Concrete Repairs / Delamination

Concrete Repairs / Delamination

When it comes to robust and long-lasting construction, concrete reigns supreme. However, like all materials, it’s not immune to wear and tear. One common issue faced is delamination – a process where layers of concrete separate, leading to a myriad of structural problems.

Let’s dive deeper into concrete repairs and delamination, equipping you with the knowledge to tackle these issues effectively. Whether you’re a property owner or a construction enthusiast, understanding these aspects plays a crucial role in maintaining the integrity of any concrete structure.

What Is Delamination on Concrete?

Delamination occurs when the upper layer of concrete separates from the underlying slab. If left unaddressed, this issue can lead to substantial repair expenses. It’s essential to deal with delaminations as soon as possible to mitigate potential costs. Although this problem can arise with any flooring option, it tends to be most noticeable and develops rapidly on decorative and polished surfaces.

Concrete delamination can cause various problems, such as the splitting of the topcoat, which can allow moisture to penetrate. It can also lead to significant separation in areas larger than the original delamination. Therefore, it is crucial to thoroughly eliminate all signs of delamination, and resurface damaged or worn concrete before installing any flooring system or floor coating.

What Causes the Delamination?

Concrete delamination can be caused by various factors, including:

  • Poor Adhesion. Insufficient bonding between concrete layers during the initial pouring and curing process can result in delamination. This can happen due to improper surface preparation, inadequate use of bonding agents, or the presence of loose material and contamination on the surface.
  • Freeze-Thaw Cycles. In regions with low temperatures and frequent freeze-thaw cycles. This is usually the case with exterior concrete on pavements, yards, driveways, and garages, water can seep into the concrete’s pores. When the water freezes and expands, it exerts pressure on the concrete, leading to cracks in concrete.
  • Chemical Attack. Exposure to aggressive chemicals such as acids, chlorides, and sulfates can cause concrete delamination. These chemicals can react with the cement paste, weakening the bonds and causing the surface to separate from the underlying concrete.
  • Moisture Ingress. Prolonged exposure to water or high humidity can saturate the concrete, causing the top layer to detach. Moisture trapped within the concrete can also contribute to freeze-thaw damage and chemical reactions, further aggravating delamination.
  • Carbonation. Carbon dioxide from the air can penetrate the concrete and react with the calcium hydroxide in the cement paste, resulting in the formation of calcium carbonate. This process, known as carbonation, reduces the alkalinity of the concrete, weakening the bond between the surface and the cementitious substrate.
  • Aging and Wear. Over time, concrete areas may deteriorate due to high foot traffic, abrasion, or impact, leading to etching or delamination of the top layer.
  • Improper Construction Practices. Inadequate compaction during concrete placement, improper curing, or the use of substandard materials can all contribute to delamination issues.
  • Corrosion of Reinforcement. If the steel reinforcement within the concrete corrodes, it can expand, causing cracks and delamination.

How Do You Avoid Delaminated Concrete?

Proper Construction Practices

Delamination can be avoided by employing proper construction techniques. This includes ensuring adequate compaction during concrete placement, correct curing practices, and the use of high-quality materials. A well-prepared surface and the use of appropriate bonding agents can significantly increase the adhesion between concrete layers, reducing the likelihood of delamination.

Regular Maintenance and Inspection

Regular maintenance and inspection also play a pivotal role in preventing delamination. By routinely checking your surfaces for signs of wear, damage, or moisture ingress, you can identify potential problems early and implement preventative measures before delamination occurs.

Use of Waterproofing and Protective Coatings

Waterproofing your surfaces or applying protective coatings that will seal the worn concrete and create a key between existing concrete and repair materials. These non-structural repairs can be anything from a polyurethane floor paint, to a full anti-slip system for added slip resistance. This prevents water and chemicals from penetrating the concrete, thereby reducing the risk of delamination and prolonging the life of a structure. Always choose waterproofing and protective concrete repair products like fillers and concrete repair mortar to address various issues such as cracks, spalling, and surface imperfections.  

Control of Environmental Factors

If your concrete is exposed to harsh weather conditions or aggressive chemicals, try to mitigate these effects where possible. This could involve installing a protective structure to shield the concrete from weather or ensuring proper ventilation to minimise exposure to harmful chemicals.

Regular pH Testing

Frequent pH testing can help to monitor the alkalinity of your concrete, allowing you to identify and address potential issues caused by carbonation before they lead to delamination. Regular pH testing is particularly important for surfaces exposed to the atmosphere or aggressive chemicals.

Concrete Delamination Repair: How to Remove Delaminations?

When it comes to repairing concrete floors, it’s important to understand the depth of the delamination. Issues caused by high air content are typically shallow, ranging from 1mm to 6mm deep. On the other hand, delaminations resulting from bleed water entrapment can be deeper, reaching up to 12mm.

Step 1: Identify Delaminated Areas

Identifying delaminations can be achieved by a simple ‘tap test’. Using a small hammer or similar tool, tap gently on the surface. A hollow sound typically indicates a delaminated area. Another method for larger areas is the ‘chain test’, which involves dragging a chain across the floor and listening for hollow sounds.

Step 2: Remove Delaminated Concrete

Once the delaminated sections have been identified, they should be removed. This can be accomplished with a jackhammer or chisel, depending on the extent and severity of the delamination. Any loose concrete around must be removed.

For shallow delamination, a large concrete grinder equipped with a low-grit diamond grinding or scabbling tool is used. This effectively removes the delaminated top and transforms the floor into a solid substrate. It’s the easiest and most cost-effective option for concrete delamination repair. Grinding through the delaminations can even expose large aggregates, providing a beautiful finish in itself. 

Dealing with deep delamination, however, requires a more intensive approach. When the delamination is more than 12mm deep, it often signifies issues with the underlying concrete or reinforcement. In such instances, full-depth repair might be necessary. This involves removing the delaminated concrete, repairing or replacing the reinforcement if needed, and then filling the area with a high strength concrete floor repair material.

Step 3: Clean the Exposed Surface

After the failed concrete has been removed, thoroughly clean the exposed surface. Use a high strength vacuum to remove any loose material, dust, or debris that may hinder the adhesion of the new material.

Step 4: Apply a Bonding Agent

The depth of the repair will determine the the range of products that we would specify for your application. Before applying the new repair material, apply a bonding agent or primer to the cleaned surface. This will help to ensure a strong bond between the existing concrete and the heavy duty repair.

Step 5: Install the repair material

There are a number of options from our repair range. Flowable epoxy resins offer excellent abrasion resistance and are highly impact resistant. Rapid set MMA resin screed gives early strength and hardens in temperatures as low as -20°C. Designed for use externally, this two pack system is perfect for repairing areas that need to be trafficked quickly.

Which Method Is Right for Concrete Delamination Removal?

DC Flooring offers a wide range of concrete repair solutions to ensure seamless and permanent repairs. Our refurbishment services include floor leveling, anchor bolt removal, crack repairs, epoxy repair mortar, self levelling compounds, scabbling, shot blasting, and concrete grinding.

To provide you with the most suitable option for your type of concrete and needs, our team conducts a complimentary initial site survey. We take into consideration your aesthetic and practical objectives, as well as your budget, guaranteeing the best outcome for your project. 

All subfloor preparation is done in-house using our specialised equipment – shotblasting, scabbling, and concrete grinding.
You’re only a phone call away from investing in leading-class flooring systems, all approved by FeRFA.

FAQs

When delaminations can be a problem?

Delaminations can become problematic when they compromise the structural integrity of the concrete, leading to further deterioration of concrete. This can result in an uneven floor, posing a safety hazard, especially in heavily trafficked areas. Further, delaminations can also negatively impact the aesthetics of the concrete surface. It’s crucial to address delamination at the earliest sign to prevent extensive damage and costly repairs.

What is the difference between delamination and spalling concrete?

Delamination and spalling are two distinct forms of concrete deterioration, each involving different types of damage.

Delamination occurs when the upper layer of concrete separates from the underlying substrate, resulting in blister-like formations and hollow spaces between the layers.

On the other hand, spalling concrete refers to the chipping or breaking away of small pieces from the concrete surface or edges. This type of damage is frequently observed on expansion joints, often caused by mechanical wear from forklifts or other wheeled vehicles. Additionally, spalling can be triggered by freezing and thawing of water within the concrete or chemical reactions, such as corrosion of embedded steel reinforcement.

Both delamination and spalling have the potential to compromise the structural integrity and aesthetic appeal of concrete surfaces. It is crucial to promptly address these issues through timely repairs and maintenance to prevent further damage and ensure the long-term performance of the concrete. Conducting regular inspections and implementing proactive measures can help detect and mitigate these problems at an early stage.

Do I need professional assistance to repair concrete delamination?

Yes, seeking professional assistance for concrete delamination repair is highly recommended. Delamination is a complex issue and if not treated correctly, can lead to further damage. Professionals have the necessary skills, knowledge, and equipment to correctly diagnose and repair delaminations. They can conduct an in-depth assessment of the damage, identify the root cause, and devise an effective repair strategy. Moreover, professionals will ensure the repair works are carried out to the highest standards, boosting the longevity of your concrete floors.

How long does it take to repair concrete delamination?

The time required to repair delamination can vary depending on the extent of the damage and the chosen repair method. Small areas of delamination may be resolved relatively quickly, while more significant damage could necessitate a longer repair process.

Typically, the repair entails several steps. First, the affected area is thoroughly cleaned and prepared by removing any loose or damaged concrete, as well as debris. Then, an appropriate repair material is applied to fill the voids caused by the delamination. The repair material needs sufficient time to cure and gain high strength, which can vary depending on the type of material used and the prevailing environmental conditions. In certain cases, the repaired section may require finishing or smoothing to ensure a seamless blend with the surrounding concrete.

Overall, repair times can range from a few hours to several days, with external factors like temperature and humidity potentially influencing the curing duration. To ensure effective and long-lasting repairs, it is crucial to seek the expertise of concrete repair professionals. They can assess the extent of the damage and recommend the most suitable repair approach. By executing the repairs properly, the structural integrity of the concrete can be maintained, reducing the risk of future delamination.

How much does it cost to repair concrete delamination?

The cost of repairing concrete delamination varies depending on several factors, including the size of the area to be repaired, the extent of the delamination damage, the method of repair chosen, and the cost of labour in your location. Small, superficial delaminations may only require inexpensive treatments, while extensive or severe delamination may necessitate comprehensive repairs and thus, a higher cost. Professional assessments are essential to accurately estimate the cost of repairing delamination. DC Flooring offers a free initial site survey to provide a tailored quote, ensuring transparency and cost efficiency in addressing your concrete repair needs.

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