LENGTH GAUGE - (BS - 812)

Complies with following International Standards :

BS 812-105.2, BS EN 12620

Purpose :

This instrument is used to determine the elongation index of aggregates. Particle is elongated when its length (longest dimension) is more than 1.8 of the midsize of the sieve fraction.

Significance & Use :

This method classifies aggregate elongation by measuring the length of individual particles. The test is not applicable to material retained on a 63.0 mm BS test sieve.

Construction Details :

1. Consists of a hard wood base with vertically mounted metal studs
2. Six metal studs are mounted.
3. All six labeled openings between pairs of metal pins measure particle from each of the six sieve cuts below 50mm.
4. Aggregate to be classified is separated into seven sieve fractions from 63 to 6.3mm, and each fraction is examined separately.
5. The mass of all elongated particles (failing to pass between pins) as percent of the sample is the elongation index.
6. The distance between nails according to following table