Quality Assurance for Chip Seals Using Mean Profile Depth

Chip sealing has numerous benefits as a pavement preservation treatment. The quality of the chip seal is assessed through various parameters, including texture depth, skid resistance, and visual evaluation. Current practice reveals that transportation agencies conduct quality assurance after construction, while contractors are typically responsible for chip seal placement and quality control. However, existing quality assurance procedures predominantly depend on visual inspection, and lack well-established methodologies. This study used Mean Profile Depth (MPD) as a macrotexture metric for the quality assurance of chip seals. Field data were collected using state-of-the-art equipment from the Virginia Department of Transportation (VDOT) area. Considering both qualitative (visual assessment) and quantitative (MPD analysis) approaches, this study delineates definitive categories representative of chip seal quality. These categories included good quality chip seals, with minimal to no signs of flushing and aggregate loss and MPD values ranging from 1 to 1.2 mm. Fair-quality seals had MPD values between 0.6 and 1 mm, while poor-quality seals were identified with MPD values below 0.6 mm. This structured classification enhances preventive maintenance strategies, improving chip seal pavements' overall sustainability and longevity.