Evaluating the potential of using foamed concrete as the insulation layer for pavements in cold regions

Abstract

Insulated pavement structures help prevent frost penetration and its negative impacts on roadways and airfields in cold regions. The most commonly used insulating material in pavements is extruded polystyrene (XPS) boards. However, the utilization of XPS boards has several unavoidable drawbacks such as degradation due to long-term moisture infiltration. For this reason, there is an increasing interest to explore alternative materials such as tire chips, bottom ash, and foamed glass aggregates as the insulation layer. This paper aims to evaluate the potential of using foamed concrete as an insulation layer. To achieve this goal, a thermo-mechanical (TM) coupled model was developed to simulate the responses of insulated pavement with a foamed concrete insulation layer. In addition, the compressive strength and thermal conductivity of different densities of foamed concrete were tested to provide the material parameters for the developed model. The model was then calibrated by a large-scale insulated pavement test. The calibrated model was used for a parametric study to reveal the influence of the thickness, depth, and density of the foamed concrete layer on the thermal and mechanical performance. Simulation results show that the developed model can accurately predict the thermal performance of insulated pavements. Compared with the performance of uninsulated pavements, the foamed concrete -insulated pavement has better performance in resisting frost effect and traffic loading. The parametric study also found that a minimum thickness exists for a foamed concrete insulation layer to ensure the subgrade layer is unfrozen. Increasing the thickness, depth, and density of a foamed concrete layer enhances its mechanical performance.