Subgrade

Layers in the construction of a mortarless pavement: A.) Subgrade B.) Subbase C.) Base course D.) Paver base E.) Pavers F.) Fine-grained sand

Section through railway track and foundation showing the sub-grade

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[]

• Subsoil
• Track bed

References[]