Improving Chip Seal Construction Using Laser Intensity Data

Chip seal is a common pavement preservation technique used to extend pavement life and improve its functional performance thoughout the United States. The need to improve chip seal design and construction is an active area of research. One area for improvement in chip seal construction is the adjustment of binder application rate based on the pavement surface condition. This paper provides a method for adjusting the binder application rate based on analysis of reflected laser signal intensity from the existing (preseal) pavement surface, converted to red, green, and blue (RGB). Using the k-means clustering algorithm as an initial step to reduce the RGB scale, a subsequent grouping step is performed before visualizing the data as a directed acyclic graph (DAG). Structuring the data into a DAG allows for the systematic description of the pavement surface condition. With the ability to accurately describe the pavement surface condition, binder rate adjustments were suggested depending on how the existing surface compares with an as-expected condition. The results of applying the method to two roadways in Texas were presented. The methodology provides binder rate adjustment for each wheel path and the area between wheel paths at 30.5-m (100-ft) intervals. (C) 2020 American Society of Civil Engineers.