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Product | Measures the Air-Permeability of the Cover Concrete - Swiss Standard Method SIA 262/1

Permea-TORR

 
Main Features
  • Fast
  • Repeatable
  • Non-destructive
  • Fully automatic operation and calibration
  • Compact (fits in single case) and light (9 kg)
  • Used in Africa, Americas, Asia and Europe
  • For more information Download the Brochure
  • Method correlates well with ASTM C1202
    and C1585, EN 12390-8, Carbonation and
    ingress

Typical Applications
  • Durability Control of finished work
  • Condition Assessment of old structures
  • Research
  • Product Development
  • Long-term monitoring of microstructural changes
  
   

Why measure the Air-Permeability of the Cover Concrete?

As the defence barrier against penetration of aggressive species , etc) the permeability of the cover concrete has a
decisive impact on the durability of concrete structures    

Concrete composition, type of formwork, concrete processing and curing are the main factors influencing the quality of the cover concrete; hence the need to measure it on the finished structure. Swiss Standard SIA 262:2003 – “Concrete Construction” states: “The impermeability of the cover concrete shall be checked by means of permeability tests (e.g. air permeability measurements) on the structure or on core samples taken from the structure”.

The Permea-TORR is an instrument designed precisely to serve that purpose: i.e. to measure the permeability to air of the cover concrete
on site, in a fast, repeatable, reliable and non-destructive manner. The results of the Swiss Standard method correlate well with other
durability related tests, such as RCPT (ASTM C1202), Water Penetration (EN 12390-8), Permeability to (Rilem-Cembureau), Capillary
Suction (ASTM C1585), etc. The site air-permeability, measured on old structures, correlates well with depth of Carbonation and Chlorides.

The method is also applicable to other porous materials such as rock, stone, clay products, ceramics, etc.

 

How the Permea-TORR works?

    Vacuum is created inside the 2-chamber vacuum cell, which is sealed onto the concrete surface by means of concentric soft rubber rings, creating two separate chambers.

 

 

When the vacuum reaches 30 mbar, Electro-Valve 2 is closed and the pneumatic system of the inner chamber (green in the diagram) is isolated from the pump.
The air, present in the pores of the concrete beneath, flows through the cover concrete into the inner chamber, raising its pressure Pi.
The rate of increase of pressure Pi is directly linked to the coefficient of air-permeability of the cover concrete.
A pressure regulator maintains the pressure of the external chamber permanently balanced with that of the inner chamber (Pe=Pi). Thus, a controlled unidirectional flow into the inner chamber is ensured and the coefficient of permeability to air kT (m²) can be calculated with the following formula, derived by modelling the test conditions.

 
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