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Debunking the myth of flexible concrete

Is flexible concrete a fact or a myth? Can a company truly offer a flexible concrete resurfacing solution that doesn’t crack? Do clever marketing and sales tactics mislead the public and create an expectation or overinflate the truth that their beautiful flexible concrete resurfacing job will never crack?

If we were to answer these questions above, and honestly consider the basic facts, we can come to a conclusion that if anyone is offering a flexible concrete resurfacing solution in the market, then they are possibly stretching the truth or taking things out of context.

In the previous post we discussed why concrete cracks, this is needed to understand this post. In summary concrete cracks for the following reasons:

  • Concrete cracks from excess water in the concrete mix.
  • Concrete cracks from the concrete drying too quickly.
  • Concrete cracks from using a lower strength of concrete than what should have been used.
  • Concrete cracks due to a lack of control or expansion joints.

Now, based on the factors above, and understanding the nature of concrete, we now add the polymer component to determine what result we can expect.

Polymer modified cement can be used for new concrete and repair of old concrete. It increases the tensile and flexural strength of mortars and concrete and reduces their brittle nature.

We need to understand that polymer-modified cement is a composite of two entirely different types of materials, and we need to consider the characteristics of the key components, cement and polymer, as well as the application of concrete repair, to get the story right in terms of a flexible concrete polymer solution.

As we know, Portland cement-based concrete and mortar are among the most widely used construction materials in the world. Concrete’s primary advantages are its low cost, high stiffness, high compressive strength, non-flammability and ease of fabrication. However, its most serious limitations are a low tensile strength, brittleness and, to some extent, long-term durability.

This is why reinforcing the concrete with steel provides the necessary tensile strength and the incorporation of fibres increases its toughness (resistance to crack propagation). Now, when the cement is modified with a polymer it increases its tensile and flexural strength and reduces its brittle nature by increasing the toughness of mortars and concrete. However, can we call it flexible? Can we now promise it will never crack? No.

Since the polymer modified cement is a composite of two entirely different types of materials, the characteristics of the key components, cement and polymer, need to be understood as well as their applications in concrete repair to give an honest answer.

The modification of cement by adding a polymer changes the properties of mortar and concrete. These effects depend mainly on the polymer content, expressed as the polymer/cement ratio, the type of polymer, and also the design of the mortar or concrete.

These factors are crucial, therefore, when a customer wants to apply a flexible overlay over their existing concrete, the reality is that the solution may not produce the results that the salesperson promised because the conditions of all the components are not perfect.

The fact is, when a polymer is added to concrete it increases the toughness and, to some extent, the tensile and bending strengths of these materials. Note, and we emphasize the point, “to some extent.” The use of polymer modified cement composites is mainly in the area of increasing its strength, durability, adhesion, flexibility and weatherability improvements of cement materials that are applied in thin sections.

Therefore, considering the facts above, without going into too much detail, if a decorative concrete solution is subscribed over concrete and a promise is made that it will never crack, then I suggest you find another solution as it’s just not the truth.

The bottom line is this, a polymer-modified concrete overlay system will increase the strength, adhesion, flexibility and weatherability of the concrete, however, it will NOT prevent cracks, it can only minimise the occurrence or recurrence of cracks.

Barefoot Concrete takes all these factors into consideration and although we offer a decorative concrete overlay solution our system takes into account the various factors that may affect the overlay and we are upfront with our customers.

Therefore, to answer the question, and to debunk the myth of flexible concrete, we conclude with the fact that a company cannot offer a flexible concrete overlay system that will not crack. This is due to the many factors affecting the concrete, both due to the type and mix and the polymers used, not to mention the concrete, the concreter, and the applicator and the application process.

In conclusion, Barefoot Concrete offers the best solution to resurface, repair and restore concrete with our durable concrete coatings, products, application systems and processes. If you want the best solution that will outperform and outlast all other existing concrete coatings on the market today, then call us to discuss your project.