A natural sedimentary rock of nature
Sedimentary rock with a grain larger than 2 mm is called gravel.
Gravel is divided into the following gradations :
- 2 mm to 8 mm is called granules
- 4 mm to 16 mm is fine gravel
- 4 mm to 32 mm is medium to coarse gravel
- gravel larger than 32 mm is called coarse to very coarse gravel. This gravel is processed into stone chippings and used as surface dressing for the road construction industry.

The outside bend of the river
Gravel is mined and used for all sorts of purposes. In The Netherlands, lots of lakes are created alongside the Maas river at places where gravel is mined with dredging mills. Nowadays, gravel is generally used as part of the concrete. Gravel is a product of erosion which originates from solid rock and is generally transported and deposited by rivers.  Consequently, gravel deposits are created in the outside bends of the river due to the weight of the gravel.

A wide range of applications
Gravel is used in all sorts of building materials and products such as concrete, asphalt, and natural hard surfaces such as paths and driveways.

Did you know that?
Black asphalt consists of more than 95% of sand and solid rock and grey concrete consists of more than 85% of sand and gravel?