The asphalt pavement on your property is being subjected to environmental damage. Left untreated, the asphalt binder that holds the pavement together will deteriorate rapidly. Water penetrates the asphalt, causing damage and deterioration to the pavement. Oil, gas, and salt cause further damage to the pavement surface.
All of this environmental distress is why asphalt goes from a newly laid fresh black appearance to a drab, aged, oxidized gray appearance.