Global Procedure for Temperature Adjustment of Measured Pavement Deflection Data: Based on the Long-Term Pavement Performance Seasonal Monitoring Program

Abstract

Pavement surface deflection testing is carried out by most state highway agencies (SHAs) on a limited basis to assess the structural capacity of existing pavements and to select and design pavement treatments. One difficulty with analyzing pavement deflection data is that, for flexible pavements, the deflection is dependent on temperature. To properly use the deflection data, the data should be adjusted on the basis of the measured temperature during the data collection process. A few temperature adjustment procedures have been developed in the past, but most cannot be used globally and for all scenarios and they require input data that are generally not collected by most SHAs. This paper details a simplified process that can be easily used by SHAs to adjust the measured pavement deflection to a 21°C testing scenario, with data they routinely collect during falling weight deflectometer testing, to design pavement treatments such as asphalt overlay. During this study, sponsored by the Long-Term Pavement Performance (LTPP) program, the LTPP database was used to develop a global procedure to adjust the measured pavement deflection to the standard testing temperature of 21°C. Most of the LTPP test sections have been subjected to deflection testing on a periodic basis; test sections included in the LTPP Seasonal Monitoring Program were subjected to frequent deflection testing over time. The 41 test sections included in the analyses had different pavement cross sections, were subjected to various maintenance activities, were located in four climatic regions, and were subjected to various traffic levels. This robust deflection database is representative of the various SHA pavement networks across North America. The results and the processes can be adopted to meet the needs of most SHAs.