Some useful tips to find out the crushing value of an aggregate
A test is recognized with IS:2386 part-IV and conducted to find out the crushing strength of aggregates. The crushing value of aggregate offers a relative measure of resistance against crushing under progressively employed crushing load. Crushing value refers to a measure of the strength of the aggregate. Hence, the aggregates should contain least crushing value.
To find out the aggregate crushing value of coarse aggregates.
To examine the relevance of aggregates to be applied in various types of road pavement.
The test sample: It comprises of aggregates sized 12.5 mm - 10.0 mm(minimum 3kg).
The aggregates should be dehydrated by heating at 100-110o C for a period of 4 hours and let it be chilled.
1) Sieve the material via 12.5 mm and 10.0 mm IS sieve. The aggregates move through 12.5 mm sieve and are stored on 10.0 mm sieve along with the test material.
2) The cylinder of the test should be provided in exact location on the base-plate and the test sample are included in thirds, each third being allowed to 25 strokes with the tamping rod.
3) The surface of the aggregate should be leveled cautiously.
4) The plunger is placed in order that it can stand horizontally on this surface, precaution should be taken to make sure that the plunger is not obstructed in the cylinder.
5) The apparatus together with the test sample and plunger in exact location, should be arranged among the plates of the testing machine.
6) The load is enforced at a consistent rate in order that the total load is attained in 10 minutes. The total load should be 40 tonnes.
7) The load should be discharged and the entire material is eliminated from the cylinder and sieved on 2.36mm IS Sieve.
8) The fraction passing the sieve shall be weighed and recorded.