Date: May 31, 2017
News - Remember Your Retarders
If you are a veteran in the concrete industry, you know placing concrete in hot weather conditions produces a rapid rate of evaporation of moisture from the surface of the concrete resulting in accelerated set times, or worse, curling and cracking.
With the hot weather coming up, the temptation can be to add more water which will lower the concrete strength. Instead, add a retarder to your order and save a lot of headaches and callbacks from customers.
Along with adding retarders, here are some additional planning and placing hot weather concrete tips to keep in mind as the temperatures start to rise:
PLANNING
- Keep in mind how many concrete workers are needed in advance to avoid delays placing, finishing and curing the concrete.
- Consider early morning or evening placement of the concrete.
- Order the mix design from a concrete producer that will ensure to deliver a product with the correct slump, strength, and performance properties to meet the job requirements.
- Schedule concrete mixer trucks to avoid waiting time so the concrete will not begin to set.
- Modify the concrete mixture to include set retarders and water reducers, and the lowest practical cement factor.
- Provide needed sunshades, wind breaks, and misting equipment.
PRE-PLACEMENT
- Sprinkle or mist cool water on forms, steel, and subgrade before placing.
- However, avoid standing water where you have moistened.
PLACEMENT
- Unload concrete within 60-90 minutes of batching.
- Request ice or chilled water to lower temperature of the plastic mix.
- Additions of water should be avoided!
Remember Your Retarders!!!
- Retarders can delay the initial setting of concrete by an hour or more by countering the rapid setting caused by high temperatures.
- Retarders allow more time for placing and finishing.
- Retarders reduce callbacks and secure a quality product for customers.