Quantification of Aggregate Embedment in Chip Seals Using Image Processing

Abstract

Chip seals are among the most popular preventive maintenance techniques implemented by many Departments of Transportation (DOTs), county road departments, and cities. The deteriorated pavement surface is sprayed with an asphalt emulsion or binder, and then a layer of uniformly graded aggregates is spread and compacted. Curing is required before opening the road to traffic to enhance bonding between aggregate particles and asphalt binder. Percent embedment of aggregate particles into the thin bituminous layer is one of the most significant parameters affecting the performance of asphalt chip seals. Bleeding or aggregate loss may be encountered in chip seal applications depending on the aggregate percent embedment. The main objective of this study is to develop a standard test procedure to directly calculate the aggregate percent embedment into the asphalt binder in a chip seal project via digital image analysis. Three image analysis algorithms were developed and used to analyze chip seal samples. Thirty-nine cores were collected from six different locations in Michigan and analyzed. The analyses were also performed using the sand patch tests and laser texture scanning techniques.