Asphalt cracks as a result of the expansion and contraction cycles that it goes through during the course of its lifetime. Consequently, cracks should be filled  when they appear to prevent water from penetrating the surface and softening the subgrade. Elam Construction uses an oil-based product that is heated and poured into the cracks. Heating the product makes it more viscous and allows it to fill the voids making a watertight seal. Filling cracks is a low-cost way to extend the life of your asphalt.