KHIT 150: Pavement Forensics and Pavement Design Technical Assistance for KYTC Six-Year Planning

Abstract KHIT 150, Pavement Forensics and Pavement Design Technical Assistance for KYTC Six-Year Planning KTC routinely conducts project-level pavement forensic analysis to assist KYTC’s Pavement Branch with selecting appropriate and cost-effective pavement design/rehabilitation concepts. Efforts have focused on individual projects identified as intermediate pavement repair projects in the Six-Year Highway Plan (SYP). Sometimes project-level analysis of in-situ pavement condition reveals more extensive repairs are needed than expected during the planning stage. When this occurs a funding imbalance results — more dollars are needed to repair a section of roadway than were allocated. To better align pavement design/rehabilitation concepts with the pavement design/rehabilitation concept specified in the SYP, pavement forensic process should be advanced from the design phase to the planning phase. If the pavement composition is well understood, the pavement is not structurally deficient, and other factors that contribute to pavement failure are held to a minimum, KYTC can opt for a design/rehabilitation concept that only involves an overlay. But for some rehabilitation projects the Cabinet lacks sufficient information on current in-situ pavement conditions and/or the root cause(s) of pavement failure. Information deficiencies produce knowledge gaps that make it difficult to select appropriate pavement design/rehabilitation concepts. Gathering additional field data can facilitate development of these concepts for projects where insufficient pavement data are available. On pavement rehabilitation projects where KYTC has insufficient pavement data to develop a design/rehabilitation concept, KTC will collect and process the necessary field data through pavement forensic analysis. Pavement forensic analysis may include destructive and non-destructive testing using technologies such as: • Falling Weight Deflector (FWD) to determine pavement and subbase stiffness and modulus values • Ground Penetrating Radar (GPR) to characterize pavement layer thickness and composition • Pavement coring for thickness/composition verification, crack propagation direction determination (top- down verses bottom-up cracking), and locating possible delamination • Optional: Cross-drain/edge-drain camera inspection KTC will upload data that have been processed and analyzed into ArcGIS Online. Project-level information will be presented through the StoryMaps platform as a series of project narratives, charts, graphs, photos, and videos. KYTC pavement design engineers can use data to select the most appropriate pavement design/rehabilitation concept. For some projects, KTC may also perform multiple pavement design calculations for alternate pavement types. This will help KYTC choose the most cost-effective and beneficial pavement design/rehabilitation concept. All calculations and analyses will adhere to best practices found in the Mechanistic Empirical Pavement Design Guide (MEPDG).