Patching and repairing concrete can be easy or difficult, depending on the project and the amount of deterioration. Most repair projects are quite simple, using some of the specially formulated patches and repair products available today. Before starting any repair, evaluate the general condition of the concrete slab. See “Patch or Replace? below) Sometimes the best strategy is to break up an entire section and re-pour it with new concrete instead of applying a patch.
The patch works best for local damage, in particular, which would otherwise be solid. You can use a standard concrete mix to apply patches to a concrete base, but the concrete patch is specially designed for those applications. Fortunately, the edges are easy to fix, and if you do the job properly, your repair should be as strong as existing concrete. If the repair is quite small, something like a chipped corner, you won't need to use any special shapes or reinforcement.
Start by chipping all the loose concrete. Use a cold chisel, a hammer and an aggressive attitude. Be sure to remove anything that is loose or chipped, until you get to the solid concrete. You can use a special cement for patching if desired, or simply mix a batch of mortar made of three parts sand and one part portland cement.
The smaller the repair, the more sense it makes sense to use special patch cements. Small repairs made with ordinary cement tend to dry out too quickly and therefore lose most of their strength. Special patch mixes contain synthetic additives that greatly eliminate this problem. If using the cement patch, simply follow the instructions on the label.
If you mix your own mortar, use enough water to make a firm paste that holds its shape. Set this aside for one minute and mix in a creamy slurry of pure Portland cement and water. Wet the exposed surface of old concrete with water, and then apply a thin layer of cement slurry. This will act as an adhesive agent and help ensure a solid repair.
Larger repairs will likely require both shapes and reinforcements, such as those shown in the sketch. Start as above, removing all loose concrete. Then place one or more reinforcements. For larger repairs, ordinary concrete mix is cheaper and stronger than mortar.
Mix it with water according to the instructions on the bag. There's always a temptation to use too much water, so the mix is easy to pour and work with, but you'll get a stronger mix if you use only the amount of water needed to make a viable mix. Allow the repair to be configured until it contains a fingerprint as described above. Then trowel again, trying to match the texture of the surrounding concrete.
A wooden trowel or float will give a rather rough texture. A magnesium trowel produces a smoother surface, and a steel trowel creates the smoothest surface of all. If the existing surface is grooved, you can duplicate this texture by brushing lightly with a broom. Again, keep the repair wet for at least a week as described above.
Then remove the form and the job is complete. If possible, avoid any stress in the repair for an additional week or two. Concrete takes a long time to reach its maximum strength. The patch mix is made of vinyl, Portland cement and sand.
Covers cracks up to Â1⁄2 inch wide. Dampen the area around the crack, and then apply a trowel over the mixture. Smooth the surface with a trowel or small float. Step 4a Mix the vinyl concrete patcher by adding approximately 10 ounces of water for every 5 pounds of vinyl concrete patcher (the vinyl concrete patcher should be poured into the mixing water).
Step 9a: The repair area must be protected from foot traffic for 24 hours and vehicle traffic for at least 3 days. Step 4b Stir the concrete patching compound with a margin trowel or spatula. The vinyl-based formula forms a concrete patch layer that is stronger than the actual concrete underneath. Once you have cut and thoroughly cleaned the loose concrete from the repair area (photos 2) and, moisten the area with a damp sponge before packing the concrete mix.
Unlike concrete mix, which is a mixture of Portland cement, gravel and sand, the concrete patch contains polymers and additives to make them more tacky and flexible. Concrete patches generally promote adhesion, but there are some additional steps you can take to ensure that the patch stays in place. Once cured, it will promote better adhesion between existing concrete and a thicker layer of patch. Narrow cracks in concrete can be filled with an elastomeric filler for masonry cracks that can be applied with a caulking gun.
Fresh concrete is easier to handle and hardens better (a process technically called “set” and “cured”) in this temperature range. Once mixed, stays in place while drying on interior or exterior concrete surfaces in crevices up to ½ inch deep, which is necessary for vertical repairs. This 12-pound dry mix container combines with water to a user's desired thickness to patch floors, walls, driveways, walkways, or other concrete surfaces. A variety of Sakrete concrete repair products are available to repair concrete that has started to deteriorate.
Textured formula blends well with other concrete surfaces, whether vertical or horizontal, indoors or outdoors. The secret to fixing wide cracks in concrete is to undermine the sides of the crack to give it an inverted V-shape. These compounds contain cement, polymers and other additives to fill cracks and form strong bonds with concrete surfaces. .