It is commonly observed that concrete structures face cracking problems during their life period. This crack must be given serious and careful attention and repair at the right time. Concrete Crack Repair involves a lot of time and cost constraints. There are several methods of concrete crack repair methods and techniques.
Choosing the appropriate crack repair techniques can help you save a lot of time, money, and energy and can give long-lasting results.
It is essential to know the type and nature of cracks that have appeared in the building to be able to select the most suitable and cost-effective method of repair. It is also important to know the cause of cracks so that they can be corrected to keep the cracks from recurring.
Concrete Crack Repair Methods:
Here are the list method of crack sealing of concrete is that can be applied to repair concrete crack:
- Concrete Crack Repair by Epoxy Injections
- Routing and Sealing
- Stitching the Cracks
- Drilling and Plugging
- Grouting Method of Crack Repair
1) Concrete Crack Repair by Epoxy Injections:
- The Epoxy Injection Method of Concrete Crack Repair may be used to bond the cracks having greater than or equal to 0.05mm opening.
- This method is not suitable for crack is active and if the cracks are large in number, or when the water leakage cannot be controlled.
- In this method of concrete crack repair, the cracks on exposed concrete surfaces are sealed by injecting epoxy under the concrete crack.
- But, 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. MOre
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2) Routing and Sealing:
- Routing and sealing the cracks is a much more common and a 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.
- It should be taken care of the width to depth aspect ratio when sealing the joint so that there is enough room left for the 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.
- The material used as the sealant can be of 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:
- It is the easiest and long-lasting method of repairing concrete cracks. In this method, a number of the hole 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.
4) Drilling and Plugging (Wall Crack Repair Methods):
- 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 in concrete helps in preventing leakages.
- Above four methods is a major method of concrete crack repair. Concrete crack can be repaired by Gravity Filling, dry packing, overlay and surface treatments, etc. selection of the method of repair depends on the nature of cracks and whether a crack requires remedial or structural repair.
- This is method also known as Wall Crack Repair Methods.
5) Grouting Method of Crack Repair:
i) Portland Cements Grouting:
- In case of gravity dam and concrete wall large-sized crack formed. They can be repaired by filling with Portland cement grout.
- This grouting method is effective in stopping water leaks, but it will not structurally bond cracked sections.
The procedure consists of,
- Cleaning the concrete along the crack.
- Installing built-up seats (grout mesh) at suitable intervals (to provide a pressure-tight connection with the injection apparatus).
- Sealing the crack between the seats with cement paint, sealant, or grout;
- 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 to maximize the 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 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.
- 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 so that the base width is slightly greater than the surface width.
- The mortar should prepare 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.
Watch Video: How to Repair Concrete Crack
Q.1 Can Cracked Concrete be repaired?
Concrete cracks can be repaired by various techniques depending on the crack type. Generally, wider cracks are sealed by patching materials whereas thinner cracks are covered by routing or liquid filler.
Q.2 What are the best techniques for Concrete Crack Repairs?
Concrete crack repair techniques are dependent on the type of crack to be sealed. However, the best techniques for concrete crack repairs are listed below:
Concrete Crack Repair by Epoxy Injections
Routing and Sealing
Stitching the Cracks
Drilling and Plugging
Grouting Method of Crack Repair
Q.3 Should you fix Hairline Cracks in concrete?
Hairline cracks are not the major trouble to be fixed in concrete. Even though the repair method is quite unworthy to fix hairline cracks. To do so the cracks are required to be wide opened for fixing.
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