17+ TYPES OF ADMIXTURE USED IN CONCRETE FOR EXAM 2024

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Why admixtures is used in concrete?

       “Admixtures is an important factor. Admixtures for cement and concrete are prepared using different chemicals, which are added in specific proportions to the cement mixture. Using admixtures reduces the consumption of water and does not compromise the strength of the concrete, thus reducing construction time. There are many types of admixtures, and they vary based on location. We will delve into further details.

From this critical foundation, you’ll understand the types of admixtures, how they work, their advantages, and their uses. Exam Point of U will present all this information in a simple and comprehensible manner.”

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What do you mean by admixture? Definition of Admixture

A material other than water, aggregate, and hydraulic cement, used as an ingredient of concrete or mortar and added to the batch immediately before or during its mixing, to modify one or more of the properties of concrete in the plastic or hardened state, is termed as Admixture.

Which admixture is used in cement? Classification / Type of Admixture ( Total 17 )

Note –  Mostly the First 5 Admixture Asked in your Exam and in this post we also explain 1st 5 Admixture in Detail 

1. Plasticizer Admixture
2. Super Plasticizer Admixture
3. Retarding Admixtures
4. Accelerating Admixtures 
5. Air Entraining Concrete Admixture
6. Pozzolanic Admixtures
7. Damp-proofing Admixtures
8. Gas forming Admixtures
9. Air detraining Admixtures
10. Alkali Aggregate Expansion Preventing Admixtures
11. Anti-washout Admixtures
12. Workability Administer
13. Grouting Admixtures
14. Corrosion Preventing Admixtures
15. Bonding Admixtures
16. Fungicidal, Germicidal, Insecticidal Admixtures
17. Coloring Admixtures

1. Plasticizer Admixture

“Plasticizer admixture makes water go away by breaking it into small particles. This makes the water amount needed become less by fifteen percent. Inside cement grains, there is a reaction because of a chemical. This makes the attraction force between cement grains weaker and they become separate. Then, the rippling force changes to become smooth. Because of this, all the water inside it goes away and the water amount needed becomes less by up to fifteen percent.”

2. Superplasticizer Admixture

Superplasticizers were developed in Japan and Germany between 1960 and 1970.

These are an advanced form of plasticizers, and this admixture helps reduce the amount of water needed in concrete by up to 30%.

Think of this admixture as a special ingredient that acts like a super version of a plasticizer. It makes the concrete more flexible without needing as much water.

3. Accelerator Admixture 

The Accelerator Admixture is like a special ingredient in concrete. It makes a chemical reaction happen faster when the concrete is getting hard because of heat and water.

commonly used admixtures are calcium formate, silica fume .calcium chloride (commonly used)

We use it for a few important reasons:

– It helps concrete become strong quickly.

– It makes the concrete turn hard faster, so builders don’t have to wait as long.

– This is handy for when we need to finish a job in a hurry.

– It’s especially useful in places where it’s very cold, like Jammu and Kashmir, because it helps the concrete not freeze too slowly.

So, in simple words, the Accelerator Admixture makes concrete strong fast, and it’s great for getting work done quickly, especially in chilly areas like Jammu and Kashmir.

4. Retarder Admixtures

In this admixture, the chemical reaction of heat hydration is very slow.

Ingredients  – Gypsum, starch, sugar, salts of acids

This method is used in hot weather areas and the RMC plant This added mixture makes the initial setting time slow for a concrete mixture.

5. Air Entraining Concrete Admixture

The Air Entraining Concrete Admixture is like a special ingredient you can put in the concrete mix. This ingredient was invented a long time ago in 1930.

Ingredients – Vinsol resin, Darex, Teepol

Two types of air-entering administrator

1. Air enters the concrete
2. There which trapped In the concrete

It helps air get inside the concrete while you’re mixing it. Think of it like blowing up a balloon inside the concrete mix. These tiny air bubbles make the concrete more robust and better at handling cold weather because it gives it some flexibility.

It also keeps some air trapped inside the concrete. This trapped air makes the concrete even more durable, especially when it’s freezing outside. It’s like having little pockets of air that protect the concrete from breaking.

So, in simple words, the Air Entraining Concrete Admixture helps make concrete stronger and better at dealing with tough weather by adding tiny air bubbles inside it. It’s like giving your concrete some superpowers!

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Difference Between Accelerator Admixture & Retarder Admixture

Property	Accelerator Admixture	Retarder Admixture
Function	Speeds up the setting and curing time of concrete	Delays the setting and curing time of concrete
Purpose	Used in cold weather or when a faster setting time is desired	Used in hot weather or to provide more working time for placing and finishing concrete
Effect on Strength	Generally does not significantly affect long-term strength	Generally does not significantly affect long-term strength
Temperature Sensitivity	Effective in cold temperatures	Effective in hot temperatures
Common Components	Calcium chloride is a common accelerator	Lignosulfonates are common retarders
Application Rate	Applied in small quantities	Applied in small quantities
Setting Time Adjustment	Reduces setting time	Increases setting time
Workability	May reduce workability	May improve workability, especially in hot weather
Compatibility	Compatible with most other admixtures	Compatible with most other admixtures
Considerations	Care should be taken to avoid excessive dosage, as it may lead to rapid setting	Dosage should be carefully controlled to prevent excessive delays and potential strength loss

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Types Of Admixtures Used In Construction | Type of Concrete Admixtures and their uses

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Extra information about Admixture

Admixture in Concrete: Definition, Types, and Applications

Admixture plays a crucial role in modern construction by enhancing the properties of concrete. From improving strength and durability to modifying setting times, admixtures offer solutions to various challenges faced in construction projects. In this article, we’ll explore the definition, types, applications, and benefits of using admixtures in concrete.

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What is an Admixture in Concrete?

An admixture is a material other than cement, water, and aggregates added to concrete before or during the mixing process. It is used to modify specific properties of concrete to meet construction requirements. Admixtures can improve the workability, strength, and durability of concrete, making them an essential component in both large-scale and small-scale projects.

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Purpose of Using Admixture in Concrete

The primary reasons for using an admixture include:

• Enhancing Workability: Makes the concrete easier to place and finish.
• Adjusting Setting Time: Allows flexibility by accelerating or retarding the setting time.
• Improving Durability: Increases resistance to environmental factors like freeze-thaw cycles.
• Reducing Water Content: Lowers the water-cement ratio while maintaining workability.
• Increasing Strength: Helps achieve high-strength concrete suitable for heavy-duty applications.

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Types of Admixture in Concrete

Admixtures are broadly classified into the following categories:

1. Water-Reducing Admixtures

• Reduce the water content without affecting the workability.
• Improve strength by maintaining a low water-cement ratio.
• Commonly used in large construction projects.

2. Superplasticizers

• Provide significant water reduction (up to 30%).
• Increase the flowability of concrete.
• Essential for self-compacting and high-performance concrete.

3. Air-Entraining Admixtures

• Introduce microscopic air bubbles into the concrete mix.
• Enhance durability by preventing freeze-thaw damage.
• Often used in cold climates.

4. Accelerating Admixtures

• Speed up the hydration process.
• Reduce setting time in cold weather.
• Useful in projects requiring quick turnarounds.

5. Retarding Admixtures

• Delay the setting time of concrete.
• Provide extended workability in hot weather.
• Ideal for large pours and complex structures.

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Applications of Admixture in Concrete

The use of admixtures is prevalent in various types of construction, including:

• Normal Concrete: To improve workability and durability.
• High-Strength Concrete: For skyscrapers, bridges, and heavy infrastructure.
• Self-Compacting Concrete (SCC): For structures with dense reinforcement.
• Mass Concrete: Used in dams and large foundations to control heat generation.

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Advantages of Using Admixture in Concrete

• Reduces construction time and labor costs.
• Enhances durability and lifespan of structures.
• Allows concrete to achieve desired strength with lower cement content.
• Provides flexibility in extreme weather conditions.
• Improves the finish and appearance of concrete surfaces.

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Factors to Consider When Using an Admixture

While using an admixture, consider the following factors:

• Compatibility: Ensure the admixture is compatible with other materials in the concrete mix.
• Dosage: Follow the manufacturer’s guidelines for correct dosage.
• Mixing Process: Proper mixing is essential to achieve the desired effects.
• Environmental Conditions: Adjust the admixture type based on temperature and humidity.

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Conclusion – 

In this post, we’ve explored 17 different types of admixtures, each with its unique purpose and benefits.

From plasticizers that reduce water requirements to super-plasticizers that increase flexibility, accelerator admixtures for faster strength development, retarder admixtures for extended setting times, and air-entraining admixtures that enhance durability, these additives offer solutions to various concrete challenges.

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FAQ – Admixture