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Concrete admixtures are typically supplied as water-based solutions and are added to concrete mixes in controlled dosages. They can be added at up to 5% by weight of cement, although most admixtures are used at levels below 2%, with many applications requiring less than 0.8%. Detailed technical information on specific admixture types is available through industry professional bodies.

Admixtures are designed to modify concrete properties without adversely affecting consistency. They allow:

• Reduction of water content without changing workability, or

• Increased slump and flow without increasing water content, or

• A combination of both effects

This performance is achieved by improving the dispersion of cement particles, resulting in enhanced workability and improved mix efficiency.

At typical dosages ranging from 0.2% to 5.0% by weight of cement, depending on the admixture type and application, plasticisers can increase workability at a constant water–cement ratio by approximately 50–100 mm slump without any loss of strength or durability.

Alternatively, admixtures can be used to reduce water content by 5–12%, which lowers the water–cement ratio and leads to significant improvements in concrete strength and durability while maintaining the same cement content.

The use of admixtures by ready-mix concrete producers helps optimize mix performance, improve quality, and enhance cost effectiveness.