2019 Highly Commended - Hawley Wharf, London

Concrete @ your Fingertips

Full list of Nuggets

Measuring gas permeability

Gas permeability tests measure the flow of a gas into the concrete under the action of a pressure gradient.  It overcomes some of the disadvantages of measuring water absorption that include:
 - In concretes that are not fully hydrated, water alters the permeability to be measured
 - A measurement cannot be repeated in the same location
 - The viscosity of water is approximately 100 times greater than that of air, with volume flows
    being far smaller
 - With water, only overpressure can be measured

Tests include the Schonlin air test, Surface Airflow Test (SAT), Vacuum test,  Torrent test, Hong-Parrott, Figg air test, and Autoclam.

Acknowledgement: Concrete Society

Concrete Bookshop - Members receive 40% discount on Concrete Society publications

TR31 Permeability testing of site concrete