Thermal Cracking: Curb This Summertime Threat to Your Concrete Flooring
Summertime brings high temperatures, which can significantly influence the surface of concrete and cause thermal cracking. Thermal cracking can compromise the long-term strength and durability of your concrete flooring, so it must be repaired and prevented before it causes further damage.
What Is Concrete Thermal Cracking and Why Does It Occur?
Thermal cracking is typically associated with mass concrete. However, it can also happen to thinner slabs and even polished concrete flooring. It occurs when there’s a great temperature difference within the concrete structure or its surroundings.
What Causes Thermal Cracking?
Your concrete floor can develop thermal cracks when its expansion and contraction due to temperature change are restrained internally or externally.
Thermal cracking usually happens several days after the placement of hydrated cement. Being anhydrous by nature, cement needs to be hydrated to gain binding strength. This hydration process generates heat. In thin sections, the heat due to hydration dissipates quickly and causes no problems. It only becomes an issue in thicker sections.
When the concrete is thick, the temperature at the center rises and drops slowly, while the temperature at the surface cools or heats rapidly to ambient temperature. These temperature variations can restrain thermal movement. This internal restraint creates tensile stress that can crack the surface of concrete.
Aside from internal restraint, external restraint can also induce thermal cracks. External restraints refer to existing structures, like walls, bonded to a freshly cast structure.
Tips to Minimize Thermal Cracking
Several methods can minimize thermal cracking. Most of these measures should be implemented during design and construction.
If the concrete floor is still under construction, pour concrete at optimal temperatures.
Mist the concrete floor occasionally or, if possible, provide shade to the area.
Use supplementary materials, such as fly ash or slag, to reduce the heat caused by hydration.
Implement thermal control measures, like monitoring temperatures and determining cement placement methods.
How to Repair Existing Thermal Cracks
Thermal cracking has long been an issue in newly placed concrete, affecting the serviceability, durability, and integrity of concrete structures. Additionally, even fine hairline cracks compromise the aesthetic appeal of your concrete flooring.
Unfortunately, thermal cracks may still occur in your concrete flooring despite your best efforts. When cracks appear, it’s important to address them immediately to prevent further damage and maintain the concrete’s structural integrity. Here are common repair methods for thermal cracks:
For wide cracks, inject epoxy and then apply a coating to seal it.
Fine hairline cracks may not cause bigger problems immediately, but you should still fix them. In the future, these can still become a durability issue. Chisel the crack, remove loose materials, and fill it with bonding adhesive.
Extensive cracks may require concrete floor replacement.
Protect Your Concrete Floor With Top-Quality Coatings
Concrete floors are durable but not indestructible. Give them the extra protection they need by applying quality coatings. Aside from protection, concrete coatings can also enhance the appearance of your concrete floor.
Anderson Painting offers Penntek polyurea floor coatings that can last for over two decades and help prevent cracking. They’re also easy to maintain and clean. Contact us to learn more about how to prevent thermal cracking and maintain your concrete floors.
