Admixtures are artificial or natural concrete additives that may be added before or during concrete mixing to alter concrete’s plastic properties or harden the concrete as required by the structure.
Concrete Admixtures may be used for the below purposes:
Functions and Uses of Additives
Concrete admixture suppliers offers you multifunctional and can be used for the following purposes:
(a) Calcium chloride can be used as an accelerator to speed up strength development in early life.
(b) To delay the concrete’s initial setting time while pumping concrete for a long distance.
(c)To increase the working ability without changing water content – Pozzolanic, such as fly ash, is used.
(d) To increase the strength
(e) Vinyl resin is used to increase the resistance against freezing and thawing. This is done by using an air entrainment mixture.
(f) To reduce heat-evolution
(g) To increase water tightness
(h) To reduce the Capillary Flow of Water
Types and Types of Concrete Mixtures
There are two types of admixtures.
- Mineral admixtures
- Chemical admixtures
(1) Mineral Additives
Below are the types of Mineral Admixture:
- Fly ash
- Silica fume
- Ground granulated blast slag
- Rice husk, ash
(2) Chemical Admixtures
There are many types of chemical admixtures.
- The substance that accelerates the hydration and setting of hydraulic cement or which increases the rate of strength development.
- Retarding– A substance that retards the setting times of cement paste.
- Hydro – Reducing admixture Concrete – A substance that increases the workability or maintains the concrete’s ability to be mixed without increasing its water-cement rate.
- The substance that causes air/Cd into tiny bubbles during mortar or concrete mixing to increase its strength and workability.
- Super plasticizing admixture – This substance has very high workability but a substantial decrease in water (at most) for given workability. The superplasticizer also refers to high-range water-reducing admixture.
How Concrete Is Made?
Concrete is a mixture of cement and water. Concrete can be cast in molds and forms. Once hardened, it will form the concrete components. Are you interested in the Microstructure of Concrete? This New Research focuses on the Microstructure of Concrete.
Chemical Reaction and Hydrogen
The chemical reaction of Portland cement with whiter is responsible for the setting and hardening of concrete. It can be easily demonstrated by adding small amounts of cement in water containing an indicator. Rapidly developing a blue color from the dissolving mortar reflects the release of hydroxyl ions. This chemical reaction between cement & water is called “hydration”.
The dissolving of cement increases levels of calcium or silicon in the solution. Once these levels reach critical levels, new products are formed via a precipitation reaction. This is a sketch showing cement grains suspended in water.
The solid hydration products form layers around the cement particles. They gradually fill in the space between them. The strength of the mixture of cement water and cement depends on how effectively they are filled in.
Concrete is hardened in just a few minutes. However, hydration takes place for weeks and even years. Here’s a picture of cement particles after exposure to water. The cement is fine dust and does not bond to each other once it has been mixed with some water.
