Study on Moisture Diffusion Behavior in Asphalt Binder Based on Static and Dynamic Pore Water Conditions

Abstract

The current research on the moisture diffusion behavior in asphalt mostly discusses static water without considering dynamic pore water. In this paper, Fick, Two-stage, and Langmuir moisture diffusion models were used to compare and analyze the diffusion behavior of static water and dynamic pore water in asphalt, and the effects of polar component content on moisture diffusion behavior was quantitatively analyzed. The results show that: (1) dynamic pore water significantly increases the moisture diffusion coefficient of the entire diffusion process; (2) the Langmuir moisture diffusion model, which considers the interaction between moisture and the polar components of asphalt, can very accurately characterize the moisture diffusion behavior in the asphalt binder; and (3) the asphaltene (polar components) content is positively correlated with the amount of asphalt moisture absorption, especially the bound phase moisture.