This test is done to determine the aggregate impact
value of coarse aggregates
AIV is basically a % ratio of 2.36mm sieved aggregate
to 14mm aggregate sieve.
The apparatus used for determining aggregate impact
value of coarse aggregates is
Impact testing machine Sieves of sizes – 14mm, 10mm
and 2.36mm,a cylindrical metal measure of 75mm
diameter and 50mm depth, A tamping rod of 10mm
circular cross section and 230mm length, rounded at
It is usually used
to tamp the
that it should
acquire all the
empty space of
metallic cup. Its
10mm and it is
230 mm in size .
A sample of
sizes for the
A digital weight
machine is also a
part of the
An average aiv machine
must have following
1-mass variable up to 13.6
2-impact energy variable
up to 132.8 J
3-impact velocity up to
4.4 m s
4-its hammer diameter is
First of all set all the sieves according to the following order:-
14mm>10mm>2.36mm or 14mm sieve on the top and 2.36 sieve at the
Pass the given amount of aggregate through the sieves according to
Collect the aggregate which passes through 14mm sieve and retained
on 10mm sieve. This aggregate is known as Coarse aggregate.
Take the metallic cup and weight it .Let its weight is W.
Now fill 1/3 of the cup with coarse aggregate and tamp it with at least 25
tamps of tamping rod. Repeat the whole procedure 3 times so that all
the empty space of cup should be completely filled with aggregate.
Weight the cup let it must be W1
Carefully place the cup beneath the hammer of the aiv machine.
Hammer it with 15 strokes of machine hammer.
Pass the retained aggregate through 2.36 sieve.
Calculate the weight of passed aggregate let it be W2
After calculation we can find aiv % by given formula
AIV % = (W1-W/W2) x 100
APPLICATION S OF AIV
Aggregate having AIV % less 50% is better to use in
construction where as those having value more than 50%
are bad for construction.
It is reliable to calculate the AIV % of the aggregate use as
road metal as it will give us the capacity of road to bear the
load on it. Aggregate having AIV % equal or greater than 35
% is considered bad to use in road construction.