How do You Cure Concrete?

There are several methods to cure concrete and the most common and the most effective ones are:

• Water curing
• Water retaining
• Sealing and chemical coating

All of these methods have the same idea – to maintain the moisture inside the concrete slab so it grows strong and doesn’t become too porous. Careful and patient curing is what makes your concrete strong and durable.

That is why it is important that your concreting is done by professionals. They understand the importance of curing and know how to do it properly. Besides understanding the instructions for different types of curing, they also have enough experience to realise how it needs to be done in specific cases and how long it needs to be done.

What Is Curing in Concrete?

When it comes to concrete slab curing, it is important to understand that it is an attempt to lock in moisture so that certain processes within concrete can occur. They are essential for the shape, density and strength of the concrete slab.

Namely, concrete is the combination of water, Portland cement and aggregates. When there is moisture present, as well as the free cement, the process that occurs is called hydration. As a result of hydration, there are some compounds that act is adhesives for the aggregates.

It takes time for them to bind the aggregates together and act as adhesives for them, so the process of hydration needs to be long and gradual. This gives the concrete the time to become denser and firmer.

If this doesn’t happen and all the moisture evaporates from the concrete quickly, it will become porous. In other words, it will crack and crumble. That is why it is essential to start with proper curing the moment the concreting is done.

What Are the Methods of Curing Concrete?

All curing methods can be classified into two groups. They are all trying to prevent the premature evaporation of moisture from the concrete or to add water during the beginning stages of the curing process.

Water-adding curing – This includes keeping the concrete moist by adding water in several ways. You can flood the concrete slab and keep it flooded until cured or you can periodically spray it with water.

Flooding is also called ponding. The idea is to create a barrier around the concrete slab and pour water into it. The barrier should keep the water on the concrete slab so the entire structure resembles a pond. This is an effective method but not always applicable due to terrain and practicality.

Misting, fogging or spraying is pretty much self-explanatory. Water is dispersed over the concrete slab in the spray. The downside of this method is that the water is not always spread evenly, so some parts are better cured than others. This can create cracks.

Water retaining methods – These are all about finding different ways to cover concrete slabs in order to prevent the evaporation of moisture. The most usual materials to use are hessian, sand, or canvas. There are also others. The downside of these materials is that they are very effective at collecting the moisture themselves, so if they are not regularly dampened, they will extract the moisture from the concrete.

Sealing – It is necessary to wait for the concrete to harden up a bit before applying this curing method. It is due to the fact that it is done with plastic films that are placed on the concrete.

If the concrete is still soft, the seal won’t work. Often, these seals can cause discolouration, so don’t use them on surfaces where the appearance of your concrete slab is important. The same mechanism is used with the chemical sealers. They are used as soon as possible upon concreting.

How Long Does It Take for Concrete to Cure?

This depends on the desired strength of the concrete as well as some other factors. For the concrete to cure entirely and leave no cement not hydrated is extremely rare. It would take months or even years. For the concrete slab to be usable, it doesn’t have to be 100% cured. It only needs to cure to a certain level. Here are some general numbers:

• Concrete setting – 24-48 hours.
• Concrete cured to 70% of the strength – 7 days.
• Concrete cured – 28 days.

There are many factors for the speed of curing:

Concrete mixes – Control over the curing process is usually achieved by adding different compounds into the concrete mix. When the concrete is mixed, the concreters add a bit more water than necessary so that they handle the concrete more easily.

This excess water makes the concrete runny and not that strong. However, by adding certain compounds, concreters eliminate the excess water and leave in only a little bit of the necessary amount of water. This little extra is just what is needed to keep the concrete moist and ensure slow and progressive hydration.

This is important because different concrete mixes can achieve their curing in different time periods.

Temperature – Cool and cold concrete achieves strength much slower than concrete at higher temperatures. In time, these differences settle, but they are drastic in the first couple of days of curing. This is important to know because you need to know if you are able to use your driveway, for example, after 3 or 7 days.

The ideal condition for curing concrete is a continuous, steady temperature of 23°C.

Curing is just one step of many during the concreting process. Therefore, it is important that you find an experienced concreter to complete all your important concreting projects. That is the only way that you can be sure your concrete slab is durable and well-made. If the money is what you are worrying about, you can stop right now.

You don’t have to overpay, and you can learn all about the prices for your project before you start it. There are no nasty surprises there. Ask for several quotes on Service Seeking and pick the most adequate one.