Difficulty: Medium
Correct Answer: 1250 tonnes
Explanation:
Introduction / Context:
Selection of rigid versus flexible pavement is influenced by traffic loading, subgrade support, climate, and life-cycle cost. Higher daily loads favor rigid pavements due to better load distribution and reduced rutting.
Given Data / Assumptions:
Concept / Approach:
Empirical thresholds guide preliminary decisions. Above a certain daily tonnage, rigid pavements often provide superior performance and economics through longer life and lower maintenance under heavy loads.
Step-by-Step Solution:
Verification / Alternative check:
Detailed design with cumulative ESALs and fatigue models can refine the choice, but preliminary screening often uses such tonnage benchmarks.
Why Other Options Are Wrong:
500–1000 tonnes may still be economical with strong flexible structures; 1300 is plausible but 1250 matches a typical rule-of-thumb breakpoint.
Common Pitfalls:
Ignoring axle-load spectra and growth rate; not considering climate-induced cracking or base erosion.
Final Answer:
1250 tonnes
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