When you pour concrete into a form, it has the form of a wet slurry mix. As the mix begins to cure or dry, the mix will slowly contract. Once the concrete fully cured, it will, due to weather conditions, expand and contract. This movement will cause the concrete slab to crack if you did not place expansion joints into the surface. If the expansion joints become exposed to the weather, water can find its way into the open joints. Over time, the water can cause problems from freezing and erosion to the concrete itself. Fill up these cracks using typical concrete caulk sealant.
Consult a local building outlet for the correct type of concrete caulk for your area. Various climates will dictate a different type of sealant. Colder climates will require a sealant that can expand and contract with the large environmental temperature swings, while a wet and hot environment may not require a compound than needs to withstand freezing temperatures. Different sealant compounds may require various application methods.
Sweep the driveway with the broom. Remove all heavy debris and any dirt or sand particles. Use either a high-pressure washer or a garden hose with a sprayer attachment. Beginning on the uppermost end of the driveway, wash the entire surface down. Concentrate on cleaning out the expansion joints. Remove all minor dirt and debris from the joint regardless of the type of sealant you plan to use.
Allow the driveway to completely dry. Keep all traffic from the driveway, as vehicles will track more dirt over the hard surface and the debris will find its way into the expansion joints.
Follow the sealant manufacturers directions for application after the thorough cleaning. In most cases, the sealant will come in a basic caulking tube. Cut open the end of the caulk tube to the desired width of the expansion joint. Insert the tube into the caulk gun, and apply the caulk to the joint. Ensure that the caulk completely fills the open void of the expansion joint.
Allow the caulk to fully cure. This may take up to 24 or even 48 hours, depending on the product. Keep all traffic off of the driveway surface during the curing time.