Design and Construction Guidelines for Thermally Insulated Concrete Pavements

1. Design and Construction Guidelines for Thermally Insulated Concrete Pavements Lev Khazanovich, UM John Harvey, UCD Joe Mahoney, UW September 12, 2007

2. Composite Pavements • AC layer over PCC layer • PCC over PCC layer (two-lift construction) • PCC over AC layer (white topping)

3. Scope of the Study • Newly constructed AC/PCC pavements • AC overlays of structurally sound PCC pavements • Other types of composite pavements (literature review only) • MnROAD AC overlay of several PCC slab • MnROAD new composite section

4. Research Objective • The main objective: • Perform life cycle cost analysis comparisons, and develop design and construction guidelines for thermally insulated concrete pavements (TICP), i.e. composite thin HMA overlays of new or structurally sound existing PCC pavements.

5. Research Objective • Secondary objectives: • Validation of the structural and climatic models of the Mechanistic-Empirical Pavement Design Guide (MEPDG) for asphalt overlays of concrete pavements. • Investigation of applicability of the MEPDG and CalME for design of TICP pavements. • Investigation of applicability of reflection cracking and asphalt rutting models developed in California. • Development of recommendations for feasibility analysis of newly constructed TICP or thin overlays of the existing concrete pavements.

6. Specific Objectives • Determine benefits of HMA layer on curling and warping potential of concrete panels • Develop a life cycle cost analysis-based guidelines for determination of economic feasibility of TICPs and thin AC overlays considering both agency and user costs. • Incorporate the results into design and construction guidelines. Also, provide recommendations on where TICPs are most effective. • Evaluate how construction processes can be modified to take advantage of the TICP design • Profile control (ride is achieved with the HMA layers) • Required cure time before the HMA can be placed • Joint forming versus saw cutting

7. Specific Objectives (cont.) • Predict extension of the fatigue life of the TICP vs. PCC pavement • Evaluate the service life of the thin HMA overlay. • Characterize initial and long term bond at the interface between the layers Determine the optimum thickness ratio of the two layers based on load and environmental conditions • Optimize layer stiffness • Select optimum pavement panel size/joint spacing for jointed designs • Determine conditions under which inclusion of dowels is more cost efficient than not including them.

8. Related Studies • SHRP-2, Project R21: “Composite Pavement Systems” • TPF 962: Pavement Surface Properties Consortium: A Research Program (Virginia) • NCHRP 1-43: Guide for Pavement Friction (ARA) • NCHRP 1-41: Models for Predicting Reflection Cracking of Hot-Mix Asphalt Overlays (Texas A&M) • TxDOT 0-4398: Develop Guidelines for Designing and Constructing Thin Asphalt Pavement (ACP) Overlays on Continuous Reinforcement Concrete Pavements (University of Texas) • TxDOT 0-4517: Develop Statewide Recommendations for Application of PCC Joint Reflective Cracking Rehabilitation Strategies Considering Lufkin District Experience (Texas Transportation Institute) • TxDOT 0-4467: Developing an Upgraded Overlay Tester System to Characterize the Reflection Cracking Resistance of Asphalt Concrete (Texas Transportation Institute) • Calibration of Mechanistic-Empirical Design Procedures using the Heavy Vehicle Simulator (University of California Pavement Research Center)

9. SHRP2 R21 vs This Study • R21 – AC/PCC and PCC/PCC; this study – AC/PCC only • This study: Literature review AC overlays, other types of pavements – to be discussed • R21 – national guidelines. This study – focus on California, Minnesota, and Washington conditions • R21 – MEPDG AC model are the first choice. This study- CalME • This study – limited attention to CRCPs. • First results of this study will be used in R21 study

10. Research Team • Lev Khazanovich (UM) – PI, Structural modeling, PCC distresses • John Harvey (UCD) – CoPI, AC distress modeling • Joe Mahoney (UW) – Construction Guidelines • Mihai Marasteanu – Literature review

11. Task 1. Development of Information on Composite Pavements • Assessment of the state practice and knowledge for the design and construction of composite pavements • Review of design procedures and methods (design criteria, basis of procedure, distress prediction models, etc.)

12. Task 2: Perform Initial Life-Cycle Analysis  • Collect the most recent information on construction cost of individual design features for California, Washington and Minnesota conditions. • Perform a Life-Cycle Analysis to determine under what conditions use of composite pavement may be viable. Compare several hypothetical TICPs and overlays with conventional asphalt and concrete pavements: • Longer pavement life of composite pavements compared to the pavement life of new PCC and AC pavements • Lower construction cost of new pavement and potential lower maintenance costs • Different materials resulting in different emissions, leachates and energy consumptions

13. Task 3: EICM Validation and Analysis • EICM sensitivity analysis • AC and PCC layer thicknesses • AC and PCC thermal conductivities and heat capacity • Properties of the base layer and subgrade • Geographic location of the pavement section • Vaidation and calibration • MnROAD data • DAKOTA • UMPC

14. EICM Validation • Thin AC overlay over several PCC slabs • Temperature measurements in the orginal slab • Temperature measurements in the overlaid slab and in the AC overlay • Temperature measurements in the new composite pavements

15. EICM Analysis • Effect of design features PCC slab curling • Effect of design features on joint opening

16. Task 4: Evaluation of Pavement Response Models The responses of the MEPDG structural model, ISLAB2000, will be compared with the measured responses from the MnROAD test section. • FWD test results • Joint opening • Strains

17. Task 5. Develop Design Guidelines • MEPDG PCC models • PCC fatigue cracking (top/down and bottom/up) of AC overlays of PCC pavements • Transverse joint faulting • CalME models: • AC reflective cracking • AC rutting

18. Task 6. Develop Construction Guidelines • A group of experts in materials and construction will be convened to determine constructability of composite pavements. • The following issues will be addressed • Profile control (ride is achieved with the HMA layers) • Required cure time before the HMA can be placed • Joint forming versus sawing • Roller compacted techniques • Construction sequence • The use of CA4PRS pavement construction schedule estimating software for TICP alternatives will be investigated

19. Task 7. Draft Final Report • Summary of experience to date based on the literature survey. • A description of the MnROAD test sections. • A detailed description of the data that has been collected, where the data is stored, and how it can be accessed. • A detailed description of the environment, structural, and performance model and their predictive capabilities.

20. Task 7. Draft Final Report (cont.) • Summary of the pavement designs considered, the expected performance, and approximate life cycle cost over a common analysis period. • A recommendation for the best structures for the different conditions (environment, traffic, costs in different locations) considered in the analyses. • Recommendations for best practice for each of the conditions considered in the sensitivity analysis factorial. • Identification of issues that need further research and development to further improve this technology.

21. Task 8. Final Report • Address TAP comments

22. Proposed Schedule

23. Proposed Budget

24. Budget (cont.) • UMN – $252,000 • UCD – $162,000 • UM – $36,000