Which material is often added to improve the workability of concrete?

The addition of admixtures is a common practice in concrete technology to enhance workability, among other properties. Admixtures are substances, typically in liquid or powder form, that are added to the concrete mix to modify its performance characteristics. Specifically for improving workability, admixtures such as plasticizers or superplasticizers reduce the water-cement ratio while maintaining or improving the flowability of the concrete. This allows for easier placement and consolidation of the concrete without compromising its strength.

While water is also an important factor in improving workability, excessive water can weaken concrete strength and increase porosity. Therefore, using appropriate admixtures is a more effective approach to achieving better workability without diluting the concrete's strength. Admixtures serve the purpose of maintaining workability with a lower water content, enhancing the overall quality of the concrete mix.

In summary, admixtures are specifically designed to improve workability and can be tailored to meet various project needs, making them the most suitable choice in this context.