DPS measurements taken directly at the core location. In this survey, once core locations were selected, the DPS cart was used to resurvey the section and determine the core location. A total of five cores were collected. High and low dielectric cores were selected with the first survey section, and high, low, and medium cores were selected within the second section. While more cores are generally desired, the cores did cover a large range of dielectric values and produced a good model. Results indicate that performing the DPS measurements directly over the core is crucial to a satisfactory calibration model (Figure 31). Moreover, results indicate that exact core locations must be known even when using highly accurate GPS and distance encoders.
Figure 31: Cherryfield, Maine calibration model [63]
This section’s results indicate inconsistent compaction as large fluctuations of dielectric data were observed. There were a few regions of very low dielectric suggesting high air voids at both the pavement lane and joint. Average air void content estimated based on DPS dielectric constant was around 6%. However, both lane and joint presented areas of substantial air void 47
