Evaluation of Composite Pavement Unbonded Overlays: Phase III Final Report August 2006 Sponsored by the Iowa Highway Research Board (TR-478) the Iowa Department of Transportation (CTRE Project 01-95) the Federal Highway Administration (Project 2) Iowa State University’s Center for Transportation Research and Education is the umbrella organization for the following centers and programs: Bridge Engineering Center • Center for Weather Impacts on Mobility and Safety • Construction Management & Technology • Iowa Local Technical Assistance Program • Iowa Traffi c Safety Data Service • Midwest Transportation Consortium • National Concrete Pavement Technology Center • Partnership for Geotechnical Advancement • Roadway Infrastructure Management and Operations Systems • Statewide Urban Design and Specifications • Traffic Safety and Operations About the National Concrete Pavement Technology Center The mission of the National Concrete Pavement Technology Center is to unite key transportation stakeholders around the central goal of advancing concrete pavement technology through research, tech transfer, and technology implementation. Disclaimer Notice The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. The opinions, findings and conclusions expressed in this publication are those of the authors and not necessarily those of the sponsors. The sponsors assume no liability for the contents or use of the information contained in this document. This report does not constitute a standard, specification, or regulation. The sponsors do not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document. Nondiscrimination Statement Iowa State University does not discriminate on the basis of race, color, age, religion, national origin, sexual orientation, gender identity, sex, marital status, disability, or status as a U.S. veteran. Inquiries can be directed to the Director of Equal Opportunity and Diversity, (515) 294-7612. Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA Project DTFH61-01-X-00042 (Project 2) IHRB Project TR-478 4. Title and Subtitle 5. Report Date Evaluation of Composite Pavement Unbonded Overlays: Phase III August 2006 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. James K. Cable, Jennifer L. Morud, Toni R. Tabbert CTRE Project 01-95 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Center for Transportation Research and Education Iowa State University 11. Contract or Grant No. 2711 South Loop Drive, Suite 4700 Ames, IA 50011-8664 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered Federal Highway Administration Iowa Highway Research Board Final Report U.S. Department of Transportation Iowa Department of Transportation 14. Sponsoring Agency Code 400 7th Street SW, HIPT-20 800 Lincoln Way Washington, DC 20590 Ames, IA 50010 15. Supplementary Notes 16. Abstract In recent years, thin whitetopping has evolved as a viable rehabilitation technique for deteriorated asphalt cement concrete (ACC) pavements. Numerous projects have been constructed and tested, allowing researchers to identify the important elements contributing to the projects’ successes. These elements include surface preparation, overlay thickness, synthetic fiber reinforcement usage, joint spacing, and joint sealing. Although the main factors affecting thin whitetopping performance have been identified by previous research, questions still existed as to the optimum design incorporating these variables. The objective of this research is to investigate the interaction between these variables over time. Laboratory testing and field testing were conducted to achieve the research objectives. Laboratory testing involved shear testing of the bond between the portland cement concrete (PCC) overlay and the ACC surface. Field testing involved falling weight deflectometer deflection responses, measurement of joint faulting and joint opening, and visual distress surveys on the 9.6-mile project. The project was located on Iowa Highway 13 extending north from the city of Manchester, Iowa, to Iowa Highway 3 in Delaware County. Variables investigated include ACC surface preparation, PCC thickness, slab size, synthetic fiber reinforcement usage, and joint spacing. This report documents the planning, construction, and performance of each variable in the time period from summer 2002 through spring 2006. The project has performed well with only minor distress identification since its construction. 17. Key Words 18. Distribution Statement maturity—portland cement concrete pavement overlays—temperature­ No restrictions. monitoring systems—thin concrete overlays 19. Security Classification 20. Security Classification 21. No. of Pages 22. Price (of this report) (of this page) Unclassified. Unclassified. 47 + appendices NA EVALUATION OF COMPOSITE PAVEMENT UNBONDED OVERLAYS: PHASE III Final Report August 2006 Principal Investigator James K. Cable Associate Professor Department of Civil, Construction, and Environmental Engineering, Iowa State University Research Assistants Jennifer L. Morud Toni R. Tabbert Authors James K. Cable, Jennifer L. Morud, Toni R. Tabbert Sponsored by the Federal Highway Administration (Project 2), the Iowa Department of Transportation (HR-1093), and the Iowa Highway Research Board (IHRB Project TR-478) Preparation of this report was financed in part through funds provided by the Iowa Department of Transportation through its research management agreement with the Center for Transportation Research and Education, CTRE Project 01-95. Center for Transportation Research and Education Iowa State University 2711 South Loop Drive, Suite 4700 Ames, IA 50010-8664 Phone 515-294-8103 Fax 515-294-0467 www.ctre.iastate.edu TABLE OF CONTENTS ACKNOWLEDGEMENTS.......................................................................................................... IX INTRODUCTION ...........................................................................................................................1 Background................................................................................................................................1 Research Objectives...................................................................................................................1 Research Plan/Approach............................................................................................................1 TEST SITE DESCRIPTION............................................................................................................7 Soil Conditions...........................................................................................................................9 Design Traffic ..........................................................................................................................11 CONSTRUCTION.........................................................................................................................12 Construction Concerns.............................................................................................................19 Field Changes...........................................................................................................................20 TEST FREQUENCY AND METHODS.......................................................................................23 Direct Shear Testing ................................................................................................................23 Load Transfer...........................................................................................................................23 Joint Openings and Faulting Measurements............................................................................24 Visual Distress Surveys ...........................................................................................................24 Weigh-in-Motion Device Measurements.................................................................................25 Profile Data Collection ............................................................................................................25 DATA ANALYSIS AND RESULTS............................................................................................26 Direct Shear Tests....................................................................................................................26 Faulting ....................................................................................................................................27 Joint Movement .......................................................................................................................28 Load Transfer...........................................................................................................................29 Visual Distress Survey.............................................................................................................30 Weigh-in-Motion .....................................................................................................................31 Profile IRI Values ....................................................................................................................31 Soil Classification ....................................................................................................................32