Does Heat and Humidity Impact Concrete?
Missouri’s summertime heat can dramatically impact the setting time and strength of finished concrete mix.
If you intend to install concrete in temperatures around 90 degrees, you’ll need to adjust the mix and installation process to accommodate the heat.
Increased Setting Time
Warm temperatures can cause the setting time of ready-mix to increase.
Concrete that is setting too fast is incredibly difficult to manage, even for a team of people. If the mix hardens before the concrete surface is entirely smoothed, the finished surface will be uneven.
Note: Rapidly-setting concrete mix isn’t an issue for vertical structures, such as walls and fence posts. If your concrete is setting too fast to make it into the mold, simply add cool water until the mix returns to the desired consistency.
When concrete sets in warm weather, the moisture in the ready-mix begins to evaporate. If the slab isn’t re-moistened, the finished product is much more susceptible to cracks and chips.
Planning your Pour:
Professional Jefferson County ready mix concrete services will always take extra steps during the summer to protect the quality of your concrete mix. For example, when the mix is prepared, the company will use the coolest water possible to combat fast setting times.
To offset the impact hot temperatures have on your concrete mix, ask your ready-mix provider about using admixtures (which are essentially additives), in the concrete mix.
Admixtures are concrete additives that alter the physical qualities of the finished slab.
They can improve concrete strength, offer corrosion protection, and slow down setting time, depending on the admixture used.
Before ordering your concrete, it is wise to speak with your concrete provider about using “admixtures” to better accommodate the warm weather.
Some specific admixtures to inquire about include:
- Set Retardation
- Hydration Stabilizers
- Water Reducers
While Your Concrete Sets:
After the concrete has set, it’s time to “cure” the slab by keeping it moist.
Jefferson County ready-mix professionals agree that keeping concrete damp while curing is crucial for a long-lasting slab.
Without adequate time to cure, the strength and durability of the concrete is put in jeopardy.
To cure your concrete properly, we recommend:
- Periodically turning on nearby sprinklers, which have been set to a “spray” setting.
- Manually spaying the slab with a hose throughout the day.
- Covering the slab with a wet cloth. If you decide to use this method, be sure to re-moisten the cloth regularly to compensate for evaporation.
Pouring concrete in the heat of Missouri’s summers is certainly possible when a few extra steps are taken to accommodate the heat. Before ordering from your preferred ready-mix provider, request the proper admixes be used in your concrete mix. After the mixture has set, keep it moist for at least 24 hours after setting using sprinklers, a hose, or a damp cloth.