"Chip seal is one of the most popularly adopted pavement preservation strategies. A chip seal treatment is constructed by adding hot asphalt or emulsion on the surface of an existing pavement, spraying aggregates on the top, followed by roller compaction. Extensive research has led to the formulation of various chip seal analysis and design methodologies. These methods are mostly empirical in nature and depend on numerous assumptions related to chip seal microstructure and their expected behavior after compaction in field. Hence, there is a need for in-depth analysis of chip seals to develop performance-based design methods addressing the primary distresses as well as the microstructural parameters such as percent embedment and aggregate orientation. The objective of this research study was to evaluate chip seals through image-based microstructural parameters and performance tests. The results of a comprehensive experimental program lead to development of a holistic approach to chip seal design, encompassing various aspects of chip seal performance through aggregate-binder microstructural perspective. New image processing techniques were developed to understand the percent embedment and aggregate orientation behavior. Additionally, finite element analyses were performed using actual chip seal images to evaluate mechanistic characteristics (e.g., magnitudes of strains at the aggregate/binder interface) responsible for chip seal performance. Further, extensive performance tests were run in laboratory to evaluate the effect of design parameters (e.g. percent embedment, aggregate orientation) on chip seal performance distresses (aggregate loss and bleeding). The results were combined and analyzed to yield new insights into effect of microstructural parameters on chip seal performance. Furthermore, a performance-based design procedure was developed for design of chip seals. This procedure integrates the chip seal microstructural behavior and its performance."--Pages ii-iii.
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