Types of admixtures for concrete

Admixtures, along with Portland cement, water and aggregates, are used in the concrete mix to reduce the cost of construction, modify the properties of hardened concrete and ensure quality concrete. Sometimes if the outside temperature is too hot or too cold, the concrete needs to be modified so that it sets correctly.

There are different types of admixtures you can add to your concrete creations. These include air entrainers, water reducers, set retarders, set accelerators, superplasticizers and specialty admixtures such as corrosion inhibitors, shrinkage control, alkali-silica reactivity inhibitors and coloring.

Custom Concrete Creations wanted to show you the different types of admixtures for concrete and which is best for what!

Admixtures and their functions

Admixtures are classified into five functional groups: water-reducing admixtures, retarding admixtures, accelerating admixtures, superplasticizers and corrosion-inhibiting admixtures. Below is a bit about each, as well as a few other types of admixtures including pozzolanic, bonding and color:

  • Water-reducing admixtures are exactly what they sound like. They reduce the amount of water needed for the concrete mixture by around 5 to 10%. These can provide more consistent setting times. For example, when you’re dealing with concrete and cold weather, reducing the water amount can help the concrete set before freezing.

  • Retarding admixtures are great for working with concrete and hot weather. These slow the setting rate of the concrete. High temperatures mean an increased set rate, which can damper the quality of the concrete.

  • Accelerating admixtures can speed up the start-to-finish process. They make the concrete become harder faster and reduce the curing time. These are more commonly used in cold weather.

  • Superplasticizers are similar to water-reducing admixtures, but they reduce the water amount by 12 to 30%. This can help make the concrete more workable in a variety of different conditions. These are usually added in at the job site, as they only last 30 to 60 minutes.

  • Corrosion-inhibiting admixtures slow the corrosion of reinforced steel used in concrete structures. These are used in the concrete creations of highway bridges, parking garages and marine facilities.

  • Pozzolanic admixtures can help create dense concrete for dams and reservoirs. These can help prevent alkali-aggregate reactions, leaching and sulfate attack. These admixtures consist of clay, shale, volcanic tuffs or pumicite.

  • Bonding admixtures are used to create a bond between old and new concrete. There needs to be a strong bond between old and new concrete if it is to perform well for a long time. They are more commonly used in pavement overlays on roads.

  • Color admixtures are how stained and dyed concrete is created. These are the pigments that produce color in finished concrete. You can create an abundance of colors with different oxides and irons, as well as manganite and chromium hydroxide.

How admixtures help make concrete creations strong

Concrete is the most commonly used material in construction today. It is a high-quality and sustainable material that can meet a variety of your construction needs. Consider using some of these admixtures in your next project. Contact us today to discuss your options and get started!