Why is Daxing Airport Expressway not easy to freeze after snow?

In order to ensure the traffic safety of high-speed vehicles, the surface layer of the 23-kilometer bridge of Daxing Airport Expressway is made of ice-melting materials, which will also become the first expressway in China with the function of "resisting the melting of ice and snow". The key of this function lies in a kind of snow melting additive in the asphalt pavement formula, which is equivalent to sticking a "warm baby" on the pavement, so as to achieve the effect of "heavy snow is not sticky, but light snow can melt".

In the heavy snow, snowflakes will remain suspended on the road, and the wheels will be taken away by the wind as soon as they pass; In the light snow, after the falling snow melts, the snow water will not freeze, which can effectively avoid the formation of "ground armor piercing" on the road surface in northern autumn and winter and early spring, and provide guarantee for driving safety.

According to reports, this is a new material jointly developed by R&D Center of Beijing Municipal Road and Bridge Building Materials Group and Harbin Institute of Technology after several years. This snow melting additive will exist in the cracks of pavement materials and will be quickly activated under the conditions of low temperature or increased air humidity. After contact with snowfall, the freezing point of pavement can be reduced to about-12 degrees, which effectively improves the influence of ice and snow weather on expressway capacity.