Three-dimensionally printed polymer lattices can toughen cementitious composites, yet how single-lattice optimisations govern fracture remains unclear. In this work, body centred cubic (BCC) lattices and two equal-mass variants (rod thickening (BCC-T) and rib addition (BCC-R)) were investigated under three-point bending using multi-modal non-destructive testing methods: acoustic emission (AE), digital image correlation and X-ray computed tomography (XCT). Compared with plain cement, the lattices markedly increased flexural capacity; BCC-T attained the highest peak load, whereas BCC-R delivered greater ductility and a smaller maximum crack width with earlier multi-crack formation. AE ringing counts and cumulative energy delineated a staged damage evolution, with lattice reinforcement redistributing energy over longer stable growth. Rise time/amplitude ratio and average frequency clustering indicates a higher share of shear cracks with lattices; rod thickening yielded up to 90.34% shear events. XCT showed that cracks initiated preferentially at the lattice–matrix interface, confirming this as the critical weakness; failures comprised matrix cracking, interfacial debonding and local lattice rupture. Overall, rod thickening mainly enhances stiffness and peak load, while rib addition improves damage tolerance and crack-width control. The findings provide mechanism-based guidance for optimising architectural lattices in cement-based composites.
Li et al. (Tue,) studied this question.