various vehicles that uses the current facility Investigate and evaluate the potential of suitable pavement alternatives for a cost effective alternative to accommodate the present and future traffic loads on the road Evaluate the potential advantages and disadvantages of pavement alternatives Carry out life cycle cost analysis on the various pavement alternatives to determine the most promising alternative Design proposal of a suitable access road based on the most promising pavement alternative

11. LIMITATIONS Selection is limited to the most feasible alternatives considered Use of the AASHTO 1993 & AASHTO 2002 Guides for the Design of Pavement structures Pavement distress is based on cracking and rutting predictions as computed from the pavement responses using the WinJULEA software

12. METHODOLOGY

13. PAVEMENT DESIGN APPROACH AASHTO 1993 Guide for the Design of Pavement Structures AASHTO 2002 Guide for the Mechanistic-Empirical Design of Pavement Structures

14. PAVEMENT RESPONSE MODELING

15. PAVEMENT ALTERNATIVES Alternative 1 Flexible Pavement Alternative 2 Semi Rigid Pavement Alternative 3 Cement Treated Pavement

16. AASHTO 1993 DESIGN Design Traffic (Overall 18kips ESALs) Graph Showing the Cumulative 18kips ESALs Over the 20 year Design Life 136, 584

17. AASHTO 1993 DESIGN Design Traffic for 20 Years W18 = D D xD L x W 18 D D = 50% (0.5) D L = 100% (1) W 18 = 136,584.6342 [18kips ESALs] Therefore, W18 = 0.5 x 1 x 136, 584.6342 18kips ESALs W18 = 68, 293 [18kips ESAL]

18. AASHTO 1993 Design Pavement Material Properties Material Function CBR (%) Modulus (psi) Structural Layer Coefficient (Correlated from AASHTO 93 ) Hot Mix Asphalt Surface Course 400,000 @ 68F 0.43 Crusher Run Base Course 60 0.12 Cement Stabilized Material Base Course 830,000 @ 7days 0.22 White Sand Subbase Course 6 0.06 In-Situ Soil Subgrade 2 3000

19. OTHER FACTORS Design Parameters Reliability, R = 75% Standard Deviation, S o = 0.45 Initial Serviceability, p i = 4.5 Terminal Serviceability, p t = 2

20. DESIGN NOMOGRAPH Required Structural Number Design Chart for Flexible Pavements used for Estimating the Structural Number Required

21. LAYER THICKNESS COMPUTATION Alternative 1 (Flexible Pavement) Initial Structural Number 2.3 Layer Thickness Determination   Layer 1 Thickness, D1 (inch) 2 Layer 2 Thickness, D2 (inch) 6 Layer 3 Thickness, D3 (inch) 12 Final Structural Number 2.3 Asphalt Concrete Crusher Run Ordinary White Sand 2in 6in 12in

22. LAYER THICKNESS COMPUTATION Alternative 2 (Semi Rigid Pavement) Initial Structural Number 2.3 Layer Thickness Determination   Layer 1 Thickness, D1 (inch) 2 Layer 2 Thickness, D2 (inch) 4 Layer 3 Thickness, D3 (inch) 12 Final Structural Number 2.5 Asphalt Concrete Cement Treated Base Ordinary White Sand 2in 4in 12in

23. LAYER THICKNESS COMPUTATION Alternative 3 (Cement Treated Pavement) Initial Structural Number 2.3 Layer Thickness Determination   Layer 1 Thickness, D1 (inch) 1 Layer 2 Thickness, D2 (inch) 7 Layer 3 Thickness, D3 (inch) 13 Final Structural Number 2.3 Chip Seal Cement Treated Base Ordinary White Sand 1in 7in 13in

24. AASHTO 2002 EVALUATION Material Function Resilient Modulus (psi) Poisson’s Ratio Hot Mix Asphalt Surface Course 400,000 0.25 Crusher Run Base Course 25,715 0.15 Cement Stabilized Material Base Course 830,000 0.35 White Sand Subbase Course 8,182 0.3 In-Situ Soil Subgrade 3000 0.2 Note: All pavement layers were assumed to be fully bonded together at the interfaces.

25. EVALUATION CRITERIA Traffic Loadings 9000 lbs 9,000 lbs 18,000 lbs Tire Radius = 6inches Tire Pressure = 75psi Fully Bonded Conditions

26. FLEXIBLE PAVEMENT Bottom Up Cracking (HMA) Chart Showing the % of Lane Area Cracked Over the Design Life for the Flexible Pavement as a Result of Bottom Up Cracking

27. FLEXIBLE PAVEMENT Top Down (Longitudinal) Cracking (HMA) Chart Showing the Length of Longitudinal Cracking of the Flexible Pavement Over the Design Life as a Result of Top Down Cracking

28. FLEXIBLE PAVEMENT Rutting (Entire Pavement) Chart Indicating Total Rutting of the Flexible Pavement Over the Design Life

29. SEMI RIGID PAVEMENT Bottom Up Cracking (HMA) Chart Indicating Predicated % of Lane Area Cracked for the HMA Layer of the Semi Rigid Pavement Over the Design Life as a Result of Bottom Up Cracking

30. SEMI RIGID PAVEMENT Top Down (Longitudinal) Cracking (HMA) Chart Indicating Predicted Longitudinal Cracking of the HMA Layer for the Semi Rigid Pavement over the Design Life as a Result of Top Down Cracking

31. SEMI RIGID PAVEMENT Rutting (HMA) Chart Indicating Total Rutting in HMA Layer of the Semi Rigid Pavement Over the Design Life

32. SEMI RIGID PAVEMENT Flexural Cracking (CTB) Chart Indicating Length of Cracking at the Bottom of the Cement Treated Layer for the Semi Rigid Pavement Over the Design Life as a Result of Fatigue Cracking

33. CEMENT TREATED PAVEMENT Flexural Cracking (CTB) Chart Indicating Length of cracks at the Bottom of the Cement Treated Layer for the Cement Treated Pavement over the Design Life as a Result of Fatigue Cracking

34. ECONOMIC EVALUATION Pavement Alternatives Construction Cost/100m (G$) Flexible Pavement 4, 601, 600 Semi Rigid Pavement 3, 153, 600 Cement Treated Pavement 1, 661, 400 Cost of Construction for Pavement Alternatives

35. PAVEMENT TYPE SELECTION Evaluation Criteria Construction Cost Ease of Maintenance Life Cycle Cost Failure potential Load Distribution Moisture Sensitivity Total Weight  25  5  30 10 20  10 100 Flexible Pavement 10 2  16   2 8 4 42 Semi Rigid Pavement 16 3 20 4 12 5 60 CTB Pavement 22 3.5 28 5 15 8 81.5 Decision Matrix for the Selection of the Most Suitable Pavement Alternative

36. PAVEMENT STRUCTURE

37. ROADWAY DESIGN Subgrade Shoulder Chip Seal (1in) Cement Treated Layer (7in) White Sand (13in)

38. CONCLUSION The pavement alternatives evaluated ranged from flexible, semi rigid to cement treated pavements Utilization of the AASHTO 2002 Guide for the Design & Evaluation of Pavement Structures The most viable pavement alternative is the cement treated pavement since it is the most cost effective pavement structure while optimizing the level of service to the road users

39. RECOMMENDATIONS Calibration of the empirical models to local conditions to relate predicted distress to actual distress occurrence The use of the axle load spectra concept instead of the 18kips ESAL concept Modeling of the environmental conditions on the performance of the pavement structures (temperature & moisture) Modeling of other distress modes such as reflective cracking

40. THE END THANK YOU FOR LISTENING! ANY QUESTIONS?