The scope of Van Asbeck apparatus is to test and assess the flexibility property and related impermeability to water under pressure of hydraulic bituminous mixes to be used to cover the water storage of dams.

The  valve of the lower conical end is then opened and the glass spheres are removed at a rate of 250 g every 15 minutes to a total of 5 kg, thus forming a hollow space under the slab to a maximum depth of 5 cm. The water pressure is then maintained for another 5 hours. The apparatus consists essentially of a steel cylindrical cell divided in two sections: the upper part that is the under pressure water container and the lower part consisting of a cone with opening in the lower end. These two parts are clamped together by two flanges (upper and lower) with the interposition of a 50 cm ID steel ring which contains the compacted bituminous sample. The lower conical part  has to be filled by 2-2.5 mm  dia. of glass spheres which support the compacted 50 cm diameter slab when it is subjected to 3 bar water pressure. The asphalt slab should remain impervious during this flexibility test, even is fine surface cracks develop in the bottom of the slab.

 

The apparatus includes:

Air pressure regulator

Safety valve

Steel cylindrical cell

Series of inlet/outlet/water discharge /overflow valves

Manometer

Level indicator

Confining steel ring with shaped steel plate for sample compaction preparation

Air/Water pressure cylinder

Overflow/water filling/ water discharge valves

Sealing material

20 kg of 2-2.5 mm dia. glass spheres

Overall dimensions: (dia.x h) 700x1000 mm

Weight approx.:  100 kg.