What are the risks associated with high water-cement ratios?

High water-cement ratios lead to increased porosity and reduced strength in concrete. When more water is added to the mix, it creates a higher volume of voids within the hardened concrete. These voids make the structure less dense, contributing to a reduction in strength because the solid components of the mix (the cement and aggregates) are not adequately bonded together. Increased porosity can also lead to other issues, such as increased permeability, which can allow water and harmful chemicals to penetrate the concrete, further compromising its integrity over time.

In contrast, the other options present scenarios that don’t accurately reflect the consequences of high water-cement ratios. Lower workability is typically associated with lower water-cement ratios, while faster curing times can vary based on many factors, not just the water-cement ratio. Improved durability and aesthetics usually relate to more optimal mix designs with appropriate water-cement ratios, leading to concrete that is both strong and well-finished. Decreased surface finish quality may happen when the mix is too dry, not when the water-cement ratio is high. Therefore, the clear and relevant consequences of high water-cement ratios point to increased porosity and reduced strength.