Balloon Density Apparatus is used to determine the in-situ density of compacted or firmly bonded soils.

Consists  of a  graduated  cylinder 1596  ml  capacity, housed  inside an  aluminium  guard, a reversible rubber aspirator pump, a density plate 9” square and 12 rubber balloons. The principle of operation is similar to the sand replacement but the hole is filled by a rubber balloon where water is pumped. The amount of water can be
easily determined by the graduation of the cylinder.

3000 ml capacity. A metal cylinder is filled with water which is then  pumped into a rubber membrane mounted on the base of the cylinder. The water pressure is controlled by a pressure gauge and the volume of the balloon is measured on the graduated piston stem.