Theory behind vibration-based, onboard asphalt density measuring system

For more than 25 years, the hot-mix asphalt paving industry has been searching for a device that can produce accurate, real-time asphalt density readings during the compaction process. A system was developed using data gathered from department of transportation (DOT) paving projects in five states and validated through testing on DOT projects in two other states. The results indicate that through a system of sensors, an onboard computer, and radio transmissions, the onboard density-measuring system provides accurate asphalt density readings in real time and transmits the information to remote locations while building and maintaining a file of all pertinent data on the asphalt compaction process. Insight into the asphalt paving process and results showing the relationship between the vibratory signature of a vibratory asphalt compactor and the density of the asphalt mat compacted are provided.