The most widely used construction material used is concrete. It is strong & durable. Any shapes can be molded using concrete. But concrete has its limitations & to overcome these limitations, Admixtures came into existence by scientists across the world. An admixture is a chemical compound which is mixed in concrete to enhance its properties & overcome its limitations.
Introduction to Admixtures in Concrete
Admixtures are used to increase concrete’s strength, durability & workability. Admixtures are added to concrete during the mixing process. They are used to modify properties of concrete like increasing or decreasing setting time, strength & durability, etc .
Admixtures & Their Usage in Concrete?
Admixtures are chemical compounds. It is added to concrete while mixing. Admixtures are used to improve workability, reduce water content needed, control setting time, increase strength & durability.
Types of Admixtures Used in Concrete
There are many types of admixtures which are used in concrete for changing its properties. Each of these admixtures have there own specific features. Some most commonly used admixture are as follows:-
Water Reducing Admixtures and Their Benefits
Water reducing admixture is used to reduce the amount of water needed for increasing workability. The benefit of adding water resistance admixtures is increased strength,durability & reduce permeability. By adding this admixture, it not reduces the water in the mix but also reduces the shrinkage which occurs during curing process which will help in preventing cracks.
Air-Entraining Admixtures and Their Benefits
Air-entraining admixtures are used to get bubbles into concrete mix. It can help in increase in workability of mix and increase its resistance to freeze and also improve its durability. It also reduces the amount of water that occurs during the curing process. It also helps in preventing surface defects.
Superplasticizers and Their Benefits
Superplasticizers are used to improve the workability without increasing water content of the concrete mix. It allows cement to easily molded & shaped by dispersing the cement more efficiently.
The benefits of superplasticizers is to improve concrete workability, strength & reduce permeability. Superplasticizers also reduces the amount of water needed which leads to reducing the amount of shrinkage that occurs during the curing process, which can help to prevent cracking.
Some Other Types of Admixtures Used in Concrete
Retarding admixtures which is used to delay setting time of concrete. It is useful during hot weather or when concrete is needed to transport long distance.
Accelerating admixtures, It is used to speeding up the setting time which could be useful in cold weather or where its needed to set quickly.
Corrosion inhibitors It is used to protect concrete from corrosion like reinforcing steel in concrete, which also can help in increasing durability & prevent damages.
The Importance of Proper Admixture Dosage
It is crucial to use admixtures correctly to achieve desirable results. If overdosing occurs then it could lead to excess bleeding, reduce strength & durability, change in setting time, etc.
The dosage of admixtures will depend on many factors, such as which type of admixtures you are using or the type of cement or the environmental conditions. It is important to follow guidelines given by the manufacturer & test the mix & check whether desirable properties has been achieved.
Common Misconceptions about Admixtures in Concrete
There are some misconceptions about admixtures. The most common misconception is that admixtures are not necessary to use, you can add some cement or water. But it is not true they are specially designed for modifying properties which is not possible by adding cement or water. Another misconception is that people think that by using admixture will reduce cement usage is also false. Using admixture will enhance quality and help them in long run.
Conclusion:
Admixtures are very important nowadays. They provide a cost effective solution for improving properties of concrete.
Using the right admixture correctly engineers can design a structure that is strong, durable & resistance to weather conditions.
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