3D Printed LC3-Based Lightweight Engineered Cementitious Composites (2024-06)¶

3D concrete printing (3DCP) technology has undergone rapid development and is poised to emerge as a crucial component of intelligent construction due to its expeditious construction process and efficient material utilization. Integrating 3DCP with engineered cementitious composites (ECC) enables self-reinforced construction without placing steel bars. However, the environmental impacts associated with ordinary Portland cement-based printable ECC impose challenges to sustainable development. This study investigates a sustainable ECC for 3DCP applications with the integration of limestone calcined clay cement (LC3) and lightweight fine aggregate. A systematic study of the innovative 3D-printable LC3-based lightweight engineered cementitious composites (LL-ECC) from fresh state to hardened state, accompanied from material level to component level was conducted. The printable mixture was designed through the optimization of the fresh properties of LL-ECC with different fiber contents. The mechanical properties of hardened LL-ECC demonstrated competitive or even superior mechanical performances compared to mold-cast counterparts, including compressive properties, fracture toughness, and shear strength. Moreover, the printed LL-ECC beams exhibited excellent flexural strength and ductility with increase of approximately 40% and 100% than mold-cast beams, respectively. LL-ECC further exhibited significant reductions in material cost, embodied energy and carbon footprint, and higher specific strength compared to those of traditional OPC-ECC. Therefore, LL-ECC is a high-performance and promising composite with balanced printability, mechanical properties, and sustainability in 3D printing.