Wearing course or Wearing Surface
Wearing course or surface is the top most portion of the road on which vehicle moves. It is made by the combination of Asphalt/Bitumen and aggregates.
Wearing course may be made by Triple surface treatment or Carpeting.
Triple surface treatment (TST)
Triple surface treatment is a double surface treatment with a thin sand seal on top to fill the voids. It is used in high stress areas. It may be desirable to use asphalt or concrete or concrete block paving in the high and very high stress areas.
- It is cheap.
- It is less smooth as compared to carpeting.
- It takes more time as compared to carpeting.
Carpeting of road (Job Mix Formula)
- This method is costly.
- Wearing course or surface made by carpeting is smooth.
- It takes less time in construction.
- For Heavy traffic load, carpeting is recommended.