Flexural behavior of cementitious backfill composites reinforced by various 3D printed polymeric lattices

During underground ore mining, the cementitious backfill composites (CBC) is used as an artificially constructed roof to safeguard workers and equipment. This poses a significant challenge to the flexural performance of the CBC. The aim of this paper is to improve the bending properties of CBC using a 3D printed polymer lattice (3DPPL). We prepared nine different 3D-PPL reinforced CBC. Three different structural units were designed for 3DPPL. Each structure of the 3D-PPL was prepared using 3 different materials. The flexural behavior of 3D-PPL reinforced CBC was investigated by three-point bending tests, digital image correlation (DIC) tomography and x-ray computed tomography (CT). The results show that non-3D-PPL (N-3D-PPL) reinforced CBC is brittle after reaching the ultimate load-carrying capacity and 3D-PPL-reinforced CBC is ductile. OR-3D-PPL is optimal for CBC ductility enhancement with about 136-413 times higher total work in comparison to N-3D-PPL. 3D-PPL can convert CBC from single to multi-crack cracking. The Cube structure is more advantageous for CBC to achieve multi-crack cracking. Cracks in the 3D-PPL reinforced CBC samples were mainly tensile and shear cracks. This work shows that 3D-PPL has great potential to improve the bending performance of CBC and offers a new approach to improving the bending performance of CBC.