 
TORRENT
PERMEABILITY TESTER
Fast, reliable and non-destructive measurement of the
permeability of concrete structures
The permeability of concrete at the surface
(concrete cover) has been recognized as a major factor
determining the durability of concrete structures. Many
specialists emphasize the importance of this property and the
possibility of measuring it reliably - not only in the laboratory
but also at the building site or at components.
Permeability Measurement
The particular features of the TORRENT method
are a two-chamber vacuum cell and a pressure regulator, which
ensure that an air flow at right angles to the surface is
directed towards the inner chamber. This permits the calculation
of the permeability coefficient kT on the basis of a simple
theoretical model.
The unit has a user-friendly menu technique and
measures the pressure increase as a function of time according to
a specific sequence. The associated data is automatically
collected by the display unit and the permeability coefficient kT
and the depth of penetration L of the vacuum are calculated. The
measurement takes 2-12 minutes, depending on the permeability of
the concrete. In the case of dry concrete, the quality class of
the concrete cover can be read from a table using the kT value.
In the case of moist concrete, kT is combined with the electrical
concrete resistance p (rho) and the quality class is determined
from a nomogram.
The TORRENT permeability tester is based on
investigations which were carried out by the research center of
“Holderbank Management and Consulting Ltd.”,
Switzerland. The results of these measurements, which were made
in the laboratory and on the building site, are in good agreement
with laboratory methods, such as oxygen permeability, capillary
suction, chloride penetration, etc.
Basic Equipment
- Display unit with
nonvolatile 1 MB memory for up to 200 measured objects
- Display on 128 x 128 graphic LCD.
- Interface RS 232 C
- Intergrated software for printing out
measured objects and transmission to PC
- Operation with batteries for 60 h or
commercial 9 VDC/0.2 A power unit
- Temperature range -10 to +60 degrees
Celsius
- Carrying case 320/285/105
mm, total weight 2.1 kg
- Control unit with
membrane pressure regulator and pressure sensor. Vacuum
connection: small flange 16 KF
- Carrying case 520/370/125
mm, total weight 6.3 kg.
Note: The unit is operated
with a commercial vacuum pump. (Not Included) Technical data according to DIN
28400: Suction capacity 1.5 m3/h, final total pressure 10 mbar, suction side
connection: small flange 10 KF/16 KF, high water vapor
toleration.
Accessory:
Active probe for determination of the
concrete resistance p according to Wenner. The
measured values are stored in the display unit for the
respective object.
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