What Are Concrete Admixtures and Their Types?

Concrete is one of the most important building materials used in construction for ages. The better the quality of the concrete, the more strong your building will become. Concrete consists of various ingredients which enhance its quality. One such key ingredient is concrete admixture. It is added during the mixing process to strengthen and enrich the workability of concrete. Concrete admixtures are broadly classified into two types – Mineral Admixtures and Chemical Admixtures.

Chemical admixtures

Chemical admixtures are produced by several well-known manufacturers like Mcon Rasayan which ensures to improve the strength, plasticity, and durability of the concrete. They minimize the construction costs by altering the hardened concrete with enriching properties to help in the mixing, curing, and transporting process.

Chemical admixtures are classified according to 5 different functions. They are:

  • Air Entraining Admixtures

Air entrainment is the process of creating air bubbles in the concrete. These air entraining admixtures are added to the concrete during the mixing process as they increase the durability and workability of the hardened concrete.

  • Water Reducing Admixtures

Water is added to the concrete mixtures but 5 to 10 percent of water content can be reduced with the help of water-reducing admixtures. This type of admixture helps in minimizing the quantity of water used in the concrete mixture and ensures that it remains stable in various temperatures.

  • Retarding Admixtures

Temperature can affect the rate at which concrete hardens or settles. High temperatures can make concrete hard sooner and it will make the finishing or placing difficult. Retarding admixtures slow the hardening process and even work as water-reducing agents.

  • Accelerating Admixtures

As the name suggests, accelerating admixtures accelerate the curing and finishing process. They help enhance the concrete properties in cold weather.

  • Superplasticizers

These types of admixtures are high-range water reducers and mixed with cement to form high-slump concrete. Superplasticizers make the concrete flowy and workable. But the workability of the concrete with added superplasticizers doesn’t last long and hence is added at the time of construction.

  • Corrosion-inhibiting admixtures

These are used to delay corrosion. They are used as a defensive technique while building structures like garages, bridges and highways which use reinforced steel and concrete in the construction.

Mineral Admixtures:

Mineral admixtures are not manufactured like chemical admixtures. They are the materials like fly ash, silica fume, metakaolin, ground granulated blast furnace slag, and rice husk ash. Usage of mineral admixtures increases the setting time and strengthens the concrete.

Fly ash is obtained from pulverized coal used in thermal power plants. They are highly reactive and increase their high durability. Silica fume makes the concrete cohesive and absorbs more water in the concrete mixture.

Mineral admixtures work similar to chemical admixtures and they improve the resistance power of the concrete and improve workability.

Conclusion

The use of admixtures has risen in popularity as they have economical benefits along with improvement in the building structures. Hence, admixtures are some of the main ingredients which make the concrete stable, workable, and have the potential to build stronger sturdy structures. Hence, the reason why admixtures are used in the concrete mix.

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