What is the primary purpose of admixtures in concrete?

The primary purpose of admixtures in concrete is to modify properties such as workability and durability. Admixtures are chemical or mineral components added to the concrete mix to achieve specific performance-related characteristics that may not be naturally present. For instance, they can enhance the workability of fresh concrete, making it easier to mix, transport, and place. Additionally, certain admixtures can improve the durability of hardened concrete by increasing resistance to water penetration, shrinkage, or chemical attacks, thereby prolonging the lifespan of concrete structures.

While changing the color of concrete is possible with specific pigments and admixtures, this is a more specialized application rather than a primary purpose. Similarly, reducing the weight and speeding up the mixing process are not typical objectives of admixtures, as these are more focused on modifying concrete's physical characteristics rather than addressing specific performance enhancements. Thus, the modification of workability and durability is truly foundational in the use of admixtures in concrete technology.