Properly designed and constructed asphalt pavements rarely wear out from the traffic. Surface deterioration is primarily caused by weathering, oxidation and the destructive softening effects of gasoline, oils, and de-icers.

		The Asphalt Institute confirms that air, sunlight and moisture are a major cause of surface deterioration. Unprotected surfaces oxidize and allow the aggregate in the asphalt mix to be washed away.			Water penetrates the cracks and damage progresses. Hydraulic pressure (expansion and contraction) enlarge the cracks. Damage occurs faster under heavy traffic and/or during freeze-thaw cycles.
		Unprotected pavements lose flexibility; aggregate ravels from the surface and the pavement becomes rough. The surface becomes brittle and cracks develop.			Cracks allow water to penetrate to the subsurface and rupture the pavement; causing small surface cracks to enlarge until the pavement actually separates.