Key Considerations To Make When Concreting In Cold Weather
In an ideal world,
concrete should be laid when the temperature is above 10ºC. But we don’t live in an ideal world and there are times, especially during the Australian winter, when temperatures can fall as low as 3ºC for several days in a row.
This creates problems for concreting because prolonged cold weather can impact set times and reduce strength. But building contractors have demanding construction schedules, which means waiting for mother nature is not an option.
With proper planning, contractors can concrete successfully. So in this blog, we’ll look at the considerations that should be made when concreting in cold weather.
How Does Cold Weather Affect Concrete?
Increases set times
Concreting in cold weather significantly increases set times. Even though concrete hydration is exothermic (produces heat), concrete laid at 1ºC takes twice as long to set as concrete laid at 10ºC.
Reduces strength
Freezing water produces ice crystals within the concrete which can significantly reduce its strength. For example, concrete that is exposed to freezing temperatures within the first 24 hours can lose as much as half its 28-day strength.
Ideally, concrete should not be exposed to freezing temperatures until its strength reaches 500 psi.
Tips For Concreting in Cold Weather
So now you know why special considerations need to be made when concreting in cold weather, what can you do to ensure your concrete is long-lasting?
Use heated water
Hot water can be used to offset the effects of cold weather. The water needs to be heated to between 60ºC and 82ºC. This reduces moisture levels which allow relatively normal set times to be achieved without compromising strength.
Use accelerating mixtures
Accelerants can be used to achieve faster set times, especially when used in combination with heated water. The type of accelerant used must be compatible with the type of concrete. For example, calcium chloride cannot be used with reinforced concrete.
Assess subgrade temperatures
You should consider the subgrade temperature before concreting over the top. Avoid laying concrete over subgrades that are frozen or have been subject to freezing temperatures within the preceding 24 hours.
Implement post-pour weather protection
Concrete remains vulnerable to freezing temperatures until its compressive strength reaches 4000 psi. So in cold climates, you should protect the post-poured concrete with insulating blankets, enclosures and even heaters in extreme circumstances.
Extend protection periods
When pouring in cold weather, you should be aware that set times may be increased, so the protection period should also be increased. Most suppliers recommend that the protection period is extended by as much as 50 to 100 per cent in cold weather.
Concreting in Westbrook, Toowoomba
McCoy Concreting
has been proudly supporting homes and businesses in Toowoomba for more than 20 years. We take great pride in our work and have earned a reputation for delivering outstanding workmanship to our clients across the region.
So if you need a concreting contractor to deliver the highest standard of workmanship no matter what the weather,
get in touch with McCoy today for a FREE quote. We can handle jobs of all sizes, including residential, commercial and rural jobs.
Alternatively, if you want to know how much concreting costs, check out our guide to the
cost of concreting a driveway. This will give you a rough estimate of what you can expect to pay for a quality concreting job across Australia.
