AGGREGATE CRUSHING VALUE

Updated: May 1, 2020

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.

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