One far too common misconception is the tendency of most homeowners, and many home builders, to equate drying to curing. This can lead to problems down the road in cases where a concrete driveway has not been allowed to cure.
What is Curing?
Curing is a chemical process that increases the strength and reduces the water permeability of concrete structures. To properly take place, the concrete must be kept within a certain range of temperature and relative humidity. While the specific ideal temperature and humidity vary with the precise mixture and brand of cement used, the general guideline is that the process works best at around 70 degrees Fahrenheit and 80% relative humidity. Temperatures below 50 degrees Fahrenheit can literally stop the process, while those above 95 degrees Fahrenheit will impede it and result in a less durable finished product. Humidity is more forgiving, with the emphasis on high humidity. Even standing water on the surface of the concrete will not prevent curing.
Depending on the thickness and exact composition of the concrete, curing completely can take as long as a month. Since a concrete driveway is a relatively low stress application, though, even a handful of days can make the driveway stable enough for light use. Asking your concrete contractor what to do is the best way to ensure that the concrete curing process is carried out as well as possible.
General Tips for a Well Cured Concrete Driveway
Keep the concrete forms in place. While many think of forms merely as something that holds the concrete in the proper shape until it hardens enough not to run, it also creates a moisture barrier. By protecting the concrete from exposure to the air, the forms will help the curing process by preventing the driveway from losing that important humidity.
Keep the driveway covered. For at least a handful of days, covering the driveway with some form of moisture barrier, like a sheet of plastic, will prevent premature drying from bringing the curing process to a halt.
In weather that is below 50 degrees Fahrenheit, some form of insulation is necessary to allow the concrete to cure. In milder weather, simply adding some blanket type insulation may be enough. In extreme cold, it may be necessary to use heaters to keep the driveway warm enough cure properly.
While not quite as bad a problem as cold, hot weather can cause the curing to take place incompletely and irregularly. The most popular methods of keeping a driveway cool during extremely hot periods are spraying cool water over the moisture barrier and adding a layer of crushed ice across it.
A concrete driveway is a major investment for most homeowners. Getting the most out of this investment requires allowing the driveway to cure completely to get the most durability out of it.
If you have any questions about concrete, give us a call at 800 -910-6928, we’d love to help you get going on your project.