TEST METHOD
WA 216.1 – 2015
FLAKINESS INDEX
SCOPE
6
This method describes the procedure for the
determination of the Flakiness Index of aggregate that
has not more that 5% retained on a 26.5 mm Test
Sieve and no more that 5% passing a 4.75 mm Test
Sieve.
2
SAFETY
This method does not attempt to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this method to establish
appropriate occupational health and safety practices
that meet statutory regulations.
3
REFERNCED METHODS
Main Roads Western Australia
WA 105.1
Preparation of Disturbed Soils and
Manufactured Granular Pavement Material
Samples for Testing
WA 200.1
Sampling Procedure for Aggregate
WA 210.1
Particle Size Distribution of Aggregate
4
DEFINITIONS
a) The Flakiness Index is the percentage, by mass,
of the particles whose least dimension is less than
three-fifths of the mean dimension.
b) The Mean Dimension is the arithmetic mean of
the smallest sieve aperture size through which the
particle passes and the next smallest sieve aperture
size on which the particle is retained.
PROCEDURE
a) Obtain a test sample taken in accordance with Test
Method WA 200.1.
b) Determine the particle size distribution of a test
portion in accordance with Test Method WA 210.1 and
after sieving keep the 26.5 - 19.0 mm, 19.0 - 13.2 mm,
13.2 - 9.50 mm, 9.50 - 6.70 mm and 6.70 - 4.75 mm
sieve fractions separate.
c) Discard material;



Retained on the 26.5 mm sieve
Passing the 4.75 mm sieve
Any sieve fraction which constitutes 5% or less of
the test portion mass.
d) Record the mass to at least the nearest 1 g, of
each of the individual sieve fractions retained for
testing.
e) If there are;
 considerably more than 200 particles for any sieve
fraction which contributes more than 15% of the test
portion mass, or
 considerably more than 100 particles for any sieve
fraction which contributes more than 5% but less than
15% of the test portion mass,
Then those sieve fractions may be reduced by sample
division to obtain a test increment of approximately 200
and 100 particles respectively. No attempt shall be
made to secure an exact predetermined number.
Record the mass of each of the individual test
increments.
Note: If the 16.0 mm sieve has been used in the
particle size distribution then the 19.0 - 16.0 mm
and 16.0 - 13.2 mm sieve fractions must be
combined to form the 19.0 - 13.2 mm sieve fraction.
f) Test each sieve fraction (or test increment)
separately by attempting to pass each stone manually
through the appropriate slot as defined in Table 1.
5
g) Record the mass, to at least the nearest 1 g, of the
particles passing the appropriate slot for each of the
sieve fractions (or test increments) tested.
APPARATUS
a) Slot gauge, essential dimensions complying with
Table 1.
b) Balance of at least 3 kg capacity readable to at
least 0.1 g and with a Limit of Performance (F) of not
more than 0.5 g.
c) Sample divider as described in WA 105.1, Clause
4(b).
MAIN ROADS Western Australia
7
CALCULATONS
a) If the sieve fractions have been reduced,
calculate the mass of the particles passing the
appropriate slot for each sieve fraction using the
formula:
𝐸=
𝑚𝑎𝑠𝑠 𝑜𝑓 𝑠𝑖𝑒𝑣𝑒 𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛
× 𝑚𝑎𝑠𝑠 𝑝𝑎𝑠𝑠𝑖𝑛𝑔 𝑠𝑙𝑜𝑡
𝑚𝑎𝑠𝑠 𝑜𝑓 𝑡𝑒𝑠𝑡 𝑖𝑛𝑐𝑟𝑒𝑚𝑒𝑛𝑡
Document 71/04/216.1
Issue Date: 26 march 2015
D10#217087
Page 1 of 2
1
TEST METHOD
WA 216.1 – 2015
Where:
8
REPORTING
E = mass of particles in sieve fraction that would
Report the Flakiness Index to the nearest 0.1 %.
pass the appropriate slot
b) Calculate the Flakiness Index using the formula:
𝐹𝐼 =
∑ 𝑀𝑎𝑠𝑠 𝑜𝑓 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠 𝑝𝑎𝑠𝑠𝑖𝑛𝑔 𝑠𝑙𝑜𝑡
× 100
∑ 𝑀𝑎𝑠𝑠 𝑜 𝑠𝑖𝑒𝑣𝑒 𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛𝑠 𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑 𝑓𝑜𝑟 𝑡𝑒𝑠𝑡𝑖𝑛𝑔
Where:
FI
= Flakiness Index as a percentage
TABLE 1
SLOT GAUGE DIMENSIONS
Slot Marking
Slot Width Tolerance
(mm)
13.65 ± 0.2
9.66 ± 0.2
6.81 ± 0.1
4.86 ± 0.1
3.44 ± 0.1
2.13 ± 0.1
26.5 – 19.0
19.0 – 13.2
13.2 – 9.50
9.50 – 6.70
6.70 – 4.75
4.75 –2.36
9
Approximate Slot
Length (mm)
70
50
30
30
20
20
ISSUING AUTHORITY
Document Owner
Delegated Custodian
Manager Materials Engineering
Pavements Manager
10 REVISION STATUS RECORD
Revision
Page No.
Section
Description / Reference
1.
All
Format Revision and Re-issue of Test Method
1
2.
5
Apparatus – reference to table 1
2
3.
7
Inclusion of table 1
Page 2 of 2
All
MAIN ROADS Western Australia
Document 71/04/216.1
Issue Date: 26 March 2015
D10#217087