AIM
To determine the aggregate crushing value of coarse aggregates
as per IS: 2386 (Part IV) - 1963.
APPARATUS
CYLINDRICAL MEASURE AND PLUNGER
i) Cylindrical measure and plunger
ii) Compression testing machine
iii) IS Sieves of sizes - 12.5mm, 10mm and 2.36mm
PROCEDURE
i) The aggregates passing through 12.5mm and retained on
10mm IS Sieve are oven-dried at a temperature of 100 to
110oC for 3 to 4hrs.
ii) The cylinder of the apparatus is filled in 3 layers, each layer
tamped with 25 strokes of a tamping rod.
iii) The weight of aggregates is measured (Weight 'A').
iv) The surface of the aggregates is then levelled and the
plunger inserted. The apparatus is then placed in the
compression testing machine and loaded at a uniform rate
so as to achieve 40t load in 10 minutes. After this, the load
is released.
v) The sample is then sieved through a 2.36mm IS Sieve and
the fraction passing through the sieve is weighed (Weight 'B').
vi) Two tests should be conducted.
REPORTING OF RESULTS
B
Aggregate crushing value = —— x 100%
A
The result should be recorded to the first decimal place and the
mean of the two results reported.