Performance Evaluation of Emulsion and Hot Asphalt Cement Chip Seal Pavements

Pavements steadily deteriorate attributable to many factors such as weather, traffic, water infiltration, and degradation of materials over time. Thus, pavement preservation and maintenance strategies have become an important field to understand and investigate for road agencies, owners, and managers of streets, highways, and parking lots. Environmental and mechanical weathering, which includes traffic loading, exposure to sun, water, freezing, and thawing, all lead to pavement deterioration and ultimate failure if maintenance and preservation are not performed on the roadway. The main objective of this paper is to verify the performance and effectiveness of using chip seal preservation techniques using either emulsified or hot mix asphalt. Two testing schemes are used; the first includes aggregate testing with an attempt to investigate how aggregate performance could relate to chip seal performance. The aggregate testing that would later reflect the pavement performance includes: gradation, flakiness, abrasion resistance, angularity, and embedment. The second testing scheme includes chip seal pavement evaluation using various laboratory and field testing. The chip seal evaluation emphasizes pavement micro- and macrotexture properties using measurements of mean texture depth and friction parameters. Moreover, pavement assessment includes evaluating the pavement performance based upon distress appearances. Distresses discussed are transverse, longitudinal, fatigue, pothole, patching, bleeding, loss of aggregate, rutting, and raveling. The case study presented includes eight sections in the State of Oregon whereby testing schemes are conducted. Pavement conditions were further analyzed prior to construction, right after construction and up to 2-year postconstruction. Findings show that aggregate properties have a significant contribution to the overall performance of chip seal pavements and the importance of the preseal pavement condition. Results further show that chip seals provide a significant performance improvement in pavement test sections by reducing the appearance of distresses after 2 years of service life. The study concludes that chip seals are an effective preservation tool when constructed with good quality aggregates and binders based on the documented improvement in cracking for all test sections observed.