What Is Curing of Concrete?
Curing, especially determining the curing period for slab, performs a crucial role in the growth as well as the resilience of concrete strengths. Since applying water to that same concrete mixture there is an exothermic process that tends to toughen the concrete.
Hardening of concrete also isn’t instantaneous yet lasts for a prolonged period of time, taking additional water to maintain hydration.
So, the concrete remained damp till the hydration process in the concrete had stopped, ensuring the minimum curing period of concrete is met. Such an approach is termed the type of curing of concrete.
Why Curing Is Important?
The activity within cement and water is referred to as hydration. That is an exothermic reaction. When applying water to just the conventional concrete, hydration occurs, which allows the concrete to dry off rapidly due to an exothermic reaction that produces heat.
In order to accomplish the hydration process, the concrete is moistened to reach the optimum workability of the material as quickly as practicable.
Method for the Cure of the Concrete:
The draining water mostly on the concrete surface is used to cure the concrete. Water colder than 50C isn’t really appropriate for the curing of concrete.
As the hydration reaction in the concrete heats up and keeps the concrete hot, utilizing cold water only about 50 C mostly on concrete will contribute to cracking and failure.
Alternating drying as well as wetting on the concrete surface induces volumetric variations in concrete as well as eventually contributes to cracks.
Concrete Cure Time:
The required time for curing concrete to reach full strength is 28 days.
Minimum Curing Period for Concrete Cement:
The initial strength of concrete is perhaps the most significant and seems to be ready for the final strength of the concrete. People should be doing thorough curing by taking into account the ambient factors, the form of structural elements, and the air temperature.
Maintaining an appropriate temperature often performs a crucial function in concrete, which can not be cooler than 50C. Concrete shall be maintained moist for a minimum of 28 days.
These day, due mainly to shortage of time, the treatment can be accomplished with the use of advanced therapies in 14-20 days. However, it is still good to place concrete damp with at least 14 days.
According to IS 456 – 2000, concrete for OPC should not be cured for much less than 7 days, and that it should be cure during at least 10 days for concrete of minerals mixes or cement mixtures.
In the event of hot weather as well as arid environmental conditions, the curing time ought not to be just under 10 days for Portland cement as well as 14 days for concrete of mixed cement including mineral admixtures.
Its minimum curing period for rcc slab and curing period of concrete shall depend on multiple factors:
- Relevant Concrete Strength.
- The grades in concrete.
- The temperature of the atmosphere.
- Related to the chemical reaction between cement and water in concrete, heat is released that needs water to achieve hydration. In summer, 50% of the water vanishes. So, extra water is necessary on sunny days.
- Width and shape of the member of the concrete.
Method Curing of Concrete
The types of Curing are as follows.
- Ponding.
- Moist Coverings.
- Membrane Curing of Concrete.
- Synthetic Resin Curing Compound.
- Acrylic Curing Compound.
- Wax Curing Component.
- Chlorinated Rubber Curing Compound.
- Steam Curing of Concrete.
- Curing of Concrete by Infrared Radiation.
#1. Ponding-
This approach has been adopted with floor slabs. Each concrete surface separated through small ponds, yet these ponds were continually full of water for 14 days.
#2. Moist Coverings-
The said type of system is used for columns, pillars, as well as the lower part of the slabs, in which it is not feasible to measure. Waterproof coatings such as gunny bags or hessian have been used to protect the concrete; such membranes are filled with water and keep the concrete wet.
#3. Membrane Curing of Concrete-
Ponding isn’t really necessary in areas when ambient temperatures become high. Water evaporates by intense heat. Membrane curing is used to avoid the removal of moisture content from concrete depending on the climatic temperature.
Membrane curing tends to close off by creating an impervious coating on the concrete surface that gradually prevents evaporation. This process is normally done by scraping or spraying the curing agent on the concrete floor.
There are various curing compounds available to accomplish membrane curing, beyond which four factors are important and commonly used.
#4. Synthetic Resin Curing Compound-
Synthetic resin is indeed a substance that creates an impermeable membrane on even a concrete surface to survive water evaporation from concrete.
For more plastering, the plastic resin membrane may be quickly dissolved by pouring hot water onto the concrete floor. It is only sufficient in locations where subsequent maintenance has been added to the concrete.
#5. Acrylic Curing Compound-
Acrylic Curing product is a based on polymer curing product derived from acrylic acid polymers. The biggest appeal of the acrylic-based curing agent is that it does not need to be removed for plastering. Acrylic helps preserve good durability in the plastering process.
#6. Wax Curing Component-
Wax curing provides common qualities to synthetic resin. Its use of wax on surfaces to also be painting or tiled also isn’t suggested since wax hampers the conductivity between both the ground as well as the plastering.
#7. Chlorinated Rubber Curing Compound-
Once placed, chlorinated rubber creates a dense layer on the concrete floor. To use a chlorinated rubber-based curing solution, the concrete is completely cured with no small particles remaining. However the lifespan of chlorinated rubber is much older, and this can survive indefinitely.
#8. Steam Curing of Concrete-
Such practice is used at the Precast Concrete Plants in which the concrete members are mass-produced.
Steam has thermal humidity in it which is poured on the concrete surface to retain concrete moisture but also to change the temperature of the concrete, which also gradually accelerates the speed of the toughening of the concrete.
#9. Curing of Concrete by Infrared Radiation-
This approach is used in cold climate areas. Throughout this process, infrared radiation is introduced to the concrete, raising the original temperature and increasing the intensity of the concrete.
This has been the most efficient method than steam curing, as increasing the initial temperature in concrete may not lower the final workability of concrete.
That methodology is used for hollow concrete components where even the heating systems are located in concrete components that produce a temperature of 900°C.
How Long Does It Take for Concrete to Dry?
The whole curing process of concrete may last only a month, concrete would be prepared to be used earlier. Every other design can vary a bit due to the variations in environmental conditions, concrete mixing, and positioning and finishing strategies.
Keep such timeframes in mind when awaiting for concrete to dry:
- 24 to 48 hours – following initial setting, forms could be eliminated and people could walk on the floor.
- 7 days- after limited healing, traffic between cars and machinery is perfect.
- 28 days – during that stage, the concrete must be completely healed.
How Long Does Cement Take to Dry?
The cement will dry in phases that will take around 30 days to finish. It requires 1 or 2 days for cement through dry for the person to cross, but 5 to 7 days until people can ride upon this.
- The temperature has a big influence on how easily cement finishes the healing process. Considerations along with rainfall, sunshine, wind as well as humidity are all determining significantly.
- Processing of freshly poured cement relies heavily on climatic conditions, as humidity fluctuations can trigger cracking when cement drying stage.
- Concrete can recover more and more if it has been fully dried gradually. Unless the circumstances are mild, it covers the cement with plastic.
- When temperatures are 80 degrees or higher, watering the garden hose also holds it damp and avoids cracking. Approximately 90% curing phase can be completed inside a right set of circumstances.
- Accelerator technologies seem to be on the market that can speeding up the processing. Accelerators are additives applied to a concrete mix which minimize the fixed process and increases the hydration factor.
- There is already Portland cement, which is formed and hardened by chemical reactions with water. The curing method is perhaps the most critical step towards the achievement of solid and sometimes even cement.
How to Cure a New Concrete Slab?
Allow time to completely cure the slab for at minimum 7 days following completion to achieve the best appearance on the new concrete slab as 28 days is ideal). Curing seems to be the method of regulating the frequency and degree of degradation of concrete moisture throughout cement hydration.
Curing plays a very important role in the production of strength and the longevity of concrete. This is achieved by constantly wetting the exterior surfaces while avoiding the lack of moisture. Unless the water evaporates so soon, the final product may be weakened by stress as well as cracking.
Sprinkle the slab with water as much as possible for the first 7 days following completion. When the asphalt has been poured, the healing process starts immediately. Correctly curing the concrete increases strength, longevity, moisture resistance as well as resistance for several decades.
FAQs on Curing Concrete
What is curing of concrete?
Curing of concrete is the process of maintaining adequate moisture, temperature, and time to allow the concrete to achieve the desired properties for its intended use. It involves keeping the concrete damp to ensure proper hydration, which is essential for strength and durability.
Why is curing important?
Curing is crucial because it ensures the concrete retains moisture for hydration, which is necessary for the chemical reactions that provide strength and durability. Proper curing prevents surface cracks, increases strength, and improves the overall longevity of the concrete.
How long should concrete be cured?
The standard curing period for concrete is 28 days. However, curing can be effective in 14-20 days with advanced treatments. According to IS 456 – 2000, concrete made with Ordinary Portland Cement (OPC) should be cured for at least 7 days, and for mixed cement with mineral admixtures, at least 10 days. In hot and arid conditions, these periods should be extended to 10 and 14 days, respectively.
What are the different methods of curing concrete?
- Ponding: Suitable for floor slabs; involves creating ponds of water on the surface.
- Moist Coverings: Uses materials like gunny bags or hessian to cover and keep concrete moist.
- Membrane Curing: Involves applying a curing compound to form an impermeable layer to prevent moisture loss.
- Synthetic Resin, Acrylic, Wax, and Chlorinated Rubber Curing Compounds: Different compounds create impermeable layers to retain moisture.
- Steam Curing: Common in precast plants; uses steam to keep concrete moist and control temperature.
- Infrared Radiation: Used in cold climates; heats the concrete to maintain moisture and accelerate curing.
How does temperature affect curing?
Temperature plays a vital role in curing. Concrete should be kept moist and at a temperature not lower than 5°C. High temperatures can cause rapid water evaporation, requiring extra water, while low temperatures can slow down the hydration process.
What is the minimum curing period for an RCC slab?
The minimum curing period for a reinforced cement concrete (RCC) slab depends on the concrete strength, grade, ambient temperature, and environmental conditions. Generally, it should be kept moist for at least 7 to 10 days.
How does water temperature affect the curing process?
Using water colder than 5°C for curing can cause thermal shock, leading to cracks and failure. The water used for curing should ideally be above 5°C to prevent such issues.
What are the stages of concrete drying?
- 24 to 48 hours: Initial setting period; forms can be removed, and foot traffic is possible.
- 7 days: Limited curing; suitable for light vehicle traffic.
- 28 days: Complete curing; concrete reaches full strength and durability.
How can you cure a new concrete slab effectively?
To cure a new concrete slab, keep it continuously moist for at least 7 days, ideally 28 days. This can be done by sprinkling water regularly, covering with wet materials, or using curing compounds to retain moisture.
What factors influence the curing period of concrete?
- Concrete strength and grade
- Ambient temperature and weather conditions
- Shape and size of the concrete member
- Type of cement and mix used
- Hydration rate and water availability
Are there any advanced techniques to accelerate curing?
Yes, accelerators and other admixtures can be added to the concrete mix to speed up the curing process. Steam curing and infrared radiation are also advanced methods used to accelerate curing, especially in precast plants and cold climates.
