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:
  Accelerated Tests Chlorine Concrete Construction Corrosion Prevention Detectors Electrochemical Corrosion Integrated Circuits Rebar Reinforced Concrete Reinforcing Steels
• 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.
  
  
• Format:
  PDF
• Funding:
  00050930
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:5b2ab5ca5d8bd966dfd5edf512cc0877698420aa2702c49c20ce2783d8e24e0f
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/15677/dot_15677_DS1.pdf
• File Type:
  [PDF - 2.69 MB ]