Study of Piezoresistive Behavior of Smart Cement Filled with Graphene Oxide.

Rongxin Guo,Yang Yang,Haiting Xia,Yuxia Suo,Feng Yan,Qianmin Ma

doi:10.3390/nano11010206

Rongxin Guo, Yang Yang + Show 4 more

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https://doi.org/10.3390/nano11010206

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Abstract

A cement-based piezoelectric composite, modified by graphene oxide (GO), was prepared to study piezoresistive capacity. The testing confirms that GO is more effective than other carbon nanomaterials at improving piezoresistive sensitivity of cement-based composites, because the content of GO in cement paste was much lower than other carbon nanomaterials used in previously published research. Further investigation indicates that the addition of GO significantly improved the stability and repeatability for piezoresistive capacity of cement paste under cycle loads. Based on experiment results, the piezoresistive sensitivity of this composite depended on GO content, water-to-cement weight ratio (w/c) and water-loss rate, since the highest piezoresistive gauge factor value (GF = 35) was obtained when GO content was 0.05 wt.%, w/c was 0.35 and water-loss rate was 3%. Finally, microstructure analysis confirmed that conductivity and piezoresistivity were achieved through a tunneling effect and by contacting conduction that caused deformation of GO networks in the cement matrix.

Highlights

Construction materials are developed to be multifunctional, including selfhealing, self-sensing and durable
Normal carbon-based nanomaterials used in cement composites include carbon fiber (CF), carbon nanofiber (CNF), carbon black (CB), carbon nanotubes (CNTs) and graphene [6,7]
The coefficients of determination (R ) were quite close to 1, reflecting a high-fitting degree of curves. It shows a quadratic polynomial correlation between electrical resistivities and moisture. This result directly indicated that the graphene oxide (GO)/CC electrical resistivity changes with the decreasing moisture in the (R2 ) were quite close to 1, reflecting a high-fitting degree of curves

Summary

Introduction

Construction materials are developed to be multifunctional, including selfhealing, self-sensing and durable. The drawbacks of traditional sensors (strain gauges, accelerometers, optical fiber sensors, etc.), including poor structural compatibility, low service life and increasing long-term maintenance cost, limit their application. Cement composites filled with conductive fillers such as carbon nanomaterials have attracted more attention because of their resistivity–strain sensitivity to external loadings, i.e., piezoresistivity [3]. Piezoresistive cement-based strain sensors (PCSS) may have industrial applications due to their good compatibility, high sensitivity and durability, and economical future maintenance expenses [4,5]. Normal carbon-based nanomaterials used in cement composites include carbon fiber (CF), carbon nanofiber (CNF), carbon black (CB), carbon nanotubes (CNTs) and graphene [6,7]. CF is one of the first materials used in PCSS, monitoring the health of concrete through the relationship between volume resistivity and compressive stress [8]

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