Flakiness index test

The total Flakiness Index is designated as the total aggregate mass passing through each bar sieve, expressed as the percentage of the total sample mass of dry aggregates tested. 

If the Flakiness Index for each aggregate size d/D, is required, it is calculated by the mass passing through the bar sieve expressed as a percentage of mass of the respective aggregate size. 

Particle size fraction d,ID, (mm) Width of slot in bar sieve (mm) 

Source Reproduced from CEN EN 933-3, Tests for geometrical properties of aggregates - Part 3 Determination of particle shape - Flakiness index, 

More information, as well as a calculation example, is presented in CEN EN 933-3 (2012). The Flakiness Index value determined in accordance with the European specification differs from the one determined by BS 812-Part 105, which was used in the past by many countries. Thus, care must be taken to the limiting values that may have been set. 

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Part 2 Determination of particle size — Test sieves, nominal size of apertures Part 3 Determination of particle shape of aggregates — Flakiness index Part 4 Determination of particle shape of aggregates — Shape index... 

This test proposed by the American standard ASTM D 4791 (2010) is equivalent to the Flakiness and Shape Index test methods proposed by the European standards. It determines the percentage of flat particles, elongated particles or flat and elongated particles in coarse aggregates (retained on 9.5 mm or 4.75 mm sieve depending on the requirements). 

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