Understanding the Curing Process of Precast Concrete

When most people think of curing, they think only of maintaining moisture on the surface of the precast concrete. But curing is more than that—it is giving the precast concrete what it needs to gain strength properly. Precast concrete strength depends on the growth of crystals within the matrix of the concrete. These crystals grow from a reaction between Portland cement and water—a reaction known as hydration. If there isn’t enough water, the crystals can’t grow and the concrete doesn’t develop the strength it should. If there is enough water, the crystals grow out like tiny rock-hard fingers wrapping around the sand and gravel in the mix and intertwining with one another.

The other important aspect of curing is temperature—the precast concrete can’t be too cold or too hot. As fresh concrete gets cooler, the hydration reaction slows down. The temperature of the precast concrete is what’s important here, not necessarily the air temperature. Below about 50 F, hydration slows down a lot; below about 40 F, it virtually stops.

Methods for Curing the Precast Concrete

There are four different types of curing methods used for a precast concrete;

Water cure

The concrete is flooded, ponded, or mist sprayed. This is the most effective curing method for preventing mix water evaporation. Make sure you allow proper time for water curing.

Water retaining methods

Use coverings such as sand, canvas, burlap, or straw that is kept continuously wet. The material used must be kept damp during the curing period.

Waterproof paper or plastic film seal          

Waterproof paper or plastic film seal is applied as soon as the precast concrete is hard enough to resist surface damage. Plastic films may cause discoloration of the concrete-do not apply to concrete where appearance is important.

Chemical Membranes

The chemical application should be made as soon as the precast concrete is finished. Note that curing compounds can affect adherence of resilient flooring, your flooring contractor and/or chemical membrane manufacturer should be consulted.

In case you still have question about modular homes and insulated precast foundation, you may contact Legendary Homes Inc in Jackson, Michigan. A representative will be happy to assist you. Meanwhile you can check our modular home price sheets by signing up to our blog

Topic: Precast Concrete