Higher workability of a concrete is required if the structure is
Correct Answer: C. thin and heavily reinforced
📚 Detailed Explanation: Workability Requirement Based on Section Type
Why C (thin and heavily reinforced) is correct: Two factors independently increase workability demand:
Thin sections: narrow formwork leaves limited space for vibration access; concrete must self-flow into position.
Heavily reinforced: dense rebar cage restricts flow; concrete must navigate around bars without segregation.
When both conditions apply (thin + heavily reinforced), the workability demand is at its highest. A thick section (options B, D) provides more room for vibration and flow, reducing workability requirements.
Thin sections: narrow formwork leaves limited space for vibration access; concrete must self-flow into position.
Heavily reinforced: dense rebar cage restricts flow; concrete must navigate around bars without segregation.
When both conditions apply (thin + heavily reinforced), the workability demand is at its highest. A thick section (options B, D) provides more room for vibration and flow, reducing workability requirements.
Workability Demand by Structural Type
| Section Type | Workability Required |
|---|---|
| Mass plain concrete | Low |
| Normal RCC (columns, beams) | Medium |
| Thick heavily reinforced | Medium–High |
| Thin and heavily reinforced | Highest |
- Thin + heavily reinforced = maximum workability demand in structural concrete practice.
- Examples: thin reinforced walls, densely-barred machine foundations, slender columns.