Water bound macadam road is a road wherein the wearing course comprises of clean squashed aggregates which are precisely interlocked by rolling. These aggregates are bound along with filler material and water laid on an all-around compacted base course. WBM road is the most regularly utilized road development strategy for over 200 years and in the principal stage in the vast majority of the road ventures, water–bound macadam road is built, and the surfacing is finished with the premix cover bituminous macadam or concrete cement.
A Scottish engineer John Loudon McAdam first introduced the concept of the macadam road in 1820.
In this type of road, coarse aggregates are mechanically interlocked together by rolling, screening, etc. Binding materials are used to fill the gap between the coarse aggregate.
Table of Contents
Material Required For Water Bound Macadam Road
- Coarse Aggregate
- Screenings (Filler Material)
- Binding Material
Advantages
- very low construction cost.
- There is no need for skilled workers.
- Material is easily available.
- It provides very good quality.
Disadvantages
- The maintenance cost is very high.
- Not much durable.
- It is permeable to water.
Difference Between WMM and WBM Road
Here are the differences between WMM (Wet Mix Macadam) and WBM (Water Bound Macadam) roads.
| WMM Road | WBM Road |
|---|---|
| WMM roads are more durable. | WBM roads are less durable. |
| WMM roads get dry very fast | WBM roads take time to get dry. |
| It can be constructed at a faster pace. | It took more time to construct. |
| It consumes less water. | It consumes more water. |
| In WMM roads stone aggregates and binders are used. | In WBM roads stone aggregates, screenings, and binder material (Stone dust with water) is used. |