Answer:
Roads (or highways, streets)
Surface materials (or concrete, asphalt, pavement)
Cold (or frost, ice, Arctic)
Explanation:
Roads (or highways, streets)
Surface materials (or concrete, asphalt, pavement)
Cold (or frost, ice, Arctic)
The above keywords makes it easy to understand the core concepts of the development in road materials for extremely cold conditions. This keywords provides us the information about what type of roadways are to be developed using what kind of materials and in what type of environment.
Thus the answer is
Roads (or highways, streets)
Surface materials (or concrete, asphalt, pavement)
Cold (or frost, ice, Arctic)
