What can be added to concrete as an admixture?

Concrete admixtures are materials added to concrete before or during mixing to enhance its performance and properties. Each of the options presented serves a specific function to improve the concrete's workability, setting time, or curing characteristics.

An accelerator, for instance, is used to speed up the setting time of concrete, which is beneficial in cold weather conditions or when quick turnaround times are needed in construction projects. This can help prevent delays and allow for earlier finishing times.

A superplasticizer improves the workability of the concrete mix, enabling it to flow better without adding more water. This can result in a more robust final product, as maintaining the correct water-to-cement ratio is crucial for strength and durability.

A retarder, on the other hand, is employed to delay the setting time of concrete. This is particularly useful in hot weather to prevent the mix from setting too quickly, which can complicate placement and finishing.

Since all three admixtures—accelerator, superplasticizer, and retarder—are commonly used in concrete production to achieve different desired outcomes, the correct response encompasses all of these options, confirming that they can be added to concrete as admixtures.