**AGGREGATE IMPACT VALUE**

This test is done to determine the aggregate impact value of coarse aggregates as per IS: 2386 (Part IV) – 1963. The apparatus used for determining aggregate impact value of coarse aggregates is

Impact testing machine conforming to IS: 2386 (Part IV)- 1963,IS Sieves of sizes – 12.5mm, 10mm and 2.36mm, A cylindrical metal measure of 75mm dia. and 50mm depth, A tamping rod of 10mm circular cross section and 230mm length, rounded at one end and Oven.

**Preparation of Sample**

i) The test sample should conform to the following grading:

– Passing through 12.5mm IS Sieve – 100%

– Retention on 10mm IS Sieve – 100%

ii) The sample should be oven-dried for 4hrs. at a temperature of 100 to 110^{o}C and cooled.

iii) The measure should be about one-third full with the prepared aggregates and tamped with 25 strokes of the tamping rod.

A further similar quantity of aggregates should be added and a further tamping of 25 strokes given. The measure should finally be filled to overflow, tamped 25 times and the surplus aggregates struck off, using a tamping rod as a straight edge. The net weight of the aggregates in the measure should be determined to the nearest gram (Weight ‘A’).

**Procedure to determine Aggregate Impact Value**

i) The cup of the impact testing machine should be fixed firmly in position on the base of the machine and the whole of the test sample placed in it and compacted by 25 strokes of the tamping rod.

ii) The hammer should be raised to 380mm above the upper surface of the aggregates in the cup and allowed to fall freely onto the aggregates. The test sample should be subjected to a total of 15 such blows, each being delivered at an interval of not less than one second.

Advertisements

**Reporting of Results**
i) The sample should be removed and sieved through a 2.36mm IS Sieve. The fraction passing through should be weighed (Weight ‘B’). The fraction retained on the sieve should also be weighed (Weight ‘C’) and if the total weight (B+C) is less than the initial weight (A) by more than one gram, the result should be discarded and a fresh test done.

ii) The ratio of the weight of the fines formed to the total sample weight should be expressed as a percentage.

** Aggregate impact value = (B/A) x 100%**

iii) Two such tests should be carried out and the mean of the results should be reported.

### Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.
If you have a query, you can **ask a question here**.

very informative

what is the important of impacts value toward pavement

what is the important of aggregate impacts value toward pavement

HELPFUL KEY

determine the best value of aggregate impact for good road pavement?

Good sites for civil engineers. Precise and accurate and informative report on AIV test

is 12.5 mm sieve acordingly BS or ASTM

i want this site to be the best site for civil engineers to access information

what is the Total load on the aggregates after stroking 15 times plz answer.

i want full documents covering aggregate impact value

what is the test procedure for the stone polishing value test

really significant..

some examples should be given for clarification

i want to know test result more and what is the diffrent between the value of this test

But what is the weight of the falling hammer ? . I guess it is important if we want to quantify the energy is applied on the aggregate sample.

The weight of the falling hammer is 13.4 to 14 kg.

Thanks for these valuable information

Please,tell something about “”THE USAGE OF AIV IN PAVEMENT DESIGN””

what a nice report!

plz say scops of the test………..

Thanks for dis good report