ACTIVE ASPHALT RESEARCH PROJECTS

1
ACTIVE ASPHALT RESEARCH PROJECTS

• Bill Maupin
• Principal Research Scientist

2

• Use of Waste Shingles
• High Binder / High Modulus Field Project
• Optimized Surface Mix Design
• Pooled Fund Studies
• Intelligent Compaction
• SM-4.75 Mix Design

3
Using Waste Shingles

• Past study Manufacturing Waste
• Present study Tear-off Waste
• Green Highway Project

4
BACKGROUND

• In the 1990s a recycling committee set up by the
  state legislature developed a list of waste
  materials that potentially might be used in
  highway construction
• One of the materials listed by the committee was
  recycled roofing material
• VDOT did a literature search and developed a
  draft special provision to allow trial of waste
  shingles upon request

5
BACKGROUND (Contd)

• In 2006 the Hampton Roads District received a
  request from Rose Brothers to try manufacturing
  shingle waste on a plant mix schedule in
  Southampton County
• Arranged to place approximately 2000 tons each of
  SM-9.5A with shingles and SM-9.5A without
  shingles for comparison

6
- PAST STUDY -Manufactured Shingle Waste

• Evaluated 2500 tons of SM-9.5A with 5 percent
  shingle waste
• Compared 2200 tons of SM-9.5A with 10 percent RAP
• Constructed by Rose Brothers in 2006
• Shingle waste from manufacturing facility in
  North Carolina

7
SHINGLE WASTE
8
SHINGLE SHREDDER
9
SHREDDED SHINGLES
10
SHINGLE CONTENT

• 18 percent asphalt
• 34 percent filler
• 45 percent granules and sand
• 2 percent fiber glass
• 1 percent tape and water

11
EVALUATION

• Observe construction
• Test pavement
• Density
• Permeability
• Test hot mix samples
• Volumetrics, Fatigue, TSR, Rut, Abson Recovery
• Pavement performance

12
RECOVERED BINDERVirgin Binder PG 64-22
13
CONCLUSIONS

• Both mixes behaved similarly during placement and
  compaction
• Both mixes behaved similarly under laboratory
  testing
• Both recovered binders passed as PG 70-22
• Performance is good for both mixes
• A Special Provision is available

14
-Present Study-Use of Tear-off Shingle Waste

• ARAC recommended that a study be done on the use
  of tear-off shingles
• Approval process is complete and research has
  started

15
Are Tear-offs Different?

• Binder in tear-off shingles has aged and may be
  more brittle
• Foreign materials such as wood and metal could be
  present if not processed properly
• Asbestos May require PLM testing

16
RESEARCH STUDY

• Purpose Determine suitability of using tear-off
  shingle waste in asphalt concrete
• Laboratory study
• Properties of binder in shingles and shingle-mix
• Test mix containing shingles volumetric,
  fatigue, rut, TSR
• Field test Install short test section(s)
  containing shingle mix and conventional mix
• Gather information on availability of shingles

17
POSSIBLE COST SAVINGS

• Asphalt cement binder selling for more than 765
  per ton (38 per lb.)
• The asphalt binder in shingles estimated to cost
  less than 3 per lb. plus transportation
• Estimated savings of several dollars per ton of
  hot mix asphalt (HMA)

18
Sources of Ground Tear-offs?

• Asphalt Roof Recycling Mt. Airy, MD Walt
  Johnson, [phone]
• Tidewater Green Corp Chesapeake, VA by
  January ?
• Waterway Materials Corp Chesapeake, VA ?

19
TEAR-OFF SHINGLESAsphalt Roof Recycling Center -
MD
20
PICKING OUT NON-SHINGLE MATERIAL
21
SHINGLES FARM ROADS
22
Test Section?

• Would like to install a small section of pavement
  containing 4 to 5 shingles
• Get construction experience, samples for lab
  testing, observe performance

23
GREEN HIGHWAY PROJECT

• Possible construction project(s) being planned to
  utilize waste materials for a Green Highway
  Demonstration Project
• Structural fill - slag, foundry sand, coal ash,
  shredded tires, compost mulch
• Asphalt pavement shingles
• Several possible future construction projects in
  tidewater area

24
HIGH BINDER HIGH MODULUSFIELD TEST

• Brian Diefenderfer
• Bill Maupin

25
Progression of Study

• Idea - Use an asphalt-rich base mix to improve
  durability and provide a perpetual pavement
  structure
• Lab study completed
• Field study in progress

26
LABORATORY STUDY
PERM
TSR
FATIGUE
RUTTING
27
LAB STUDY RESULTS

• Predicted field voids decreased 1.0 1.5 for
  each 0.4 increase in AC
• Decrease in voids reduced permeability and should
  produce less chance of moisture damage
• Increase in AC benefited fatigue life
• Lab rut tests were acceptable for at least 0.8
  extra AC with PG 70-22

28
PAVEMENT ANALYSIS

• Performed theoretical pavement analysis based on
  I-81 traffic
• Used MEPDG to determine effect of changing mix
  properties
• Types of binders (64-22, 70-22, 76-22)
• Asphalt content ( 0.6, 1.2)
• Air void content (- 2.0, 2.0)
• Ran 21 different combinations

29
TYPICAL PAVEMENT SECTION
30
PAVEMENT ANALYSIS FINDINGS
31
Conclusions MEPDG Analysis

• Stiffer binder in IM mix offered improvement in
  resistance to rutting
• High binder low air void content base mix
  showed potential for resistance to fatigue
  cracking
• Suggest development of a design following
  perpetual concepts
• fatigue resistant base mixes

32
FIELD TEST SECTION

• ARAC recommended that a field test section with
  high binder be installed
• A construction project has been located in the
  Fredericksburg District near Carmel Church,
  relocation near intersection of Rtes 207, 652 and
  I-95
• Section consists of 6 of BM-25.0D
• Goes to ad in December, 2008

33
FIELD TEST SECTION (Contd)

• 3 sections to be built and evaluated
• Conventional BM-25.0D
• Conventional BM-25.0D 0.4 AC
• Conventional BM-25.0D 0.8 AC
• Tests to be performed by VDOT / VTRC in lab and
  field for each section on various layers
• Desire to instrument base layer with strain
  gauges

34
FIELD TEST SECTION (Contd)

• Construction will be observed
• Test results on various layers will indicate
  in-place properties
• Properties will be used to predict future
  performance of pavement sections
• Long term performance will be monitored

35
OPTIMIZED SURFACE MIX DESIGN PROJECT

• Other states believe durability to be a problem
  and have made mix design changes
• We decreased our compaction level to 65 gyrations
  to increase asphalt content
• The general feeling is that still some of our
  mixes are not durable

36
Questions

• Has Superpave resulted in lesser amount of
  designed asphalt content?
• Pre-Superpave design mix temperature was the same
  between mixes therefore did the equiviscous
  Superpave requirement produce thinner films for D
  and E mixes?
• How much asphalt will mixes safely tolerate?
• Superpave gradation band is wide therefore,
  where on the band are mixes being designed?
• Are optimum gradations being used?

37
RESEARCH PROJECT

• Develop a brief history of past VDOT design
  requirements
• Examine production QC/QA test results of
  Superpave and pre-Superpave mixes
• Use lab rut test procedure to determine if
  asphalt contents are near the safe maximum amount
• Determine how to make design changes if changes
  are justified

38
POOLED-FUND STUDIES

• Each state contributes an equal amount to conduct
  a study
• Current studies
• Intelligent Compaction
• SM-4.75 mix design

39
INTELLIGENT COMPACTION

• Accelerated Implementation of IC Technology for
  Soils, Base, and Asphalt Materials -
  http//www.intelligentcompaction.com/
• Develop experience and identify needed
  improvements
• Possible benefits
• Improve density
• Improve efficiency
• Improve quality control information

40
IC STUDY

• 12 DOTs are participating
• Managed by FHWA
• Research conducted by Transtec Group
• At least 1 field demonstration in each state
• IC roller requirements
• Stiffness measuring system
• Self adjusting feedback system
• GPS mapping system

41
IC ROLLER CAPABILITIES
42
NUMBER OF ROLLER PASSES
Shoulder
Longitudinal Joint
Courtesy Sakai America
43
SM-4.75 MIX DESIGN STUDY

• Do we need thin mixes?
• Refine procedures and criteria for 4.75mm
  Superpave mix design
• National Center of Asphalt Technology
• 8 states are supporting the study
• Conducting field tests in several states

44
SM-4.75 MIX DESIGN STUDY

• Delayed several times because of the lack of
  field sections
• New completion date of March 1, 2009

45
NEW STUDY Catfish Slime Asphalt Release Agent
46
THE END