A comparative study of steel- and carbon-fibre cement as piezoresistive strain sensors

Abstract

Carbon-fibre (15 μm diameter) cement is a better piezoresistive strain sensor than stainless steel-fibre (8 μm diameter) cement at a similar fibre volume fraction, as shown by a higher signal-to-noise ratio and better reversibility upon unloading, albeit having a lower gauge factor (particularly under tension). Steel-fibre cement containing 0·36 vol% fibres is a better piezoresistive strain sensor than that containing 0·72 vol% fibres, as shown by better reversibility upon unloading and the higher gauge factor under compression. The difference in performance of carbon- and steel-fibre cement is attributed to a difference in piezoresistivity mechanism.

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.…”

A microstructure-guided numerical approach to evaluate strain sensing and damage detection ability of random heterogeneous self-sensing structural materials

“…For real-scale industrial structures, use of smart composites is gaining popularity in recent times for strainsensing in structures [4][5][6]. In particular, such smart composites achieve damage-sensing capability by utilizing piezoresistivity which is an electromechanical phenomenon that enables certain electrically conductive composites to respond electrically under the influence of strain [7][8][9][10][11][12][13][14]. Electrical resistance methods in these composites have been shown to be sensitive to minor and microscopic changes that include defects or damage [10,[14][15][16] Design of such smart materials requires a reliable numerical method that can predict electro-mechanical response at different length scales.…”

“…In cement-based materials self-sensing capability has been achieved using carbon fibers, steel fibers and carbon nanotubes [7,9,14,17]. Although a variety of experimental studies [8][9][10][11][12][13][14][15]18] report on electro-mechanical response of these systems under tension and compression, limited studies exist on prediction of strain-sensing and damage-detection efficiency in such self-sensing cementitious materials which is the primary goal of this research paper. The numerical simulation framework, presented in this paper, is developed for the first time in order to incorporate an applied strain range that encompasses both the elastic and the post-peak constitutive behavior thereby achieving both strain and damage sensing by electrical measurements in these cementitious matrices.…”

Effect of Moisture on Piezoresistivity of Carbon Fiber-Reinforced Cement Paste

“…Piezoresistivity is a phenomenon in which the electrical resistivity changes with strain. [1][2][3] It allows the detection of strain through electrical resistance measurement. Such detection is needed for structures for the purpose of vibration control, stress monitoring, and load scaling.…”

“…The piezoresistive behavior is relatively weak for cement-based materials reinforced with steel fibers or carbon nanofibers. 2,3 The electrical conductivity of cement-based materials is affected by moisture, as water provides ions that contribute to ionic conduction. Due to a decrease in the amount of free water (which is to be distinguished from water trapped in the hydrate that is formed during the curing reaction), the electrical conductivity of carbon fiber-reinforced cement paste decreases with time during curing.…”