Self-sensing based full-range prestress-loss quantification for P-FRCM plates

Prestressed fabric-reinforced cementitious matrix (P-FRCM) systems enhance serviceability and fiber utilisation, but their behavior is controlled by complex prestress-loss mechanisms that are not well captured by conventional homogeneous-based models. This study focuses on P-FRCM plates and develops a full-process self-sensing framework for prestress monitoring and loss quantification. A total of 36 P-FRCM plates, comprising 12 test groups with 3 replicates each, were tested with distributed resistance measurements recorded during tensioning, curing, prestress release and subsequent uniaxial tensile loading. The P-FRCM plates exhibit a clear three-stage tensile response: elastic, multiple cracking and fiber-dominated crack widening, whose initial stiffness, cracking load and peak load increase with prestress level but progressively deteriorate when the prestress is maintained for longer than about 14 days. The Mechano-electrical responses show a corresponding evolution, from an elastic regime with ΔR/R₀ = 0.1–0.2% to a multiple-cracking regime with slopes > 0.5% per unit strain, and finally a rupture regime with sensitivities of 1–5% per unit strain, enabling reliable crack localisation. A coupled self-sensing model, combining a micromechanical tensile formulation with a piecewise piezoresistive law, reproduces the full load–displacement and resistance-strain histories and allows the total prestress loss to be decomposed into anchorage slip, mortar compression and time-dependent relaxation. Homogenisation-based theory is shown to be conservative (overestimating loss by up to 20.6%), whereas the self-sensing approach yields more realistic residual prestress (38.69–55.73 MPa).