If the water-cement ratio is too high, which is a likely consequence?

• A. Increased strength and reduced permeability.
• B. Decreased strength and decreased permeability.
• C. Increased permeability and decreased strength.
• D. Lower water demand.

Answer: (C)

High water-cement ratio means more water in the mix than the paste can effectively use. As concrete cures, excess water leaves, leaving behind voids that form interconnected capillary pores. Those pores create paths for fluids to flow, so permeability goes up. At the same time, the extra voids weaken the cement paste and the bond with aggregates, reducing compressive strength. So the likely outcome is higher permeability and lower strength. The other possibilities don’t fit because adding more water doesn’t strengthen the concrete, and it doesn’t reduce permeability or imply a lower water demand.