Self-recovery and mechanical behavior of SMAF-ECC under monotonic and cyclic tensile loading with constitutive model

This research investigates the axial tensile behavior and self-healing properties of Shape Memory Alloy (SMA) fiber-reinforced Engineered Cementitious Composite (ECC) for enhanced crack recovery and strain performance. The study addresses the limitations of conventional ECC through the integration of SMA fibers, optimizing strain improvement and mechanical recovery under monotonic and cyclic loading. SMA fiber volume fractions of 0 %, 0.5 %, 0.75 %, and 1.0 %, geometries straight, indented, hooked, and surface treatments sandblasting and abrasive paper were systematically explored to assess their effects on crack closure, strain capacity, and self-healing behavior. Experimental findings show that the use of sandblasted hooked fibers significantly improves the strain capacity, achieving up to 15 %, while enhancing crack recovery and tensile strength. Notably, hooked fibers demonstrated a 40 % improvement in self-healing capacity compared to the control mix. The indented fibers showed a 30 % improvement, and linear fibers showed a 15 % improvement in self-healing capacity. Digital Image Correlation (DIC) was employed to monitor crack propagation and recovery during cyclic loading. The optimal performance was observed at a 0.75 % fiber volume fraction, balancing mechanical strength and ductility. A constitutive model was created to predict the tensile behavior of SMAF-ECC, using key parameters like initial crack stress, peak stress, ultimate strain, and damage factor. SHAP (Shapley Additive Explanations) analysis was employed to understand how fiber geometry, surface treatment, and volume fraction influence tensile behavior, offering data-driven insights into the model’s accuracy. • Enhanced crack recovery with SMA fibers in ECC. • Optimal self-healing at 0.75 % hooked fiber volume. • Sandblasted fibers boost strain capacity by 15 %. • Constitutive model predicts tensile behavior accurately. • Systematic evaluation of fiber effects on performance.