Curing concrete in a deep freezer is a unique experience. Walk-in freezers are crucial to any organization that handles temperature sensitive material. The ability to store mass amounts of cold product in a controlled environment allows for meat, ice cream, cadavers, liquid oxygen and more to be used nearly anywhere in the world, so long as there is a freezer to put it in.
Most often, these freezers have a concrete flooring that is specially cured to handle the frozen environment around it, while keeping the heat from nearby room temperatures out. On top of all this, concrete flooring also needs to be able to withstand everything from footsteps to forklifts in ways that mitigate as much repair as possible.
When preparing and pouring cement for freezer floors, there are several steps that one should consider, especially since this isn’t your usual concrete constructing picnic:
- Maintain the mix: Be sure that your mix of concrete doesn’t contain too much water. Not only is it likely to cause cracking due to shrinkage, but it can also lead to water freezing within the concrete if it’s not cured enough by the time the freezer begins operating.
- Seal the deal: The United States Dairy Association has a zero-tolerance policy regarding leaks in the freezer space. Frozen food should be stored at 0°F (-18°), as “freezing to 0° F inactivates any microbes — bacteria, yeasts and molds — present in food.” Any leakage would lead to moisture invading the freezer, potentially allowing mold and other harmful bacteria to grow. Any concrete installed as part of a walk-in freezer must be properly set and sealed to prevent leaks from happening.
Restoring Concrete Freezer Floors
With that in mind, you might be wondering how to repair concrete floors in freezers. Damage to the concrete floor like cracking or chipping can happen via forklift accident, replacing glycol heating systems, or subsoil moisture freezing.
Cracking occurs naturally in concrete, and there’s virtually no way to prevent it from ever happening. The best tools for repairing concrete freezer floors are low-temperature grade epoxy seals and additional concrete.
Equally important of what to use is what not to use. Repair product manufacturers like Polycote advocate against hard repair mortar when fixing floor joints. Doing so will create an inflexible bond that will not allow for any concrete movement, increasing the chances of additional concrete cracking.
Things to Keep an Eye Out For
Our friends at Concrete Mender offer several challenges that pose a problem when repairing concrete, which include frost, working conditions, and curing:
- Frost: Frozen moisture in the concrete will act as a barrier between the repair material and the pores of the concrete. Most repair materials will try to bond to the frost coated concrete. When the temperature increases, the frost melts and so does the bond.
- Working conditions: Working with materials in the cold is challenging to both man and materials. Mixing epoxies or mortars in the cold is especially challenging. As the temperature decreases, the viscosity and flow rate of these materials increase making them harder to mix and much more difficult to work with. Drum heaters are an excellent solution to keeping epoxy and mortar warm while waiting to use on a freezer job.
- Curing: With most materials, cure times in cold environments are extended significantly. A product that normally cures in an hour at room temperature may take as much as 12 hours in a cold environment. Some materials may not cure at all before actually freezing solid. Use a concrete curing blanket to help the concrete cure for maximum strength.
If You’re Gonna Do a Job, You’d Better Do It Right
Fixing a freezer is a job you only want to do once. Making crack repairs can be tedious and have to be done exactly to specifications in meeting safety requirements. After all, keeping that freezer sealed tight with a good concrete job will keep the cadavers cold and food frozen.
The best tools to help with a quick, clean concrete repair job are drum heaters and curing blankets. For more information on these items, check out Powerblanket’s concrete solutions.