Since the invention of the wheel, man has cursed the mud and devised ways to defeat it. Materials have evolved from Roman stone roads, to cobblestone streets, to concrete and asphalt pavements. Pavements act as a roof over the road base. If water gets under this roof, it loses its support and will fail. With asphalt, this is the beginning of the dreaded Pothole.
Concrete pavement is basically a mixture of rock and sand held together by Portland cement.
When water is added a chemical reaction takes place. The mud must be placed and finished before the reaction is too far along or it will lose its strength. For some applications wire mesh, rebar or fiber mesh are included in the pavement for additional strength. Concrete does not bend. It is strong but brittle.