Cracks are likely to be a problem at some point in an asphalt driveway or a concrete driveway. Water that seeps under the driveway freezes and thaws, creating cracks. These cracks usually worsen over time as grass and weeds grow in between them. Some of the materials used to repair asphalt and concrete differ, but the process is generally the same.
Clean the cracks thoroughly. Remove loose debris with an awl and broom. Rinse small debris from the cracks with the garden hose spray attachment and let them dry completely.
Fill cracks that are larger than 1/4 inch but smaller than 1/2 inch with a patching compound (for asphalt) or a pre-mixed mortar or sealant from a can (for concrete). After mixing, these fillers can be poured into the crack or scooped onto the crack. Smooth it down with a putty knife, and repeat if needed.
Seal the driveway with a water sealer using either a roller or sprayer. The driveway cannot be walked on or driven on for several days as the sealer hardens, so put up some sort of barricade.