17+ TYPES OF ADMIXTURE USED IN CONCRETE FOR EXAM 2024

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

Admixtures in Concrete

Definition:

Admixtures in concrete are specialized materials added in small quantities to the mix to create a tailored composition, enhancing workability, durability, or strength.

Purpose:

Improve Performance: Admixtures play a pivotal role in improving concrete performance by addressing specific challenges or requirements.

Enhance Workability: They achieve superior workability without compromising strength through the careful application of admixture technologies.

Modify Setting Time: The judicious use of admixtures can either accelerate or retard the setting time, providing flexibility based on project needs.

Common Types:

1. Water Reducers:
   • Reduce water content without compromising workability, thanks to the incorporation of water-reducing admixtures.
   • Improve strength by lowering the water-cement ratio through the use of specific admixture formulations.
2. Superplasticizers:
   • Significant water reduction is achieved through the application of superplasticizing admixtures while preserving workability.
   • This results in the production of highly flowable and high-strength concrete, showcasing the efficiency of superplasticizing admixture technologies.
3. Air-Entraining Agents:
   • Microscopic air bubbles are introduced through the application of air-entraining admixture agents.
   • These air bubbles enhance durability, especially in challenging freeze-thaw conditions, highlighting the protective effects of air-entraining admixture.
4. Accelerators:
   • Admixtures classified as accelerators speed up the setting time, proving invaluable in cold weather or scenarios where a rapid set is imperative.
   • The controlled addition of accelerators as admixture components ensures timely and efficient project execution.
5. Retarders:
   • Retarder admixtures slow down the setting time, offering benefits in hot weather or large projects requiring extended workability.
   • The deliberate use of retarders as admixture components provides a strategic approach to managing setting times.

Applications:

• Normal Concrete: Admixtures find extensive applications in normal concrete, enhancing various properties to meet specific project demands.
• High-Strength Concrete: Superplasticizers, as high-performance admixtures, play a crucial role in achieving superior strength in high-strength concrete mixes.
• Self-Compacting Concrete: The strategic use of admixture technologies ensures proper flow without segregation in self-compacting concrete applications.

Proportioning and Mixing:

Adhering to the manufacturer’s guidelines for proper proportioning is vital when incorporating admixtures.

Careful mixing procedures, considering the unique characteristics of each admixture, contribute to achieving the desired results.

The compatibility of admixtures with other components of the mix is a critical aspect to ensure optimal concrete performance.

Conclusion:

Understanding the diverse applications and functions of admixture in concrete is essential for optimizing properties such as workability, strength, and durability. The meticulous selection and proportioning of admixtures contribute significantly to enhancing concrete quality in various construction projects.

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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.

Important Links

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FAQ – Admixture