Experimental investigation on performance of composite thermochromic and ice-melting coatings for dynamic pavement temperature control

Abstract

As the main type of urban roads, the surface temperature of asphalt pavement can reach 70 °C in summer because high heat absorption, causing pavement disease and aggravating the heat island effect. Solar reflective coating is an effective way to tackle the problem in summer but may bring certain negative effects in winter. In this paper, a kind of composite coating containing thermochromic (TCM) materials and snow melting and ice suppression (SMIS) functional fillers was developed. The reflective properties, thermal behavior and road performance of the pavement coatings were investigated. The results showed that the optimal TiO2 contents in TCM-black coating for pavement was 3 wt% to make full use of optical variation range. Long-term solar radiation destroyed the structure of thermochromic microcapsules and caused degradation of color and visible reflectance of TCM coatings, which could be alleviated by ultraviolet absorbers and light stabilizers. The optimal double-layer coating structure with TCM on the top and SMIS at the bottom could achieve cooling effect of 9 °C, pavement icing temperature of −5 °C and faster ice melting rate. The skid and temperature change resistance with the coatings also met requirements. This study provides a reference for developing novel pavement materials with balanced cooling effect and ice suppression capacity for mitigating heat island effect, improving driving safety, and ensuring the optimal service state and longer service life of pavement at the same time.