Determination of flakiness & elongation index (FI & EI) of coarse aggregate using thickness & length gauge. Shape and size aggregate is one of the major contributing factors to the quality of concrete. The test methods are given below for flakiness & elongation index of coarse aggregate.

**Test standard : **IS 2386-Part I: 1963

**Test Appratus flakiness & elongation index**

- Weighing Balance
- IS sieves 63mm, 50mm, 40mm, 31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10nm, 6.3mm
- Thickness gauge for flakiness and length gauge for elongation.

**Dimension of Thickness and Length gauge**

**Test procedure for FI & EI **

** Prepared the sample of Each fraction as: **

- Passing 63mm IS Sieve & Retained on 50mm IS Sieve
- Passing 50mm IS Sieve & Retained on 40mm IS Sieve
- Passing 40mm IS Sieve & Retained on 31.5mm IS Sieve
- Passing 31.5mm IS Sieve & Retained on 25mm IS Sieve
- Passing 25mm IS Sieve & Retained on 20mm IS Sieve
- Passing 20mm IS Sieve & Retained on 16mm IS Sieve
- Passing 16mm IS Sieve & Retained on 12.5mm IS Sieve
- Passing 12.5mm IS Sieve & Retained on 10mm IS Sieve
- Passing 10mm IS Sieve & Retained on 6.3mm IS Sieve

- Take test sample (Minimum number of 200 pieces ) on any fraction to be tested.
- Weigh the sample on each sieve fraction
- Pass the sample of each fraction (Each piece) through respective sizes on thickness gauge.
- Weigh the sample passed in each size of the thickness gauge and Note it.

**Flakiness Index (%) **= 100x (Total weight of sample passed in each size of thickness gauge / Total weight of sample )

- Collect all material retained on thickness gauge
- Note the weight of each size fraction.
- Pass the pieces on each fraction through respective sizes in the length gauge manually.
- Weigh the sample passed in each size of the length gauge and note it.

**Elongation Index (%)** = 100x Total weight of sample retained in each size of length gauge / Total weight of sample gauged (i.e retained on thickness gauge)

**Combined Flakiness & Elongation Index (%)** = Flakiness index (%) + Elongation index (%)

**Read more : **

- Method Abrasion value test of aggregate
- Method of Impact value test of aggregate
- Method of ten Percent fine value of Coarse Aggregate
- Method of crushing value test of aggregate

Founder & Admin of civilengineeringsolution.com, I am a civil engineer working as a Engineer (QA/QC).