Last edited 02 Dec 2020

Admixture, additive or agent

The use of the different terms ‘admixture’, ‘additive’ and ‘agent’ in relation to concrete production can lead to confusion.

The practical difference between the terms 'admixture' and 'additive' is the time at which the ingredient is added during the mixing process. An admixture is a prepared substance which can be added to concrete for the purposes of achieving or modifying certain properties or characteristics. Admixtures are added to the concrete, in addition to cement, water and aggregate, immediately before or during the mixing process.

The same substance can be referred to as an additive when it is added to cement during the manufacturing process.

The term ‘agent’ can be used to describe a substance that may be used as an additive to cement or an admixture in concrete, such as a binding agent.

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Concrete is a mixture of three ingredients: aggregates, cement and water. Adding concrete admixtures will result in better quality, better performance and it makes the construction last longer.

Admixtures for concrete to be added in low doses (less than 5% of total volume). This should be added at the time of mixing the concrete. They accelerate the hydration of the concrete. The accelerators are of two types, setting accelerator and hardening accelerator. They facilitate the concrete layers by making it more manageable. The water-reducing plasticizers give it better resistance.

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