If your construction job is taking place in the summer, you may be concerned about the problems hot weather poses for concreting. According to the American Concrete Institute (ACI), hot water concreting occurs when conditions such as warm outdoor temperatures, hot concrete temperatures, low humidity and high winds damage newly poured or mixed concrete.
Concrete needs to retain moisture as it cures. Concrete is most at risk of curing too fast in hot temperatures — the water evaporates from the concrete, causing the concrete to lose its strength or crack. It’s not inherently a bad idea to pour concrete in hot weather, but you should be aware of what to expect and know what precautions you may need to take as the temperature rises. With proper planning, you can pour new concrete in the summer months safely and productively without compromising strength or appearance.
Does Cement Cure Faster in Hot Weather?
To put it simply, the answer is yes. Warm temperatures cause cement to set faster, and the faster cement sets, the faster it begins to cure. At 80 degrees, concrete usually sets in about four hours. At 90 degrees, you can expect it to set in 2.5 hours, and at 100 degrees, your concrete will set in roughly an hour and a half. With an increase of 20 degrees Fahrenheit, the concrete’s setting time will reduce by as much as 50 percent.
What temperature is too hot for pouring concrete? There’s no exact answer, but the hotter it is, the faster you’ll need to work and the more work you’ll have to do to maintain your concrete as it sets and cures. The ideal temperature for pouring concrete is between 50 and 60 degrees.
You’ll also want to consider the effect of outdoor temperature on your workers. You want to keep your employees safe when the temperature outside gets hot.
Problems Associated With Concreting in Hot Weather
As the concrete sets, it undergoes a strengthening process called cement hydration. During hydration, water bonds the concrete mixture together and forms crystals in the concrete. Curing methods usually take weeks, sometimes longer, and it’s critical for the concrete to be as strong and durable as possible.
Concreting in hot weather can lead to certain issues if you’re not properly prepared. A few problems can occur when concreting in warm weather:
- Water evaporates from the concrete, and the concrete dries out, leading to weaker concrete. Weakened concrete is more prone to cracks, chips and other structural issues.
- Concrete dries too fast and might become weak or soft.
- The strength of the concrete after the initial curing period might decrease.
- Due to rapid water loss, plastic shrinking cracks might appear on the concrete’s surface.
- The concrete could see reduced 28-day strength of up to 10 percent.
What Are Some of the Best Ways to Protect Your Concrete in Hot Weather?
The risks of pouring concrete in hot weather include plastic shrinking cracks and decreased long-term strength of concrete. These are a real danger when you’re pouring concrete in hot weather, as surface moisture can evaporate too quickly. With enough preparation and the right strategies, you can pour concrete when the temperature increases without compromising quality. There are a number of ways to control your concrete’s temperature for pouring in hot weather conditions. They include:
- Using a concrete mix that’s designed for hot weather applications
- Making mixture adjustments and using chilled mixing water for your concrete mixture
- Dampening the substrate before you place the concrete
- Applying a retarding admixture
- Placing your concrete early in the day before the sun reaches its height or in the late afternoon so that temperatures are lower
- Putting up sunshades around your concrete to keep it cooler
- Employing more workers if possible so that you can finish working with the concrete faster
The Key Elements of Hot Weather Concreting
Some best practices you can utilize if you’re pouring concrete in hot weather include:
- Planning ahead to account for any problems that may crop up at the job site.
- Dampening the surface before placing concrete.
- Accelerating the time of transport, placing and finishing.
- Creating a plan of action, including a project timeline, several days before beginning the project.
When it comes to hot weather, preparation is key. When you have a construction job that involves laying concrete, be sure to check the weather well in advance so you know what to expect. However much you normally prepare for a construction job, build in extra prep time if you think you may face high-temperature conditions.
If hot weather is likely, make sure you have clear communication between the contractor, engineers and concrete producer so that you’re aware of exactly what challenges you’re likely to encounter and how you can handle them. If you’re fully prepared, there will be no reason you can’t pour concrete even when conditions are hot, dry or windy.
Union Quarries Can Assist Your With Hot Weather Concreting
Need hot weather concreting tips or help finding the right ready-mix concrete for your hot weather job in central PA? Union Quarries is ready to assist. We’re the concrete experts in PA, with thousands of satisfied customers for our concrete products and decades of experience manufacturing and distributing construction materials. Make sure you’re prepared for your next hot weather concreting job by contacting us today!