Question

draw a typical cross section of flexible pavement and show what type of material can be used for each layer (ex: water bound macadam for base)

Answer 1

Answer is okay with drawing

Answer 2

The flexible pavement is generally composed of bitumen mixed with aggregates.

What is flexible pavement?

• It is a type of pavement such that when the load is applied to it, the force is equally distributed through underlying layers by a grain-to-grain mechanism.

• This structure is thus incorporated into the construction of highway pavements.

Composition

• Surface course(25-50 mm)

It is the uppermost layer which is composed of strong materials as it has to withstand a great amount of force.

• Binder layer(50-100mm)

It is the middle layer that transfers load between the surface course and base course.

• Base course(100-300mm)

It is the lowermost layer of the flexible pavement and is usually composed of bitumen- aggregate or unbound aggregate.

• Sub-base course(100-300mm)

It is an optional layer present beneath the base course to provide additional support.

• Sub-grade course(150-300mm)

It is the natural composite layer present beneath the manmade layer and provides support to the structure.

Refer to the attached diagram for the cross-section of flexible pavement.