1. Composite Pavements: Design, Construction, and Benefits
Michael I. Darter & Derek Tompkins
Pavement Research Institute
University of Minnesota

2. History of Composite Pavements Critical Issues for Composite Pavements
Presentation Outline
History of Composite Pavements
Critical Issues for Composite Pavements
Design
Construction
SHRP2 R21 Composite Pavements
12th Annual MN Pavement Conf
14 Feb 2008

3. Types of pavements generally called “Composite” Pavements:
Brief History of
Composite Pavements
All pavements are “composite” since they consist of layers of different materials bonded together.
Types of pavements generally called “Composite” Pavements:
AC/PCC (new construction)
PCC/PCC (“wet-on-wet”)
12th Annual MN Pavement Conf
14 Feb 2008

4. European usage with AC/CRCP is common on major freeways
AC-over-PCC
Composite Pavements
North American urban areas, US States, & Canadian Provinces have built AC/PCC for many years
European usage with AC/CRCP is common on major freeways
Relatively
thin AC
surfacing
Newly placed
PCC w/ local
aggregates
12th Annual MN Pavement Conf
14 Feb 2008

5. Composite Pavements (Cont.)
AC-over-PCC
Composite Pavements (Cont.)
New AC/JPCP composite pavements built by NJ, WA, WI, and Ontario in the past on major highways
New AC/JPCP and CRCP on lane addition projects
Urban areas such as Columbus, OH; NYC and adjoining boroughs; Wash. D.C.; and City of Toronto
Construction of AC/CRCP on major European highways: Holland, Austria, Germany, France, Italy, and UK
Relatively thin AC layer (2-3 in) over relatively thin CRCP
Considerable AC/Roller Compacted Concrete has been built in various locations (e.g., Columbus, OH; Spain)
12th Annual MN Pavement Conf
14 Feb 2008

6. PCC-over-PCC Composite Pavements
PCC / PCC composite pavements used frequently in Europe
State-of-the-art construction expertise & equipment resides in Europe
High quality smaller-
Sized aggregates
Lower-cost local
aggregates
12th Annual MN Pavement Conf
14 Feb 2008

7. Composite Pavements (Cont.)
PCC-over-PCC
Composite Pavements (Cont.)
First concrete pavement built in the U.S. (1891 in Ohio) was a two-lift composite pavement.
12th Annual MN Pavement Conf
14 Feb 2008

8. Composite Pavements (Cont.)
PCC-over-PCC
Composite Pavements (Cont.)
European countries: Germany, Austria, Belgium, Netherlands, and France.
PCC/PCC built mainly to provide a cap of high quality aggregate concrete over a thicker layer of lower quality local aggregates or recycled concrete
Some projects included porous concrete as the top layer
US applications (Detroit freeway, 1993), though not as numerous as those of Europe, have resulted in useful research results.
12th Annual MN Pavement Conf
14 Feb 2008

9. Two Layer Concrete With Exposed Aggregate
Permanent high skid resistance
Low development of noise
Long term life
Exposed aggregate surface

10. Critical Issues for AC/PCC Composite Pavements
Quality of the AC mixture is critical. The most critical issues include permanent deformation, stripping of asphalt, de-bonding with the PCC, and reflection cracking.
Functional performance of the AC surfacing ideally also provides low noise, high friction, reduced splash and spray, and smoothness.
The ability of the AC surfacing to bond securely and have full friction with the PCC slab surface.
12th Annual MN Pavement Conf
14 Feb 2008

11. Cold milling equipment
Critical Issues for AC/PCC:
Rapid renewal
Cold milling equipment
Ability to remove and replace the AC surfacing rapidly and reliably
12th Annual MN Pavement Conf
14 Feb 2008

12. Needed: A reflection cracking solution for JPCP or RCC
Critical Issues for AC/PCC:
Reflection cracking
Needed: A reflection cracking solution for JPCP or RCC
12th Annual MN Pavement Conf
14 Feb 2008

13. AC over PCC (NYC experiment)
12th Annual MN Pavement Conf
14 Feb 2008

14. Critical Issues for AC/PCC: Reflection cracking (cont.)
New AC
Possible solution: ‘Saw and Seal’ joints in the AC surfacing over joints in JPCP or RCC
12th Annual MN Pavement Conf
14 Feb 2008

15. Example 1: Saw and Seal 15+ year old Saw & Seal transverse joints
12th Annual MN Pavement Conf
14 Feb 2008

16. Example 2: Saw and Seal Sawing missed joint
12th Annual MN Pavement Conf
14 Feb 2008

17. Composite Pavements (Cont.)
Critical Issues for
Composite Pavements (Cont.)
Design of the JPCP or RCC slab is critical. The key factors include thickness, joint spacing, load transfer at joints, slab width/shoulders, PCC coefficient of thermal expansion, PCC strength/modulus, and base course.
Slab should be designed to have low fatigue damage over the entire analysis period so that fatigue cracking will not develop.
12th Annual MN Pavement Conf
14 Feb 2008

18. Design to Minimize Fatigue Damage and Cracking
12th Annual MN Pavement Conf
14 Feb 2008

19. Composite Pavements (Cont.)
Critical Issues for
Composite Pavements (Cont.)
Development of construction guidelines and QA procedures are also critical, both for composite AC/PCC and PCC/PCC pavements
12th Annual MN Pavement Conf
14 Feb 2008

20. SHRP 2 Renewal Goal Successful Renewal Rapid Approaches
Minimal
Disruption
Successful
Renewal
Long-Lived
Facilities
To develop a consistent, systematic approach to performing highway renewal that:
is rapid
causes minimum disruption
produces long-lived facilities
The overall SHRP II Renewal program goal as stated in TRB Special Report 260 is:
To develop a consistent, systematic approach to performing highway renewal that is rapid, causes minimum disruption, and produces long-lived facilities.
A successful renewal project is one in which expedited applications of existing and new techniques and technology reduce disruptions and yield long-lived facilities. These three principles are key for the delivery of a successful Renewal program…..“Expedited Applications + Minimized Disruption + Long-Lived Facilities = Successful Renewal
Emphasize that this is an integrated approach…..
Rapid Approaches involve
Faster In Situ construction
Minimizing Field Fabrication Effort
Faster construction Inspection/Monitoring
Facilitation of innovative contracting environment
Minimal Disruption involve
Planning improvements to mitigate disruption
Improving Customer relationships (i.e. utility companies vs. DoTs)
Long-Lived Facilities involve
Designing and constructing low-maintenance facilities
Preserving facility life
In many instances, these three principles are interrelated. For example, producing a long-lived facility will minimize disruption since maintenance will be minimized.

21. SHRP 2 Renewal Projects R21. Composite Systems Rapid Approaches
Long-Lived Facilities
R01. Locating &
Characterizing Utilities
R19. Durable Bridge
Systems
Minimize Disruption
R16. Railroad-DOT
Mitigation Strategies
R02. Geotechnical
Solutions
R21. Composite Systems
R21. Composite
Systems
R04. Innovative Bridge Designs
R15. Integrating Utility and Transportation Agency Priorities
R23. Using Existing
In-place Pavement & Achieving long Life
R05. Modular Pavement
R06. High-Speed NDT
R26. Preservation
Approaches for High Traffic Volume Roadways
A second Strategic Objective of the Renewal Program is “Facilitating Project Start-Up”
This Strategic Objective addresses primarily the Minimum Disruption and Rapid Approach principles.
As stated before, the Renewal Program aims for input and balance among Technology and Project Delivery Innovations
[NOTE: blue indicates Technology Innovation and orange indicates Project Delivery Innovation]
[NOTE: R01 and R15 are placed together because both projects relate to Utilities]
[NOTE: R04 and R05 are placed together because both project relate to Minimizing Field Fabrication]
R07. Performance Specs For Rapid Highway Renewal
R09. Risk Manual for Rapid Renewal
Technology related
Project Delivery related

22. SHRP2 R21: New Research in Composite Pavements
Two strategies show great promise for providing strong, durable, safe, smooth, and quiet pavements that require minimal maintenance
Surfacing of new portland cement concrete (PCC) layer with high quality asphalt concrete (AC) layer(s), and
Relatively thin, high-quality PCC surface atop a thicker, less expensive PCC layer.
12th Annual MN Pavement Conf
14 Feb 2008

23. HMA Upper Lift PCC Lower Lift
AC over PCC
HMA Upper Lift
(HMA, PMA, SuperPave)
PCC Lower Lift
(JPCP, CRCP, RCC)
12th Annual MN Pavement Conf
14 Feb 2008

24. AC over PCC
12th Annual MN Pavement Conf
14 Feb 2008

25. PCC Upper Lift PCC Lower Lift
PCC over PCC
H1, E1
PCC Upper Lift
(Exp Aggr, Porous, High Strength, etc. )
PCC Lower Lift
(Recycled/Low Quality Materials, etc. )
H2, E2
12th Annual MN Pavement Conf
14 Feb 2008

26. PCC over PCC PCC Lower Lift (JPCP, CRCP, RCC) H1 = 3 in E1 = 4.4 Mpsi
E2 = Varies
3.2 Mpsi
3.5 Mpsi
PCC Lower Lift
(JPCP, CRCP, RCC)
4.4 Mpsi
12th Annual MN Pavement Conf
14 Feb 2008

27. PCC over PCC PCC Lower Lift (JPCP, CRCP, RCC) H1 = Varies
E2 = 2.85 Mpsi
H1 = Varies
E1 = 4.4 Mpsi
3.2 Mpsi
H2 = 6.5 in
E2 = Varies
3.5 Mpsi
PCC Lower Lift
(JPCP, CRCP, RCC)
4.4 Mpsi
12th Annual MN Pavement Conf
14 Feb 2008

28. Composite Pavement Surfaces
Exposed Aggregate Surface
Porous Asphalt Surface

29. Motivation for SHRP2 R21: Composite Pavements
The structural and functional performance of these two types of composite pavements is not well understood or documented.
Models for predicting the performance of these pavement systems need to be developed for use in design, pavement management, and life-cycle cost analysis (LCCA).
Construction techniques, guidelines, and specifications are limited and insufficient.
12th Annual MN Pavement Conf
14 Feb 2008

30. Focus on new AC/PCC and new PCC/PCC composite pavement systems to:
Goals of R21 Project
Focus on new AC/PCC and new PCC/PCC composite pavement systems to:
Determine the behavior and identify critical material and performance parameters
Develop and validate mechanistic-empirical performance models and design procedures that are consistent with the Mechanistic-Empirical Pavement Design Guide (MEPDG)
Develop recommendations for construction specifications, techniques, and quality management procedures for adoption by the transportation community.
12th Annual MN Pavement Conf
14 Feb 2008

31. Applied Research Associates, Inc. Minnesota DOT & MnROAD
SHRP2 R21 Project Team
PI: Mike Darter, PRI
Applied Research Associates, Inc.
Co-PI: Harold Von Quintus
Minnesota DOT & MnROAD
University of Minnesota
Co-PI: Lev Khazanovich, UMN Civil Engineering
University of California at Davis
Co-PI: John Harvey, UCPRC
University of Pittsburg
International Consultants
12th Annual MN Pavement Conf
14 Feb 2008

32. SHRP2 R21 and Minnesota Pavement Research
$4 Million in FHWA funding over 48 months
Over half of funding to the State of Minnesota (Mn/DOT and UMN)
UMN will investigate modeling and accelerated loading, Mn/DOT will implement experimental design in MnROAD test sections
R21 is an opportunity to bring more federal attention to quality and depth of research in Minnesota
12th Annual MN Pavement Conf
14 Feb 2008

33. Summary Composite Pavements
Benefits
Long life PCC surfacing
Rapid renewal of AC surfacing
Surface characteristics
Use local aggregates lower PCC slab
Long life PCC slab, no fatigue cracking
Utility repair
Lower life cycle costs
Relatively
thin AC
surfacing
High quality smaller-
Sized aggregates
Newly placed
PCC w/ local
aggregates
Lower-cost local
aggregates
12th Annual MN Pavement Conf
14 Feb 2008