Concrete admixtures are substances added to concrete during mixing to enhance its properties. These additives can improve workability, increase strength, reduce water content, or accelerate curing time. Common types of admixtures include water-reducing agents, accelerators, and retarders, each serving a specific purpose in the concrete formulation. Using admixtures can lead to better performance and durability of concrete structures. For instance, superplasticizers help achieve a smoother finish, while air-entraining agents create tiny air bubbles that improve resistance to freeze-thaw cycles. Overall, admixtures play a crucial role in modern concrete technology.