Concrete is the second-most consumed substance in the world, behind water. This billion-dollar market is essential for construction, as its versatility and availability make it an essential part of modern structures.
Curing concrete is a key part of ensuring concrete maintains its inherent durability—so let’s take a look at why it is so essential.
Why Cure Concrete?
Note that when we’re talking about a curing concrete definition, we are referring to the process of controlling the loss of moisture from concrete that has already been set down. The most important concrete curing time is within 28 days of the concrete already being placed.
What makes this process and timing so critical? It’s all about concrete’s components. We know that cement and water undergo a chemical reaction that binds sand and gravel together to create concrete. However, during this process, it’s important to have a proper amount of water in that mixture. If the water evaporates too quickly, you will still have concrete; however, it will be far less durable and more likely to crack. While this can happen in just about any circumstance, there’s an especially larger risk for concrete projects in arid areas or places with plenty of sunlight exposure.
This is where concrete curing comes in. During those initial 28 days after the concrete is installed, curing either adds more water to offset evaporation or tries to slow the evaporation to keep more water inside.
The Curing Concrete Steps You Need To Take
There are three main concrete curing methods that most sites use in order to increase durability. These are all effective, but the ideal match for your job site may be contingent on resources at your disposal.
The first, and most traditional, method of curing concrete is using water. On paper, this makes a lot of sense. The water creates a layer for an extended amount of time, and in turn, this controls the evaporation of moisture from the surface of the concrete. This helps ensure more moisture is present as the chemical reaction that hardens the substance progresses. In fact, water curing is so useful that even if you opt for one of the other methods, it’s recommended that you utilize water curing as well.
There are a few techniques that can be done to add water to concrete for curing purposes:
- Immersion: is usually done during the concrete testing stage, rather than after the slabs are put down.
- Misting: is best used in situations where humidity is low and there is no risk of temperatures dropping below freezing. This involves spraying mists of water regularly to raise the humidity above the concrete.
- Ponding: is generally utilized on flat surfaces or any area where it’s easy to retain water on the slab. For this process, the slab is surrounded by dikes to keep a layer of water on top.
- Wet Covering: Just like how immersion is generally done earlier than usual for curing, this is done later, after the concrete has begun to harden. A burlap, sand, or canvas covering is placed over the concrete and kept damp.
While water is effective, in some cases, there’s not enough of it available on a site for water curing. In addition, there’s the risk of impacting the strength or finish of concrete if you don’t apply it properly. In these circumstances, membrane curing is often preferred. This uses a membrane or plastic sheeting to cover the concrete, sealing off the pores to slow water from evaporating.
The two most common methods to do this are plastic sheeting or curing compounds that create a membrane. A plastic sheet is best used over flat surfaces, covering all exposed areas without damaging the finish. For curing compounds, these are generally chemical products that are sprayed over the surface. When they dry, they create a membrane that keeps water from evaporating too fast.
However, the most common form of curing concrete is by using specific curing chemical compounds. These are optimally used when the concrete has already hardened, but still has some water present. Because there are so many different compounds on the market, construction professionals need to do their research to find what suits them best, as well as the optimal form of application.
Supporting Your Curing Concrete
When it comes to the best way to cure your concrete, not all situations are the same. One of the most important factors is temperature. Ideally, concrete should stay in the optimal temperature range for placement (50 to 75 degrees Fahrenheit) during curing. If it goes outside of this range, it may impede crystal growths in the concrete. This leads to a weaker result.
Other factors can impact how successful curing concrete is as well. These include:
- Size and shape of the concrete: You need to make sure water is evenly distributed throughout your concrete for consistent durability.
- Weather: We mentioned temperature already, but the nearby humidity also plays a key role in how well concrete cures, especially if you are using misting.
- Taking other steps too fast: Even if you see the concrete is starting to harden, it’s recommended you avoid painting it or putting excess weight on it during this initial period.
While curing concrete is an essential step of a lot of construction applications, it’s important that you take the time to properly go through the process. This not only means following best practices and adapting for specific scenarios, but having all the resources you need. This becomes more and more difficult the larger the project, so it’s important that you have the tools to help you scale your curing concrete process. This is where eSub comes in. Our project management software makes it easier for construction subcontractors to chart and check the progression of various tasks, curing concrete included.