Recent advances in auxetics: Applications in cementitious composites

Abstract

Auxetic materials, possessing negative Poisson’s ratios (NPRs), have the ability to shrink (or expand) in the lateral direction under an axial compressive (or tensile) force respectively. Due to this unique feature, an auxetic material is found to sustain high energy absorption capacity, fracture toughness and shear resistance and thus regarded as one of the future materials in the field of impact protection. However, civil engineering applications of auxetic structures or materials are minimal due to miscellaneous restrictions on NPR effects. Accumulative developments in auxetics have facilitated their applications in cementitious materials in recent years. This paper presents an overview of recent advances in the development of auxetic cementitious composites and analyses and summarises their mechanical properties under different loading conditions. Prior to extensive finite element simulations, more attention has been given to the limited experimental results. Particular attention is paid to the expansionary feasibility of the parent material to introduce auxetic behaviour, with precise identification of the limitations, innovative composition methods and facilitation of auxetic features. Finally, the paper outlines the limitations of the current research and envisages few future research opportunities in auxetic cementitious composites.

Flexural behaviour of cementitious composites embedded with 3D printed re-entrant chiral auxetic meshes

“…The interest in using auxetic material is progressing in the direction of developing auxetic composites of various forms including auxetic cores in sandwich panels [7][8][9][10], auxetic geometries inclusions in polymeric matrix [11][12][13], auxetic tubes inclusions in polymeric foams [14,15], tubes with auxetic fillers [16,17] and polymer/foam filled auxetic structures [18,19]. Another type of auxetic composites is auxetic cementitious composites (ACCs), in which auxetic materials in the form of additively manufactured auxetic geometries, foams or fabrics are embedded into a cementitious matrix [20,21].…”

“…Additive manufacturing of auxetic metamaterials is an alternative option, which has opened opportunities of their applications in ACC. However, research in additively manufactured ACC has only been started recently and is slowly evolving [21].…”