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Description: Electrical resistivity techniques are used to give an indication of the relative permeability of concrete. The ASTM C 1202 (Standard Test Method for Electrical Indication of Concrete's Ability to Resist chloride Ion Penetration), more commonly known as the rapid chloride permeability test (RCPT), is widely specified as a quality control method in concrete construction. However, this test is time consuming and is highly dependent on the chemistry of the pore solution.
This test program studied the relationships between the RCP test and instantaneous resistivity measurements and the relationship between resistivity, or its inverse conductivity, and the rate of diffusion of chlorides into concrete.
Theoretically, conductivity and diffusion are linked by what is known as a formation factor in which, among other things, the resistivity of the pore solution must be known. The feasibility of two methods to obtain the pore solution conductivity was examined. It was hoped that the results obtained from the pore solution conductivity tests could be used to develop a new test to determine chloride diffusion coefficients.
Finally, factors such as presence of reinforcing steel and humidity were examined to determine their effect on concrete resistivity when surface measurements are taken on field structures.
This thesis was developed as part of the educational requirements of the University of New Brunswick under a fellowship grant from the PCA Education Foundation.
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