RESISTIVITY CHARACTERISTICS OF CONCRETE

A series of experiments has been carried out to determine the electrical resistivity characteristics of concrete of different mixes and neat cement pastes. Experimental techniques have been developed which allow accurate measurements to be made with relative ease. The effects of ambient temperature on the value of resistivity determined have been quantified over a practical working range. The effects of temporal variations of the resistivity of the concrete have been established over periods of more than 100 days, i.e. to a point where the rate of change of resistivity has become negligibly small. The electrical resistivity of concrete has been shown to be dependent on mix proportions and water/cement ratio. For a particular mix an increase in water/cement ratio means a decrease in resistivity, i.e. as the strength decreases the resistivity decreases. The resistivity of concrete is dependent on ambient temperature and relationships are given which can account for this variation. As the electrical resistivity of aggregate can be regarded as infinite compared with the resistivity of the paste, the resistivity of a concrete mix is dependent almost entirely on the resistivity of the pastewithin the concrete. The electrical resistivity of concreteis directly related to the rate of hydration of the cement paste within the concrete. This is shown by the fact that the experimental graphs for concrete follow the same trend as those for neat cement pastes, the only difference being that the curves for concrete are displaced upwards.(a) (TRRL)

Media Info

  • Features: Figures; References;
  • Pagination: p. 107-117

Subject/Index Terms

Filing Info

  • Accession Number: 00335032
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Sep 16 1981 12:00AM