It’s so important to stay behind maintenance repairs so that the condition doesn’t deteriorate further. A surface crack across a concrete driveway or patio may not seem like a big deal, but if left unrepaired over time it can become wider, deeper, and become chipped.
Why Does Concrete Crack?
Concrete can crack from various conditions. The forces that work against concrete are compressive and tensile. Concrete has high compressive (withstanding direct pushing force) strength, but low tensile (pulling apart) strength. Since concrete shrinks as it dries, many concrete slab installations are reinforced with wire mesh or steel rebar because of this low tensile strength, to help reduce cracking.
Another technique used in building concrete slabs is to apply control joints during finishing to help control where a crack will occur (within the control joint) which helps to make the crack less noticeable.
Some of the conditions that cause concrete slabs to crack include:
- too much water in the mix
- poor, or lack of, subgrade compaction
- settling of ground adjacent to the slab
- concrete mixture with the incorrect strength for the projects intended use
- improper curing
- in a restraint or confined situation where concrete has no room to expand under thermal changes, such as placing separate slabs directly against one another without using an expansion joint between the slabs
Why Should a Crack Be Repaired?
One condition that can cause a crack to worsen overtime is being exposed to repeated freeze-thaw cycles. A high volume of water can get inside the crack and freeze in cold temperatures. As the water freezes, it will expand in volume causing pressure inside the confined area of the crack. Overtime, this can break up the surface of the concrete and create a larger crack.
The appearance of the concrete slab can be enhanced by repairing cracks, as well. And besides, weeds can grow in these cracks which can become additional maintenance for a homeowner.
How to Fix a Crack in a Concrete Slab
This is a simple repair, and well worth the effort to preserve the beauty of a concrete surface.
- Clean out the crack with a strong stream of water from an adjustable nozzle connected to the hose – this will get rid of the dirt and debris inside the crack
- Use a wire brush to remove any loose concrete along the entire length of the crack and inside the crack, too.
- Use a stiff bristle broom or a leaf blower to remove any loose particles from the wire brushing – a clean surface will allow the concrete repair material to be able to bond directly with the concrete slab
- Use a high quality concrete crack repair and follow the manufacturer’s instructions. We used Quikrete Concrete Repair – the material in this product has a rough texture like outdoor concrete which allows the finished appearance to blend with the adjacent concrete. It can be applied with a caulking gun.
- Use a putty knife to smooth out and level the repair material
Let it cure, per the manufacturer’s instructions.