Asphalt Paving, Driveway Maintenance
Asphalt is a black construction material – much like cement – that varies from solid to semisolid in consistency at room temperature. When heated to the temperature of boiling water, it can be poured. Asphalt is used in surfacing roads, lining the walls of water-retaining structures such as reservoirs and swimming pools, and in manufacturing floor tiles and roofing materials. Asphalt should not be confused with tar, a substance made from coal or wood. It is found in natural deposits, but almost all of the asphalt used commercially is made from petroleum. Natural asphalt was used extensively in ancient times. Deposits occur in pits or lakes as residue from crude petroleum that has seeped up through cracks in the earth. Its use for street paving in the United States began in 1870.
We once had a home with a driveway that was 300-feet long. It was paved – you guessed it – with asphalt (black top). What a lesson we learned. Asphalt costs about the same to install as concrete. In some instances it costs more. On top of that, it doesn’t hold up nearly as well as concrete. Also, when it gets extremely hot, asphalt softens and is easily damaged. However, there is a plus that makes it worth considering. It is easy to repair and, if properly maintained, can last for decades.
Whereas patching damaged concrete requires cutting a section with an expensive saw, a damaged area of black top can be filled and sealed with a minimum of effort and quickly. Whereas a concrete patch can take a day or two at best, an asphalt patch can be made in an hour or less.
Remember, an asphalt surface needs to be maintained on a regular basis. The surface should be cleaned and sealed every other year.
Patching cracks begins just like any other crack repair. Stucco, concrete, grout, mortar – the first step is always the same. Clean out the crack. Brush away loose dirt and debris, all the while making sure that the area to be patched is solid and stable. All loose surface material must be removed. Weeds are a special cleaning problem and should be completely removed. A trowel, shovel, knife or wire brush are all handy for this purpose. The most effective weed removal procedure is to spray the unwelcome sprouts a week or so before the repair is to be made. This will kill the roots and reduce the chance of their return. This also makes removal much easier. Finally, use a shop vacuum or a leaf blower to remove every last bit of dust and debris. For a premium cleaning job, use a pressure washer. Don’t be surprised if areas loosened by dripping petroleum products begin to splatter under the force of the pressure washer. Removing the contaminated material and patching it will add life to the entire surface. With everything neatly cleaned, the repair can be made.
Wider cracks and potholes can be easily repaired with ready-mix asphalt which is available in 60-pound bags. Use caution here. The best result is achieved when the blacktop patch is tightly compacted. First, fill about one-third of the depth of the hole with the asphalt mix and tamp it in place. You can make a tamping device by nailing a small piece of plywood onto the end of a piece of 2×2 lumber or a pole. You also can rent one made of steel or rent a gas-powered tamp known as a “sheep’s foot.” With the first layer firmly compressed, follow with another one-third, and tamp some more. Finally, mound the last layer higher than the surface – making sure that there is no patch material on the adjacent asphalt – and begin tamping it. For superior results, lay a board over the patch and drive your car over it. Wait for about three months before coating with a protective sealer.
Smaller cracks can be repaired with a liquid sealant. Clean and vacuum the area and pour the asphalt filler onto the cracks. This will leave a dark glossy strip that will look shiny and different than the surrounding paved surface. To dull the shine and blend the liquid in, sprinkle sand over the filler and brush it in with a broom.
As we mentioned, it is important to follow your patch job with a sealer. You can choose from: 1) asphalt base, 2) tar-emulsion base, or 3) tar base with aggregate. The asphalt base is the most expensive. Tar is most popular because it is the least expensive and because it resists damage from dripping gas and oil. The third alternative mixes tar with black aggregate making it the best for sealing larger cracks. Five gallons will cover about 350 square feet.
Before sealing make sure to wash the area thoroughly with a mixture of trisodium phosphate. Doing so will remove gas and oil drips and other debris that will inhibit a bond between the asphalt and the sealer. Don’t wash the patches with anything but fresh water.