Enhancing compressive behaviour of masonry columns using auxetic cementitious composite confinement

Masonry columns play a crucial role in masonry construction as the primary load-bearing elements of structures. However, they are susceptible to sudden failure owing to their inherent brittle nature, causing significant structural destructions. The existing external strengthening techniques are limited to traditional approaches that often involve inevitable challenges. In this study, a novel confinement method is investigated using auxetic cementitious composites (ACC) as external reinforcement to improve the axial compressive behaviour of masonry brick columns. Auxetic materials demonstrate promising confinement competence due to their enhanced energy absorption capacity characterised by a negative Poisson's ratio (NPR) effect.

Masonry brick columns were constructed with two different heights (1 m and 2 m) and confined with ACC as external render incorporating auxetic materials as embedded medium. The effects of the auxetic material type (auxetic fabric and 3D printed auxetic meshes), render mortar type (high strength and low strength) and corner continuity, on the confinement effectiveness were experimentally investigated. The results demonstrated that the columns confined with auxetic fabric and without corner continuity exhibited minor improvements, while the full height columns confined using 3D printed meshes with high strength mortar demonstrated substantial improvements in mechanical properties compared to their unstrengthened columns, achieving increases of 103% in axial load capacity, 314% in ultimate deformation and 607% in energy absorption capacities.