04.09
product manual
H-1684
Flakiness Gauge for
Classification of Aggregate
Introduction
This method is based on the classification of aggregate particles as flaky when
they have a thickness (smallest dimension) of less than 0.6 of their nominal
size, this size being taken as the mean of the limiting sieve apertures used for
determining the size fraction in which the particle occurs. The flakiness Index of
an aggregate sample is found by separating the flaky particles and expressing
their mass as a percentage of the mass of the sample tested. The test is not
applicable to material passing a 6.30 mm BS test sieve or retained on a
63.0 mm BS test sieve.
Apparatus
The following apparatus is required.
1. A metal thickness gauge of the pattern shown in Figure 5 or special
sieves having elongated apertures. The width of the apertures and the
thickness of the sheet used in the gauge or sieve shall be as specified
in Figure 1.
2. BS test sieves as shown in Table 9 as appropriate.
3. A balance accurate to 0.5% of mass of the test sample.
C. Sample for test:
The sample for this test shall be taken in accordance with BS 812. It shall
comply with the appropriate minimum mass, for sieve analysis with due
allowance for 63.0 mm BS test sieve and passing a 6.30 mm BS test sieve.
The sample shall be taken from the laboratory sample by quartering or by
means of a sample divider. Before testing it shall be brought to a dry
condition by standard methods.
D. Procedure:
Carry out a sieve analysis using the sieves given in Table 1.
Figure 1— Thickness Gauge (Flakiness Index) indicating sizes of openings.
Discard all aggregate retained on the 63.0 mm BS test sieve and all
aggregate passing the 6.30 mm BS test sieve. Then weigh each of the
individual size-fractions retained on the sieves, other than the 63 mm BS
test sieve, and store them in separate trays with their size marked on the
trays. Where the number of particles in any size fraction is considered to
be excessive i.e. more than the appropriate mass given in Table 1, the
fraction may be subdivided by standard methods. Under such
circumstances the rest of the procedure should be suitably modified, and
the appropriate correction factor applied to determine the mass of flaky
particles that would have been obtained had the whole of the original
size-fraction been gauged.
From the sums of the masses of the fractions in the trays (M1), calculate the
individual percentage retained on each of the various sieves. Discard any
fraction of which the mass is 5% or less of mass M1. Record the mass
remaining (M2).
Gauge each fraction by one of these procedures:
1. Using the gauge: Select the thickness gauge appropriate to the
size-fraction under test (see Table 1) and gauge each particle separately
by hand, or
2. Using the special sieves: Select the special sieve appropriate for the
size-fraction under test. Place the whole of the size-fraction into the
sieve, which shall then be shaken until the majority of flaky particles have
passed through the slots. The gauge the particles retained individually
by hand. Combine and weigh all the particles passing the gauges or
special sieves (M3).
E. Calculating & Reporting (Flakiness Index): The Flakiness Index shall be
reported to the nearest whole number. The sieve analysis obtained in the
test shall also be reported.
Flakiness = M3 x 100
M
2
Table 1. Dimensions of Thickness Gauge.
Aggregate Size-fraction
BS Test Sieve
Nominal Aperature Size
100% Passing 100% Retained
63.0mm 50.0mm 33.9 ± 0.3mm 50kg
50.0mm 37.5mm 26.3 ± 0.3mm 35kg
37.5mm 28.0mm 19.7 ± 0.3mm 15kg
28.0mm 20.0mm 14.4 ± 0.15mm 5kg
20.0mm 14.0mm 10.2 ± 0.15mm 2kg
14.0mm 10.0mm 7.2 ± 0.1mm 1kg
10.0mm 6.30mm 4.9 ± 0.1mm 0.5kg
Warranty
Humboldt Mfg. Co. warrants its products to be free from defects in material or
workmanship. The exclusive remedy for this warranty is Humboldt Mfg. Co.,
factory replacement of any part or parts of such product, for the warranty of this
product please refer to Humboldt Mfg. Co. catalog on Terms and Conditions
of Sale. The purchaser is responsible for the transportation charges. Humboldt
Mfg. Co. shall not be responsible under this warranty if the goods have been
improperly maintained, installed, operated or the goods have been altered or
modified so as to adversely affect the operation, use performance or durability
or so as to change their intended use. The Humboldt Mfg. Co. liability under
the warranty contained in this clause is limited to the repair or replacement of
defective goods and making good, defective workmanship.
Thickess Gauge
Width of Slot
Minimum Mass
for Subdivision
Humboldt Mfg. Co.
875 Tollgate Road
Elgin, Illinois 60123 U.S.A.
Testing Equipment for
HUMBOLDT
www.humboldtmfg.com
U.S.A. Toll Free: 1.800.544.7220
Voice: 1.708.456.6300
Fax: 1.708.456.0137
Email: hmc@humboldtmfg.com
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