AVA
The Air Void Analyzer (AVA) is used to measure the size distribution of voids and the air-void parameters (spacing factor and specific surface) of the fresh, still-plastic, air-entrained concrete.
A mortar sample of the air entrained concrete is obtained from the fresh concrete with a sampling tool and injected into the blue AVA release liquid at the bottom of a riser column with water above.
The mortar sample is stirred gently into the release liquid by which the air bubbles are released and start rising through the water following the Stoke’s Law: larger bubbles will rise faster than smaller bubbles. At the top of the riser column a buoyancy pan attached to a balance measures the change in the pan’s weight caused by the rise of the air bubbles. Those changes are continuously collected over the test, when it ends, the information in analyzed and the size distribution of the bubbles is obtained