Effects of Asphalt Pavement Instrumentation on In Situ Density

The National Center for Asphalt Technology (NCAT) Test Track has generated valuable information related to the installation of gauges, methodology for data collection and data analysis. However, information regarding the effect of pavement instrumentation on in situ properties is nonexistent. The objective of this study was to evaluate the effect of pavement strain gauges on the in situ density. In 2009, during construction of two test sections it was necessary to remove and replace the bottom lift since quality control targets were not met. Prior to removal, cores were taken in the gauge array and outside the array so that a two-sample T-test could be conducted for each section, respectively. The results showed that there were no significant differences between air void content and consequently no negative effect caused by the presence of pavement instrumentation. Additional density testing was conducted in and around the gauge array in these two test sections after completion of the surface layer. The data indicated no difference in measured density resulting from the presence of embedded instrumentation.