There are many factors that affect concrete properties. It’s important to us that our clients have the best possible experience with their concrete products; so, we thought a little insight into cold weather concreting, what to expect, and how to prepare – would be important. Cold weather concreting is, quite simply, pouring concrete during the cold weather months. When cold weather hits, it creates conditions that affect the placing, finishing, curing and protecting of concrete.
From the National Ready Mixed Concrete Association (NRMCA):
Low concrete temperature has a major effect of the rate of cement hydration, which results in slower setting and rate of strength gain. A good rule of thumb is that a drop in concrete temperature by 20°F [10°C] will approximately double the setting time. The slower rate of setting and strength gain should be accounted for when scheduling construction operations, such as form removal.
Consider that newly placed concrete is already saturated with water. That concrete, exposed to the cycles of freezing and thawing, will create large temperature differences between the surface and the interior of the newly placed concrete. This can cause cracking to happen when the temperature difference exceeds 35°F.
There can actually be some benefits to placing concrete in cold weather. When concrete has a cooler initial temperature, it will generally end up with a higher ultimate strength. The catch is that it takes careful planning and proper preparation to ensure that the concrete is placed correctly and cures correctly during the cold weather months. When that care isn’t taken, you will have issues with the surface scaling, pop-outs, cracking, and an overall weaker concrete.
What are your objectives when engaging in cold weather concreting?
- Prevent damage to concrete due to early-age freezing
- Ensure that the concrete develops the required strength
- Limit rapid temperature changes
It is essential that you plan, well in advance, how you’re going to protect the concrete after the pour. In our next articles in the cold weather concreting series, we will cover how to properly place concrete in cold weather and how to protect the concrete after it’s been poured. Do you have any questions about what cold weather concreting is and why it’s important to understand the specifics? Comment below with your thoughts and any questions we can answer. Contact us today to get started!