Evaluation of composite pavement unbonded overlays : phase III.

783299673Final report.PDFTech ReportFHWA Project DTFH61-01-X-00042 (Project 2)IHRB Project TR-478CTRE Project 01-95Concrete overlaysOverlays (Pavements)WhitetoppingFalling weight deflectometersKansasIowa State University. Center for Transportation Research and EducationCable, James K.Morud, Jennifer L.Tabbert, Toni R.Iowa State University. Center for Transportation Research and EducationIowa. Highway Research BoardIowa. Dept. of TransportationUnited States. Federal Highway AdministrationNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsUS Transportation CollectionIn 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\ue2\u20ac\u2122 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