What is a common reason for adding water reducers to concrete mixes?

Adding water reducers to concrete mixes primarily serves to improve workability while simultaneously reducing the water content in the mix. This process allows for easier handling and placement of the concrete, making it less viscous, which can be particularly beneficial in intricate or detailed work where spreadability is essential.

Water reducers achieve this by modifying the surface chemistry of the cement particles, which enhances the flowability of the concrete without the necessity of increasing water content. Maintaining lower water content is critical for achieving stronger concrete, as excess water can dilute the cement paste and lead to an increased porosity, ultimately reducing strength and durability.

The other choices, while they touch on aspects related to concrete, do not capture the primary purpose of water reducers. Increasing concrete volume isn't necessarily a goal when using a water reducer; rather, achieving the desired performance and strength with a lower water-to-cement ratio is the focus. Lowering the cost of concrete is not a direct effect of using water reducers; the cost can be influenced by many factors, including material prices and mix design. Lastly, curing is a necessary process that cannot be eliminated by using water reducers; it’s essential for the hydration of the cement and achieving the ultimate strength of the concrete.