Pressure equalization procedure
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DIN EN 12350-7 |
|---|---|
| Area | Testing of concrete |
| title | Testing of fresh concrete - Part 7: Air content - Pressure method |
| Latest edition | 2009-08 |
| ISO | - |
The pressure equalization process is a standardized procedure in accordance with EN 12350-7 for testing the air content of a completely compacted fresh concrete . The standard is published in Germany as DIN standard DIN EN 12350-7.
The air content is an important parameter , especially when manufacturing components made of air-entrained concrete . In the concrete plant and, if necessary, on the construction site before the concrete is installed, this parameter must be checked using the pressure equalization process.
A special container is required for the pressure equalization process. This air content tester (also called the air void measuring pot or colloquially known as the LP pot ) consists of a pot with a capacity of at least five liters and a corresponding lid with a small pressure chamber and a manometer . The fresh concrete is poured into the pot in layers until it is full to the brim and thereby compacted (usually with a vibrating table). After closing the pot, the remaining cavity under the lid is filled with water via two valves so that, apart from the air pores in the concrete, there is no air in the container. A (hand) pump is then used to generate a defined excess air pressure in the pressure chamber of the lid. The air content in the concrete is then measured by equalizing the pressure between the pressure chamber and the pot by opening a third valve. The air content in percent by volume can be read immediately on the manometer. Depending on the aggregate must be a correction factor to be considered.
Web links
Individual evidence
- ↑ Zement-Merkblatt Betontechnik B 4 3.2013 - Fresh concrete: Properties and tests. BetonMarketing Deutschland, accessed on December 23, 2013 .