Compaction Factor Test

Objective: To assess the workability of concrete (using compaction factor test)


  • Compaction factor apparatus’ trowels
  • Hand scoop (15.2 cm long)
  • Steel rod or other handy equipment (1.6 cm diameter, 61 cm long rounded at one end) and a balance.


Concrete mix (M15) is blended according to the specified mix design in the laboratory.


(I) put the concrete specimen quietly in the upper hopper to its rim with help of the hand scoop and even it.

(ii) Cover the cylinder

(iii) unlock the trap door at the base of the upper hopper so the concrete goes in to the lower hopper .Shove the concrete sticking on its sides smoothly with the road.

(iv) Open the trap door of the lower hopper and permit the concrete to reach the cylinder below

(v) Cut of the surplus of concrete on top of the top level of cylinder utilizing trowels and even it.

(vi) Tidy the exterior of the cylinder.

(vii) Weigh the cylinder with concrete to the nearest 10 g. This weight is known as the weight of partially compacted concrete (wi).

(viii) Empty the cylinder and then refill it with the same concrete mix in layers about 5cm deep, each level being greatly slammed into to acquire full compaction.

(ix) Even out the top surface.

(x) Measure the weight of the cylinder with fully compressed This weight is also called as the weight of wholly compacted concrete (w2).

(xi) Measure the weight of empty cylinder (W).


The test is adequately susceptible to facilitate dissimilarity in workability starting from the early procedure in the hydration of cement concrete to be premeditated. Each test, thus has to be undertaken at a unvarying time gap after the blending is accomplished, if severely analogous outcomes are to be achieved. Convenient time for discharging the concrete cement from the upper hopper has been established to be approximately two minutes after the conclusion of blending.


  1. The compaction factor is known as the proportion of the mass of moderately compressed concrete to the mass of completely compacted concrete. It should usually be affirmed to the nearby second decimal place.
  2. Compaction Factor= (W1-W2 / W2-W)


Compaction factor of the concrete =