Hot Weather Concreting

David Welch | April 15, 2022

When it’s hot outside, special precautions should be taken to address the challenges of pouring concrete in the summer. Furthermore dry, low humidity conditions present even more of challenge.

Control Concrete Temperature to Slow Curing

Concrete sets-up when water evaporates from the mixture. Controlling the rate of evaporation in the summer can avoid plastic shrinkage cracking, and allow the concrete to meet its designed strength. Here are a few common tips and tricks:

Ice

Instead of using liquid water, we can use ice. As with a ice in a drink, the mix will temporarily be colder. Chilled water is also effective, but not as effective as ice.

Lowering Aggregate Temperature

Shading aggregate bins or sprinkling water on them can lower the overall temperature of the mix. Lower temperature concrete delays the curing process, giving more time to pour and finish.

Dampen Forms and Reinforcement

If forms are set up ahead of time during summer, they have a chance to get hot. Forms can be chilled with water prior to pouring. Just be sure to avoid ponding that will occur if too much water is added.

Mix Design

Use of supplementary cementitious material like slag or pozzolans can slow the reactions during the curing process that generate heat. The heat generated during curing is unnecessarily accelerates the process when it’s already hot outside.

Additionally the proper use of admixtures can make a great impact on moderating the heat. Proper use of retarders, water reducers, extended set-control all make the concrete easier to pour and finish.

Environment

Misters, shade screens, and wind breaks can offset the local environmental conditions (high heat and humidity) that would cause water to evaporate quicker.

Work Quickly to Combat Heat

Finishing

Finishing, cutting of control joints, and the like should being as soon as the water sheen has left the surface.

Staffing

Have appropriate manpower on site to pour, finish and cure the concrete.

Scheduling

Advance planning should be done with your ready-mix supplier so that deliveries arrive in such a way that avoids interruptions.

Other Items

Onsite Water

Limit the addition of water at the jobsite to what is recommended. Inappropriate or excessive addition of water can limit the concrete’s final strength.

Years of experience mixing, pouring, and finishing concrete have made Bay Ready Mix and Parker Block experts. Give us a call. We are happy to make sure your next pour this summer goes seamlessly. For a more detailed resource on hot weather concreting: click here. Or if you are pouring in the cold, check out our Cold Weather Concreting tips.