Effect of Coarse Aggregate Morphologies on the Hydrodynamic Pressure–Resulted Moisture Susceptibility of Asphalt Mixtures

Many pavement field distresses are caused by moisture damage. However, hydrodynamic pressure is not taken into account by a common laboratorial moisture test of asphalt mixture. Furthermore, aggregate morphology was not considered as an influence factor of moisture susceptibility by most researchers. In this study, the morphologies of aggregate were quantified and used as fundamental backup and moisture susceptibility of a mixture was evaluated by the original and improved moisture test. The relationship between moisture susceptibility and morphological features was then established. Recommendation scopes of aggregate morphologies were concluded. Results show that moisture susceptibility of asphalt mixture has a rising trend with the increase of angularity, texture, coarse aggregate angularity texture value (CAAT), and decrease of sphericity. It was found that texture, sphericity, and CAAT are closely related to moisture sensitivity of the asphalt mixture, while the correlation of angularity is relatively weak. Recommendation scopes of morphological characteristics can be used to initially evaluate moisture stability, guide the aggregate production of quarry, and provide reference for the design of aggregate crusher and shaping machines.