• Advances in concrete construction
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• v.2 no.3
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• pp.163-176
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• 2014

Essentially, when electrical current flows easily in concrete that has large pores filled with highly connective pore water, this is an indication of a low resistivity concrete. In concrete, the flow of current between anodic and cathodic sites on a steel reinforcing bar surface is regulated by the concrete electrical resistance. Therefore, deterioration of any existing reinforced concrete structure due to corrosion of reinforcement steel bar is governed, to some extent, by resistivity of concrete. Resistivity of concrete can be improved by using SCMs and thus increases the concrete electrical resistance and the ability of concrete to resist chloride ingress and/or oxygen penetration resulting in prolonging the onset of corrosion. After depassivation it may slow down the corrosion rate of the steel bar. This indicates the need for further study of the effect of electric arc furnace dust (EAFD) addition on the concrete resistivity. In this study, concrete specimens rather than mortars were cast with different additions of EAFD to verify the electrochemical results obtained and to try to understand the role of EAFD addition in influencing the corrosion behaviour of reinforcing steel bar embedded in concrete and its relation to the resistivity of concrete. The results of these investigations indicated that the corrosion resistance of steel bars embedded in concrete containing EAFD was improved, which may link to the high resistivity found in EAFD-concrete. In this paper, potential measurements, corrosion rates, gravimetric corrosion weight results and resistivity measurements will be presented and their relationships will also be discussed in details.

• Computers and Concrete
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• v.15 no.3
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• pp.461-471
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• 2015

The permeability is the most direct indicator to reflect the durability of concrete, and the testing methods based on external electric field can be used to evaluate concrete permeability rapidly. This study aims to use an experiment method to accurately predict the permeability of concrete box beam during service. The ion migration experiments and concrete surface resistivity are measured to evaluate permeability of five concrete box beams, and the relations between these results in service concrete and electric flux after 6 hours by ASTM C1202 in the laboratory are analyzed. The chloride diffusion coefficient of concrete, concrete surface resistivity and concrete 6 hours charge have good correlation relationship, which denote that the chloride diffusion coefficient and the surface resistivity of concrete are effective for evaluating the durability of concrete structures. The chloride diffusion coefficient of concrete is directly evaluated permeability of concrete box beam in service and may be used to predict the service life, which is fit to engineering applications and the concrete box beam is non-destructive. The concrete surface resistivity is easier available than the chloride diffusion coefficient, but it is directly not used to calculate the service life. Therefore the mathematical relation of the concrete surface resistivity and the concrete chloride diffusion coefficient need to be found, which the service life of reinforced concrete is obtained by the concrete surface resistivity.

• International Journal of Concrete Structures and Materials
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• v.9 no.1
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• pp.119-132
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• 2015

Electrical resistivity is an important physical property of portland cement concrete which is directly related to chloride induced corrosion process. This study examined the electrical surface resistivity (SR) and bulk electrical resistivity (BR) of concrete cylinders for various binary and ternary based high-performance concrete (HPC) mixtures from 7 to 161 days. Two different types of instruments were utilized for this investigation and they were 4 point Wenner probe meter for SR and Merlin conductivity tester for bulk resistivity measurements. Chronological development of electrical resistivity as well as correlation between two types of resistivity on several days was established for all concrete mixtures. The ratio of experimental surface resistance to bulk resistance and corresponding resistivity was computed and compared with theoretical values. Results depicted that bulk and SR are well correlated for different groups of HPC mixtures and these mixtures have attained higher range of electrical resistivity for both types of measurements. In addition, this study presents distribution of surface and bulk resistivity in different permeability classes as proposed by Florida Department of Transportation (FDOT) specification from 7 to 161 days. Furthermore, electrical resistivity data for several HPC mixtures and testing procedure provide multiple promising options for long lasting bridge decks against chloride induced corrosion due to its ease of implementation, repeatability, non-destructive nature, and low cost.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.27-33
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• 2014

Electrical resistivity of concrete can be measured in a more rapid and simple way for estimating durability of the concrete, however, carbonation causes a result of misleading for durability testing because carbonation leads to a significant reduction in the permeability and porosity of concrete. The purpose of this study is to estimate and quantify the effect of carbonation of concrete on a surface electrical resistivity measurement. Samples of three mixes with difference w/c were prepared and exposed in a carbonation chamber for 330 days. The results show that carbonation leads high electrical resistivity. The increase is substantial and has been shown to proportional to the extent of the carbonation by some of extent. The relationship between electrical resistivity and carbonation depth is taken in the study. Resistivity ratio of carbonated concrete to air concrete decreased significantly from the specific carbonation depth, however, resistivity ratio of carbonated concrete to air concrete had a linear relation with carbonation depth. From the relationship between electrical resistivity and carbonation depth, it is expected that the result should be subsequently used as a calibration curve for estimating carbonated concrete to overcome the interruption effect of carbonation on regular measurements of the electrical resistivity.

• Computers and Concrete
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• v.19 no.5
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• pp.467-475
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• 2017

The purpose of this study is to establish a prediction model for the electrical resistivity ($E_r$) of self-consolidating concrete by using waste LCD (liquid crystal display) glass as part of the fine aggregate and then, to analyze the results obtained from a series of laboratory tests. A hyperbolic function is used to perform nonlinear multivariate regression analysis of the electrical resistivity prediction model, with parameters such as water-binder ratio (w/b), curing age (t) and waste glass content (G). Furthermore, the relationship of compressive strength and electrical resistivity of waste LCD glass concrete is also found by a logarithm function, while compressive strength is evaluated by the electrical resistivity of non-destructive testing (NDT). According to relative regression analysis, the electrical resistivity and compressive strength prediction models are developed, and the results show that a good agreement is obtained using the proposed prediction models. From the comparison between the predicted analysis values and test results, the MAPE value of electrical resistivity is 17.0-18.2% and less than 20%, the MAPE value of compressive strength evaluated by $E_r$ is 5.9-10.6% and nearly less than 10%. Therefore, the prediction models established in this study have good predictive ability for electrical resistivity and compressive strength of waste LCD glass concrete. However, further study is needed in regard to applying the proposed prediction models to other ranges of mixture parameters.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.90-96
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• 2014

The electrical resistivity of concrete can be related to two processes involved in corrosion of reinforcement: initiation (chloride penetration) and propagation (corrosion rate). The resisistivity of concrete structure exposed to chloride indicates the risk of early corrosion damage, because a low resistivity is related to rapid chloride penetration and to high corrosion rate. Concrete resistivity is a geometry-independent material property that describes the electrical resistance, which is the ratio between applied voltage and resulting current in a unit cell. In previous study, it was realized that the resistivity of concrete depended on the moisture content in the concrete, microstructural properties, and environmental attack such as carbonation. The current is carried by ions dissolved in the pore liquid. While some data exist on the relationship between moisture content on electrical resistivity of concrete, very little research has been conducted to evaluate the effect of chloride on the conduction of electricity through concrete. The purpose of this study is to examine and quantify the effect of chloride content on surface electrical resistivity measurement of concrete. It was obvious that chloride content had influenced the resistivity of concrete and the relationship showed a linear function. That is, concrete with chloride ions had a comparatively lower resistivity. Decreasing rate of resistivity of concrete was clear at early time, however, after 50 days resistivity was constant irrespective of chloride concentration. Conclusively, this paper suggested the quantitive solution to depict the electrical resistivity of concrete with chloride content.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.57-63
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• 2017

PURPOSES : The pole electrode method damaged the concrete pavement on inserting the electrode into the pavement surface. This study examined the feasibility of the flat electrode method to observe the concrete pavement instead of the pole electrode method and analyzed the resistivity characteristics of the concrete by performing laboratory tests. METHODS : The resistivity of the concrete specimens manufactured with three different mixing ratios (38.50%, 39.50%, and 40.50%) were measured using the pole and flat electrode methods according to the concrete age (7 and 28 days) and electrode spacing (20 mm, 30 mm, and 40 mm). RESULTS :In both pole and flat electrode methods, the resistivity increased with increasing fine aggregate proportion regardless of the concrete age. The resistivity measured at a concrete age of 28 days was slightly larger than that measured at 7 days. In the case of a concrete age of 7 days, the resistivity measured by the flat electrode method was larger than that measured by the pole electrode method. The difference disappeared at 28 days. CONCLUSIONS :The results suggest that the flat electrode method can replace the pole electrode method because the resistivity measured by both methods was similar. Hence, the development of a technology to apply the flat electrode method to actual concrete pavement is necessary.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.6
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• pp.122-129
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• 2013

Since electrical resistivity of concrete can be measured in a more rapid and simple way than chloride diffusivity, it should be primarily regular quality control of the electrical resistivity of concrete which provides the basis for indirect of quality control of chloride diffusivity during concrete construction. If this is realized, the electrical resistivity of concrete can be a crucial parameter to establish maintenance strategy for marine concrete structures. The purpose of this study is to develop, design and test a surface electrical resistivity measurement protocol. Microstructural affecting factors such as capillary water, porosity, tourtousity, and so on, on the electrical resistivity of concrete were examined taking into account for mixing proportion properties, and hydration stage. This study can provide a non-destructive approach for durability design of marine concrete. From the relationship between electrical resistivity and chloride diffusivity, it is expected that the result is subsequently used as a calibration curve for an indirect control of the chloride diffusivity based on regular measurements of the electrical resistivity during concrete construction.

• Computers and Concrete
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• v.21 no.1
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• pp.1-9
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• 2018

Electrical resistivity is a property associated with both the physical and chemical characteristics of concrete. It allows the evaluation of the greater or lesser difficulty with which aggressive substances penetrate the concrete's core before the dissolution of the passive film process and the consequent reinforcement's corrosion begin. This work addresses the steel fiber addition to concrete with two types and various contents from 0% to 1.3%, correlating it with its electrical resistivity. To that effect, 9 different mixes of steel fiber reinforced concrete (SFRC) were produced. The electrical resistivity was evaluated on the on six years aged SFRC by direct measurement at different frequency from 0.1 kHz to 100 kHz. The results indicate that steel fiber content is strongly conditioned by the type and quantity of the additions used. It was also found that long type of fibers has more effect on decreasing the electrical resistivity of concrete than short fibers. Therefore, they increase the corrosion risk of concrete depending on fiber volume fraction and moisture percentage.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.457-459
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• 2006

In this paper was analyzed and compared the resistivity characteristic of concrete between moisture condition and dry condition to measure the variation of resistivity by water after making concrete scale block. The resistivity was decreased when the moisture of concrete block was gradually increased.