3. Electric methods

Title: 3. Electric methods
Author(s): N. Han, A. van Beek, E.A.B. Koenders
Paper category : book
Book title: Advanced Testing of Cement-Based Materials during Setting and Hardening - Final Report of RILEM TC 185-ATC
Editor(s): H.W. Reinhardt and C.U. Grosse
Print-ISBN: 2-912143-81-0
e-ISBN: 2912143705
Publisher: RILEM Publications SARL
Publication year: 2005
Pages: 35 - 79
Total Pages: 45
Nb references: 36
Language: English

Abstract: Electrical methods have been used widely in the last decades to non-destructively determine the changes in the structure. These methods are based on the application of current (direct current DC or alternating current AC) to the structure. By means of the electrical properties of materials, such as electrical resistance (conductivity), dielectric constant, polarization resistance, etc, the changes in the material can be measured. The applications of the electrical methods in the concrete firstly focused on the electrical resistance (conductivity) to investigate the setting behaviour of high-alumina and Portland cement pastes [Calleja (1952), (1953a) and (1953b)]. Then this method has been used to determine the bulk density, aggregate-cement paste interface microstructure, aggregate content, strength development and ionic diffusivity [Wittington et al. (1981), McCarter et al. (1988) and Xie et al. (1993)]. In addition, this method has been widely used to investigate the corrosion of reinforcement by means of fixing of the moisture situation in the concrete [Bungey and Millard (1996), Malhotra and Carino (1991)]. In early 90's, Alternating Current Impedance Spectroscopy (ACIS) method was firstly suggested by McCarter and Brousseau (1990) for studying the hydration process of cement. This method was further developed and applied by Scuderi et al. (1991), Brantervik et al. (1991), Gu et al. (1992), Christensen et al. (1992a, 1992b) to investigate the hydrated cement paste. Later on, the microstructure of the cement paste, its porosity and other properties were also studied by using of ACIS method. [Gu et al. (1993), Christensen et al. (1994) and Ford et al. (1998)]. The physical and chemical state of cement hydration was also studied by focusing on the dielectric constant [McCarter et al. (1984)]. To achieve an accurate measurement of electric resistivity for cement-based material, a non-contacting device was invented [Li et al. (2003)]. By means of this device the hydration process of cement pastes with different water cement ratio was monitored. A microstructure-based model was developed to account for the dielectric properties of cement based materials [Ford et al. (1997)]. Recently, research on the dielectric properties of young concrete in relation to the strength development has brought the new prospect as far as the practical application of the electrical method is concerned [van Beek (2000)].

In this paper critical review has been carried out concerning the electrical method and its application. Special attention has been paid on Alternating Current Impedance (ACIS) Method and the dielectric method. Other applications of the electrical method can be found in the books of Bungey and Millard (1996), Malhotra and Carino (1991), Schickert and Wiggenhauser (1995) and Skalny and Mindess (1995). This paper is specially prepared as one of the chapters in the state-of-the-art report of RILEM Committee TC ATC (Advanced testing of cement based materials during setting and hardening).

Online publication: 2006-09-22
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143705.003