Self-healing strain-hardening concrete cover

An experimental study is carried out to investigate the structural behaviour and durability performance of hybrid reinforced concrete beams with U-shaped covers made via mould-casting method and 3D printing method.Structural behaviour, surface crack pattern and crack propagation between the reinforced concrete core and U-shaped SHCC cover are studied.A qualitative assessment of the crack appearance before and after healing was also performed.Findings reveal that mouldcasted SH-SHCC covers enhance crack control without compromising beam properties, offering comparable or improved load capacity and ductility under shear and flexure.Although 3D-printed covers are slightly less effective in crack control, they still improve overall performance and offer advantages in manufacturing efficiency.Both cover types effectively prevent delamination and disperse major cracks into finer, healable cracks, facilitating crack healing observed after one-month moist curing.