From Command and Conquer Wiki

Pavements, most often made from concrete, are widely used in modern construction, as a way of providing foundations for building as well as preventing explosives from creating craters in the ground.

In the Second Tiberium War, military bases around the world found themselves vulnerable not only to Tiberium infestation but also from subterranean APCs and combat vehicles developed by Nod. Pavements offered a degree protection from attacks by these vehicles, as the drills of these vehicles cannot penetrate the concrete. Pavements also offered some protection from certain invasive tiberium lifeforms.