Early road construction methods – identify the incorrect historical statement Considering classical methods (Tresaguet, Telford, Macadam), which of the following statements is incorrect with respect to camber and layering practices?
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ATresaguet did not provide the top camber for the drainage of surface water
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BTresaguet provided the top camber for the drainage of surface water
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CTelford provided two layers of stones in the central 5.4 m width and one layer was provided on the sides
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DMacadam provided a camber to the formation at the dug-up state, to drain percolated water
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EAll statements are correct
Answer
Correct Answer: Tresaguet did not provide the top camber for the drainage of surface water
Explanation
Introduction / Context:Understanding historic road-building methods helps explain today’s pavement fundamentals: drainage by camber, subgrade preparation, and layer gradation. Tresaguet (France), Telford (UK), and Macadam (UK) each refined technique and drainage philosophy.
Given Data / Assumptions:
- Statements concern the presence of camber and the arrangement of stone layers.
- We compare the practices attributed to Tresaguet, Telford, and Macadam.
Concept / Approach:Historical accounts describe Tresaguet’s provision of a cambered surface to shed water into side ditches, Telford’s thick stone foundation with stepped central thickness, and Macadam’s emphasis on well-graded broken stones and positive camber to drain water rapidly from the formation.
Step-by-Step Solution:
Assess statement about Tresaguet → he provided camber for drainage; therefore the claim that he did not provide camber is incorrect.Check Telford → central width built with two stone layers and side thinning is consistent with descriptions.Check Macadam → cambered formation and surface drainage philosophy are correctly stated.Verification / Alternative check:Historic references and standard highway engineering texts consistently attribute surface camber to the early European methods, highlighting its role in durability by minimizing water ingress.
Why Other Options Are Wrong:Option B, C, and D align with documented practices, so they are not incorrect. All statements are correct cannot be true because Option A is false.
Common Pitfalls:Confusing Telford’s level subgrade with absence of camber at surface; mixing subgrade treatment and surface camber concepts.
Final Answer:Tresaguet did not provide the top camber for the drainage of surface water