A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Study on half-cell potential measurement for NDE of rebar corrosion
Corrosion of Reinforcement (rebar) is nondestructively estimated by the half-cell potential measurement. As is the case with other nondestructive testings (NDT), understanding of the underlying principles should be clarified in order to obtain meaningful results. Therefore, the measurement of potentials in concrete is analytically investigated. The effect of internal defects on the potentials measured is clarified numerically by the boundary element method (BEM). Thus, an inverse analysis of the half-cell potentials is developed, taking into account the concrete resistivity. In experiments, reinforced concrete (RC) slabs were corroded by an electrolytic corrosion test. Because the potentials measured on concrete surface are so sensitive to moisture content, concrete resistivity, surface condition and so on, an inverse procedure to convert the potentials on concrete surface into those on rebars is developed on the basis of BEM. It is found that ASTM criterion is practically applicable to estimate corrosion from the potential values converted. By BEM analysis, potentials at the top surface were determined. It is found that potentials at the top surface are amplified due to the presence of the void. It implies that potentials more negative could be measured by the half-cell potential measurement in the case that the void exists inside the concrete cover. The potentials at rebars were computed, to which the ASTM criterion was applied to the estimation of corrosion. Good agreement between predicted corrosive region of rebars and actually corroded region is observed in the intact specimen. In the case of the specimen with a void, it is confirmed that the half-cell potential measurement misleads to more negative values than the actual potentials of the reinforcement. It is found that concrete resistivity of void part is higher than that of no void part. The procedure is improved, taking into account the effect of the void on the concrete resistivity. The applicability of the procedure is confirmed in the experiment of RC slab with a void. Thus, a reliable procedure to identify corroded region of rebars is developed.
Study on half-cell potential measurement for NDE of rebar corrosion
Corrosion of Reinforcement (rebar) is nondestructively estimated by the half-cell potential measurement. As is the case with other nondestructive testings (NDT), understanding of the underlying principles should be clarified in order to obtain meaningful results. Therefore, the measurement of potentials in concrete is analytically investigated. The effect of internal defects on the potentials measured is clarified numerically by the boundary element method (BEM). Thus, an inverse analysis of the half-cell potentials is developed, taking into account the concrete resistivity. In experiments, reinforced concrete (RC) slabs were corroded by an electrolytic corrosion test. Because the potentials measured on concrete surface are so sensitive to moisture content, concrete resistivity, surface condition and so on, an inverse procedure to convert the potentials on concrete surface into those on rebars is developed on the basis of BEM. It is found that ASTM criterion is practically applicable to estimate corrosion from the potential values converted. By BEM analysis, potentials at the top surface were determined. It is found that potentials at the top surface are amplified due to the presence of the void. It implies that potentials more negative could be measured by the half-cell potential measurement in the case that the void exists inside the concrete cover. The potentials at rebars were computed, to which the ASTM criterion was applied to the estimation of corrosion. Good agreement between predicted corrosive region of rebars and actually corroded region is observed in the intact specimen. In the case of the specimen with a void, it is confirmed that the half-cell potential measurement misleads to more negative values than the actual potentials of the reinforcement. It is found that concrete resistivity of void part is higher than that of no void part. The procedure is improved, taking into account the effect of the void on the concrete resistivity. The applicability of the procedure is confirmed in the experiment of RC slab with a void. Thus, a reliable procedure to identify corroded region of rebars is developed.
Study on half-cell potential measurement for NDE of rebar corrosion
Untersuchung der Halbzellen-Potentialmessung zur ZfP von Armierungskorrosion
Kyung, J.W. (author) / Ohtsu, M. (author)
2001
11 Seiten, 13 Bilder, 2 Tabellen, 11 Quellen
(Nicht paginiert).
Conference paper
English
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