Objective

For determination of consistency of concrete where the nominal maximum size of aggregate does not exceed 38 mm using compacting factor test apparatus. 

Reference Standards

IS: 1199 – 1959 – Method of sampling and analysis of concrete.

Equipment & Apparatus

• Compacting factor apparatus. 

Procedure

1. The sample of concrete to be tested is placed gently in the upper hopper, using the hand scoop.
2. The hopper is filled level with its brim and the trap – door is opened so that the concrete falls into the lower hopper. The cylinder is covered by the trowels.
3. When all the concrete has come to rest in the lower hopper, the cylinder is uncovered, the trap door of the lower hopper opened and the concrete is allowed to fall into the cylinder.
4. The excess of concrete remaining above the level of the top of the cylinder is then cut off by trowel and the outside of the cylinder is wiped clean.
5. The weight of the concrete in the cylinder is measured to the nearest 10 g. This is known as ‘the weight of partially compacted concrete’.
6. The cylinder is refilled with concrete from the same sample in layers approximately 5 cm. deep and vibrated to obtain full compaction.
7. The top surface of the fully compacted concrete is struck off level with top of the cylinder. The outside of the cylinder is to be wiped clean. 

Calculation

The compacting factor is calculated by dividing the weight of partially compacted concrete to the weight of fully compacted concrete. 

Report

The result is reported to the nearest second decimal place 

Safety & Precautions:

• Use hand gloves & shoes at the time of test.
• Equipment should be cleaned thoroughly before testing & after testing.
• Petroleum jelly should be applied to the mould.
• Wear the apron at the time of test.