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Construction Site Handbook

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[English | 简体] Compacting Factor Test

This is a site test to determine the consistency or self compaction of the green concrete and is conducted by the supervisor on site . But in nowadays , this test is commonly replaced by the Slump Test to determine the workability of the green concrete . The procedure of this test in brief is as follows : -

1. Ensure the apparatus and associated equipment are clean before test and free from hardened concrete and superfluous water . For set up of apparatus , see Fig 7 – 5 .
2. Weigh the bottom cylinder to nearest 10gm , put it back on the stand and cover it up with a pair of floats .
3. Gently fill the upper hopper with the sampled concrete to the level of the rim with use of a scoop .
4. Immediately open the trap door of the upper hopper and allow the sampled concrete to fall into the middle hopper .
5. Remove the floats on top of the bottom cylinder and open the trap door of the middle hopper allowing the sampled concrete to fall into the bottom cylinder .
6. Remove the surplus concrete above the top of the bottom cylinder by holding a float in each hand and move towards each other to cut off the concrete across the top of cylinder .
7. Wipe clean the outside of cylinder of concrete and weigh to nearest 10gm .
8. Subtract the weight of empty cylinder from the weight of cylinder plus concrete to obtain the weight of partially compacted concrete .
9. Remove the concrete from the cylinder and refill with sampled concrete in layers .
10. Compact each layer thoroughly with the standard Compacting Bar to achieve full compaction .
11. Float off the surplus concrete to top of cylinder and wipe it clean .
12. Weigh the cylinder to nearest 10gm and subtract the weight of empty cylinder from the weight of cylinder plus concrete to obtain the weight of fully compacted concrete .
13. The compacting factor ( CF ) = ( weight of partially compacted concrete ) divided by ( weight of fully compacted concrete ) .

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