Increasing the southern side-slope albedo remedies thermal asymmetry of cold-region roadway embankments

Abstract

Roadways in permafrost regions usually need embankments to disperse the traffic loadings to the underlying layer. Most roadway embankments have differential solar absorption across the embankment due to the slope-facing problem, which can cause longitudinal cracking along the roadway. This problem may be remedied by increasing the albedo of the sun-facing side slope because the solar absorption of the slope is the product of solar radiation and absorptivity (absorptivity=1-albedo). This study fabricated eight embankment models with differential surface albedo on the one side slope. The albedo of the models was measured on June 22, 2015, by a proposed method for measuring the albedo of bent surfaces. It is found that raising the albedo of the side slope of the embankment can increase the embankment's albedo about 0 to 0.2. Therefore for the cold-region roadway embankments in the Northern Hemisphere, painting the southern side slope with highly reflective, non-white pigments can cool the roadbed and remedy the thermal asymmetry across the embankment.