In situ sensor for critical corrosion conditions in a material
First Claim
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1. An in situ sensor to determine the state of corrosion of rebar in a cement matrix, comprising:
- a test wire having a diameter smaller than the rebar embedded in said matrix;
four electrically conductive leads attached to said test wire for measuring the resistance along a length of said test wire, wherein a portion of said test wire is electrically contacted to a segment of said rebar at points which are recessed and wherein the recessed region is filled with mortar;
a reference wire embedded in said matrix to which four electrically conductive leads are attached for measuring the resistance along a length of said reference wire, said leads of said test wire and said reference wire being connected to a source of electrical current and a means for determining resistance in said test wire and said reference wire.
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Abstract
An in situ sensor for monitoring the degree of corrosion of rebar in a concrete structure relies on a four-point resistance measure of a test wire embedded in the concrete structure. The resistance across the wire is compared with the resistance of a reference wire, which is corrosion resistant. As corrosion advances, the cross-sectional area of the wire decreases, effectively increasing the resistance measured. The sensor may be used to measure corrosion inhibitor performance, and the effect of dilution.
44 Citations
8 Claims
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1. An in situ sensor to determine the state of corrosion of rebar in a cement matrix, comprising:
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a test wire having a diameter smaller than the rebar embedded in said matrix; four electrically conductive leads attached to said test wire for measuring the resistance along a length of said test wire, wherein a portion of said test wire is electrically contacted to a segment of said rebar at points which are recessed and wherein the recessed region is filled with mortar; a reference wire embedded in said matrix to which four electrically conductive leads are attached for measuring the resistance along a length of said reference wire, said leads of said test wire and said reference wire being connected to a source of electrical current and a means for determining resistance in said test wire and said reference wire. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification