Concrete

Concrete surfaces (specifically, PCC) are usually used on roads with heavy traffic of heavy vehicles and created using a concrete mix of Portland cement, coarse aggregate, sand and water. In virtually all modern mixes there will also be various admixtures added to increase workability, reduce the required amount of water, mitigate harmful chemical reactions and for other beneficial purposes. In many cases there will also be Portland cement substitutes added, such as fly ash. This can reduce the cost of the concrete and improve its physical properties.

Concrete surfaces are divided into three common types: jointed plain (JPCP), jointed reinforced (JRCP) and continuously reinforced (CRCP). Each of the jointing system types is used to control crack development.

Jointed reinforced concrete pavements control cracks by dividing the pavement up into individual slabs separated by contraction joints. However, these slabs are much longer than JPCP slabs, so JRCP uses reinforcing steel within each slab to control within-slab cracking. Today very few of agencies use this design, because it is not recommended as both of the other types offer better performance and are easier to repair.

Continuously reinforced concrete pavements use reinforcing steel rather than contraction joints for crack control. Cracks are held tightly together by the underlying reinforcing steel. A number of agencies have made decisions to use continuously reinforced designs in their heavy urban traffic corridors.

One of the major advantages of concrete pavements is that they are typically stronger and more durable than asphalt roadways. They can also provide a durable skid-resistant surface. A notable disadvantage is that it can typically have a higher initial cost, as well as can be more time consuming to construct. This cost can typically be offset through the long life cycle of the pavement.

Source: http://en.wikipedia.org/wiki/Road_surface