Dear Pat: I am tired of repairing and sealing my asphalt driveway, so I want to replace it with a concrete one. Some seem to hold up well, and others crumble and crack. Why do some hold up so much better? – Alexandra F.

Dear Alexandra: From an aesthetic standpoint, the driveway is the first thing guests see and walk on when they visit your home. An asphalt driveway is probably more attractive when brand-new than concrete, but over its entire life, concrete wins out. Also, there basically is no regular maintenance required for a concrete driveway.

When a concrete driveway deteriorates, it is generally caused by improper installation techniques. The quality of the concrete itself is seldom the problem because it is mixed at the concrete plant under controlled conditions.

If you live in an area where much road salt is used during the winter, the salty water can cause problems. Although concrete feels very hard, it is porous, and the salty water will penetrate the surface. This does not harm the concrete, but it will make the steel reinforcing rods corrode. When steel corrodes, it expands, and this cracks the concrete.

To minimize this problem, use a clear concrete sealer on the driveway after it has fully cured. Sealers are available at most home center and hardware stores. If you cannot find it, contact SaverSystems at (800) 860-6327 for local retail outlets.

Since the quality of the installation is critical for a long-lasting concrete driveway, contact several contractors and do not necessarily accept the lowest bid. There are ways a contractor can lower the costs, but the driveway may begin to fail quickly if not installed properly.

As with most home-improvement projects, the initial preparation of the driveway is an important step. Keep in mind, concrete is very strong in compression. When it is bent or stretched, it is extremely week. Having a strong, stable base under the concrete ensures it is compressed under the weight of your car and not bent or stretched over voids from an unstable base. Creating a suitable base may increase a cost estimate significantly.

Ask the contractors about the type of concrete each plans to use. The proper type to use for a driveway is a 4,000-psi (pounds per square inch) concrete. There are weaker concrete mixtures available. Also, request a 5-inch thick driveway. Some contractors recommend only 4 inches to lower the costs. The extra inch thickness typically costs only several hundred dollars more, depending upon the size of your driveway.

Ask them about how the reinforcing steel will be installed. Some just lay it loosely over the ground and then start pouring concrete. For the maximum strength and longevity of the driveway, the reinforcing steel should be placed well up in the concrete. The driveway should be sloped slightly so water does not stand in puddles, especially with salty water.

No matter how well everything is done, some cracks are unavoidable. This is because concrete shrinks as it cures. The contractor should make deep control joints in the concrete so any cracking occurs in the joints and is not noticeable. If a proper base was laid, the surface should remain even. The best type of surface for a driveway is a light broom or wood trowel finish.

Send your questions to Here's How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com. COPYRIGHT 2011 CREATORS.COM