How does the water-cement ratio influence concrete?

The water-cement ratio is a critical factor in determining the performance characteristics of concrete. Specifically, it significantly influences the strength, durability, and workability of the concrete mix.

When the water-cement ratio is low, there is less water relative to cement, which generally leads to higher strength and durability because the concrete becomes denser and less permeable. This density helps to prevent the ingress of harmful substances, which contributes to the longevity of the structure. On the other hand, a higher water-cement ratio can lead to lower strength and increased susceptibility to cracking, as the excess water can create voids when it evaporates, weakening the structure.

In terms of workability, a higher water-cement ratio can improve the flow of the concrete mix, making it easier to place and finish. However, there's a fine balance to strike, as too much water can detrimentally affect the overall integrity of the concrete once it has cured.

Thus, the correct choice accurately reflects the multifaceted impact that the water-cement ratio has on concrete properties, including strength, durability, and workability, which are all crucial for the performance and longevity of concrete structures.