Home » Concrete Contractor

Category Archives: Concrete Contractor

Factors That Affect the Success of Concrete Repair

Concrete repair requires a combination of many factors to be successful. These include physical properties of the repair material, such as drying shrinkage and modulus of elasticity, permeability, and freeze-thaw durability.


The location of the damage must be evaluated and the correct preparation of the old concrete should be done to ensure a good bond with the new repair. Visit https://www.concreterepaireauclaire.com/services for more details.

Crack repair is an important part of concrete restoration. This is especially true for cracks that are deemed active and non-dormant and that have a significant effect on the structural integrity of a structure or its safety. Identifying what type of cracks are present and the status they are in is critical to selecting suitable crack repair methods. Cracks indicating a design, construction or material failure may be structurally significant and therefore require a different repair method than cracking that is due to intrinsic volume changes such as drying shrinkage or thermal expansion and contraction.

When repairing a crack, it is important to first clean the crack and remove any debris from the surface. This will ensure that the crack repair is adhered to a clean surface and that any potential water ingress from the crack will be sealed. Then, the crack must be routed and sealed with an appropriate filler for that type of crack. Routing and sealing is a simple process that involves widening the crack and filling it with a sealant that can move with the crack. For example, epoxy or polyurethane resins can be used as a concrete crack filler and are ideal for widening and sealing non-dormant and active concrete cracks. They can also be used for wet cracks when combined with a moisture tolerant epoxy.

An alternative to a poured epoxy crack filler is the use of concrete caulks. These can be injected into the cracks to form an effective seal, and they will allow the concrete to flex with its natural movements without breaking down. Moisture tolerant silicone and acrylic caulks can be used for this purpose.

Another option is to inject a wet crack with a hydrophilic polyurethane resin. This will be able to react with the water within the crack and chase it, effectively closing the leakage. This is a good choice for wet cracks that cannot be dried out using moisture tolerant epoxies. This injection technique can be used for both dormant and active cracks, but it is important to anticipate future movement and cater for this with the design of the structure.

Filling Cracks

Concrete is strong in compression, but weak in tension, which results in cracking during the curing process. These cracks are mainly due to exothermic chemical reactions, thermal expansion or contraction and drying shrinkage. They are not structurally significant and may not even affect the load-carrying capacity of the concrete. Cracks that imply a design, detailing or construction error, however, raise serious concerns and may be detrimental to the performance of the concrete structure.

It is important to identify and rectify the causes of the cracking before attempting any repairs. If the cracking is due to the lack of a suitable aggregate or if a concrete mix was incorrectly designed or poured, the cause must be addressed to prevent it from occurring again.

Once the cause has been identified, a repair procedure should be selected that is appropriate for the type and size of crack. Small cracks can be filled with a commercial masonry concrete crack filler that is sold in cartridges to fit a caulking gun or a vinyl concrete patching compound that can be applied with a wet margin trowel and smoothed with a putty knife. It is important that the crack area be thoroughly cleaned of any loose debris to ensure a good bond. It is also advisable to dampen the area to avoid pulling moisture from the fresh concrete repair material, as this will decrease its adhesion and durability.

In many cases, hydraulic cement is used to repair cracks in concrete. While this product is relatively inexpensive and easy to use, it does not form a good bond with the existing concrete, which can result in the cracks widening over time. For this reason, a stronger repair method such as epoxy injection should be considered for larger cracks.

When using either a commercial crack filler or an epoxy injection system, the concrete should be thoroughly dampened to reduce the possibility of the new material pulling moisture from the existing concrete. In addition, if the crack is going to be exposed to water, it should be covered with a wet burlap sheet or plastic and taping down the edges to keep the moisture in place.

Patching Cracks

Many of the same factors that cause cracking also affect the quality of concrete products. It is very important that they are identified and corrected at the appropriate stage of production to prevent recurrence of the problem. It is easy to see when there is a crack in concrete; however, it takes more in-depth evaluation to determine the cause and severity of deterioration and/or failure.

For minor defects, routing and sealing is a quick and relatively inexpensive repair method. Routing involves sawing or chipping out the affected area, followed by the filling of a chemical grout or epoxy resin. This method is useful for cosmetic cracks that do not extend to the steel reinforcement or the surface of the concrete.

When repairing these types of defects, it is critical that the concrete surface be clean and free of loose debris. This will allow the filler or sealant to adhere to the concrete and thereby maintain its effectiveness.

If the concrete is not sufficiently consolidated before patching, it will become displaced in time and the repaired areas may fail. The addition of a water reducer to the concrete mix will help to avoid this. It is also a good idea to use a mix design that contains less water than the original concrete to help minimize shrinkage cracking.

A good rule of thumb is to use the same ingredients for a repair mix as in the original mix if possible, with the exception of a lower water content. Having the concrete accept an integral bond is one of the most critical aspects of a successful repair.

Concrete patch kits and overlays are often used for the repair of trip hazards, or as a surface cover for spalling concrete. These types of repairs are usually a temporary solution, and can fail quickly as the concrete continues to deteriorate and experience fluctuations in temperature.

Unless the concrete is at an early age, it should be replaced with a fresh batch of replacement concrete to ensure that the cracks will not reappear. Replacement is also a good choice when there are large sections of honeycombing that have not extended to the steel reinforcing bars or to the surface of the concrete.

Repairing Holes

In some cases, concrete repair is needed to address holes caused by corrosion or other reasons. Holes from corrosion are often round with a small opening, while holes from cracks have more of a square-shaped appearance. In either case, these can be repaired using a concrete patching compound or concrete plugs.

It is important to make sure that the existing concrete is a sound, dense material before the application of repair materials. This is critical to ensure that the bond between the existing concrete and the repair is strong enough to withstand the stresses created by thermal expansion and contraction of the repair material. It is also important that the material used for the repair has a compressive strength comparable to the existing concrete.

When repairing a hole, it is important to remove any loose pieces of concrete and to clean the area thoroughly with a wire brush. This is especially important in areas that have been damaged by salt or acidic cleaners. The area should then be swept and rinsed with water from a garden hose.

Once the surface is ready, the hole can be filled with a dry concrete mix. Dry concrete mixes are a popular choice for repairs because of their ease of use and durability. However, it is critical to ensure that the mixture contains no gypsum cement, which can swell when exposed to moisture. It is also critical to follow the mixing instructions carefully.

If the concrete is very deteriorated, it may be necessary to use a concrete replacement method instead of a mortar or dry pack repair. This will involve digging out the old concrete and replacing it with new, ideally tying in any existing reinforcing steel in the process.

Concrete replacement can be a messy process, so it is best done in a garage or other area where the mess can be controlled.

Concrete repair needs to take into account the environment and society, as well as its performance requirements. In order to minimize the impact on the environment, it is critical that the repairs are made quickly and correctly. Increased concrete repair activity due to durability failures contributes to depletion of natural resources, produces massive quantities of waste and inert debris, and causes pollution. Engineers have an essential role to play in designing eco-efficient repair systems that achieve specified levels of durability and strength while minimizing the need for repairs.