After curing, overloading or a poor base under the pavement may also cause it to crack and break. Cracking in asphalt generally occurs as it ages. Exposure to the sun evaporates the light volatiles from the liquid asphalt that binds the aggregate together. This causes shrinking and eventually the asphalt pulls apart at a weak point. Control joints are not used in asphalt to guide this cracking as they are in concrete.
Heavy loads are another cause of cracking in asphalt.
They can compress the asphalt beyond its design, breaking the bond, and leaving cracks. The ultimate goal in asphalt pavement maintenance is to protect the surface from the elements and to prevent water from infiltrating through cracks into the base. Nearly everything that contacts asphalt is bad for it. Vehicles can cause compression damage from overloading Car tires can, especially on turns, scrub away the finer aggregates from the pavement surface leaving a rough texture and a weaker pavement. Oil and fuel spills, which are petroleum products like the asphalt cement, can soak into and soften the pavements so the aggregate isn't bound together as good as it was originally.