A key component of any concrete application is the curing process. Curing is the process of maintaining the right level of moisture inside the concrete within the ideal temperature range to aid the cement in setting properly.
Maintaining this moisture level is key to creating the right environment for the chemical reaction between the cement and water to occur. The process of maintaining this moisture level will differ somewhat depending on the ambient temperature, rain, and moisture levels, as well as the particular concrete mix and application.
Generally speaking, you’ll want to start watering concrete when the surface is solid and strong enough to walk on.
Let’s take a closer look at how soon to start watering concrete and how to determine what sort of curing procedure will work best for your situation.
Spraying and misting freshly applied concrete is merely one of many methods of assisting proper curing. There are multiple techniques that can be deployed to help concrete retain moisture during the early portion of the curing period.
The goal of these techniques is to maintain a consistent level of water in the early hardening period. They will also prevent the surface from drying out excessively, and maintain heat in and around the curing concrete in colder weather.
Spraying and Misting
Spraying and misting concrete with water is done to reduce water evaporation from the surface. These techniques work best when humidity is fairly low.
Spraying and misting concrete slabs only add a small amount of moisture. This means it needs to be done repeatedly to maintain a consistent moisture level. Spraying inconsistently can lead to cycles of wetting and drying which can cause cracking at the surface.
Another way to maintain moisture levels is to spray or mist in conjunction with a covering to saturate the concrete’s surface.
Saturated Concrete Coverings
Saturating coverings in water work well to maintain a consistent water level on the surface of curing concrete. Burlap, old rugs or carpets, and other scrap materials can all work for this task.
Once again, this technique should be used when humidity is relatively low and temperatures are higher.
Leaving Forms in Place
Another method of assisting proper curing is simply leaving the forms in place throughout the beginning of the curing process. If you don’t need the forms for immediate use elsewhere, then simply leaving them in place for the first 7 days or so will help with proper curing.
Leaving forms in place will help to trap moisture in place and prevent excess evaporation, which means you won’t need to rely on other curing methods as much. If you’re working with wood forms, then keeping them well hydrated with regular misting is recommended.
Immersion (or ponding) is a method involving flooding the entire concrete application while it cures. It’s used on horizontal or flat structures, like flat slabs, and is one of the most complex and labor-intensive methods of assisting curing.
To do this properly, you need to build an artificial pond around the entire slab and then flood it with water. This can be tricky to do without water breaking through your damn, which will dry up your pond.
Generally speaking this method is not necessary for most simple concrete applications, and is better suited to expert use.
When to Start Watering?
So now you have a good understanding of the different methods of curing concrete, when should you begin watering your concrete?
For most concrete applications, you’ll want to add water once the concrete has dried sufficiently that the surface is no longer pliable and can be walked on. There isn’t an exact timeline for this, as it will depend on how hot it is outside, how thick the concrete is, and the specific type of concrete mix.
For a typical concrete mix, you can start watering after about 12 hours. For fast-dry concrete like quikrete, which is designed to dry much quicker, you can start watering as soon as an hour or two after application.
Continue applying water regularly for the first 7 days of curing, after which point, the concrete will have cured sufficiently to not require further moisture.
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