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    Volume 8, Issue 1

    Activation Energy of Conduction for Use in Temperature Corrections on Electrical Measurements of Concrete

    (Received 29 April 2018; accepted 20 December 2018)

    Published Online: 2019

    CODEN: ACEMF9

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    Abstract

    The formation factor obtained through electrical resistivity measurements is becoming a popular method to determine transport properties of concrete. Resistivity measurements are dependent on multiple factors, including degree of saturation, pore solution conductivity, and temperature. The Arrhenius equation is used to correct electrical resistivity for temperature effects using an activation energy of conduction (Ea-cond). This parameter has been measured on a wide variety of materials, including pore solutions, pastes, mortars, and concretes (with a variety of saturation states). The reported values of Ea-cond typically range from 9 to 39 kJ/mol. This article examines the factors affecting Ea-cond in order to select an appropriate temperature correction. In this study, Ea-cond was determined from data measured on various concrete mixtures used in transportation infrastructure applications as well as extracted and simulated pore solutions. The Ea-cond of pore solutions remains relatively constant (an average value of 13.9 ± 1.5 kJ/mol) for typical pore solutions and was slightly lower than the Ea-cond of saturated specimens (an average value of 15.8 kJ/mol). It was found that Ea-cond increases as the degree of saturation of the specimen is reduced. Drying increases the ionic concentration of the fluid in the pores; however, this does not explain the changes in Ea-cond. The effects of drying were determined to be primarily due to a change in the volume of the conductive fluid film in the concrete and in the connectivity of the fluid-filled pores. While it is better to directly measure the Ea-cond of a concrete mixture, this is not always feasible or practical. In such cases, for pore solutions, a value of 13.9 kJ/mol can be used, and for saturated concretes, a value of 15.8 kJ/mol can be used. For concretes with a varying degree of saturation, the Ea-cond can be estimated using the developed equation.

    Author Information:

    Coyle, Alex T.
    School of Civil and Construction Engineering, Oregon State University, Corvallis, OR

    Spragg, Robert P.
    SES Group & Associates LLC, Turner-Fairbank Highway Research Center, McLean, VA

    Suraneni, Prannoy
    Department of Civil, Architectural, and Environmental Engineering, University of Miami, Coral Gables, FL

    Amirkhanian, Armen N.
    Department of Civil, Construction and Environmental Engineering, University of Alabama, Tuscaloosa, AL

    Tsui-Chang, Marisol
    School of Civil and Construction Engineering, Oregon State University, Corvallis, OR

    Weiss, William Jason
    School of Civil and Construction Engineering, Oregon State University, Corvallis, OR


    Stock #: ACEM20180045

    ISSN:2379-1357

    DOI: 10.1520/ACEM20180045

    Author
    Title Activation Energy of Conduction for Use in Temperature Corrections on Electrical Measurements of Concrete
    Symposium ,
    Committee C09