Compaction factor test of concrete

Compaction factor test of concrete :-

The compacting factor test is performed to find out the workability of concrete. From Compaction factor test, we doesn’t give accurate results for the low workability of concrete when the slump is less than 50 mm. 

If we have to dealt with Compaction factor test used for concrete mixes of very low workability.

It may be also defined as the ratio of the weight of partially compacted concrete to the weight of fully compacted concrete.

The other different  workability tests are clearly explained here:

1. Slump test
2. K Slump test
3. Flow table test
4. Kelly ball test
5. Vee-Bee consistometer test.
6. Compaction factor test.

Where we use low workable concrete?

These concrete can be used in Mass concreting foundations & lightly reinforced sections. 

These concrete can be used to minimize the thermal stresses development which is caused due to the large volume of the heat of hydration.  

These helps to Lowering water/cement ratio avoids bleeding & weak zones. 

For obtaining the required workability, use of admixtures can be adopted. 

Compaction factor test Apparatus:-

As per IS 1199 : 1999, the apparatus consists of : 1. two conical hoppers & a bottom cylinder,

2. steel rod of 1.6 cm Diameter having length of 61 cm is used to tamp the concrete,

3. weight balance.

Procedure for compaction factor test:

1. For the Compaction factor test, we can have to Take M20 grade concrete.
2. For Preparing, the mix with 1 : 1.5 : 3 by adding a required amount water as per Water cement ratio. Now mix the fresh concrete.
3. We have to check, that the Inner surfaces of conical hoppers should be free from moisture. Also to use the grease to the surface. Close the trap door of the upper hopper.
4. Now, we have to measure the weight of the empty bottom cylinder & note it as W1
5. After these, we have to Fill the fresh concrete into the upper conical hopper using trowel without compacting it. 
6. Now, trap of the door of upper hopper is opened. Thus the concrete falls on the lower hopper.
7. Then, after that we have to Wait for 2-3 secs and check whether the entire concrete is fallen from the upper hopper to bottom hopper. 
8. We have to now, open the bottom hopper trap door & the entire concrete is fallen to the cylinder. Trim off the excess concrete on the top surface of a cylinder using the trowel.
9. After that, we should have to take the Weight of the cylinder with partially filled concrete & note it as W2.
10. Atlast, we have to empty the cylinder, then we have to filled the concrete sample again by filling it in 3 layers each layer is compacted by giving 25 blows using the tamping rod. Now, the concrete inside the cylinder is fully compacted.
11. Measure the weight of cylinder with fully compacted concrete and write it as W3.

Compaction factor test of Concrete Formula:-

Important : The Compaction factor of concrete ranges from 0.7 to 0.95. 

Compaction factor test is most suitable for concrete having a low water-cement ratio.

The weight of fully compacted concrete can also be calculated by knowing the Proportion of materials and specific gravities of materials, and the volume of the cylinder. 

After some research & observation,  it makes very little difference in compacting factor value, whether the weight of fully compacted concrete is calculated theoretically or found out actually after 100%  compaction.

The Compacting factor test measures the inherent characteristics of the concrete which is releated with the workability of concrete.

These test helps to determine, the workability of concrete.

Also Read:- 

Slump test of concrete  
Important Properties of Cocncrete

Watch Video of the Slump test of concrete .

Video 1 :

Thankyou friends for reading my Blog.  I hope you definitely like these bolg. 

For such new Blog releated updates, subscribe to our website. Thankyou.