How to Repair Cracks in Concrete

Before you begin repairing cracks in concrete, you need to determine what caused the problem. Many times, concrete cracking is the result of unraveling, inadequate expansion joints, or concrete sinking. Regardless of the exact cause, crack repair should address possible future movement and stresses.

Epoxy injection

Epoxy injection is a method used to repair cracks in concrete. Its main objective is to restore structural integrity and resist moisture penetration. It is commonly used on horizontal and vertical cracks. It can also be used on overhead cracks where conventional repair methods cannot penetrate.

Before applying epoxy, it is necessary to clean the crack thoroughly. This can be achieved by steam cleaning or high-pressure washing. The crack should also be dry. If the crack is wet, the coating may lift under the pressure of the injection. To avoid this, it is recommended to route the opening of the crack in a “V” shape before injecting the epoxy.

To repair cracks in concrete, use a TxDOT-approved Type V or VII concrete epoxy adhesive. Then, drill holes, mount the injection ports on the surface, and space them accordingly. If a horizontal crack is extensive, begin the injection process at the widest point of the crack. Then, close the second port to accommodate the epoxy below the surface of the concrete.

Textured concrete filler

If you have cracks in your concrete, one way to fix them is by using a textured concrete filler. This product comes in liquid form and is easy to apply. It should be troweled into the crack, then smoothed out with a putty knife. Then, after the filler has dried, you can paint the crack. This product works best on cracks that are about an inch wide.

Although concrete is exceptionally durable, it can still crack due to various factors. These can include too much water in the mix, poor construction, or weather. A concrete crack filler will help you repair your cracks and make them almost invisible. This will also make your slab look better and increase its lifespan.

Bonded flush fittings

A bonding adhesive is essential for a successful repair when repairing cracks in concrete. It helps the filler and sealer adhere to the old concrete, increasing the repair’s flexibility and resilience. You can apply the adhesive with a caulking gun or a caulking tube.

The bonded flush fitting can be used in both V-grooved and non-V-grooved cracks. The flange at the bottom of the fitting provides an entry port for the adhesive to penetrate the crack. Alternatively, you can install special gasket devices over the unsealed portion of the crack.

The bond strength of the repair layer is high. It means that stress inside the repair layer is redistributed at the interface. Crack development is stabilized when this stress is less than the tensile strength of the repair layer. However, if the tensile strength of the repair material is high, it may lead to interlamination.

Water ingress

The problem of active water leakage in concrete structures is unsightly and a safety concern. It can damage equipment and even cause settlement problems. The leaks will only get worse if they are left untreated. In such cases, crack injection of polyurethane grout can be a viable solution. This material is pressure injected into cracks through pre-drilled holes. Once injected, the material expands into a foam-like substance and bonds to wet surfaces. As it cures, the material has a flexible seal that can accommodate movement.

The type of concrete crack that needs to be repaired can determine the method that will work best. Generally, the repair process will require preparing the concrete cracks before applying the material. This step is essential to making the repair waterproof. If unsure how to prepare the cracks, you can use an electric chipping hammer to create a narrow, deep chase. Once the chase is formed, you can apply concrete crack filler to the area.