Question

Is hot asphalt poured onto flat ground cools to from a solid road surface a physical or chemical change?

Answer 1

1. ⇒Tar is mainly made up of a collection of very heavy hydrocarbons, with rather high melting temperatures. Commonly, it is mixed with some stones or gravel to make a harder surface for roads. It is possible to heat this up to soften or melt this; you can try it yourself by heating it in a metal can over a stove (don't use a container that you plan to keep clean) or in a wood or coal fire.
2. it is reversible

Answer 2

When hot asphalt is poured onto flat ground cools to form a solid road surface is a chemical change.

Asphalt is a plastic hydrocarbon ,when in liquid condition reacts with oxygen in air to react  to become a solid.