1.0 Centre Road

1.1 South Road

1.2 Choice of Pavement

The Road is a Flat country straight rural road.
1.2.1 Flexible or Rigid

1.2.2 Empirical or Mechanistic

There are two design options for Flexible Pavements:
1. Empirical Design: Bituminous layer over the granular material
2. Mechanistic Design: Pavement contains two or more layers
The Former has only one type of damage which is: deterioration of the pavement. Whereas the latter has 3 types of damages:
1. Fatigue damage to Asphalt
2. Rutting and loss of surface shape
3. Fatigue damage to cemented material
In order to reduce the damages and hence the maintenance costs, the empirical design option for flexible pavements will be chosen in our design.
1.2.3 Sprayed Seal or Asphalt Surface

The two main design options available for granular pavements are:
1. Granular Pavement with sprayed seal:
This is made up of a Subgrade, 500mm Granular base and sub-base and a bituminous seal
2. Granular Pavement with Asphalt wearing surface:
This comes in two options:
1. A subgrade with 500mm granular base and a 215mm Asphalt surface
2. A subgrade with 100mm granular base and a 240mm Asphalt surface
Before an ideal option can be chosen, the advantages and disadvantages of both surfaces will be considered:
Bituminous Seal
Advantages
1. Low cost
2. Good skid resistance
3. Good service life
Disadvantages:
1. Loose stones from compaction
2. Tracking of Bitumen onto driveways

Asphalt Surface