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The Challenges of Measuring Concrete Temperatures
by TRP Ready Mix on June 3, 2021
Debunking Common Myths About Optimal Concrete
When we mix concrete the temperature of the concrete has a significant impact on how the concrete will cure.
In this blog post, we will explore the challenges of measuring concrete temperatures. We’ll also examine how that affects the overall strength and durability of concrete structures.
Finally, we’ll take a look at some common myths about concrete curing temperatures and set the record straight.
Why You Need to Measure Concrete Temperatures
The temperature of concrete is one of the most important factors to consider when pouring concrete.
If the concrete is too cool, it will not cure properly and may end up with reduced strength and durability. Conversely, if the concrete is too hot, it can cause cracking and other structural problems.
Ideally, you want to pour concrete at a temperature that is within the optimal range for curing. The minimum and maximum temperatures for curing concrete will vary. This depends on the mix design but typically falls somewhere between 50 and 95 degrees Fahrenheit.
It’s also important to note that the temperature of concrete will continue to rise after you have poured it. For this reason, it’s important to leave the thermometer in the concrete when reading the temperature.
Concrete Strength and How Temperature Plays a Role
Temperature plays a key role in concrete curing and strength because concrete is a composite material.
The concrete matrix (the binder that holds the aggregate together) cures at a slower rate than the aggregates. The aggregates are cured by the water and Portland cement in the concrete mix.
When the concrete reaches its final strength, it is the combination of both the cured matrix and cured aggregates. So, the temperature of the concrete mix and the curing environment play a significant role in the final strength of the concrete.
Optimal Concrete Temperatures
There are a few common myths about optimal concrete curing temperatures that we would like to dispel…
Myth 1: You don’t have to worry about the temperature of concrete if you’re using a concrete mix with air-entraining agents.
Fact: The temperature of concrete still has a significant impact on the strength and durability of concrete. That’s true even with air-entraining agents.
Myth 2: Concrete will cure at 30 degrees.
Fact: While concrete may start to cure at 30 degrees, it will not reach its full strength until the temperature is within the optimal range. There is no fool-proof concrete setting temperature.
Myth 3: The ideal temperature for concrete to cure is 100 degrees.
Fact: While the ideal temperature for concrete to cure is within the 50 to 95-degree range, there is no one ideal temperature. The strength and durability of concrete will vary depending on the mix design and ambient conditions. There is definitely a concrete setting temperature limit after which the concrete becomes brittle and weak.
Concrete Temperature Tests
To ensure that construction firms cure concrete properly, most states require tests. Concrete contractors to perform a series of temperature tests on the concrete and submit them to the council.
The most common test is the seven-day concrete core temperature test. This test involves drilling a hole into the fresh concrete and taking a core sample. The core sample is then sent to a lab to be analyzed.
Other common concrete temperature tests include the three-day concrete prism test. There’s also the 28-day concrete cylinder test.
The results of these tests will help you determine if the concrete has reached its full strength and is ready for use.
Why Concrete Temperatures May Differ Onsite
The temperature of concrete will typically be highest in the morning and early afternoon, and lowest at night.
Weather conditions can also affect concrete temperatures. Windy conditions can cause concrete to cool down faster, while sunny conditions can cause concrete to heat up.
The type of aggregate and the amount of water in the mix will also affect concrete temperatures.
So, it’s important to take all of these factors into account when measuring the temperature of concrete.
Challenges of Onsite Temperature Measurement Using Thermocouple
One of the main challenges of measuring concrete temperatures is they can vary significantly from one spot to another.
This is especially true if you’re trying to measure the temperature of concrete near the surface. To get an accurate reading, it’s important to take into account all of the variables.
The best way to do this is by using a thermocouple. A thermocouple is a device that measures the temperature at two different points. By comparing the two readings, you can get an accurate reading of the concrete’s surface temperature.
There are some disadvantages to using a thermocouple such as the time it takes to take the reading. But, it is the most accurate way to measure concrete temperatures.
When taking a concrete temperature reading, it’s important to leave the thermometer in the concrete. You should keep it there for a few minutes to get an accurate reading.
This will help ensure that you’re not just measuring the ambient temperature.
How to Effectively Measure Concrete Onsite
Here are three different ways to measure the temperature of concrete.
- Use a handheld infrared thermometer. This is a quick and easy way to get an overall reading of the concrete’s temperature. It’s not always accurate.
- Use a concrete thermometer. This is a specialized thermometer that is designed to measure the temperature of concrete. Thermocouple measuring is advised.
- Use a probe thermometer. This type of thermometer can be inserted into the concrete to get a more detailed reading of the concrete’s temperature. Again, thermocouple the measurement for a more accurate reading.
Are you unsure about what temperature to pour your concrete at? Do you want to ensure that your concrete cures within the optimal range? Then, it is best to consult with a professional engineer.
They will be able to help you select the right mix design for your project and give you specific instructions on how to properly measure the concrete’s temperature for the location.
Advances in Technology – Best Tools to Use
Some smart products and clever tools are coming to the market to get more accurate measurements of temperature for concrete, such as concrete Rebar Locators with embedded thermometers to measure concrete temperature during the pour, and lasers that can identify wet concrete and then take a surface temperature.
The US Army Corps of Engineers is currently working on a project where they are using drones to fly over curing concrete slabs and capture thermal images to better understand the temperature distribution across the concrete surface.
You can then use this data to create a model that predicts the temperature of concrete as it cures.
The more we know about how concrete behaves under different conditions, the better we can ensure that our concrete is reaching its desired strength and properties.
The Takeaway
By taking concrete temperature measurements, you can ensure that your concrete is reaching its desired properties and avoid any costly mistakes.
When measuring the concrete temperatures, it’s important to take into account all of the variables involved. If you’d like to buy any of our concrete products or have any questions please feel free to get in touch.
