Investigation on the comprehensive durability and interface properties of coloured ultra-thin pavement overlay

Coloured pavement provides benefits for improving functionality and safety in pavement infrastructure. In this investigation, a coloured ultra-thin pavement overlay was prepared with a resin-based binder and artificial coloured ceramic aggregates. The overlays were prepared in various binder thicknesses (0.8 mm, 1.2 mm, and 1.6 mm) and aggregate spreading ratios (50 %, 75 %, and 100 %). The specimens were experimentally tested with a wheel abrasion tester followed by the analysis of apparent colour loss, rutting depth, mass loss, and skid resistance in accordance with a proposed comprehensive durability evaluation method. The colour-cooling performance was evaluated with the sunlight simulation test. In addition, the interface properties were tested based on the flexural toughness test, pull-off test, and shear test. The comprehensive durability evaluation results indicated that coloured overlay with 1.2 mm binder depth and 75 % aggregate spreading ratio had the highest durability score among all samples. The sunlight simulation test results verified the positive cooling effect of the coloured overlay on the pavement structure. The bottom-up cracking resistance based on the flexural toughness test was also improved with overlays by comparing that with specimens without covering. The pull-off test and shear test results illustrated that the interface adhesion was correlated to environmental temperature and binder thickness. This study provided a comprehensive durability scoring method for coloured ultra-thin functional overlays, and the optimized material compositions enhanced the durability and interface adhesion, which could be utilized for future field applications of coloured ultra-thin functional overlays and contribute to infrastructure sustainability.