The best time to mitigate crack formation in a concrete driveway is when you are having it installed. Cracks that form later can be patched, but the repair work can detract from the drive's appearance so crack prevention is preferred. The following are the three main strategies your concrete contractor will use to prevent cracks on your new driveway.
1. Base Preparation
Settling of the base beneath the driveway and water incursion underneath the paving are the two main causes of cracking on your new driveway. Construction should begin with a thorough preparation of the subgrade soil beneath the base, as it will need to be leveled and compacted well to prevent settling. Then a thick layer of gravel and sand is put down and compacted, which allows for drainage and further stabilizes the base.
Your contractor may also install reinforcing structures in the base or just on top of it, such as repair or stabilization grids. These are helpful in areas where shifting soils are an issue, such as areas with extreme freeze-thaw cycles that cause the ground to heave.
2. Expansion Joints
A large slab of concrete, such as that poured for a driveway, is typically installed in sections with joints between each section. These joints, which may have a wood or foam form in them, are called expansion joints. The form inside the joint is flexible to allow for normal expanding and contracting that concrete experiences in relation to temperature changes.
Properly placed expansion joints remove stress from the concrete when expansion and contraction occurs, thus preventing the formation of cracks. The joints are often installed at the time the concrete is poured, but sometimes a contractor will pour a solid slab and then cut the joints into the slab where they need to be.
3. Proper Curing
The final key to a crack-free driveway is allowing the concrete to cure thoroughly after installation. It can take up to a month for the concrete to thoroughly cure, but the first week is the most important if you want to prevent cracks. Follow your installer's recommendations for when to begin using the driveway. Depending on the weather you may need to wait up to two weeks before driving your vehicle onto the driveway.
Concrete must be kept damp in the initial concrete curing phase, so make sure to follow any instructions provided on how often to spray the concrete down. Your concrete installer may also apply a curing compound to the drive's surface to help speed the curing process.
For more information on concrete driveways, contact a professional near you.