Development of an embeddable microinstrument for corrosivity monitoring in concrete.

Details

• Creators:
  Kelly, R. G. ; Jones, S. H.
• Corporate Creators:
  Virginia. Dept. of Transportation ; United States. Federal Highway Administration. Office of Engineering Research and Development ; University of Virginia. School of Engineering and Applied Science
• Subject/TRT Terms:
  • Concrete construction
  • Electrochemical corrosion
  • Accelerated tests
  • Chlorine
  • Corrosion prevention
  • Detectors
  • Electrochemical corrosion
  • Integrated circuits
  • Rebar
  • Reinforced concrete
  More +
• Publication/ Report Number:
  VTRC 00-CR1 ; FHWANTRC OO-CRI
• Resource Type:
  Tech Report
• Geographical Coverage:
  Virginia
• Edition:
  Final Contract, 10/96-6/99
• Corporate Publisher:
  Virginia Transportation Research Council (VTRC)
• Abstract:
  The aim of this program was the development of a small and completely embeddable microinstrument for corrosivity measurement ; in concrete. It should contain all the electronics for the electrochemical measurements, the means for data transfer between engineer ; and device, and sensors sensitive to the different corrosivity parameters. The goals of the work reported here were to develop and ; test the required sensors and electronics in a laboratory setting. ; Sensors for the measurement of corrosion rate, corrosion potential, chloride concentration, and concrete conductivity were ; developed and tested in laboratory-scale concrete slabs. The tests included electrochemical chloride driving as a method for test ; acceleration and wet/dry cycling. The corrosion sensor consists of a piece of reinforcing steel as working electrode, another rebar ; piece or a platinized Nb-mesh as counterelectrode, and an Ag/AgCI electrode as reference electrode. The conductivity sensor is ; based on a modified Wenner four-pin method and made of four parallel Au wires. Both sensors work very well. Chloride ; introduced into the concrete electrochemically induced corrosion on the corrosion sensor, as seen by a decrease in potential and in ; the polarization resistance. The potentials recovered after more than 1000 h of electrochemical chloride removal, but the corrosion ; resistance did not regain its original value. The change in chloride content was monitored by a silver/silver chloride chloride sensor. ; The only present drawback of the microinstrument is the construction of a long-term reliable reference electrode. The best ; candidates seem to be Ni/W galvanic couple and lead. ; A micropotentiostat coupled to a zero-resistance ammeter and a microgalvanostat based on operational amplifiers were designed: and ; heart of a complete measurement system, which includes on two double surface mount boards the ASIC, a microprocessor, control ; circuitry, and connections to the external corrosivity sensors, as well as RF transceiver circuitry for the wireless communication with ; the instrument.
  More +
• Format:
  PDF
• Funding:
  00050930
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/15677/dot_15677_DS1.pdf
• File Type:
  [PDF - 2.69 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:5b2ab5ca5d8bd966dfd5edf512cc0877698420aa2702c49c20ce2783d8e24e0f