Curing concrete flatwork plays an imperative role in the strength and durability development of concrete over time. Curing is the maintenance of satisfactory moisture content and temperature in concrete for a period immediately following the placing and finishing so that the desired properties may develop. 50% of surface strength can be lost if the concrete is not cured. Concrete is most likely to surface scale, has been weakened at the surface during the finishing and/or curing process. Curing assures the proper hydration, which allows the concrete to reach its highest potential strength. Concrete that is properly cured will decrease abrasion damage due to increased surface hardness, reduce shrinkage of concrete to prevent surface cracking, and resist damage from deicers or freezing and thawing cycles. Follow these tips from Liberty Ready Mix for how to use best practices to cure concrete on your latest project.
Without curing concrete, many problems can arise that can reduce the overall durability of concrete and require additional work or money in order to fix it. There are a variety of benefits that concrete curing can provide.
Popouts occur when concrete swells due to absorbing too much moisture or freezing under moist conditions. Without curing, concrete is less durable and more susceptible to damage like this.
Concrete is most prone to damage during freezing and thawing cycles that occur throughout winter and spring. During these cycles, concrete can often crack, scale, or deteriorate. Curing concrete correctly increases the concrete flatwork’s durability to make it strong enough to combat these harsh cycles and prevent surface deterioration.
A lot of factors go into increasing the strength of concrete including its porosity, absorptivity, and permeability. Well-cured concrete can reduce shrinkage cracks and make concrete more watertight, reducing the chances of additional moisture entering into the concrete and damaging it during colder months.
There are three important components when it comes to curing concrete. Keep mixing water in concrete during the beginning stages of the hardening process, reduce the loss of mixing water from the surface of the concrete, and use heat and additional moisture to increase the amount of strength the concrete has. Typical concrete contains enough moisture if curing begins within an hour after finishing is complete. Concrete flatwork must be kept warm and moist continually until strength is achieved.
Concrete gains its strength and durability through hydration, in which the water and concrete chemically react to form a hardened paste. In order for hydration to occur, concrete must be moist and stay at a temperature above 55 degrees for at least a week.
During cooler temperatures, insulating blankets should be used in order to keep the temperature above 55 degrees. You may need to consider ground or vented heaters in order to keep the concrete warm enough to cure fully.
There are a couple of different methods you can follow after your concrete is finished in order to make sure your concrete is properly cured.
Place moist cotton mats, curing mats, or burlap over the concrete to keep it hydrated during the curing process. You can also pond water or sprinkle water on the surface continually in order to keep it hydrated.
This method should especially be used if the local sand aggregate is prone to producing popouts.
In order to retain moisture already on the concrete, plastic sheets can be placed over to hold moisture in. Keep in mind that if the sheet is not completely flat to the concrete surface, areas of the concrete may discolor.
Like plastic sheets, waterproof paper manages to retain moisture already on the concrete surface. The benefit of waterproof paper over plastic sheets is that they will not discolor the concrete surface you’re curing.
For larger commercial concrete surface areas, liquid membrane-forming curing compounds are a good curing solution. This is done by spraying or rolling compounds onto the surface at a rate of 150-200 sq. ft. per gallon. Talk with your ready mix concrete company for more information or to understand the manufacturer’s recommendations and follow them closely.
Liberty Ready Mix has years of experience with providing quality concrete and ready mix concrete delivery to clients in a variety of industries including commercial, governmental, industrial, and residential. To schedule a concrete delivery in Des Moines, or for more information on how to properly cure concrete, contact us at Liberty Ready Mix!