Dragos Andrei presented on sustainable road maintenance strategies. He discussed his background and experience in pavement engineering. The presentation covered the state of pavement infrastructure in California and the need for sustainable maintenance approaches. Andrei described key aspects of sustainable roads including durability, recyclability, and use of recycled materials. Various asphalt and concrete recycling techniques were outlined, including cold planning, hot in-place recycling, cold in-place recycling, and full depth reclamation. Implementation of sustainable strategies through pavement management systems and green rating programs was also discussed.

1. Sustainable
Road Maintenance
Dragos Andrei, Ph.D., P.E., M.ASCE
45th Annual MSA Conference
September 2013

2. About Dragos
• Associate Professor, Civil Engineering, California
State Polytechnic University
• Previous experience with Fugro and MACTEC
• P.E. California, Texas
• Ph.D. Arizona State University, M.S. University of
Maryland
• Director, Pavement Recycling and Reclaiming
Center at Cal Poly Pomona
• Principal Engineer and Partner, West Coast
Engineering Consultants

3. Outline
• State of the Pavement
• Sustainability and Sustainable Roads
• “Green” Asphalt Maintenance/Rehabilitation
Strategies
• “Green” Strategies for Concrete and Other
Pavements
• Implementation of Sustainable Maintenance
Strategies

4. Section 1
STATE OF THE
PAVEMENT

6. Source: California Local Streets and Roads Needs Assessment, January
2013, http://www.savecaliforniastreets.org/

8. 2011:
Source: Caltrans State of the
Pavement
2011, http://www.dot.ca.gov/hq/
maint/Pavement/Pavement_Progr
am/PDF/2011_SOP.pdf
2007:

9. Bottom Line
• We inherited a vast road network:
~ 50,000 lane miles state roads
~ 200,000 lane miles local roads
• More than 50% of these pavements are “at risk”
• For local roads, the funding available for
maintenance and rehabilitation is less than half
the funding required to maintain the current
condition.
• Traffic (demand) will continue to increase
• $$$ Needs will continue to increase

10. How Did We Get Here?
• Build, build, build … but how about the future?
– Don’t think about the future, enjoy the present …
• Who will maintain these pavements?
– Not my problem … I will be retired by then
• Who will pay for this?
– Don’t worry, THEY will find money, things will never
change …
• How are THEY going to rebuild these pavements?
– Don’t worry, there’s plenty of oil, cement, aggregate …

11. Section 2
SUSTAINABILITY
AND SUSTAINABLE ROADS

13. Sustainability Paradigm

14. Sustainable Roads: Key Features
•
•
•
•
•
•
•
•
•
Durability
Low maintenance
Low emissions/energy
Recyclable
Permeable
Cool
Smooth
Quiet
Complete, aesthetically pleasing.

15. Pavement Condition Index (PCI)
VERY GOOD
GOOD
FAIR
POOR
M&R Immediate Effect
Without M&R, Pavements Will Fail …
Life Extension
due to M&R
Original Service Life
VERY POOR
M&R Effect
Do Nothing
Curve
Time/Traffic

16. Long-Life, Low-Maintenance Roads

17. Low-Emissions/Energy Construction
and Maintenance
• Energy = fuel consumption = fossil fuels =
emissions
• Greenhouse Gases (GHG): water vapor, carbon
dioxide, methane, nitrous
oxide, ozone, CFC, other
• Carbon Footprint: measure of carbon dioxide
and methane emissions expressed in CO2e
(carbon dioxide equivalent for 100 years
global warming potential)

18. Source: The Environmental Road of the Future, Colas 2003

19. Carbon Footprint Categories:
• “Cold” M&R strategies: emulsion-based
seals, cold recycling, full-depth
reclamation, soil stabilization, etc.
• “Warm”: warm mix asphalt, maintenance
treatments with warm mix additive, etc.
• “Hot”: hot in-place recycling, hot mix
asphalt, etc.
• “Big Foot”: portland cement concrete (due to
the manufacturing of cement and steel)

20. Road Recycling - Asphalt
Store for later use in:
Hot Mix Asphalt (HMA)
Warm Mix Asphalt (WMA)
Crushed Miscellaneous Base (CMB)
Hot In-Place Recycling (HIR)
Cold In-Place Recycling (CIR)
Cold Central Plant Recycling (CCPR)
Full Depth Reclamation (FDR)

21. Road Recycling – Portland Cement
Concrete
Store for later use in:
Portland Cement Concrete (PCC)
Hot Mix Asphalt (HMA)
Crushed Miscellaneous Base (CMB)
Rubblization:
Break and Seat
Crack and Seat

22. RAP, RCA Management
• Both concrete and asphalt are 100% recyclable
• Avoid contamination of RAP/RCA stockpiles by
using good management practices:
– Use single-source stockpiles
– Separate stockpiles by size (fractionating)
– Ensure drainage and cover stockpiles to prevent
excessive moisture
– Use low slope to prevent segregation
• More information: http://www.morerap.us/
http://www.fhwa.dot.gov/pavement/recycling/rca.cfm

23. Recyclable Import
•
•
•
•
•
•
RAS: Recycled Asphalt Shingles
Crumb Rubber from Waste Tires
Blast Furnace Slag
Coal Ash
Silica Fume
Others

24. Permeable Pavements
• Reduce stormwater runoff
• Filter pollutants from water
• Permeable pavements are also “cool”
pavements when wet!
• More information:
– Pervious concrete: http://www.perviouspavement.org/
– Porous asphalt:
http://www.asphaltpavement.org/index.php?option=com_content&view=
article&id=359&Itemid=863
– Permeable pavers: http://www.icpi.org/permeable

25. Source: A permeable paver demonstration, Austin's Ferry, Tasmania, Australia, J.J.
Harrison, 2011

26. Cool Pavements
• Reduce the “heat island” effect by:
– Shading
– Increasing Solar Reflectance (Albedo)
• Painting/Coating low albedo materials
• Use high albedo materials
• Apply thin maintenance treatments with high albedo
materials: e.g. microsurfacing and whitetopping
– Increasing Thermal Emittance
• Use permeable pavements, water retentive pavements
– More Info: http://www.epa.gov/heatisland/mitigation/pavements.htm

28. Quiet Pavements
• Reduce the tire-pavement noise
• Methods:
– Open-graded friction course asphalt (+ rubber)
– Diamond grinding concrete pavements
– Noise barriers, sound walls
– Lowered alignment
• Challenges:
– Texture wears off with time and needs
maintenance/replacement

29. Source: Washington DOT Quieter Pavement
Research, http://www.wsdot.wa.gov/Business/materialslab/quieterpavement

30. Complete Streets
Source: Complete Streets, http://www.smartgrowthamerica.org/completestreets/complete-streets-fundamentals/complete-streets-faq

31. Section 3
ASPHALT
RECYCLING
IN-PLACE

32. In-Place Asphalt Recycling Techniques
•Milling
•Micro Milling
•Surface Recycling (Resurfacing)
•Remixing
•Repaving
•Cold In-Place Recycling (CIR)
•Cold Central Plant Recycling (CCPR)
•Pulverization
•Mechanical Stabilization
•Bituminous Stabilization
•Chemical Stabilization

33. Cold Planing/Milling Process

34. Cold Planing Applications
• Remove existing asphalt concrete surface
before overlay or for cold recycling (in-place or
central plant)
• Correction of longitudinal profile and crossslopes
• Restore pavement smoothness or help
achieve better smoothness upon resurfacing
• Restore surface friction (micro-milling)

35. CP Pattern Comparison
• Tool spacing and pattern, drum speed and
advance rate, will influence the final milled
pattern:
Source: Milling for Smoothness, Eric Baker, Roadtec
2013, http://www.arra.org/index.php?option=com_docman&task=doc_download&gid=510&Itemid=157

36. CP Equipment

37. CP Project Selection
Pavement Condition Index (PCI)
VERY GOOD
FAIR
Cold
Planing
POOR
Hot
In-Place
Recycling
GOOD
Cold
Recycling
Full Depth
Reclamation
VERY POOR
Time/Traffic

38. More CP Resources
• Basic Asphalt Recycling Manual, ARRA and
FHWA, Second Edition: expected January 2014
• Asphalt Recycling and Reclaiming
Association, http://www.arra.org/presentatio
ns/cold_planing.pdf

39. Hot In-Place Recycling (HIR): Remixing

40. Hot In-Place Recycling (HIR): Repaving

41. HIR Methods
• Recycling: add rejuvenating agent, no additive
• Remixing: add rejuvenating agent and additive:
– Virgin aggregate
– Asphalt cement
– Plant mix HMA
• Repaving: remixing + HMA overlay
• Stages:
– Single: up to 2 inch depth
– Multiple: up to 3 inch depth

42. HIR Applications
• Purpose: rejuvenate/renew/improve the
asphalt concrete surface, up to 2-3 inches
deep
• Use to address
raveling, weathering, bleeding, other types of
distress confined to the pavement surface.
• Will not mitigate structural problems
• Can be covered with chip seal or other thin
maintenance treatment

43. HIR Equipment
•
•
•
•
Heating units
Milling/Scarifying unit
Drying/Mixing unit
Paver
• Rollers
• Rejuvenating Agent
• Admixture truck
Source: Martec, http://martec.ca/2010/11/november-2010-ar2000-super-recycler-at-tradeshow/

44. HIR Train
Source: Brian Hansen, Dustrol, Inc.

45. HIR Equipment

46. HIR Project Selection
Pavement Condition Index (PCI)
VERY GOOD
FAIR
Cold
Planing
POOR
Hot
In-Place
Recycling
GOOD
Cold
Recycling
Full Depth
Reclamation
VERY POOR
Time/Traffic

47. More HIR Resources
• Basic Asphalt Recycling Manual, ARRA and FHWA, Second Edition:
expected January 2014
• Construction Inspection Checklist #11 Hot In-Place Asphalt
Recycling Application, FP2 and FHWA
http://www.fhwa.dot.gov/pavement/preservation/ppcl00.cfm a
second edition of this checklist is available in print and will soon be
available online.
• Caltrans Maintenance Technical Advisory Guide (MTAG) Volume I Flexible Pavement Preservation Second Edition, Chapter 13: InPlace
Recycling, http://www.dot.ca.gov/hq/maint/MTA_GuideVolume1Fl
exible.html
• Hot In Place Asphalt Recycling, Brian
Hansen, Dustrol, Inc., http://www.savemyroad.com/cir_hir/files/Ho
t-In-Place-Asphalt-Recycling.pdf

48. HIR Construction Checklist Contents
•
•
•
•
Document Review
Project Review
Materials Checks
Preconstruction
Meeting
• Pavement Preparation
• Equipment Inspections
•
•
•
•
•
•
Weather Requirements
Mix Design
Traffic Control
Project Inspection
Opening to Traffic
Common Problems and
Solutions

49. Cold In-Place Recycling (CIR)

50. CIR Applications
• Restore the structural integrity of the top 2-4
inches of the asphalt concrete
• Cover with HMA overlay or thin maintenance
treatment
• Effective in treating distress confined to the
pavement surface as well as thermal cracking.
• CIR is generally softer than HMA and may
delay reflective cracking.

51. CIR Equipment
•
•
•
•
•
•
Tankers
Milling machine(s)
Crushing and screening units
Mixer
Paver
Rollers

56. Cold Central Plant Recycling (CCPR)

57. CIR Project Selection
Pavement Condition Index (PCI)
VERY GOOD
FAIR
Cold
Planing
POOR
Hot
In-Place
Recycling
GOOD
Cold
Recycling
Full Depth
Reclamation
VERY POOR
Time/Traffic

58. More CIR Resources
• Basic Asphalt Recycling Manual, ARRA and
FHWA, Second Edition: expected January 2014
• Construction Inspection Checklist #12 Cold In-Place
Asphalt Recycling Application, FP2 and FHWA
http://www.fhwa.dot.gov/pavement/preservation/ppcl
00.cfm a second edition of this checklist is under final
review by ARRA and FHWA.
• Caltrans Maintenance Technical Advisory Guide (MTAG)
Volume I - Flexible Pavement Preservation Second
Edition, Chapter 13: In-Place
Recycling, http://www.dot.ca.gov/hq/maint/MTA_Guid
eVolume1Flexible.html

59. Full Depth Reclamation (FDR)

60. FDR Methods
• Pulverization
• Stabilization
– Mechanical = with aggregate or RAP
– Bituminous = with emulsified or foamed asphalt
– Chemical = with cement or other pozzolanic
materials
• No. of Passes:
– Single pass
– Multiple pass

61. FDR Application
• Restore the structural integrity of the
pavement over the entire treated depth
• Produce a uniform, stabilized, crack-free
material by mixing asphalt concrete with
underlying materials
• Cover with thin maintenance treatment,
asphalt concrete or other surfacing material.

62. FDR Equipment

63. FDR with Emulsified Asphalt

64. Grading
and
Compaction

65. FDR Project Selection
Pavement Condition Index (PCI)
VERY GOOD
FAIR
Cold
Planing
POOR
Hot
In-Place
Recycling
GOOD
Cold
Recycling
Full Depth
Reclamation
VERY POOR
Time/Traffic

66. More FDR Resources
• Basic Asphalt Recycling Manual, ARRA and
FHWA, Second Edition: expected January 2014
• FDR Construction Checklist, PRRC – FHWA ARRA available in print, it will be soon
available online
• Full Depth Reclamation, ARRA:
http://www.arra.org/presentations/fulldepth_reclamation.pdf

67. Section 4
IMPLEMENTATION

68. Green Up!
• Use a pavement management system
– Include sustainable maintenance and rehabilitation
strategies in the PMS (see article in August 2013
APWA Reporter)
– Keep the PMS data up to date
• Add or include a pavement preservation program
– Define pavement preservation triggers/criteria
– Establish default frequency for preservation
treatments

69. Green Up!
• Manage your resources better:
– Even when damaged, pavements have value:
aggregate, asphalt, cement, steel, etc.
– Use RAP/RCA best management practices
– Reuse materials as much as possible
• Require minimum three design/rehabilitation
alternatives for each project of which at least
one should specifically address sustainability

70. Green Up!
• Don’t forget the 4 R’s: Right treatment, Right
pavement, Right time, Right contractor.
• Learn more about sustainability and green
rating systems for pavements:
– LEED/Green Building Council
– Greenroads
– Invest
– Green Up

74. “Green Up”
• Software application to compare pavement
rehabilitation alternatives in terms of
sustainability; not a rating system;
• Under development at Cal Poly Pomona;
• Includes:
– Materials
– Technologies
– Surface Properties
– Life vs. Cost Analysis

75. Green Up: Materials

76. Green Up: Technologies

77. Green Up: Surface Properties and
Life/Cost

78. Green Up: Alternative Comparison
Mill and Fill
Mill, CIR and Overlay

79. Thank you
Dragos Andrei, Ph.D., P.E., M.ASCE
Associate Professor, Civil Engineering
Director, Pavement Recycling and Reclaiming Center
CAL POLY POMONA
dandrei@prrcenter.org
www.PRRCenter.org