The concrete curing process, which contains five phases, is designed to maintain appropriate moisture content and temperature levels in early-age concrete so it can reach its specific mix strength. Why is achieving the right amount of moisture so important during this process? Because hydration tends to dry out the concrete due to the loss of heat.

Furthermore, in order to guarantee the strength and quality of a concrete pour, it must undergo cooling to reduce its temperature. A concrete pour generates an appreciable amount of heat (i.e. it creates an exothermic reaction), which raises the overall temperature of the element. Generally speaking, the greater the concrete content, the higher the temperature will be.

Cold Weather Concreting

Completing construction projects in cool or cold temperatures requires special consideration. As stated in ACI 306, Guide to Cold Weather Concreting, cold weather concreting is “a period when for more than three successive days the average daily air temperature drops below 5°C (40°F) and stays below 10°C (50°F) for more than one-half of any 24 hour period.”

When the ambient temperature is too low, hydration of the concrete slows down or even stops completely. This is an undesirable outcome because the concrete’s strength development will either be significantly reduced or come to a complete stop.

For example, if the concrete freezes while it’s still fresh or before it has developed sufficient strength, the ice that forms results in the disruption of the cement paste matrix, causing an irreparable loss in strength. This diminished strength means the concrete pour will crack in the future, or in some cases, it’s rendered useless, causing massive delays in project completion. One way to prevent this from happening is to avoid pouring concrete over frozen ground, snow, or ice and use heaters to thaw the ground before pouring.

Keep reading this blog on Giatec.ca