Procedure

As per IS 1199, the procedure for conducting the Compaction factor test is as follows:

1. Preparation: Dampen the inside surfaces of the hoppers and cylinder with a moist cloth.

2. Filling Upper Hopper: Place the concrete sample gently into the upper hopper using a scoop. Fill it to the brim.

3. Transfer to Lower Hopper: Open the trap-door of the upper hopper to allow concrete to fall into the lower hopper. If concrete sticks, gently push it using a tamping rod. Keep the cylinder covered with trowels during this process.

4. Transfer to Cylinder: After the concrete comes to rest, uncover the cylinder. Open the trap-door of the lower hopper to allow concrete to fall into the cylinder.

5. Levelling the Surface: Remove excess concrete using two trowels moved horizontally across the top. Ensure the surface is level with the top of the cylinder. Clean the outside of the cylinder.

6. Weighing (Partially Compacted Concrete): Weigh the concrete in the cylinder to the nearest 50 g. Record as the weight of partially compacted concrete.

7. Refilling for Full Compaction: Refill the cylinder with concrete from the same sample in layers (~5 cm thick).

8. Full Compaction: Compact each layer thoroughly by tamping or preferably by vibration.

9. Final Leveling: Strike off the top surface level with the cylinder. Clean the outside of the cylinder.

10. Weighing (Fully Compacted Concrete): Weigh again to the nearest 50 g. Record as the weight of fully compacted concrete.

11. Calculation

    • Compaction Factor = (Weight of partially compacted concrete) ÷ (Weight of fully compacted concrete)
    • Express the result to two decimal places.