As water cement ratio increases, ……… also increases.
Correct Answer: D. Workability
📚 Detailed Explanation: W/C Ratio and Workability
Workability is the ease of mixing, transporting, placing, compacting, and finishing fresh concrete. The water-cement ratio is the primary dial that adjusts workability because water acts as the lubricant in the fresh concrete system.
Why D (Workability) is correct: Increasing w/c adds more water per unit of cement. This extra water: reduces inter-particle friction; increases paste volume; makes the mix more fluid (higher slump). All of these raise workability. Option A (compressive strength) decreases with rising w/c — the opposite of what the question asks. Option B (tensile strength) also decreases. Option C (bleeding) does increase with w/c, but the question asks what “also increases” — the most standard and examined answer is workability since Abrams' Law specifically addresses this trade-off.
Effects of Increasing W/C Ratio
| Property | Change |
|---|---|
| Workability | Increases ↑ |
| Bleeding | Increases ↑ |
| Segregation tendency | Increases ↑ |
| Compressive strength | Decreases ↓ |
| Tensile strength | Decreases ↓ |
| Durability | Decreases ↓ |
Key Concepts for Students
- Workability increases with w/c — the fundamental trade-off between workability and strength in mix design.
- In mix design (IS 10262), target w/c is set for strength first; then workability is achieved using admixtures (not excess water).
- Each 25 mm increase in slump requires approximately 3 kg/m³ additional water, raising w/c and reducing strength.