How to Prevent De-Icing Salt from Damaging Concrete In Winter
by TRP Ready Mix on December 20, 2017
Concrete Suppliers Offer Tips to Help Keep Your Concrete in Good Condition during the Winter
Winter weather means plenty of salt on roads and driveways. But that salt can cause damage to concrete, especially when it’s new. If your concrete is not mixed, installed, sealed, and/or cured properly, it will be at risk of being weaker and more susceptible to damage in winter from below-freezing temperatures and de-icing salts.
So the best thing you can do to protect your concrete during winter is to ensure you have quality concrete from concrete suppliers and understand these causes of damage and how you can prevent it.
How De-Icing Salt Damages Concrete
Concrete absorbs water. So if you add rock salt to ice and snow, it will form salt-water slush. As this melts, the concrete will absorb the water. While this water absorption is fine on a warm summer day, winter temperatures drop well below freezing, causing the absorbed water to freeze, expand, and break the concrete.
Salt also attracts water, so it will lead to concrete becoming saturated with water. As more water freezes in concrete and the pressure from growing ice crystals increases, your concrete will become more damaged, with the surface likely to spall—peel, flake, or pop out.
Freshly poured concrete is the most susceptible to this damage since it is still highly saturated with water. If you poured concrete in the late fall, it will need a minimum of 30 days to dry. The only way young concrete can withstand the below-freezing temperatures of winter is if your concrete suppliers added enough cement to the mix, and this cement was not diluted with water. Cement creates a hydration reaction that emits heat in the concrete, preventing it from freezing.
How to Prevent Damage To Concrete
The first step to preventing winter damage, especially from salt, is to ensure you have a strong, durable, and high-quality concrete. This requires the right mix, installation, seal, and curing. Concrete suppliers can help you find the right mix depending on your concrete project.
Here are some suggestions for ensuring your concrete will be strong and able to withstand many winters without damage:
- Use concrete with a minimum compressive strength of 4,000 PSI;
- Use air-entrained concrete;
- Don’t add water to the concrete mix at the work site;
- Seal the concrete to prevent water absorption, but avoid foam-forming sealers;
- Have workers with experience mixing and installing the concrete; and,
- Use sand instead of salt on your concrete in winter.
While a strong quality concrete mixed from expert concrete suppliers will be at less risk of damage from de-icing salt, you can avoid the risk altogether and use sand instead. Sand will not melt the ice and snow, but it will provide traction, making your walkways and driveways safer to walk on in slippery winter conditions. Take care of your concrete in winter so it will last for many years to come.
Concrete Construction in Ottawa’s Winter
by TRP Ready Mix on December 8, 2017
How Concrete Construction Projects Continue, Even in the Winter Months
With Ottawa’s winter here in full force, the weather is becoming less ideal for concrete construction. Cold winters pose a threat to the quality of concrete because concrete will set slowly in colder temperatures, plus there is an added risk of freezing. If this happens, the concrete matrix will break up, resulting in a weak concrete that is prone to cracking.
But there are concrete construction projects that continue into the winter months. So how do they do it? Concrete experts in Ottawa know the trick to keeping concrete strong, even in cold weather. With a special winter mix, your concrete can set fast without freezing, maintaining its strength and quality.
Here’s how concrete suppliers mix concrete for use in winter.
To keep the concrete warm for longer in cold temperatures, concrete suppliers will mix the concrete with hot water at the plant. They will consider the outside air temperature and travel time for delivery to make sure the temperature of the concrete is still warm enough when it arrives at the construction site.
Since concrete sets extremely slowly—or not at all—in cold temperatures, suppliers will add accelerators to the concrete mix to speed up the setting time and prevent the concrete from freezing. Some accelerators include calcium chloride, which speeds up the hydration reaction in concrete. There are also non-chloride accelerators available. The type of accelerator your concrete supplier uses will depend on your concrete project needs.
Concrete suppliers may also add extra cement to the mix to increase the hydration reaction. This reaction generates more heat, leading to a hotter concrete that will set faster and is less likely to freeze.
Avoid Slag & Fly Ash
Since slag cement and fly ash generate less internal heat and set slowly compared to other concrete materials, concrete suppliers may not use these two materials in concrete mixes during the winter. These materials are more prone to freezing and are not able to set in cold temperatures.
Additional tips concrete suppliers will follow for concrete projects in winter include:
- Using entrained concrete to reduce bleeding;
- Specifying the slump at less than four inches;
- Being cautious with water reducers—they may not be necessary; and,
- Avoiding the use of admixtures onsite if they have frozen.
Although concrete construction projects in winter are not ideal, they can be done. With the expertise of concrete suppliers in Ottawa, you can have a concrete mix to suit your project needs in cold temperatures. These concrete experts will create a special winter mix that will stay warm and set faster, so you won’t have to worry about your concrete freezing and losing strength.