Balloon Density Apparatus determines in-situ density and unit weight of soil when testing compacted earth fills. The Balloon Density Apparatus is a water-filled, calibrated vessel fitted with a hand-operated pump to pressurize the chamber. A thin, flexible membrane (rubber balloon) on the bottom displaces under pressure to fill a void. Using the base plate as a template, a hole is dug in the surface and the excavated soil is retained as a moisture specimen. To determine the volume of the hole, the density tester is mounted on the plate, the balloon is pumped into the hole, and fluid displacement from the vessel is noted. In-place density is computed by dividing the weight of the retained soil by the measured volume of the hole. A portion of the retained specimen is used to determine moisture content. Water volume is read from the double-graduated scale on the high-strength clear plastic cylinder. Selection of Balloon Density Tester is determined by top-size of soil particles.
HM-66 model has 1/20ft³ (1,600ml) capacity and is used for soils with 1/2in (13mm) maximum particle size.
HM-67 model has 1/13ft³ (2,230ml) capacity and used for soils with particle size up to 1in (25mm).
Each apparatus consists of a graduated cylinder (0.00025ft³ and 7cm³ graduations), base plate, pressure/vacuum pump assembly with quick-coupler, ten balloons, and an integral gauge for controlling pressure during calibration and testing. MA-26X Aqua-Check Moisture Tester for moisture determinations and HMA-8 In-Place Density Accessory Kit are recommended optional accessories.
Note: this method is not suitable for very soft, easily deformed soils or in a hole which will not maintain constant volume.
- Durable, clear plastic cylinder makes double-graduations easy to read
- Comes with all components needed to measure the in-place density of soil
- 1/20ft³ HM-66 model is used for soils with particle size up to 1/2in (13mm)
- 1/13ft³ HM-67 model is for soils with particle size up to 1in (25mm)
- Balloon Density Apparatus
- Double-graduated cylinder
- Base plate
- Pressure/vacuum pump assembly with quick-coupler
- Pressure gauge
- Rubber balloons (pkg. of 10)
- HMA-5 Voluvessel Balloons are used to pump in hole to fill the void, comes in a pack of 10
- HMA-8 In-Place Density Accessory Kit includes sample bags, pocket thermometer, bristle brush, chisel, stainless steel spoon, and rubber mallet all necessary for field density tests for Balloon Density or Sand Cone Density
- MA-26X Aqua-Check Moisture Tester allows for fast, accurate testing of sand, soil, or other aggregates