Concrete curing is most important, without curing concrete is useless also proper curing time-duration, method play a great role in the gaining strength of concrete so must read these civil experience articles on Concrete Curing in which we cover all related key fundament of civil engineering for concrete curing. Which you don't want to miss if you gain some valuable information then don't forget to share with friends.
What is Concrete Curing?
Curing of concrete is the process of preventing the loss of moisture from concrete to maintaining a satisfactory temperature regime. Let's see the definition of curing.
Concrete Curing Definition
Concrete curing is defined as maintaining suitable moisture, time duration, and temperature for concrete material so that concrete material able to gain the best desired properties which we want to achieve by making a concrete mix design. (You can also download Concrete mix design excel spreadsheet to create mix design of concrete)
This would mean maintaining a proper level of humidity greater than 80% for chemical-hydration reaction in concrete, concrete curing temperature more than 50 degrees Fahrenheit for a time period from 3 to 14 days depending on the specific application. When these recommendations are properly specified and performed in the field, the final properties of the concrete mixture will be achieved.
Important of Concrete Curing
Why Curing of Concrete is Necessary is a common question and here we provide an answer for the Important of Concrete Curing below
The curing of concrete must start as soon as possible after placement of concrete in formwork shuttering and must continue for a reasonable period of time as per the relevant standards, for the concrete to achieve its best-desired strength and durability of concrete material.
Uniform concrete temperature should also be maintained throughout the whole concrete layer to avoid thermal shrinkage cracks.
Also, protective measures to control moisture loss from the concrete surface are essential to prevent plastic shrinkage cracks.
Why curing of concrete is important is wider topics but some of important describe below as an advantage of curing concrete
- To achieve the desired strength of concrete by improving hydration
- To reduce cracks by enhancing durability
- To improve the serviceability of concrete
Why We Cure Concrete?
There are several important reasons to cure concrete that are explained below in detailed
Improved Durability of Concrete
The durability of concrete is affected by a lot of factors which are its permeability, absorptivity, and porosity. Concrete that is properly cured minimizes thermal, drying, and plastic shrinkage cracks, making concrete more watertight, thus preventing moisture and water-borne chemicals from entering into the concrete and thereby increasing its durability.
Concrete Strength Gain
Concrete strength (strength of concrete) increases with age as moisture in concrete and a favorable temperature are present for hydration of cement.
An experimental investigation was conducted by “Cement, Concrete & Aggregates Australia” (CCAA) and the same was published in their datasheet on “Curing of Concrete,” which has been included in this article for reference. Figure-1 illustrates a comparison of the strength of concrete at 180 days of moist curing with various periods of moist curing (0, 3, 7, 14 & 28 days) and then allowing it to dry out. From the graph below, it can be observed that concrete allowed to dry out immediately, achieves only 40% of the strength of the same concrete water cured for the full period of 180 days.
Concrete that is allowed to dry out quickly undergoes considerable early age shrinkage. Inadequate curing contributes to weak and dusty surfaces having poor abrasion resistance.
Material properties are directly related to their microstructure. Curing assists the cement hydration reaction to progress steadily and develops calcium silicate hydrate gel, which binds the aggregates leading to a rock-solid mass, making the concrete denser, decreasing the porosity, and enhancing the physical and mechanical properties of concrete.
Types of Concrete Curing Methods
Types of curing concrete meaning as the process of maintaining required moisture, temperature, and time for freshly placed plane green concrete to gain proper hardening of concrete
Curing is the most important key point in the early stage. Curing plays a very important role in strength development and durability for final concrete structure building
Normally curing process of concrete take 14 days is very important better to continue curing for 7 to 14 days more depending on the specific application
If curing is not properly done then may create serious issues like the strength of concrete reduces, a concrete crack develops due to shrinkage, and also durability of concrete structure building reduces
Methods of Curing of Concrete
Here we make a list of concrete curing methods with an overview. If you want to learn any concrete curing methods in deep then please put the name of Methods of Curing of Concrete in the comment so we provide our best for you.
The following curing of concrete methods are employed by the concrete contractors for their site of construction
- Spraying of water
- Covering the surface with wet guuuy bags, straw, etc
- Stream curing
- Application of curing compounds
#1 Spraying of water
Spraying of water method generally used for walls, columns, Surface plaster
#2 Wet covering the surface
A vertical component like columns may be cured covering the surface with wet gunny bags or straw
The horizontal surface like slab and floor are cured by stagnating the water to a height of 25 to 50 mm by providing temporary small hands with mortar
#4 Steam curing
In the manufacture of prefabricated concrete units, steam is passed over the units kept in closed chambers, it accelerates the curing process, resulting in the reduction of the curing period
#5 Application of curing compounds
Compounds like calcium chloride may be applied on the curing surface. The compound shows affinity to the moisture and retains it on the surface. It keeps the concrete surface wet for a long time
This is only a short article on the curing of concrete because the civil engineering field has a wider range to done work by different kind of ideas and evaluation
Duration of Curing
The duration of curing of concrete depends on the grade & type of cement, mix proportion, desired concrete strength, shape, and size of the concrete member, and environmental & exposure conditions. The duration may vary from a few days to a month.
Minimum Curing Period as per IS Code
IS-456:2000 provisions for the duration of Curing (Indian Standard-Plain & Reinforced concrete-Code of Practice, 4th revision, page 27)
Exposed surfaces of concrete shall be kept continuously damp or in a wet condition by ponding or by covering with sacks, canvas, hessian, or other similar material and kept continuously wet for at least 7 days from the date of placing, in case of Ordinary Portland Cement (OPC) and at least 10 days when mineral admixtures or blended cement are used.
In the case of concrete where mineral admixtures or blended cement are used, it is recommended that the above minimum periods may be extended to 14 days, for assisting the secondary reaction.
Minimum Curing Period as per ACI
ACI (American Concrete Institute) Committee 301 recommends a minimum curing period corresponding to concrete attaining 70% of the specified compressive strength
The often specified seven-day curing commonly corresponds to approximately 70% of the specified compressive strengths. The 70 percent strength level can be reached sooner when concrete cures at higher temperatures or when certain cement/admixture combinations are used.
Similarly, a longer time may be needed for different building material combinations and/or lower curing temperatures. For this reason, ACI Committee 308 recommends the following minimum curing periods
- ASTM C 150 Type I cement seven days
- ASTM C 150 Type II cement ten days
- ASTM C 150 Type III cement three days
- ASTM C 150 Type IV or V cement 14 days
- ASTM C 595, C 845, C 1157 cements variable
FAQ 1: What is Concrete Curing?
Concrete curing is defined as maintaining suitable moisture, time duration, and temperature for concrete material so that concrete material able to gain the best desired properties which we want to achieve by making a concrete mix design.
FAQ 2: Important of Concrete Curing
1. To achieve the desired strength of concrete by improving hydration, 2. To reduce cracks by enhancing durability, 3. To improve the serviceability of concrete… this is short answer read full answer in civil experience blog
FAQ 3: Why We Cure Concrete?
1. Improved Durability of Concrete, 2. Concrete Strength Gain, 3. Enhanced serviceability, 4. Improved microstructure…
FAQ 4: Types of Concrete Curing Methods
1. Spraying of water2. Covering the surface with wet guuuy bags, straw, etc3. Ponding4. Stream curing 5. Application of curing compounds
FAQ 5: Duration of Curing
#1 Minimum Curing Period as per IS CodeIS-456:2000 provisions for duration of Curing (Indian Standard-Plain and Reinforced concrete-Code of Practice, 4th revision, page 27)Exposed surfaces of concrete shall be kept continuously damp or in a wet condition by ponding or by covering with sacks, canvas, hessian or other similar material and kept continuously wet for atleast 7 days from the date of placing, in case of Ordinary Portland Cement (OPC) and atleast 10 days when mineral admixtures or blended cements are used. In case of concrete where mineral admixtures or blended cements are used, it is recommended that the above minimum periods may be extended to 14 days, for assisting the secondary reaction.#2 Minimum Curing Period as per ACIACI (American Concrete Institute) Committee 301 recommends a minimum curing period corresponding to concrete attaining 70% of the specified compressive strengthThe often specified seven-day curing commonly corresponds to approximately 70% of the specified compressive strengths. The 70 percent strength level can be reached sooner when concrete cures at higher temperatures or when certain cement/admixture combinations are used.Similarly, longer time may be needed for different building material combinations and/or lower curing temperatures. For this reason, ACI Committee 308 recommends the following minimum curing periodsASTM C 150 Type I cement seven daysASTM C 150 Type II cement ten daysASTM C 150 Type III cement three days ASTM C 150 Type IV or V cement 14 daysASTM C 595, C 845, C 1157 cements variable