Electrical resistivity measurements in steel fibre reinforced cementitious materials

Abstract

This paper reports results from experiments aimed at better understanding the influence of fibre dosage and fibre geometry on the AC frequency needed to determine the DC resistivity of cementitious materials containing steel fibres. Impedance spectroscopy and DC galvanodynamic measurements were performed on mortar prisms with varying fibre reinforcement to determine the matrix resistivity (related to ionic current within the pore solution) and composite resistivity (accounting for both ionic current and electronic current through the fibres). The results showed that adding steel fibres did not significantly affect the DC nor the AC matrix resistivity of the mortar prisms. However, the steel fibres yielded a drastic reduction of the frequency associated to the AC matrix resistivity from ~1 kHz in plain mortar to ~1 Hz in steel fibre reinforced mortar. These findings revealed the need to adequately adjust the frequency in AC resistivity measurements of steel fibre reinforced cementitious materials.

The Effects of Multi-Walled Carbon Nanotubes and Steel Fibers on the AC Impedance and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

“…This behavior has been previously reported [3]. Nevertheless, given that R cusp at low frequency (corresponding to the impedance of the reinforced composite) coincides with R DC(rm) (the four-point DC resistance of the reinforced composite) in conductive fiber/cement composites [3,4,10], we can find the positions of R cusp at high frequency, R cusp at low frequency, and R DC from the Nyquist plots of the HPFRCC. At 0.3% MWCNT and 2.0% steel fiber (Figure 6b), the dual arcs can be observed, and R cusp at high frequency and R rm are significantly decreased, compared with those of HPFRCCs with 0% MWCNT and 2.0% steel fiber.…”

“…The high electrical conductivity of steel fibers can make the HPFRCC conductive. The conductivity of normal-strength concrete, particularly when containing steel fibers and carbon nanotubes (CNTs) [3,4,5,6,7,8,9], has been studied. However, studies on the electrical conductivity of HPFRCCs are lacking.…”

“…However, steel fibers lead to a drastic reduction in the frequency associated with the AC matrix resistivity, ranging from ~1 kHz in plain mortar to ~1 Hz in steel fiber-reinforced mortar. These findings reveal the need to appropriately adjust the frequency while measuring the AC resistivity of steel fiber-reinforced cementitious materials [4].…”

Elucidation of Conduction Mechanism in Graphene Nanoplatelets (GNPs)/Cement Composite Using Dielectric Spectroscopy

“…To overcome such a drawback, different conductive fillers have been indicated as good aggregates to achieve the design of conductive concrete [1,16]. Metal conductive admixtures have been proposed with the addition of steel fibers and micro fibers [17][18][19] and steel shaving [2]. Among the carbon admixtures, graphite [20][21][22], carbon fibers [3,18,19,[23][24][25][26] and graphene [27,28] have been investigated for electrical conductive concretes.…”

Evaluation of Engineering Properties of Calcium Sulfoaluminate Cement-based Concretes Reinforced with Different Types of Fibers

“…The properties of CSA cement-based concretes and particularly their hydration products have been assessed by other researchers [31,32,33]. Additionally, fiber-reinforced concrete (FRC) was developed as a material with enhanced ductility and durability features [34,35,36] and its mechanical and durability properties have been intensively investigated by other researchers. To the best of the authors’ knowledge, there is no previously published work investigating the effect of different fibers on the features of CSA cement-based concrete.…”