Concrete crack repair method

Concrete Repair Methods: Crack Repair Techniques

Concrete is a popular building material that is known for its strength and durability. However, over time, concrete can develop cracks due to a range of factors such as changes in temperature, shrinkage, or settling. Concrete cracks not only impact the appearance of structures but can also lead to further damage if not repaired in a timely and appropriate manner.

Thankfully, there are various methods available to repair concrete cracks, ranging from simple DIY solutions to more complex professional techniques.

In this article, we will explore some of the most common concrete repair methods including their advantages, disadvantages, and applications.

Whether you are a homeowner looking to repair a minor crack in your driveway or a contractor dealing with more significant structural damage, this guide will provide you with the knowledge you need to choose the most effective concrete crack repair method for your needs.

Concrete Repair Methods

The following are the best Concrete Repair Methods,

1. Concrete Crack Repair by Epoxy Injections

The Epoxy Injection may be used to bond the cracks having greater than or equal to 0.05 mm opening. This method is not suitable for crack that is active and if the cracks are large in number, or when the water leakage cannot be controlled.

 Epoxy Injection
Epoxy Injections

In this method of concrete crack repair, the cracks on exposed concrete surfaces are sealed by injecting epoxy under the concrete crack. However, it is essential to find and fix the major cause of cracks before injecting the epoxy into the cracks otherwise the cracks will keep on emerging again and again.

Problems such as leakages and silt contamination damage the efficiency of epoxy, therefore it is recommended to fix these issues before injecting the epoxy to make it last longer.

The epoxy injection method of crack repairing requires a lot of discipline and skillful execution so you need to be sure that the person executing the repairs knows his work.

Epoxy resin loses strength when exposed to fire or sustained elevated temperatures and fireproofing protection is required for such structural repairs.

Read More: Which Cement Is Best For House Construction

2. Routing and Sealing

Routing and sealing the cracks is a much more common and much simpler method to repair cracks. That said, it can be only used in cases where only remedial crack repairing is required and structural repairs are not needed.

Routing and sealing of cracks in concrete can be used for inactive cracks not involving the restoration of tensile strength. Under this method, the crack is enlarged along its exposed face and the V-shaped groove is formed up to a minimum width of 6 mm and a depth of 6 to 25 mm.

This V-shaped groove is filled and sealed with suitable material. This is a Popular concrete crack repair.

Methods of Repairing Cracks in Concrete
Routing and Sealing

Should be taken care of the width to depth aspect ratio when sealing the joint so that there is enough room left for movement. While repairing roadway pavements, pouring hot tar within the cracks is a simple and inexpensive method.

Be careful when using hot joint sealants and make sure that they bond with the concrete and do not melt and flow under operating conditions.

Routing and Sealing Method of Concrete Crack Repair

The material used as the sealant can be any material that can balance cyclic expansion and contraction and which does not become brittle with time, including epoxies, urethanes, silicones, polysulfides, asphaltic materials, or polymer mortars. Cement grouts are not to be used due to the chances of future cracking.

3. Stitching the Cracks

Stitching the Crack
Stitching the Cracks

Stitching the Cracks is the easiest and long-lasting method of repairing concrete cracks. In this method, a number of holes are drilled along the crack surface and stitched with metallic wire.

This metallic U-shaped wire is then passed through holes and anchored strongly in the holes with grout or an epoxy-based system.

Stitching Cracks
Stitching Cracks

4. Drilling and Plugging

Drilling and Plugging
Drilling and Plugging

When it is required to repair a vertical crack in the concrete that runs in straight lines, this is a good method for its cost-effectiveness and less time-consuming. 

In this method, holes are drilled vertically in the cracks and a key is formed by passing down a grout. The grout key drilled into concrete helps in preventing leakages.

A Concrete crack can be repaired by Gravity Filling, dry packing, overlay, surface treatments, etc. selection of the method of repair depends on the nature of the cracks and whether a crack requires remedial or structural repair.

This is method also known as Wall Crack Repair Method.

5. Grouting Method of Crack Repair

i) Portland Cements Grouting

In the case of gravity dams and concrete walls, large-sized cracks formed. They can be repaired by filling them with Portland cement grout.

This grouting method is effective in stopping water leaks, but it will not structurally bond cracked sections.

Cement Grout Repair
Grouting Method of Crack Repair

The procedure consists of,

  1. Cleaning the concrete along the crack.
  2. Installing built-up seats (grout mesh) at suitable intervals (to provide a pressure-tight connection with the injection apparatus).
  3. Sealing the crack between the seats with cement paint, sealant, or grout; 
  4. Flushing the crack to clean it and test the seal; and then grouting the whole area.

In this method, mixtures of grout may contain cement and water or cement plus sand and water, depending on the width of the crack.

However, the water-to-cement ratio should be kept as low as practical to minimize shrinkage and maximize strength. Other admixtures or water reducers may be used to improve the properties of the grout.

For this treatment a manual injection gun may be used in case of small-volume crack filling and for larger volumes, a pump should be used.

The good pressure should be maintained for several minutes after the group is filled over a surface to ensure good penetration.

ii) Dry Packing

In the Dry packing method, the hand placement of a low water content mortar is done by tamping or ramming the mortar into place to make intimate contact between the mortar and the existing concrete.

Concrete Dry Packing Method
Dry Packing

As we use the low water-cement ratio for grout mix, there are chances of little shrinkage, and the patch remains tight and can have good quality concerning durability, strength, and water tightness.

The dry pack method can use for the small-sized crack of inactive nature. The dry pack method is not suitable for filling or repairing active cracks.

Before applying grout by dry pack method the slot of 25mm x 25mm must open to a concrete surface. The slot opening should be such that the base width is slightly greater than the surface width.

The mortar should be prepared 30 min after mixing water to minimize chances of shrinkage and then should be remixed before use. This mortar should be placed in layers about 3/8 in. (10 mm) thick.

Each layer should properly be compacted by a blunt stick or hammer, and the old layer should be scratched to facilitate bonding with the next layer.

The repaired surface should be cured by using either water or a curing compound.

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3 thoughts on “Concrete Repair Methods: Crack Repair Techniques”

  1. You did a great job explaining how a vertical crack could be repaired by drilling and plugging concrete. My brother bought an unfinished house, and he wants to repair the foundation because there is a huge crack on the wall. I will pass him the info so he can start looking for a paving contractor in the area.

  2. roundrockconcrete

    thanks for this very informative post. This will help us as an Austin concrete contractors

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