Without curing, moisture is lost too quickly and there isn't enough water necessary for the crystals to grow, resulting in weaker concrete. Concrete should be placed ideally in conditions between 50 degrees and 75 degrees Fahrenheit, and this temperature must be maintained during concrete curing.
If it is too hot or too cold, the crystal growth process is either curtailed or accelerated, leading to weak results. The proper curing process is vital to quality, durability, strength, water tightness and resistance to freezing and thawing.
Curing concrete with water prevents excessive loss of moisture as the water will create a layer for an extended period of time that can control the evaporation of moisture from the surface. After some time the concrete will start the chemical reaction that will eventually harden the concrete.
Even if alternative curing procedures are used, it is desirable that a certain amount of water curing is done to prevent cracking. Water curing can be done using the following techniques:.
Curing concrete with a membrane or plastic sheeting is the most practical and efficient way to cure concrete in today's construction industry—sometimes water is unavailable for water curing or, if it's done improperly, it can affect the strength or the surface finishing of the concrete product. Concrete should be covered with a membrane, either plastic or chemical compound that will seal off the pores and retard the evaporation of water from concrete.
Two common types of membrane curing are:. Purpose of Curing of Concrete:- The reaction between cement and water is called hydration. It is an exothermic reaction the reaction which releases heat. After adding water to the concrete mix, hydration starts, which makes the concrete to dry out quickly due to an exothermic reaction which releases heat.
To complete the hydration process, concrete is kept moist to attain the maximum strength of concrete as soon as possible. As there are many frequently asked questions about the curing of concrete.
Below are some of them. Draining water on the concrete surface cures the concrete. Water cooler than 5 0 C is not suitable for curing concrete. As the hydration reaction in concrete expels heat and keep concrete warm, Using cold water less than 5 0 C on concrete may lead to cracking and failing. Alternate drying and wetting on the concrete surface causes volumetric changes in concrete and ultimately leads to cracking.
The minimum period for curing concrete to attain maximum strength is 28 Days. So it is clear as time increases on the concrete strength increased. The early strength of concrete is most important, and it is responsible for the ultimate strength of concrete. We should do proper curing by considering the environmental conditions, type of structural members, atmospheric temperature. Maintaining the proper temperature also plays a vital role in concrete as mentioned, it should not be colder than 5 0 C.
Concrete is kept moist for at least 28 days. Nowadays, due to lack of time, the curing can be achieved by following modern techniques in Days. Nevertheless, it is always advisable to keep concrete moist for at least 14 days.
This method adopted for floor slabs. The concrete surface divided into small ponds, and these ponds are filled with water continuously for 14 days. Wet coverings: This type of method performed for columns , footings , and the bottom surface of slabs , where ponding is not possible. Impermeable coverings like gunny bags or hessian are required to cover the concrete; these membranes sprayed with water to keep the concrete moist.
Ponding is not suitable at the places where the atmospheric temperatures are high. Water gets evaporated due to the excessive heat. Membrane curing is adopted to prevent the loss of water content due to atmospheric temperature from concrete. If the forms are made of wood, they should be kept moist, especially during hot, dry weather.
Covering concrete with impervious paper or plastic sheets Impervious paper and plastic sheets can be applied on thoroughly wetted concrete. The concrete surface should be hard enough to prevent surface damage from placement activities. Applying membrane-forming curing compounds Membrane-forming curing compounds are used to retard or reduce evaporation of moisture from concrete. They can be clear or translucent and white pigmented. White-pigmented compounds are recommended for hot and sunny weather conditions to reflect solar radiation.
Curing compounds should be applied immediately after final finishing. Live steam Live steam at atmospheric pressure and high-pressure steam in autoclaves are the two methods of steam curing. Steam temperature for live steam at atmospheric pressure should be kept at about degrees Fahrenheit or less until the desired concrete strength is achieved. Heating coils Heating coils are usually used as embedded elements near the surface of concrete elements.
Their purpose is to protect concrete from freezing during cold weather concreting. Electrical heated forms or pads Electrical heated forms or pads are primarily used by precast concrete producers. Concrete blankets Concrete insulation blankets are used to cover and insulate concrete surfaces subjected to freezing temperatures during the curing period. The concrete should be hard enough to prevent surface damage when covering with concrete blankets. Other forms of curing include internal moist curing with lightweight aggregates or absorbent polymer particles.
It takes about a month for all of the water to get used up in the hydration process. Brush on paint too soon while moisture is still rising to the surface, and it can put pressure underneath the hard barrier of paint, causing it to peel away or break the bond. For this reason, paint may not adhere as well, and the final color and appearance of stained concrete may also be affected.
To achieve the best results, wait until the day period is over to apply paint or stain, and then follow the top tips outlined in this video from the concrete pros at Quikrete.
After that, you can drive regular passenger cars on the concrete; heavy pickups or RVs can roll onto the driveway once the concrete reaches its full strength, at around 28 days.
This content has been brought to you by Quikrete. Its facts and opinions are those of BobVila. Disclosure: BobVila. You agree that BobVila. All rights reserved.
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