Subgrade
Appearance
In transport engineering, subgrade is the native material underneath a constructed road,[1] pavement or railway track (US: railroad track). It is also called formation level.
The term can also refer to imported material that has been used to build an embankment.
Construction
Subgrades are commonly compacted before the construction of a road, pavement or railway track
See also
References
- ^ http://www.highwaysmaintenance.com/drainage.htm The Idiots' Guide to Highways Maintenance highwaysmaintenence.com