What is involved in structural concrete repair?
Structural concrete damage is typical nowadays in most modern construction works. This results from many causes, some notorious ones being negligence in construction processes and hiring unqualified concrete contractors. While this is rampant, it is fair to say that it has cost many concrete project developers a great deal of fortune, with losses amounting to billions of dollars every year.
Different methods involved in structural concrete repair.
This is a standard method used in the repair of dams, bridges and other concrete structures. It is used for cracks ranging from 0.002 to 0.09 inches in width. So, here is the procedure used;
- The cracks are initially cleaned to remove dirt like oil or grease that would prevent proxy penetration.
- The surfaces are then wrapped to keep the epoxy airtight before it is gelled.
- Installation of venting and entry ports by methods including bonded flush-fitting, interruption in seal and inserting fitting into drilling holes.
Once this is done, the epoxy is mixed and injected by hydraulic or paint pressure ports. Finally, the surface seal is removed by grinding.
Drilling and plugging
In this, drilling is done down the length of the flaw and grouting it to form a key. This is commonly applied in retaining walls to repair vertical cracks. The grout key impedes traverse movements of parts of the concrete laying near the cracks.
Cracks with widths of between 0.002 to 0.09 inches are sealed using low viscosity monomers and resins. The lower the viscosity, the better. This is because even the most minor cracks can be filled effectively.
Overlays and surface treatment of cracks
For concrete with no significant movements across the cracks, surface treatments and overlays are used.
- Surface treatments. This uses polyesters, acrylics, and epoxies on cracks with a thickness of between 0.04 and 2.0 inches. These are low solids and low viscosity resin-based systems that are used to seal concrete surfaces.
- Overlays. Used to seal dominant cracks. An overlay thickness of about 1 to 0.25 inches can seal such cracks using polymers such as acrylic latexes and butadiene.
Causes of concrete damage
Failure to use air entertaining admixtures. It will be entirely naive for a concrete contractor to underestimate the importance of the type of admixture they intend to use in a block of concrete. Air entertaining admixtures could prove critical to the lifespan of concrete since they could help increase its resistance to freeze and thaw deterioration.
- Poor concrete positioning
If a concrete mixture is not proportioned as required, the chances are that it may result in a weak construction. This could be compounded by excessive weight that gradually weakens it. Finally, the concrete section will give in to the pressure.
- Use of excess water.
Excessive water used in mixing concrete reduces concrete strength, increases creep, reduces the concrete abrasion resistance, increases curing and drying shrinkage, and increases its porosity. This makes the concrete extremely weak with a shorter life span.
- Dirty or low-quality aggregate. This lowers the adhesiveness of concrete, causing damage earlier than expected.
- Sulphate exposure and induced chlorides. These weaken the concrete structurally and causes freeze-thaw damage.