As the name implies, Blockfill / Cavity fill is applied when there is a need to fill up the blocks or double-layer a bricked wall for retaining the strength. This is also used when the engineers have designed walls that require extra support and strength. The mix used in cavity walls can range anywhere between 20-40mpa with an aggregate of 7 millimetre. This mix is generally ordered anywhere from a slump of 120 to 360.
The amount of slump/wetness present in concrete is usually higher, this allows the voids to be filled leaving no room for the formation of air pockets, as voids or air pockets can weaken the base of these walls. The mixes created are filled through using a concrete pump while employing a second delivery line to ensure the ease of filling, with the least mess.