Water in concrete — effects of quality and quantity on strength Which of the following statements regarding the influence of mixing water on concrete strength and properties are correct?

Introduction / Context:
Mixing water governs workability and water–cement ratio, which is the primary driver of concrete strength and permeability. Impurities in water can interfere with hydration and reinforcement protection, while excess water increases porosity after drying.

Given Data / Assumptions:

• Normal-weight concrete using potable-quality water where possible.
• Qualitative percentages reflect typical trends, not strict universal constants.
• Aggregate grading and compaction influence water demand.

Concept / Approach:

Clean water avoids deleterious ions and organics that can retard set or corrode steel. Finer aggregates and hand compaction require more water for the same slump than coarser aggregates and vibration. Extra water raises w/c, increasing capillary porosity and reducing strength; the approximate loss figures (15% for 10% extra water and about 50% for 30% extra) indicate the steep penalty of high w/c.

Step-by-Step Solution:

Verification / Alternative check:

Empirical strength–w/c relationships (e.g., Abram’s law) corroborate large strength reductions with increasing water at constant cement content.

Why Other Options Are Wrong:

• Any single statement alone would be incomplete; the collective “All of the above” captures the full picture.

Common Pitfalls:

• Chasing workability with extra water instead of using admixtures or improving grading.

Final Answer:

All of the above.