Wearing behaviour of Microsurfacing mixtures: macro- and micro-texture evolution and their correlation

Microsurfacing is widely used as a cost-effective, environmentally friendly maintenance technique that enhances skid resistance and restores the surface texture of structurally sound pavements. Its successful adoption by road agencies hinges on a detailed analysis of its long-term surface performance. Therefore, this study focuses on optimising the mix of various bituminous cold Microsurfacing mixtures and analysing their surface performance (specifically micro- and macro-texture) under an accelerated laboratory traffic simulator. The collected data enabled the development of a novel model to describe the evolution of the Pendulum Test Value (PTV) and Mean Profile Depth (MPD) over time, identifying the key phases of the wearing process (a three-stage trend) and facilitating direct comparison between mixtures. Notably, the Microsurfacing mixtures maintained high skid resistance and surface texture values overtime. Additionally, macro-texture indicators, Abbott curves, and Texture Level spectra were assessed to investigate surface texture evolution further. Pearson’s correlation analysis confirmed a strong relationship between PTV and macro-texture parameters, particularly with peak-to-peak profile excursion indicators and texture wavelengths in the 5-8 mm range. Overall, this study proposes an integrated approach for assessing pavement surface properties, combining multiple analytical methods to provide valuable insights into the performance of Microsurfacing, investigating on the relationship between surface texture and skid resistance through its service life, and support the development of more effective maintenance strategies.