Water Retention and Evaporation Characteristics of Porous Asphalt

Porous asphalt, crucial for material transmission between a permeable pavement system and the environment, exhibits vital water retention and evaporation properties impacting pavement environment and durability. Understanding the water retention and evaporation characteristics of porous asphalt is significant to clarifying the water distribution in microscopic voids, which are the main avenues for water distribution. In this paper, we illustrate the water retention and evaporation characteristics of porous asphalt with computerized tomography (CT) and the microanalysis method, focusing on void structure, temperature, and clogging particle size. The effect of clogging on the water retention and evaporation characteristics of porous asphalt was analyzed. Results indicate small voids and void throats primarily govern water retention, while water near the surface readily evaporates. The low void content endowed porous asphalt with a strong water retention ability but prevented the evaporation of porous asphalt. High temperature had a significant effect on the water retention and evaporation characteristics of porous asphalt. Clogging shrunk the void structure and deteriorated the water retention properties of porous asphalt, hindering water evaporation. Furthermore, clogging reduced the difference in water retention and evaporation capacity of the samples with different initial void contents. Larger clogging particles further decrease retention and evaporation capacities.