Chip seal aggregate embedment has a significant influence on long-term chip seal performance. Too little embedment can cause raveling, revealing bare asphalt (safety and performance are compromised), and too much embedment can lead to bleeding (safety is compromised). Ensuring proper chip seal aggregate embedment should be evaluated as a critical factor when considering the proposed design of a chip seal project. However, there is no method to measure chip seal aggregate embedment quickly and accurately in the field.
The objective of this research project is to develop a rapid, in situ method to determine the embedment depth of chip seal aggregate soon after placement. This information could then be used to address any contractor workmanship issues that may be occurring on the project in near real-time (vs. having to wait until after the project is entirely completed), as well as an indicator of performance relative to the initial chip seal design (target emulsion and aggregate application rates, percent embedment range, etc.)
The results of this research will be used as an objective measure to evaluate initial acceptance of the chip seal project. In addition, the research results could be incorporated into the construction specifications to provide an incentive for contractor workmanship. Specific incentives and disincentives would need to be studied based on percent embedment. All these factors are directly related to the total life cycle and overall performance of the chip seal surface treatment in-place.