What is Concrete Curing?
Concrete curing is the process of maintaining the moisture content within the concrete to ensure it has enough water available to hydrate all of its pores. To create a strong, durable, abrasion-resistant material that doesn’t leach or exfoliate chlorides over time, cement-based materials require chemical hardening through hydration.
Tips for Curing Concrete in Cold Weather
Concrete curing is a time-consuming process, but it’s crucial to the life of your concrete. Curing slows down the hydration process and prevents the structure from cracking or deteriorating. If you want your concrete to last as long as possible and maintain its structural integrity, then there are certain steps that you should take during concrete curing.
The process of curing concrete in cold weather is more difficult because the concrete has to cure without the help of heat. This means that you have to monitor the curing process more closely, but it’s still possible to achieve a high-quality product even in harsh winter conditions.
According to the American Concrete Institute, cold weather is considered as a period of more than three consecutive days where the air temperature is below 40 degrees Fahrenheit. If temperatures below 50 degrees Fahrenheit persist for more than one and a half days, special concrete curing techniques are applied.
Concrete May Freeze Sooner than Expected
When the concrete is fresh, it might freeze before it is cured or gains strength enough to resist expansion caused by freezing. If this happens, the strength of the concrete is reduced by half. Therefore, where the weather conditions prove to be cold according to the American Concrete Institute’s guidelines, contractors have a set procedure they have to follow to get through with the task if it must be done in these conditions.
Process of Preparation
The process of curing concrete in cold conditions can happen through these preparation practices:
Heating one or more of the constituent materials before mixing them up can keep the concrete’s temperatures high enough during the pouring of the concrete.
The most ideal components that can be pre-heated are water and sand and not cement. Alternatively, the ready-mix concrete companies have the capability of pre-heating the concrete before delivering it at the site or the components can be stored indoors to prevent them from freezing.
The mixture of the concrete may be altered before mixing. For instance, a higher ratio of cement could be added or calcium chloride could also be added.
There is a type of cement that does not degrade in strength no matter the condition. It could be used in this case especially where steel needs to be reinforced.
You need to avoid materials that are set up slower and that generate a low amount of heat such as slag cement or fly ash.
Tips for Pouring and Placing
Plan for the construction crew to stay longer at the site. It’s established that concrete with cold temperatures take more time to settle as needed which means that the workers need to be there to work on it. Erecting windbreaks could also be a constructive solution as it prevents the wind from moving in to lower the temperatures of the concrete. The windbreaks need to be around 6 feet or higher.
Heat enclosures made of wood, polyethylene sheets, tarps, or canvas could either maintain the temperatures or increase the temperature such as wood. Wood may also be used to warm water that is then sprinkled on the floor.
On concrete surfaces where forms are placed for instance the corners and edges, they should be left because they retain the heat in the concrete. To fight against the low humidity levels synonymous with cold weather, a live stream can be pumped into the area with the concrete to maintain higher temperatures.
During the cold weather, the bleed water secreted by the concrete does not evaporate and is delayed. You need to wait for that scenario to clear that water.
Use an infrared temperature gun every time to make sure that the concrete’s temperature is maintained at above 40 degrees Fahrenheit during the curing process.
Another method to maintain steady temperatures is to cover the concrete using insulating blankets. Uncover the blankets gradually and not rapidly as the sudden change in temperatures could cause cracking. The ACI Committee 308 has certain recommendations that need to be followed during the curing of the concrete.
There are times when you find it difficult to concrete curing in San Rafael, Ca. In such a scenario, call San Rafael Concrete at (628) 215-0488. We are one of the best companies in concrete works by setting professionally acceptable concrete curing times.