Using lattice and hollow architected polymeric reinforcement to improve flexural performance of cementitious composite

Engineered materials, unlike natural counterparts, often suffer from obtaining competing mechanical properties. This study examines the mechanical properties of 3D-printed polymeric reinforcements with architected designs of cementitious composites inspired by natural reinforcement. A systematic process was developed to determine the reinforcement configurations with different architected design motifs while maintaining the reinforcement ratio constant. Using three-point bending tests, two classes of reinforcements were investigated: (1) lattice-architected polymer including Sinusoidal, Hexagonal, and Kagome, and (2) hollow-architected polymer including Simple and Hierarchical hollow tube(s). Micro-computed tomography ( µ -CT) was utilized to investigate the fracture patterns in lattice-architected samples. The flexural behavior of cementitious composite beams was then compared to reference unreinforced mortar beams. The findings illustrate that the modulus of rupture, toughness, and ductility were enhanced by introducing architected 3D-printed polymeric constituents into mortar as reinforcements compared to the unreinforced beam. Hollow reinforcements mechanically outperformed the lattice class in both strength and toughness. µ -CT results demonstrate the presence of crack at the interface of the polymer and cementitious mortar in the composite samples with lattice-architected reinforcement, signifying the importance of interface properties. The composite samples reinforced with hollow-architected polymeric constituents on the other hand, demonstrate reinforcement rupture rather than presence of crack at the interface, contributing to a higher flexural strength and mid-span deflection. • Macro-architectural motifs were introduced in reinforcement design of mortar beams. • Architected reinforcements improved modulus of rupture, toughness, and ductility. • Architectures enhanced the failure mechanism through additional fracture patterns. • Hollow architectures outperformed lattice designs in strength and toughness.