Concrete Mix Design

Summary

Concrete Mix Design - is the process of deciding the constituents of a concrete mix and their quantities in order to obtain the best concrete properties to comply with design requirements.

Technical Information

The mix design is very important for controlling the properties and performance of a concrete element throughout its lifecycle.

The main variables to consider in the mix design include:

The type of cement used.
The type of aggregate used.
The water/cement ratio.
The cement/aggregate ratio.
Whether to include any admixtures.

The properties which can be altered by the mix design include:

Workability.
Strength. Permeability.
Air content.
Durability.
Hydration.

The mix design also needs to take site conditions into account such as temperature and humidity.

Another important aspect of mix design is minimising the cost of the concrete. One common way to reduce the cost of concrete is to reduce the Portland cement content as this is the most expensive constituent of concrete. However, reducing the cement content too much can have negative effects on the properties of the concrete.