In the context of construction in Australia, "admixtures" refers to a range of specialized additives or substances that are intentionally introduced into concrete, mortar, or other building materials to enhance their properties, performance, and workability. These admixtures can be in the form of liquids, powders, or other materials, and are designed to improve the mix's strength, durability, flowability, or other characteristics, allowing for more efficient and effective construction processes

In Australian construction, admixtures are commonly used to:

1. Improve concrete workability and flowability in hot or cold weather conditions

2. Enhance strength and durability of concrete structures

3. Reduce water content and minimize shrinkage

4. Increase resistance to chemical attacks, corrosion, or environmental degradation

5. Modify setting times to accommodate specific construction schedules or techniques

6. Improve surface finish and appearance

7. Reduce material waste and environmental impact

Admixtures can include a wide range of products, such as:

• Air-entraining agents to improve freeze-thaw resistance
• Retarders to slow down setting times
• Accelerators to speed up setting times
• Superplasticizers to enhance workability and flowability
• Corrosion inhibitors to protect reinforcing steel
• Fibres to improve tensile strength and crack resistance

The use of admixtures in Australian construction is subject to strict regulations and standards, including compliance with AS 1478 (Chemical admixtures for concrete, mortar and grout) and other relevant building codes.