Status of roller mountable microwave asphalt pavement density sensor

This paper describes the status of development and initial field test results of an innovative roller-mountable asphalt pavement density sensor. This concept measures the density of asphalt in real time using a differential microwave signal approach. Two antennas, one in front of a roller and the other behind it, measure reflected microwave signals from the asphalt, and a change in signal variability shows the operator when optimal compaction has been reached. This technique minimizes the need to quantify the hot mix asphalt properties that change during the compaction process. Several field studies have been conducted as part of this study to investigate microwave properties of asphalt pavement. Additionally, laboratory experiments were conducted at Vilnius University to better understand the electrodynamical properties of hot mix asphalt pavement. This paper briefly discusses the current asphalt density measurement approaches. This is followed by a description of the prototype design, construction, and subsequent field testing. Initial results show that this new approach has promise and that additional refinement is necessary. Future recommendations for enhancing this innovative asphalt pavement density sensor are also discussed.