Thermal Performance Analysis of Hollow Cellular Concrete Block Air Convection Embankment for Cold Regions

• Published in: Cold Regions Science and Technology
• Main Authors: Wu, Hanli, Zhang, Xiong, Liu, Jenny
• Format: Text
• Language: unknown
• Published: Scholars' Mine 2023
• Subjects: Air Convection Embankment; Cellular Concrete; Crushed Rocks; Permafrost; Thaw Settlement; Architectural Engineering; Civil and Environmental Engineering; permafrost; Alaska
• Online Access: https://scholarsmine.mst.edu/civarc_enveng_facwork/2259; https://doi.org/10.1016/j.coldregions.2022.103733

Crushed-rock air convection embankment (ACE) is an excellent passive cooling technique that uses open-graded crushed rocks as a "thermal semi-conductor" to prevent roadbeds from thawing in summer and enhance the cooling effect in winter in permafrost regions. However, the desired crushed rocks needed for ACE are not readily available in interior Alaska, resulting in extremely high construction costs. Previous studies indicated that using the cost-effective cellular concrete for ACE could effectively enhance the cooling performance of ACE and mitigate moisture warping and temperature curling of the asphalt concrete layer. It is promising to be an alternative to crushed rocks for ACE to mitigate pavement distresses. However, the design of cellular concrete ACE needs to be further studied to maximize performance and facilitate future implementation. Hence, two design configurations of cellular concrete block ACEs were proposed in this study. The thermal performance of pavement structures with these two designs was investigated by comparing them with the other four. A total of six pavement structures were analyzed, including a typical flexible pavement in the Northern Region of Alaska and five pavement structures reinforced with different paving interlayers, i.e., silty sand/gravel, crushed rocks, cast-in-place cellular concrete (full insulation), and two types of precast cellular concrete blocks. The thermal profiles, air pressure gradients, and velocities were numerically analyzed in ANSYS Fluent. The numerical results indicated that the two proposed cellular concrete ACEs exhibited a significant heat insulation effect in summer and a desired cooling effect in winter, which raised the permafrost table significantly. The maximum thaw depth of the two proposed cellular concrete ACEs was only 15% of the thaw depth of traditional silty sand/gravel embankment.