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Concrete Freeze-Thaw Cycles: Everything You Need to Know

April 25th, 2023 | 4 min. read

By Sarah Etler

Wintertime can hit concrete hard with damage from constant freeze-thaw cycles.

Building snowmen, drinking hot chocolate, and enjoying time with family over the holidays are some of the highlights of wintertime in many parts of the US.

As we all know, however, not all aspects of winter are as delightful. Icy conditions causing dangerous delays, snow storms keeping everyone inside, and short days bringing spirits down are all part of wintertime, too.

While you may not think of it first, the concrete around your home or property can also be negatively impacted by wintertime weather. In areas with temperatures constantly fluctuating above and below freezing, concrete can face all kinds of issues if not properly protected.

These temperature fluctuations are referred to as “freeze-thaw cycles”, and after 30 years in the concrete repair industry, we here at A-1 Concrete Leveling know just how much they can affect the integrity, durability, and aesthetics of concrete.

In this article, you’ll learn more about what freeze-thaw cycles are, how they impact concrete, the types of damage they cause, and how you can prevent them from damaging your concrete surfaces in the first place.

What are freeze-thaw cycles?

Freeze-thaw cycles occur when temperatures drop below freezing, then rise back above freezing. During freeze-thaw cycles, water expands when frozen, then thaws again as temperatures rise.

Because concrete is porous, it absorbs water. As the water within the concrete freezes and expands, it breaks down the concrete from the inside. It can also freeze and thaw within the soil or sub-material underneath the concrete, which can eventually cause the slab to settle.

These cycles typically repeat multiple times throughout the winter season in many regions throughout the US, which can compound the damage done to the concrete.

How do freeze-thaw cycles affect concrete?

As a result of freeze-thaw cycles, the concrete slab itself can become damaged, and/or the base that holds the concrete up can weaken and cause the slab to settle.

Concrete Damage

When concrete absorbs moisture and that moisture freezes, the pores within the concrete expand and pop. As the water freezes, its volume increases by 9%, which puts pressure on the concrete from the inside and causes it to break down and crack.
The voids within the concrete that have opened up due to the freezing water are larger after every cycle. This means that during the next thaw, more water will be able to make its way into the concrete and freeze again. The damage is continuously compounded with every freeze-thaw cycle.

Soil or Sub-Material Weakening

Concrete slabs are held up by soil or other sub-materials, like gravel. When these materials move or compact, it causes the slab on top to go with them.

Like concrete, the soil under the slab absorbs water, which expands when frozen. When the ice thaws, however, it leaves gaps where the expanded water used to be. These now-empty gaps cause the soil or other sub-material to collapse in on itself.

This soil movement due to continuous freeze-thaw cycles can cause the concrete slab to settle and sink over time, and this can be made worse if there are gutters, downspouts, or cracks in the concrete slab directly supplying water to the sub-material underneath.

Types of Concrete Damage From Freeze-thaw Cycles

Freeze-thaw cycles can cause damage to concrete in many ways, including:

  • Internal or surface cracking 
  • Surface spalling, pitting, or flaking
  • Pebbles popping out of aggregate 
  • Slabs settling and becoming uneven

How to Help Prevent Freeze-thaw Concrete Damage

As mentioned previously, once freeze-thaw damage occurs, you have limited options to help slow down the progression of the damage. The best way to deal with this damage is by trying to prevent it in the first place with these methods:

Seal Concrete With a High-Quality Sealer

A high-quality penetrating sealer will create a hydrophobic barrier that prevents water from absorbing into the concrete. If water can’t enter the concrete and instead runs off its surface, it won’t be able to cause freeze-thaw damage by freezing and expanding on the inside.

If you’re already facing surface damage due to freeze-thaw cycles, sealing the surface can help slow down the progression of the damage.

Caulk Cracks and Joints

Sealing gaps and cracks in the concrete prevents water from entering and being absorbed by both the slab itself and the soil underneath it, minimizing the effects of freeze-thaw cycles due to the lack of overall moisture available to freeze and expand.

Redirect Downspouts & Fix Leaky Gutters

In addition to eroding away the soil or sub-material under a concrete slab, a direct flow of water from a leaky gutter or downspout can supply a large amount of moisture to be absorbed by the slab itself or the soil underneath. Rerouting downspouts to flow away from the concrete and making sure gutters aren’t leaking can also help minimize damage from freeze-thaw cycles.

Remove Snow to Keep Concrete Dry

The main way to prevent freeze-thaw damage is to reduce the amount of excess moisture in, on, and around your concrete as much as possible. Clearing off the snow and keeping your concrete as dry as possible throughout the winter can help achieve this goal.

Stabilize Concrete Slabs With Concrete Leveling

Voids occur as a result of freeze-thaw cycles because the substrate underneath the slab expands and contracts with the changes in temperature, but the slab itself is being held up by rebar. Filling the voids in order to stabilize the slab, which is done via concrete leveling, will help the concrete from collapsing on itself.

What to Do About Concrete Freeze-Thaw Cycles

Now that you know what concrete freeze-thaw cycles are, how they impact your concrete, and how you can prevent the damage that comes with them, you’re ready to implement your knowledge to protect the concrete around your property.

At A-1 Concrete Leveling, we’ve been helping homeowners across the country do just that for over 30 years. If you’re interested in concrete cleaning, sealing, caulking, or leveling to protect and restore your concrete, we’ve got you covered.

To request a free onsite consultation and cost estimate, click the link below!

Want to know more? Concrete Academy is A-1’s extensive library of online resources aimed at helping you learn as much as possible about all things concrete repair and maintenance. Check out some of these related topics:

Sarah Etler

Sarah Etler joined A-1 Concrete Leveling after receiving her Bachelor of Arts degree in English from Northern Kentucky University. As A-1's Content Marketing Manager, she works closely with industry experts to produce content that will best answer questions related to concrete repair and maintenance practices. Sarah loves living a life full of discovery and is excited every day to see what new things she can learn and share with those around her.