Types of Base Course - Granular, Base, Macadam, Water Bound
Granular Base Course:
A mixture of soil particles ranging in size from coarse to fine. Processing involve crushing oversized particles and screening where it is necessary to secure the desired grading. The requirements of a satisfactory soil aggregate surface are:
- Stability
- Resistance to abrasion
- Resistance to penetration of water
- Capillary properties to replace moisture lost by surface evaporation upon the addition of wearing course requirement change.
Macadam Base:
Successive layers of crushed rock mechanically locked by rolling and bonded by stone screening (rock duct, stone chips etc).
In-water bound Macadam:
The crushed stones are laid, shaped and compacted and then finer materials are added and washed into surface to provide a dense material.
Treated Bases:
Compose of mineral aggregate and additive to make them strong or more resistant to moisture. Among the treating agents is bitumen.