How Does Weather Effect Pouring & Curing Concrete?

drivewayP1Most construction projects require concrete to be used in order to have strong and stable structure. Different weather patterns can have adverse effects on how concrete solidifies and how long it lasts.

Temperatures that are less than 40°F for more than three days straight is considered cold by the concrete contractors definitions. Cement mixture transforms from liquid to a solid through a series of chemical reactions. This process is  dependent on the temperature of the concrete as it determines how fast it will dry. If it is warm, then the drying will be fast. However, if temperatures are low then the whole process slows down and may even cause the water to freeze resulting in it breaking apart.

Pouring & Curing Concrete In Optimal Weather

Once concrete poured, it must be maintained at temperatures between 50 F and 75 F through a process known as curing. If concrete is not cured properly then it can lead to less than optimal strength, short life and cracking. The process should be started as soon as the last stage of laying the concrete is finished.

The process of curing involves keeping the driveways and aprons that have freshly poured concrete wet for a minimum of three days. Some of the techniques used to ensure wetness is through use of sprinklers and hoses or covering the areas with plastic to hold the water. If there is freezing weather, then straw may be used to insulate the slabs. Just like excess water that bleeds from the concrete, rain water must be troweled in order for evaporation to occur.

Extreme Weather Conditions

In very cold and snowy conditions, concrete should never be poured and curing blankets should be used ahead of time. There are some anti-freeze mixtures that can be added to the concrete to prevent the water in it from freezing. It is also possible to warm up the concrete so that it will resist the cold winter temperatures and dry in the right way.
When the weather is hot, concrete can dry quickly and with lots of cracks. It is recommended that pouring be done during the coolest part of the day or night in order to lessen evaporation. Windbreaks and sunshades should be employed in order to control the surface temperature of the concrete for extreme weather concrete pouring.

Plan Concrete & Asphalt does not recommend pouring concrete in extreme climates.