ODOT_TM782_flakiness_index~1.pdf

ODOT Provisional TM 782

Provisional Method of Test for

FLAKINESS INDEX OF AGGREGATES

SCOPE

This test method describes a procedure to determine the Flakiness Index (FI) of aggregates. The flakiness index is a measure of the cubical shape of the aggregate and is used as a design input to determine the rate of application of aggregate and asphalt material for seal coats.

REFERENCES

AASHTO M92

AASHTO M231

AASHTO T2

AASHTO T27/11

AASHTO R76

TERMINOLOGY

APPARATUS

1. Balance, Class G2, in accordance with AASHTO M231

2. Sieves, in accordance with AASHTO M92.

3. Metal plate, approximately 0.1175 ± 0.0100 in. thick with slotted openings conforming to the dimensions indicated in Figure 1 and Table 1.

Figure 1. Slotted Sieve Openings

Table 1.

Opening Widths and Tolerances

Passing Sieve Retained on Sieve

Width (in.)

Width Tolerance (in.)

Length (in.) Length Tolerance (in.)

1 3/4 0.525 0.0160 2.36 0.0630 3/4 1/2 0.375 0.0120 1.97 0.0590 1/2 3/8 0.263 0.0080 1.57 0.0430 3/8 1/4 0.184 0.0060 1.18 0.0310 1/4 No. 4 0.131 0.0040 0.79 0.0240

SAMPLE PREPARATION

1. Sample the aggregate in accordance with AASHTO T2.

2. Reduce the sample in accordance with AASHTO R76. The sample size shall meet the following requirements:

Test Sample Size

Specified Maximum Size, inch Minimum Dry Mass, g

1/2" (12.5mm) 2000 3/8" (9.5mm) 1000 1/4" (6.3mm) 1000

4.75 (No. 4) 500

3. Determine the percentage of materials finer than the No. 200 sieve in accordance with

AASHTO T11.

4. Determine the gradation in accordance the AASHTOT 27

PROCEDURE

1. For each size aggregate, determine the weight of the aggregate retained on the No. 4, 1/4 in., 3/8 in., 1/2 in. and 3/4 in sieves, if applicable.

2. Determine the percentage of aggregate retained on each sieve to the nearest 0.1% by dividing the weight of the aggregate on each sieve by the total weight of the sample and multiplying by 100. Each size fraction present in the amount of 4 % or more will be tested.

Size fractions containing less than 4% are not tested and shall be discarded.

3. Combine the aggregate retained on the No. 4, 1/4 in., 3/8 in., 1/2 in. and 3/4 in sieves, if applicable. Reduce the sample in accordance with AASHTO R76 to the following minimum size sample:

Specified Maximum Size, inch Minimum Dry Mass, g

1/2" (12.5mm) 2000 3/8" (9.5mm) 1000 1/4" (6.3mm) 1000

4.75 (No. 4) 500

4. Determine the gradation of the reduced sample in accordance with AASHTO T27. For aggregates retained on each applicable size sieve, each particle shall be tested by attempting to pass the particle through the appropriate slot for the size of material being tested.

5. The weight of the particles not passing the slot opening and the weight of the particles passing the same slot opening shall be determined to the nearest 0.1 g.

H. CALCULATIONS

The FI shall be determined to the nearest whole percentage as follows:

Flakiness Index (FI), % = Total Weight Passing Slots

Total Weight Retained on No. 4 Sieve x 100

I. REPORT

The flakiness Index shall be reported to the nearest whole number using the Flakiness Index Worksheet shown in Appendix A.

APPENDIX

FLAKINESS INDEX WORKSHEET

Project: Source:

Flakiness Index (FI), % = Total Weight Passing Slots

Total Weight Retained on No. 4 Sieve x 100

Comments:

Tested by: Date:

Sieve Size Wt.

Retained, g

% of Total Sample Slot Size

(A) Weight not passing slot, g

(B) Weight passing slot, g

(C) Total weight, g

(A + B)

3/4" 1 to 3/4"

1/2" 3/4 to 1/2"

3/8" 1/2 to 3/8"

1/4" 3/8 to 1/4"

No. 4 1/4 to No. 4

Total

This test method describes a procedure to determine the Flakiness Index (FI) of aggregates. The flakiness index is a measure of the cubical shape of the aggregate and is used as a design input to determine the rate of application of aggregate and asph...