Asphalt Pavement Design Guide for Parking Lots and Low-Volume Roads

1. South Carolina Asphalt Pavement Association Asphalt Pavement DesignGuidefor Parking Lots and Low-Volume Roads Brad Putman, PhD Associate Professor Glenn Department of Civil Engineering putman@clemson.edu

2. Agenda Background Design considerations Thickness design Mix selection Construction Bonus features Focus group input

3. Please Note The contents of this presentation is based on the upcoming South Carolina Asphalt Pavement Design Guide for Parking Lots and Low-Volume Roads This publication is currently under development by SCAPA and will be available in the Fall 2013. The final contents of the guide may vary somewhat from this presentation.

4. The Road Show SC Engineering Conference & Trade Show North Charleston, SC (June 14, 2013) ASCE Upstate Branch Greenville, SC (June 25, 2013)

5. SCAPA Non-profit trade association dedicated to the promotion of asphalt concrete. “Together we know more” A resource…here to help www.scasphalt.org

6. Background and Need What guidelines are available for commercial and local paving projects? Is a parking lot or subdivision the same as US 17, Dorchester Rd., or other high traffic roadways? Is the traffic the same? Do low-volume pavements fail in the same way as higher-volume roads? So why do we use the same design methods and specifications? Potential cost savings with alternate designs and materials.

7. Typical Asphalt Pavement Section Asphalt Base Course (Full-Depth Asphalt) Aggregate Base Course Asphalt Surface Course Asphalt Intermediate Course Asphalt Base Course Aggregate Base Course Subgrade

8. Design Considerations • Why do pavements fail? • Traffic • Subgrade • Drainage • Environment • Materials • Construction • Design • Other

9. Other Pavement Design Guides There are others, but I left my list in Clemson

10. Contents of the Design Guide • Construction • Best practices • Checklists • Glossary • Technical Notes • Specific topics • Contact Information • SCAPA • Introduction • Mission of the Guide • Asphalt and its advantages • Pavement Design • Design considerations • Pavement materials • Thickness design

11. Design Considerations [Traffic] Class 1 (≤ 50 cars/day) Class 2 (≤ 5 trucks/day) Class 3 (≤ 65 trucks/day) Class 4 (≤ 200 trucks/day) • Driveways • Play areas • Parking lots (≤ 50 stalls) • Seasonal recreation roads • Residential streets • Parking lots (> 50 stalls) • Collector streets • Industrial lots, truck stalls • Bus driveways & loading zones • Major arterial streets • Local business streets • Local industrial streets • Major service drives or entrances

12. Design Considerations [Subgrade] Any structure is only as good as the foundation upon which it is built.

13. Design Considerations [Subgrade] Poor Medium Good • Retain a moderate degree of firmness under adverse moisture conditions. • Loams, silty sands, and sandy-gravels containing moderate amounts of clays and fine silts. • Typical properties • CBR: 6–9 • LL: 25–40 • PI: 6–10 • Soil types • A-4, A-5 • Become soft and plastic when wet. • Clays and fine silts • ≥ 50% passing No. 200 • Coarse silts and sandy loams • Deep frost penetration • High water table • Typical properties • CBR < 6 • LL ≥ 40 • PI ≥ 10 • Retain a substantial amount of their load-supporting capacity when wet. • Clean sands, sand-gravels, and those free of detrimental amounts of plastic fines. • ≤ 10% passing No. 200 • Relatively unaffected by moisture or frost. • Typical properties • CBR ≥ 10 • LL ≤ 25 • PI ≤ 6 • Soil types • A-1, A-2, A-3

14. Design Considerations [Subgrade]

15. Design Considerations [Drainage] • Three keys to pavement design: • DRAINAGE, DRAINAGE, DRAINAGE • Surface drainage • Safety • Prevent water from entering pavement surface • Subsurface drainage • Areas with high water table • Areas where water accumulates in low areas

16. Design Considerations [Drainage] Tuesday, July 23, 2013

17. Design Considerations [Drainage]

18. Thickness Design • Design inputs • Subgrade • Traffic • Asphalt or aggregate base?

19. Layer Thickness Selection Full-Depth Asphalt

20. Thickness Design • Design inputs • Subgrade • Traffic • Asphalt or aggregate base? • Equivalence • 1 in. of Asphalt Base ≈ 2–3 in. of Aggregate Base

21. Layer Thickness Selection Asphalt with Aggregate Base Course

22. Asphalt Mix Selection Project A • City street reconstruction as part of a downtown redevelopment. • Total thickness = 5½ in. 5½ in. What mix should I choose and how thick should each layer of asphalt be?

23. Asphalt Mix Selection High Traffic 3 Medium Traffic 2½ 2 Minimum Lift Thickness, in. Low Traffic 1½ 1 ½ 0 E D C B Surface Mix Type

24. Asphalt Mix Selection Type C Surface Course • Typical Applications • Traffic Class 2 & 3 • ADT: 1,500 – 5,000 Example Surface Texture

25. Asphalt Mix Selection Project A • City street reconstruction as part of a downtown redevelopment. • Total thickness = 5½ in. 1½ in. Surface C Intermediate Type C 2½ in. 5½ in. 2 in. 4 in. 2 in. 1½ in. What mix should I choose and how thick should each layer of asphalt be?

26. A typical parking lot Access Street Building Building Building Building

27. Thickness Design Class 1 (≤ 50 cars/day) Class 2 (≤ 5 trucks/day) Class 3 (≤ 65 trucks/day) Class 4 (≤ 200 trucks/day) • Driveways • Play areas • Parking lots (≤ 50 stalls) • Seasonal recreation roads • Residential streets • Parking lots (> 50 stalls) • Collector streets • Industrial lots, truck stalls • Bus driveways & loading zones • Major arterial streets • Local business streets • Local industrial streets • Major service drives or entrances

28. A typical parking lot Access Street Building Building Building Building

29. A typical parking lot Access Street Building Building Building Building

30. A typical parking lot Access Street Building Building Building Building

31. Pavement Construction • Best practices • Subgrade preparation • Base construction • Asphalt paving • Conditions • Tack • Laydown • Compaction • Asphalt mix production • Staged construction (especially for subdivisions) • Quality contractors (SCAPA members)

32. What Else? • Asphalt pavement glossary • Sample specifications • Special topics • Distress glossary • Resurfacing • Maintenance • Surface treatments • Aggregate • Sustainability • …and much, much more

33. We Asked Attendees for Their Input

34. Focus Group Suggestions • Annual maintenance plans & costs • Change of ownership from private to public • Staged construction • Warranties • Maintenance of existing pavements • Details for tie-ins • Porous asphalt • Maneuvering of large trucks in small areas • Geosynthetics • Soil amendments • Buy-in from cities and counties • Separate guides for parking lots and low-volume roads • Vehicle types to consider • Verify pavement designs with established methods

35. Coming Soon FALL 2013 South Carolina Asphalt Pavement Design Guide for Parking Lots and Low-Volume Roads “Together we know more” www.scasphalt.org

36. Brad Putman, PhD • Associate Professor • Glenn Department of Civil Engineering • putman@clemson.edu