Method of ascertaining fully grown passive film formation on steel rebar embedded in concrete

Abstract

The method of ascertaining fully grown passive film formation on steel rebar embedded in concrete utilizes electrochemical impedance spectroscopy (EIS) to determine, in situ, the degree of passive film formation on steel rebar embedded in concrete. A length of steel rebar and a counter electrode are both embedded in a concrete slab. A reservoir is supported on an external face of the concrete slab and filled with an electrolytic solution. A reference electrode is then positioned in the electrolytic solution, and the length of steel rebar, the counter electrode and the reference electrode are electrically connected an EIS test instrument to perform electrochemical impedance spectroscopy. The quality of passive film formation on the length of steel rebar is determined based on comparison of the electrochemical impedance spectroscopy results with known passive film formation data.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to procedures for testing structural materials used in the construction industry, and particularly to a method of ascertaining fully grown passive film formation on steel rebar embedded in concrete using electrochemical impedance spectroscopy (EIS).[0003]2. Description of the Related Art[0004]Electrochemical impedance spectroscopy (EIS) (sometimes also referred to as “dielectric spectroscopy” or “impedance spectroscopy”) is a technique for measuring the dielectric properties of a medium as a function of frequency. EIS is based on the interaction of an external electric field with the electric dipole moment of a sample, typically expressed by electrical permittivity. EIS is often used as an experimental method for characterizing electrochemical systems. The technique measures the impedance of a system over a range of frequencies, and therefore the frequency response of the system (including ...

AI Technical Summary

Benefits of technology

This patent describes a method for determining the quality of a protective film formed on steel reinforcement embedded in concrete using electrochemical impedance spectroscopy (EIS). The method involves measuring the electrical properties of the steel reinforcement and comparing them to a known pattern of passive film formation. By doing this, the degree of protection provided by the protective film can be determined. The method can be performed in real-time, allowing for the assessment of the quality of the protective film during construction. Overall, this method provides a reliable and non-destructive method for inspecting the quality of protective films on steel reinforcement in concrete.

Problems solved by technology

However, since the rebar is placed in SPS, rather than an actual concrete environment, the EIS results are typically not representative of the actual behavior.

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