Alabama Asphalt Pavement Association 630 Adams Avenue Montgomery

Alabama Asphalt Pavement Association 630 Adams Avenue Montgomery, AL 36104 334/834/5314 (Phone) 334/834/5537 (Fax) E-mail: alapa@bellsouth. net Web site: www. alasphalt. com 1

PAVEMENT PRESERVATION AUGUST 18, 2016 ACCA CONVENTION

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. 3

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

Why Thin Lift Asphalt?

Why Thin Lift Asphalt? Funding Crisis � Escalating Construction Cost � Flat Revenue cti u r t ns os C n o Co t Fewer Road Miles Less New Construction Dollars � Revenue Time

Why Thin Lift Asphalt? � Concept Of Pavement Preservation

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

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 √

Specifications For Thin Lift Asphalt

Alabama DOT Specifications

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

3/8 Inch Maximum Aggregate Size Mix Sieve Size 3/8 Inch Mix ½” 100 Section 416 , Mix 6 100 3/8” 95 - 100 90 - 100 #4 75 -100 65 - 82 #16 30 - 60 32 - 49 #200 6 - 12 3 -9 13

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

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. 15

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

Liquid Asphalt Binder Requirements � � PG 67 -22 Required For Less Than 10 Million 20 Year Design ESALs. PG 76 -22 Required For Between 10 Million And 30 Million 20 Year Design ESALs. 17

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. 18

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. 19

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. 20

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. 21

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

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 50 F 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. 23

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

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%. 25

Economic Value Of RAP And RAS

Economics Of RAP § § Value Of RAP § Assume AC Liq. Ton @ $320. 00 / Ton § Assume Virgin Agg. @ $ 15. 00 / Ton § RAP - 5% AC And 95% Aggregate Per Ton Value Of RAP. 05 x $320. 00 = $16. 00. 95 x $ 15. 00 = $14. 25 One Ton Of RAP = $ 30. 25* *Does not include costs to mill, haul and process

Economics Of RAS § § Value Of RAS § Assume AC Liq. Ton @ $320. 00 / Tn § Assume Virgin Agg. @ $ 15. 00 / Tn § RAS - 20% AC And 35% Aggregate Per Ton Value Of RAS. 20 x $320. 00 = $64. 00. 35 x $ 15. 00 = $ 5. 25 One Ton Of RAS = $69. 25* *Does Not Include Costs To Haul, Process, And Store.

Future - Other HMA Pavement Preservation Options

Thin Lift HMA – Less Than 80 Pounds Per Square Yard

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

100% RAP Mixes For Base Layers And Surface Layers

Questions ? ? ? 33

Alabama Asphalt Pavement Association 630 Adams Avenue Montgomery, AL 36104 334/834/5314 (Phone) 334/834/5537 (Fax) E-mail: alapa@bellsouth. net Web site: www. alasphalt. com 34