Question

The sub-base is __________

(a) below the base course

(b) above the base course

(c) below the sub-grade

(d) above the wearing course

The question was asked in my homework.

Question is from Design of Flexible Pavements in chapter Design of Flexible & Rigid Pavement of Geotechnical Engineering II

Answer 1

Correct answer is (a) below the base course

To explain I would say: The sub-base is below the base course and above the sub-grade. Sub-base is often the main load-bearing layer of the pavement. The sub-base spreads the load evenly over the subgrade. The materials used may be either unbound granular, or cement-bound.