What should the water-cement ratio be in concrete designs to meet durability requirements?

The ideal water-cement ratio in concrete designs to meet durability requirements is the lowest value necessary for achieving the desired workability and strength. This ratio is crucial because it directly affects the porosity and permeability of the concrete. A lower water-cement ratio typically enhances the density of the concrete, reducing the risk of water and aggressive chemicals penetrating the concrete matrix, which can lead to deterioration over time.

When the water-cement ratio is minimized, it helps ensure that the hydration process of the cement is efficient, thereby resulting in a more robust and durable concrete structure. Additionally, keeping the ratio low reduces the likelihood of cracking and structural failures caused by shrinkage during the curing process.

Selecting the lowest adequate value also promotes sustainable practices, as it optimizes the use of resources and minimizes the environmental impact associated with concrete production. In contrast, excessively high ratios or inappropriate comparisons with aggregates can compromise the structural integrity and longevity of the concrete.