Flexural Performance of ECC Thin-Plate Reinforced with Shape Memory Alloy Fibre Fabricated by Extrusion-Based 3D-Printing (2026-04)¶

This study develops hybrid Shape Memory Alloy Fibre-Reinforced Engineered Cementitious Composites (SMAF-ECC) to enhance flexural strength, self-centring capacity, and cyclic resilience. Thin plates were fabricated using both conventional casting and 3D printing and tested under monotonic and cyclic four-point bending. The effects of SMA fibre content 0-1.0% and length 26 mm, 32 mm on crack recovery, stiffness degradation, and crack closure performance were evaluated through Digital Image Correlation (DIC) and finite element (FE) simulations using the Concrete Damaged Plasticity (CDP) model. Results showed that optimal performance was achieved at 1.0% SMA for cast and 0.7% SMA for printed specimens. Compared with plain ECC, initial crack strength and ultimate deflection increased by up to 41.5% and 36.3%, while residual deflection decreased significantly. Specimen with 32 mm SMA fibres exhibited better crack bridging, higher flexural toughness, and improved stress transfer than shorter fibres. Under cyclic loading, SMAF-ECC displayed stable hysteretic loops, high energy dissipation, and notable self-centring, with a recovery factor of 0.85 and an equivalent viscous damping coefficient (ξ) improved by 5-12%. The FE model closely matched experimental responses, validating the observed recovery and energy absorption mechanisms. The proposed 3D-printed SMAF-ECC offers a feasible and scalable approach for constructing lightweight, damage-tolerant, and self-recovering structural elements, suitable for seismic-resilient bridges, protective panels, and modular infrastructure in harsh environments.