How Soon Should I Water Concrete After Pouring?

The Do’s and Don’ts Of Concrete Curing

Concrete is one of the strongest materials in the world, making it a popular choice amongst many construction projects. It becomes stronger as time goes on, and is often considered a more aesthetic option relative to other materials of the same caliber. Successfully pouring a concrete slab that is durable against weathering and traffic takes several steps. To ensure that the slab remains crack-free for as long as possible, curing is one of the most important elements. 

 

Why do you have to cure concrete? 

As aforementioned, an integral part of the concrete pouring process is curing. Curing is responsible for the durability, stability, and strength of concrete slabs. It refers to the process of providing the concrete with the correct moisture, time, and temperature for it to develop its desired properties. Depending on the intended use, the variables of moisture, time, and temperature will change. For the most part, curing time ranges from 72 hours to 2 weeks. Other elements will vary as well depending on the size of the slab, the density, etc. 

 

Dry Vs. Cure

Curing and drying, though similar, mean slightly different things when it comes to concrete. Curing is defined as the process of supplying a new concrete slab with the right levels of moisture, temperature, and time to develop the properties needed for a specific project. Drying, on the other hand, is supplying the right conditions for the concrete to reach the right levels of moisture during the hardening process. Depending on what it is being used for, different types of concrete projects will require the slabs to have different amounts of moisture in them. 

 

How soon should I water concrete after pouring?

Keeping concrete moist is essential to the concrete curing process, but too much water and the concrete may not form in the way it needs to. If it loses too much moisture through evaporation, it will not cure properly and will become prone to cracks. Many construction specialists recommend watering it down five to ten times per day, for the first week, starting 2-4 hours after it has been poured. The first two to four hours lets the concrete “finish”, which refers to the setting process. If it is predicted to rain before the first two to four hours have passed, the slab should be covered to protect it from too much moisture.

 

How long does it take concrete to cure?

Concrete curing is generally considered a finished product after 28 days (for 4 in. thick slab). However, the thicker the slab of concrete, the more time it takes to cure. Curing time compounds itself, meaning the time can double and triple exponentially. The industry rule-of-thumb for estimating curing time is one month of drying for every inch of concrete. Thus, a 7-inch slab of newly poured concrete would roughly take 7 months to be fully cured. 

The Do’s

To ensure proper curing, there are several key things to ensure optimal results. 

 

• Spray: To maintain the proper moisture levels, concrete should be sprayed with water frequently. This is known as moist-curing. Most specialists recommend watering the slab 5 to 10 times per day for the first seven days. Moist-cured concrete can be up to 50% stronger than dry-cured concrete.

 

• Pond-cure: Pond-curing is another option if spraying is not possible. Pond-curing involves setting up temporary berms and flooding the slab with roughly one foot of water. Depending on how quickly it absorbs, you may need to refill the berms, as the water level has to stay above the slab. Three days of this method does the equivalent of one week of spray-curing. Often this strategy is used when builders are pressed for time and need to speed up the curing process.

 

• Cover: Covering concrete is useful for a variety of reasons. Concrete should be left to sit for 2-4 hours after pouring before watering. If it is supposed to rain in that window, the concrete should be covered. Additionally, if you cannot water the concrete as regularly as is recommended, covering concrete helps trap the moisture and slow the evaporation. If covering, be sure to fasten your sheet down bricks, sandbags, or other heavy items.

 

• Apply a compound: Curing compounds are used as an alternative method to curing when other strategies aren’t available. Curing compounds can be purchased from constructions that sell ready-mix solutions. Ready-mixes contain soluble emulsions that form a protective layer over the concrete slab. This helps prevent the water from evaporating, allowing for it to properly cure.

 

The Don’ts

To avoid premature cracking and structurally unstable concrete, there are some practices to avoid.

 

• Paint: Do not paint concrete while it is still in the curing process. The potential moisture in the paint can harm the concrete and disrupt the final product. As a general rule, avoid doing anything that could affect the curing and potentially result in concrete that doesn’t have the desired properties.

 

• Let it get too cold: The temperature at which the concrete cures is important for ensuring its durability. Generally, concrete should be poured only when the ambient temperature is predicted to stay above 50𝆩 Fahrenheit for the next five to seven days. If the temperature does drop, cover the concrete with insulating blankets to keep it warm.

 

• Add excessive weight: Concrete that has hardened doesn’t necessarily mean it is ready to be used. It is best to wait about a day (24 hours) before allowing any foot traffic, including pets. For vehicles, allow for up to 10 days prior to opening the roadway. Larger, heavier trucks, RVs, or trailers should refrain from driving on the concrete until about a month after pouring.

 

• Skip control joints: While the process of concrete curing is put in place to prevent cracking, some breakage is inevitable. Control joints are one of the many ways to protect the slab from large, damaging cracks. They are placed in certain areas and relieve stress caused by the shrinkage that occurs during the curing process.

 

A-Core Concrete Specialists 

A-Core Concrete Specialists have been serving the Mountain West and surrounding states since 1974. Our dedicated team of professionals works to assist you in any of your concrete construction needs. We offer services in concrete cutting, drilling, pouring, scanning, grinding, grooving, and so much more. For any of your concrete needs, call us today.