The graining of gravel overlaps with chippings and scraps

Gravel grading is classified differently in geoscience than in construction. While in geology grain sizes of more than two millimeters, but with a high proportion of gravel, are considered as gravel, the building industry defines the graining area between 32 and 64 millimeters as gravel.

Mixed forms are the rule

All grain sizes below 32 millimeters are assigned to the grit or in the smallest area of ​​the crushed sand, from 64 millimeters is spoken by Schroppen. In practice, most sortings of crushed rock used as aggregates or fillers are mixed forms.

In general, the grain size is assigned to the ballast when the largest grain size available is in the range of 32 to 64 millimeters. Decisive for the character of the gravel is the proportion of the grain fractions. The larger coarse-grained fractured rock, the more "gravelly" are the properties of the grain.

Zero shares and grading curve

Gravel with a restriction of the smallest grain sizes, such as a gravel with a grain size of 32-45 millimeters, is a gravel with no zero shares. The grain size is compiled by several sieves, which leave only the desired grain sizes by a successive sieving line.

In addition to the range of grain sizes, the proportionate distribution is decisive. Gravel for drainage purposes and with frost resistance needs minimum amounts of coarse grains. Also, gravel with zero fractions can obtain these properties with appropriate division of the grain fractions.

Typical gravel grains

If you are looking for gravel in the building material trade or in gravel works, you will also find many grits under this designation, which are actually splits in terms of terminology. Common grits for gravel are:

  • With zeros: 0-5, 0-32, 0-45, 0-56, 0-63 and 0-100 millimeters
  • Without zero shares: 5-32, 5-45, 16-32, 32-45, 32-56 and 60-120 millimeters

Depending on the supplier, for example, the grain size 45-100 is offered as a schroppen or the grain size 0-32 or 16-32 as a chippings. Alternative tradenames, often dependent on the source material of the ballast, are antifreeze, granules, brick recycling or crusher product.

Tips & Tricks

Unlike gravel, gravel is only released from its zero shares by seven. If you get offered a washed product, it is usually not gravel, but gravel or concoctions. Mixtures of round grained gravel with quarry stone are also available.

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