What effect do superplasticizers have on the water-to-concrete ratio?

Superplasticizers are chemical admixtures used in concrete that significantly improve its workability. Specifically, they allow for a reduction in the water-to-cement ratio while maintaining the same level of workability. This means that with the addition of superplasticizers, it is possible to use less water in the mix without adversely affecting the flow and ease of placement of the concrete.

By reducing the water content in the mix, superplasticizers help increase the concrete's strength and durability. A lower water-to-cement ratio is typically associated with higher compressive strength, reduced porosity, and improved resistance to various environmental factors that may lead to degradation.

The ability of superplasticizers to enable the effective reduction of water content while achieving desired workability is crucial for producing high-performance concrete. This capability is why the correct answer is that superplasticizers reduce the water-to-concrete ratio.