2. Asphalt is flexible.
Most houses and other structures in the world must have a foundation that extends below the frost line. When soil gets wet and cold, it freezes and expands. Asphalt, being a flexible product compensates for the heaving earth. Concrete, being inflexible, cracks when the earth below it freezes. Cracks are built into concrete slabs when they are installed. That's why you hear the "clump, clump, clump" as you drive along a concrete slab. The contractor that laid the slab built in cracks on a regular basis to permit the concrete to rise when the ground freezes. If he didn't, it would crack willy-nilly and come apart. The footing that concrete rests upon must extend below the freeze line. Since highways are not built like houses, and are without deep foundations, concrete rises and falls as the earth expands, and it cracks.