Impedance-based characterization and equivalent circuit modeling of recycled carbon fiber-enabled self-sensing cementitious composites

Document Type

Article

Publication Date

5-23-2026

Abstract

Electrical impedance in self-sensing cementitious composites (SSCCs) responds to mechanical loading through the piezoresistive effect, enabling intrinsic strain and damage sensing. As such, SSCCs represent a promising alternative to conventional structural health monitoring (SHM) systems due to their sensing efficiency, material compatibility with concrete infrastructure, and cost-effectiveness. These properties are typically achieved through the incorporation of electrically conductive fillers. In this study, recycled milled carbon fiber (mCF) was investigated as a cost-effective, environmentally sustainable conductive filler capable of enabling the large-scale implementation of SSCC. The effect of recycled mCF on enhancing the compressive strength, durability property, and promoting self-sensing capability was evaluated. The incorporation of recycled mCF led to higher compressive strength and lower chloride ingress, as evidenced by portlandite quantification alongside microstructural and porosity analyses. Furthermore, recycled mCF content of 0.5 wt% or higher significantly enhanced the self-sensing performance of the composites, with the highest stress sensitivity being 0.73 %/MPa. Additionally, by leveraging the varied impedance response of concrete phases, an indirect evaluation of pore structure is possible. To this end, to interpret the impedance spectra of SSCCs, a physically grounded model that closely correlates experimental data was developed and proposed. A quantitative relationship between porosity and the mCF dosage with key circuit parameters of this model was established. The modeling framework developed in this study serves as a basis for exploring potential relationships between electrical response and pore structure in cementitious composites.

Publication Source (Journal or Book title)

Construction and Building Materials

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