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

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.