Can Concrete Be placed in extremely Hot or cold Weather?

Many people do not know that placing concrete in cold, and hot weather is entirely possible. In most areas, temperatures are characterized by long periods of hot or cool weather, and concrete construction continues year round. Although it is possible to place concrete in any weather condition, we strongly recommend making sure that the contractor you chose has experience, and a plan prepared to deal with the challenge. Below are a few of things that could go wrong when pouring in the extreme heat or cold as well as a couple steps we take to meet our commitment to quality on every project.

Cold Weather:
With the coldest time of the year approaching, you may be wondering if it would be better to postpone your project until next year. This is not necessary provided your contractor takes a few simple precautions when working on your cement. The biggest issue to manage when pouring concrete in cold weather, is the concrete freezing before reaching optimal strength. Concrete sets slower in cold weather, and when it freezes (especially over-night) the expansion cycle will cause significant structural damage. When we manage a project, we ensure the concrete set’s properly by doing everything necessary to control the conditions.

The first thing we do to ensure a quality pour in cold weather, is use the hottest water possible in our mix. Secondly, the mix itself often contains accelerators to speed up the curing time. Knowledge of these products are key, as some can cause damage to projects with rebar or mesh. An additional measure we often take is a heating system involving power blankets and space heaters that ensures a stable temperature is maintained. Using these techniques and more we have been able to pour projects perfectly in -40C weather.

Hot Weather:

Although our summers are less extreme than our winters in Calgary, just as much precaution should be taken, when placing concrete during the hottest months. High temperatures, low humidity, direct sunlight and wind all are factors that can cause considerable cracking and structural damage. In extreme heat, ready-mix companies will often substitute water for ice for maximum control of the concrete’s temperature. Extra attention is taken to ensure the concrete’s moisture is ideal, this can be controlled easily with sprinklers for example. On the very hottest day’s, the extra step of covering the concrete’s surface with burlap or tarp, may be required to ensure an even cure.