Preparation and performance of colored ultra-thin overlay for preventive maintenance

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Department of Civil, Environmental, and Geospatial Engineering


Ultra-thin overlay is one of the most popular preventive maintenance techniques used in pavement engineering. Usually, asphalt mixture materials in such overlay and the underlying asphalt pavement are prone to high-temperature related distresses. The objective of this study is to prepare a colored ultra-thin overlay with a better cooling effect to reduce this distress. In this overlay, a waterborne epoxy resin (WER) was added into styrene–butadienestyrene (SBS) modified emulsified asphalt as binder, traditional fine aggregates were replaced by emery, and an iron oxide red was used as the filler. The optimum contents of the WER, iron oxide red, and binder of the overlay were determined by the shear strength test, outdoor cooling test, wet track abrasion test (WTAT), and load wheel test (LWT). Then, the pavement performance of this overlay was comprehensively evaluated by the outdoor cooling test, skid resistance test, permeability test, WTAT, LWT, and aging test. The results showed that both the shear strength of the binder and cooling effect of the overlay increased with an increase in the WER and iron oxide red content. As the binder content increased, the WTAT value decreased, while the LWT value increased linearly. The shear strength of the binder, cooling effect, skid resistance, water permeability, and wearing resistance of the overlay were all significantly improved by the WER, but only the cooling effect was improved by the iron oxide red. After indoor and outdoor aging, the long-term shear strength, cooling effect, skid resistance, water permeability, and wearing resistance of the aged overlay slightly decreased but were still acceptable. Therefore, the proposed colored ultra-thin, with an excellent cooling effect, aging characteristics, and pavement performance, can be used as a preventive maintenance measure to extend the entire pavement life in high-temperature areas.

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Construction and Building Materials