by Staff Writers
London, UK (SPX) Jan 30, 2012
Innovative sensors have been developed that will dramatically improve the ability to spot early warning signs of corrosion in concrete.
More resilient and much longer lasting than traditional corrosion sensors they will make monitoring the safety of structures such as bridges and vital coastal defences much more effective.
The carbon steel bars used to reinforce submerged concrete in tidal zone areas are at particular risk of corrosion caused by wet conditions*.
The breakthrough has been made by researchers based at City University London and Queen's University Belfast following several research projects funded by the Engineering and Physical Sciences Research Council (EPSRC).
Because the sensors can withstand long-term placement within concrete - unlike any equivalent sensors currently available - they can constantly monitor conditions, enabling a warning to be sent when conditions for corrosion threshold have been crossed.
Thanks to an internet connection, the notification can be sent in the form of an email or text to the structure's maintenance team.
A trio of novel, robust probes is at the heart of the team's work: one that monitors temperature, one for humidity while the other senses chloride and pH levels. Changes in these factors indicate the onset of the potentially destructive corrosion. Within the probes are advanced optical sensors specifically designed and built for this project in City's laboratories. These have been patented for potential commercial exploitation.
Tong Sun, Professor of Sensor Engineering at City and Principal Investigator on the project says: "Key to this successful prototype is our monitoring the variation of the sensor signals of a sample as an indicator of corrosion levels. This means we can use optical sensors made of polymer, which is much more resistant to the high alkaline environments of these structures than sensors currently on the market."
Traditional optical corrosion sensors have only a limited lifetime, usually of several weeks, because of the corrosive alkaline levels within concrete. The new sensors are expected to last for several years, with proper protection, even where pH levels are higher than 12. For comparison, domestic bleach has a pH value of between 12 and 13.
"Our design means several probes can be installed semi-permanently in a structure and then connected to a computer data logger, which will constantly collect readings.
This can be left until the readings indicate conditions have changed enough to warrant a full investigation. Remedial work will be simpler, cheaper and more effective at this stage, rather than waiting until there is visible damage, such as parts of the concrete coming away," said Professor Sun
Engineering and Physical Sciences Research Council
Water News - Science, Technology and Politics
Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.
Scientists Aboard Iberian Coast Ocean Drilling Expedition Report Early Findings
Washington DC (SPX) Jan 30, 2012
Mediterranean bottom currents and the sediment deposits they leave behind offer new insights into global climate change, the opening and closing of ocean circulation gateways and locations where hydrocarbon deposits may lie buried under the sea. A team of 35 scientists from 14 countries recently returned from an expedition off the southwest coast of Iberia and the nearby Gulf of Cadiz. The ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|