Compacting Factor test

The compacting factor test determines the workability of concrete with aggregate sizes up to a maximum of one and a half inches.

The test equipment consists of two truncated cone-shaped hoppers with hinged doors at the bottom and a cylinder, all stacked sequentially, with polished interior surfaces to reduce friction.

Concrete is placed in the top hopper without compacting, and the bottom door is opened, letting the concrete flow into the lower hopper.

Next, the bottom door of the lower hopper is opened, allowing the concrete to fall into the cylinder below, and the excess concrete is struck off.

A steel rod is used to gently poke and dislodge the concrete that gets stuck in one or both hoppers during the test.

The final weight of the concrete in the cylinder's set volume is determined, and the density for this partially compacted is calculated.

Fully compacted density is determined by filling the cylinder with concrete in four layers and tamping each layer.

Finally, the compacting factor is calculated as the ratio of the density of partially compacted concrete to the density of fully compacted concrete, which indicates the workability of the mix.