Evaluating the Chloride Absorption of Unsaturated Cover-Concrete Using Electrical Measurements

• Published in: KSCE journal of civil engineering Vol. 26; no. 3; pp. 1354 - 1364
• Main Authors: Kim, Jaehwan, You, Young-Jun
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Civil Engineers 01.03.2022; Springer Nature B.V; 대한토목학회
• Subjects: Absorption; Cement; Chloride; Chlorides; Civil Engineering; Concrete structures; Conduction; Corrosion; Electrical conductivity; Electrical measurement; Electrical resistivity; Engineering; Frequency ranges; Geotechnical Engineering & Applied Earth Sciences; Impedance; Impedance measurement; Industrial Pollution Prevention; Moisture content; Portland cement; Portland cements; Reinforced concrete; Reinforcing steels; Sodium chloride; Structural Engineering; Water content; 토목공학; Acceptable frequency; Concrete; Chloride; Absorption; Electrical conductivity
• ISSN: 1226-7988; 1976-3808
• DOI: 10.1007/s12205-021-5138-8

To avoid chloride induced corrosion of steel in reinforced concrete structures, it is firstly important that the chloride amount in cover concrete is quantified. This study investigates the influence of chlorides on the electrical conductivity of Portland cement concretes through a chloride absorption test conducted over a wide frequency range (10 H z–1 MHz). To this end, the concretes were exposed to 10% NaCl solution for up to 48 h. In addition to calculating the sorptivity of concrete, its electrical conductivity was de-embedded from the impedance measurements, fitted to the Jonscher equation to determine the bulk conductivity, and presented in the frequency domain to investigate the main conduction processes with chloride penetration. Further, chloride profiling was performed to quantify the chloride concentration and identify the transport behaviour within concrete. Ionic conduction was shown to be the main conduction process in concrete containing absorbed chlorides, and the amount of absorbed chlorides was shown to have a linear relationship with the conductivity. In addition, the acceptable frequency range for representing the bulk conductivity of Portland cement concretes was confirmed to be 450 Hz–1 kHz. Moreover, the moisture content was shown to be an important factor in the impedance measurement.