Driveway cracks are a common occurrence and can lead to superficial as well as structural damage. So it is important to have those driveway cracks filled as soon as possible.
The first thing you are going to need to is clean the driveway crack thoroughly.
Using a chisel or screwdriver and a hammer you can remove small pieces of asphalt or scrap out any loose debris from the driveway crack. You can also use the chisel to remove any weeds, grass or small plants that may have started to grow in the crack.

Next using a broom you are going to sweep out the smaller material like sand, pebbles, rock salt and any loose asphalt left behind.
Finally using a garden hose or a power washer, spray the inside of the driveway crack to remove any left over material. Allow to dry before applying any filling products.

Filling Cracks ¼ inch or Smaller

For cracks up to ¼ inch wide you can use a chalk cartridge style filler as shown (left). These are easily applied using a chalking gun.
Most of the liquid crack fillers will shrink as the water inside them starts to evaporate. So you have 2 options here. You can first fill the driveway crack level and wait for it to sink and dry, then reapply or you can overfill the crack slightly so that it sinks and dries level.
In either case you are going to want to spread the top of the filler using a putty knife over the edges of the crack. This will give it a nice smooth appearance as well as help to keep the water out.

Filling Cracks up to 1/2 Inch

For these wider cracks you have to use pour able liquid crack filler. These usually come in one gallon jugs (3.7 liters) and are known as “cold pour” crack fillers.
To apply simply pour the filler into the crack and smooth the edges using a putty knife. The compound should be dry in a few hours.
It’s important to note that for deeper cracks you may need to pre fill the crack with coarse sand in order to provide a more stable base for the filler to adhere to.

For Cracks Larger than ½ Inch

Unfortunately most liquid crack fillers won’t adequately fix the problem and you are left with 2 choices. If the crack is really wide you may have to cut out the affected area and lay new asphalt down.

In most cases you can fix the crack using a cold patch compound. These are available in either bags or buckets. Simply spread the compound into the crack using a small shovel or your putty knife until the crack is completely filled.

You will need to tamp the compound firmly until it is flat and level. You can use a 4 x4 post, a metal tamper of even your car tires to do this.

Learn how to fix driveway potholes at: Fixing Potholes In Your Driveway