How to Repair Cracks in Your Concrete Driveway
Where do cracks come from?
Cracks in concrete driveways develop from a variety of reasons. In some areas of the country cracks develop due to extremes in weather like heat and ice. If a hairline crack begins water may seep in. If the temperature drops below freezing while the water is still in the crack the water will freeze and expand. The pressure from this expansion causes the crack to widen slightly. After the ice melts more water makes its way into the larger crack, and refreezes. Over time, a hairline crack can become a gaping hole in your concrete driveway. Other cracks develop from normal wear and tear. Over time dropped tools, rocks and other normal driveway activities take their toll on the concrete.
Preparing to Repair
Before you repair your concrete driveway you will need to get a few items together and do a little prep work on the area to be repaired. Depending on the size of the crack there are several options on the market for repair. Products range from pre-mixed epoxy to bags of quick drying concrete. For the intent of this article we are going to assume that you are repairing a fairly large crack in your driveway.
You will need a hammer, a chisel, a trowel or small hand shovel, a source of water such as a garden hose, a bag of concrete, something to mix the concrete in such as a wheelbarrow or bucket and some plastic wrap. Also, make sure to wear eye protection and gloves while repairing the concrete in your driveway.
Remove the old concrete
To being the job you will need to remove all of the old and damaged concrete from around the crack. Using the hammer and chisel carefully chip away at the damaged concrete down to a depth of one to two inches.
Once the cracked concrete is removed you will need to undercut the hole you made. Undercutting is simply widening the bottom of the hole while leaving the top of the hole the same size. To achieve this angle your chisel at approximately a 45 degree angle inward.
Make sure to clean out all of the dirt and debris from the newly chiseled hole.
Prep the area
Over the course of the rest of the day, or over night, you will need to moisten the concrete in and around the area to be filled. This can be done manually every hour or so, or by allowing a hose to drip into the hole over night. The concrete should remain moist without allowing any standing water to accumulate. Concrete cure by sapping all of the moisture up from the surrounding area, so this step is key to a successful job.
Mix the concrete
To fully repair your concrete driveway you will need to mix two batches of concrete. It is important that you use them as quickly as possible to avoid the mixtures becoming too dry to use.
Begin by mixing some of the concrete with water at a ratio of about three parts concrete to one part water. This mixture should have a very thick consistency. This will be your filler concrete. Set this mixture aside for the time being.
Next make a thinner mixture at a ratio of about 1.5-2 parts concrete to one part water. This mixture should be thin, but still thick enough to stick to the bottom and sides of the hole.
Apply the concrete
Quickly apply the thin mixture of concrete to the bottom and sides of the hole. Apply just enough to coat all of the sides. This coat acts as the glue that anchors the filling. Now fill the hole with thicker concrete mixture.
Finishing up
Let the newly filled hole sit for a few hours while you clean up your work area and tools. After a few hours time cover the newly repaired area with the plastic wrap. Leave the repaired concrete covered and moisten it every few hours over the course of the next few days. This ensures that the concrete stays moist enough to fully cure and harden. After a few days remove the plastic wrap and check for coverage and seal. There should not be any small cracks or visible creases in the new concrete work.
