Design and mechanical performance of perforated and core-filled SIFCON-based compression-yielding (CY) blocks: An experimental study

Compression-yielding (CY) mechanisms have recently been proposed as an effective strategy to enhance ductility and damage control in fibre reinforced polymer (FRP)-reinforced concrete systems, where brittle tensile failure often governs structural response. By introducing a ductile compressive zone that undergoes controlled yielding, CY systems enable improved deformation capacity and delay catastrophic failure. This study proposes a SIFCON-based CY block design with engineered perforations and investigates its compressive behaviour through an experimental programme. Specimens with solid, perforated, and core-filled configurations were tested under uniaxial compression, considering variations in perforation number, diameter, arrangement, and hydrophobic core filling. The results show that the solid specimen exhibited the highest strength but a brittle response, while perforated specimens achieved improved ductility and more stable post-peak behaviour. The mechanical response was governed primarily by perforation arrangement rather than void ratio alone, with a three-column configuration providing more effective stress redistribution. Core filling produced configuration-dependent effects, enhancing performance when effective confinement was achieved, but reducing ductility in some cases due to stiffness mismatch and interfacial debonding. The findings provide practical design guidance for CY blocks and confirm their effectiveness as compression fuses for ductile and damage-controlled structural systems.