AGGREGATE CRUSHING VALUE

By : Unknown

On : 06:28

In : Civil Lab Report

       Aggregate Crushing Value Test is for determining the aggregate crushing value of coarse aggregates.
APPARATUS 

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
             Aggregate crushing value = B/A x 100%
      The result should be recorded to the first decimal place and the mean of the two results reported.