1. Alabama Asphalt Pavement Association
630 Adams Avenue
Montgomery, AL 36104
334/834/5314 (Phone) /834/5537 (Fax)
Web site:

2. PAVEMENT PRESERVATION AUGUST 18, 2016 ACCA CONVENTION

3. Agency Funding
ALDOT And County Funds Are Limited And Are Expected To Remain Limited.
ALDOT And County New Construction Projects Are Becoming Rare.
If You Can Not Afford To Maintain Existing System, Why Add New To System?
ALDOT And County Priority Is Maintaining Current System.

4. Objectives - Why Thin Lift Asphalt?
Specifications For Thin Lift Asphalt.
Economic Value Of RAP And RAS
Future - Other HMA Pavement Preservation Options

5. Why Thin Lift Asphalt?

6. Why Thin Lift Asphalt? Funding Crisis Escalating Construction Cost
Flat Revenue
Construction Cost
Fewer Road Miles
Less New Construction
Funding Crisis –
As construction and material cost continue to rise, revenue from fuel taxes remains flat.
This fact creates a situation in which fewer miles of road can be paved per year and less new construction can be expected.
Both areas are important. New construction is needed to alleviate congestion and provide opportunity for economic development. Maintenance of our existing roads is important to keep a good level of service and avoid major reconstruction efforts.
Dollars
Revenue
Time

7. Why Thin Lift Asphalt? Concept Of Pavement Preservation
Pavement Preservation Concept –
Describe Level of Service Curve vs. Time
Motto of Pavement Preservation – “The right treatment at the right time”
This mindset AVOIDS/Postpones major reconstruction cost.

8. Why Thin Lift Asphalt? Benefits To The Traveling Public Improved Ride
Improved Smoothness
Public Perception – Freshly Paved Road – New Road
Public Perception – No Broken Windshields
Local / In State Contractors – Contributing To Tax Base And Employment At Local / State Level
Benefits to the Traveling Public
Improved Ride – Even at ¾” good paving practices indicate that there WILL be an improvement in the ride. We have excellent producers and lay down crews in Mississippi that will maximize the ride.
Public Perception – The public expects and wants fresh, newly paved asphalt pavements. The public perception of a single lift overlay is that it is a NEW ROAD.

9. Pavement Preservation Comparisons
Thin Lift
Micro-Surface
Scrub Seal
Chip Seal
Corrects Surface Distress √
Increase Skid Resistance
Minimizes Curb Loss
Can Be Applied In One Pass
Eliminates Loose Aggregate
Corrects Minor Rutting
Minimizes Delamination
Improves Ride Quality
Increases Structural Strength
Improves Pavement Drainage
And Pavement Cross Slope

10. Specifications For Thin Lift Asphalt

11. Alabama DOT Specifications

12. 3/8 Inch Maximum Aggregate Size Mix
SuperPave Mix
ALDOT Uses Maximum Aggregate Size Mixes
Finer Gradation Than Old ALDOT Section 416, Mix 6

13. 3/8 Inch Maximum Aggregate Size Mix
Sieve Size
3/8 Inch Mix
Section 416 , Mix 6 ½”
100
3/8” #4
#16
#200
6 - 12
3 - 9

14. 3/8 Inch Maximum Aggregate Size Mix – Design Considerations

15. Fine Aggregate Angularity (FAA) Requirements
FAA Greater Than Or Equal To 43 For Less Than 1 Million 20 Year Design ESALs.
FAA Greater Than Or Equal To 45 For Between 1 Million And 30 Million 20 Year Design ESALs.

16. Carbonate Stone (Limestone) Requirements
Varies From A Maximum of 30% To A Maximum of 50% Depending Upon BPN 9 Value of Aggregate Source.

17. Liquid Asphalt Binder Requirements
PG Required For Less Than 10 Million 20 Year Design ESALs.
PG Required For Between 10 Million And 30 Million 20 Year Design ESALs.

18. Design Gyration And Minimum Design AC Requirements
Design Gyration Of 60 Gyrations.
Minimum Design AC Content Of 5.90%For Mixes Without RAS.
Minimum Design AC Content Of 6.10% For Mixes With RAS.

19. Air Voids, VMA, Dust Proportion And TSR Requirements
Design Air Voids Of 4.0% For Mixes Without RAS.
Design Air Voids Of 3.5% For Mixes With RAS.
Minimum Design VMA Of 16.5% And Maximum Design VMA Of 18.0% With A 0.5% Production VMA Tolerance.
Dust Proportion Range Of 0.90 To 2.00 Based On Effective Asphalt Content.
TSR Minimum Of 0.80.

20. Spread Rate And Density Requirements
Spread Rate Can Be Specified From A Minimum of 80 Pounds Per Square Yard (0.72 Inches)To A Maximum Of 110 Pounds Per Square Yard (0.99 Inches).
Density Requirement Is To Satisfaction Of Engineer. Typically A Roller Pattern Using Non Destructive Density Gauges.

21. RAP And RAS Requirements And Warm Mix
Maximum 20% RAP Use.
Maximum 5% RAS Use.
Warm Mix Asphalt Allowed As Contractor Option On All Superpave Mixes.

22. Recommended Specification Changes For RAS
ALDOT Job Special For County Use Prohibiting Use of RAS In 3/8” Mixes.

23. Recommended Specification Changes For RAS
ALDOT General Use Special Provision For All Size Wearing Surface Mixes.
Reduce Allowable Maximum RAS Limit From 5% To 3%.
Require Air Temperature To Be At Least 50F And Rising Before Placing Wearing Surface Mixes Containing RAS.
Prohibit Ground Blending Of RAS At HMA Plant.
Require RAS To Be Metered In At HMA Plant.

24. Performance To Date No Structural Failures Reported.
No Major Performance Issues Reported.
No Friction Number Issues Reported.

25. 3/8 Inch Maximum Aggregate Size Mix Sample Mix Design
50% Limestone Screenings.
38% Granite Screenings.
10% Sand.
2% Baghouse Fines.
Design Asphalt Content : 6.25%.

26. Economic Value Of RAP And RAS

27. Economics Of RAP Value Of RAP Assume AC Liq. Ton @ $320.00 / Ton
Assume Virgin $ / Ton
RAP - 5% AC And 95% Aggregate
Per Ton Value Of RAP
.05 x $ = $16.00
.95 x $ = $ One Ton Of RAP = $ 30.25*
*Does not include costs to mill, haul and process

28. Economics Of RAS Value Of RAS Assume AC Liq. Ton @ $320.00 / Tn
Assume Virgin $ / Tn
RAS - 20% AC And 35% Aggregate
Per Ton Value Of RAS
.20 x $ = $64.00
.35 x $ = $ One Ton Of RAS = $69.25*
*Does Not Include Costs To Haul, Process, And Store.

29. Future Developments Future - Other HMA Pavement Preservation Options

30. Thin Lift HMA – Less Than 80 Pounds Per Square Yard

31. RAP Mixes Greater Than 20% Surface Layers and Greater Than 35% Binder Layer Different Liquid AC Grades (Softer) And / Or Rejuvenators

32. 100% RAP Mixes For Base Layers And Surface Layers

33. Questions ?????

34. Alabama Asphalt Pavement Association
630 Adams Avenue
Montgomery, AL 36104
334/834/5314 (Phone) /834/5537 (Fax)
Web site: