Assessment of Smart Fibers for Concrete under Mechanical Stress Mechanical Performance, Piezoresistive Sensing, and Structural Health Monitoring

Smart fibers can give concrete two complementary capabilities: improved resistance tocracking and deformation, and the ability to indicate changes in its mechanical state through measurable electrical or optical signals. This paper presents a theory-based assessment of fiber-reinforced smart concrete under mechanical loading. It distinguishes conventional reinforcing fibers, which primarily bridge cracks and redistribute stress, from conductive or sensing fibers that also enable self-sensing. The mechanisms considered include fiber–matrix load transfer, crack bridging, electrical percolation, contact-resistance change, and, in opticalsystems, strain-dependent changes in transmitted or backscattered light. A constitutive framework is presented to relate stress, strain, damage, and electrical-resistance response,together with practical measures for calibration and experimental evaluation. The analysis emphasizes that fiber type, geometry, dispersion, interface quality, moisture, temperature, and electrode configuration all affect the measured response. No new experimental results are claimed: the proposed equations and test programme are intended as a basis for laboratoryinvestigation and subsequent structural validation. Existing research supports the feasibility of self-sensing cement-based composites, while also identifying repeatability, environmentalinterference, and scale-up as important engineering challenges.