The workability of concrete is influenced most by its
Correct Answer: A. Water-cement ratio
📚 Detailed Explanation: Water-Cement Ratio — Most Influential Factor
Why A (Water-cement ratio) is correct: The w/c ratio determines:
1. Workability: Higher w/c = more free water = less friction between particles = more fluid = more workable.
2. Strength: Higher w/c = more evaporable pores after hardening = lower strength (Abrams' Law).
This dual control makes w/c the most critical single parameter in concrete design. Option D (water content alone) also affects workability, but the ratio to cement is the controlling factor because it governs both fluidity and strength. Same water content but higher cement = lower w/c = less workable but stronger.
1. Workability: Higher w/c = more free water = less friction between particles = more fluid = more workable.
2. Strength: Higher w/c = more evaporable pores after hardening = lower strength (Abrams' Law).
This dual control makes w/c the most critical single parameter in concrete design. Option D (water content alone) also affects workability, but the ratio to cement is the controlling factor because it governs both fluidity and strength. Same water content but higher cement = lower w/c = less workable but stronger.
Influence of Each Factor on Workability
| Factor | Influence Level |
|---|---|
| Water-cement ratio | Highest — controls both workability and strength |
| Water content | High, but secondary to w/c ratio |
| Aggregate-cement ratio | Moderate |
| Grading of aggregate | Moderate |
| Aggregate shape | Moderate |
- Water-cement ratio = most influential factor in determining workability of concrete.
- Also controls strength, durability, and permeability — making it the primary mix design parameter.