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Steve Jackson, PE Technical Manager NB West Contracting As seen on shinglerecycling.org 6 th Asphalt Shingle Recycling Forum Denver, CO With Solutions.

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Presentation on theme: "Steve Jackson, PE Technical Manager NB West Contracting As seen on shinglerecycling.org 6 th Asphalt Shingle Recycling Forum Denver, CO With Solutions."— Presentation transcript:

1 Steve Jackson, PE Technical Manager NB West Contracting As seen on shinglerecycling.org 6 th Asphalt Shingle Recycling Forum Denver, CO With Solutions

2 Joe Schroer, PE Field Materials Engineer Missouri Department of Transportation Steve Jackson, PE Excellence Engineer NB West Contracting

3  B.S. of Civil Engineering  B.S. of Economics  University of Missouri- Rolla  Professional Engineer  23 years in construction  15 years in asphalt

4  First shingle research in 2003  2.5%, 5%, 7.5%, 10%, 15%  First shingle project 2004  First MoDOT shingle project 2005  First MoDOT shingle – WMA project 2009

5  Most contractors were using RAP & RAS concurrently ( )  18% RAP and 2% RAS  17% RAP and 3% RAS  Due to the Smooth Road Initiative most work was being done on interstates  Superpave mixes  Percent Within Limits (Pay Factors)

6 Tonnage

7  Can we eliminate the fibers in SMA (Stone Matrix Asphalt) and replace them with shingles?  Can we use shingles and PG asphalt cement in lieu of polymer modified asphalt?

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9 PG PG 76-22

10  Iowa State, Dr. Chris Williams, P.I.  Missouri Lead State  FHWA, MN, IA, IN, CA, CO, IL, WI (IL Tollway)  Binder & Mixture Properties  QC/QA  Grind Size  RAP & FRAP  Preconsumer vs. Postconsumer  Demonstration Projects

11 COARSEFINE

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13 COARSEFINE

14 (139) (145) (159)

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17  At the same time we introduced shingles we also made other changes:  Warm Mix Asphalt to eliminate joint bumps  Added an elastic recovery specification for asphalt binder  AASHTO Mechanistic – Empirical Design ▪ AMPT/SPT – Mixture evaluation led to thinner pavements  9.5 mm Superpave mixture laid 1 ¼” thick

18  Shingle size is key to success  Overheating shingle mixes to “melt” the shingles (370° - 390° F)  Variability in RAS asphalt content  Real and perceived  Inflated specific gravities impact mixes*

19  Emphasis shifted from Primary Routes to Secondary Routes  Bituminous Pavements (MoDOT Section 401) in lieu of Superpave (MoDOT Section 403)  Less advanced quality control testing ▪ Gradation, deleterious, asphalt content and density ▪ No Percent Within Limits

20  Contractor Perspective  Asphalt Cement prices are high  Supply of shingles is high  Less “Mill & Fill” projects ▪ Less RAP from projects ▪ Large amounts of RAP stockpiled  Fiercely competitive market  Longer haul distances

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22  Base, BP-1 and BP-2 mixtures shall have the following properties, when tested in accordance with AASHTO T 245. The number of blows with the compaction hammer shall be 35 or the number of gyrations shall be 50 with the gyratory compactor. Air Voids Stability lb (N) VMA (3350) 13.0

23 SievePercent Passing by Weight (Mass) BaseBP-1BP-2 1 inch (25.0 mm) 100 ¾ inch (19.0 mm) ½ inch (12.5 mm) No. 4 (4.75 mm) No.8 (2.36 mm) No. 30 (1.18 mm) No. 200 (75 µm)

24 SievePercent Passing by Weight (Mass) BP-1BP-2 1 inch (25.0 mm) 100 ¾ inch (19.0 mm) 100 ½ inch (12.5 mm) No. 4 (4.75 mm) No.8 (2.36 mm) No. 30 (1.18 mm) No. 200 (75 µm) 5-12

25  Reclaimed Asphalt Shingles. Reclaimed Asphalt Shingles (RAS) may be used in any mixture specified to use PG in accordance with AASHTO PP 53 except as follows: When the ratio of virgin effective binder to total binder in the mixture is between 60 and 70 percent, the grade of the virgin binder shall be PG or PG  Shingles shall be ground to 3/8-inch minus.

26  Higher percentages of recycled materials  Less virgin binder in the mixes  Dryer looking mixes  Rut resistant roadways  Fatigue cracks earlier?  Is there a limit on recycled materials?  Contractors attempted to run up to 12% RAS  Not the mix Ron Sines spoke about yesterday

27  Changed design air voids to 3.5%  Increased VMA requirements:  Bit Base 13.0%  BP %  BP % (Surface Leveling)  50 gyration mix design was eliminated and replaced with a 35 gyration mix design  Requires a higher asphalt content

28  Corelok specific gravities were used in lieu of traditional AASHTO T 84/T 85  Gse values were variable  to  Could be impacted by reported asphalt content  No significant change in virgin binder content in some areas, but some higher quality aggregates were used

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31 Volumetric Properties of High RAP Mixtures Based on Calculated Bulk Specific Gravities of RAP and Constituent Aggregates Nassim Sabahfer Mustaque Hossain, Ph.D.,P.E. Department of Civil Engineering Kansas State University

32 VMA Obtained Using Gsb from Different Methods (Shilling RAP)

33 Reclaimed Asphalt Shingles. Reclaimed Asphalt Shingles (RAS) may be used in any mixture specified to use PG in accordance with AASHTO PP 53 except as follows: When the ratio of virgin effective binder to total binder in the mixture is between 60 and 70 percent, the grade of the virgin binder shall be PG or PG

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35 71%

36 58%

37  Sporadic Mixing Problems  Confined to Plants not Mixture  Harder to Place in Cool Weather  Low Voids on Long Haul  Tenderness  Asphalt Foamers Run at HMA Temps.  Shingle Pancakes – Clumps, Wads, Clinkers

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40  No shingles were permitted to be used in the surface leveling mixtures for the May and June contracts.  Not very many contracts - 2  Did not impact Superpave or other low volume route mix designs

41  Contractors got together in a morning session, worked together to provide recommended specification changes.  Met with MoDOT representatives after lunch and discussed the recommendations.  Adopted as a job special provision for the next bid letting.

42  Set Gsb of RAS at  Changed the gradation of the Surface Leveling mix design: % passing the 3/8” sieve.  Set Gsb of RAP at the Gsb of the virgin aggregates*  VMA minimum: 14.5%

43  Mixtures containing a combination of RAS and RAP may have a 30 to 40 percent effective virgin replacement under the following conditions: (1) with a virgin binder grade change from a PG64-22 to a PG or (2) with a combination of a PG64-22 binder and a rejuvenator provided testing demonstrates that a PG58-28, meeting the requirements of AASHTO M320, is achieved.

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47  Compaction Aid  Surfactant  Anti-Strip

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49 56 th ANNUAL ASPHALT CONFERENCE December 3-4, 2013 Havener Center, Campus of Missouri S&T Rolla, MO asphalt.mst.edu

50 Steve Jackson


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