Flexural Strength of 3D Printed Concrete Beams (2024-09)¶

3D printing in construction allows for diverse, lightweight flexural members with enhanced performance. This study investigated the effects of materials (two cementitious mixtures), reinforcement (barbed wire vs. none), and cross-sections (including Full section, T section, U section, and Hollow section) on 3D printed concrete beam strength. While the mixture with higher compressive strength offered greater moment capacity, the increase in moment capacity was lower than that in compressive strength, suggesting other factors like printing quality and bond strength can influence flexural performance. Barbed wire reinforcement was explored as a viable method for reinforcing concrete in 3D printing and it substantially improved moment capacity for both materials compared to Plain sections, even exceeding ACI standard expectations for cast beams. Utilizing T, U, and H cross-sections achieved material reduction (up to 43%) compared to full sections. The T section exhibited the greatest deflection and ductile failure with the highest material reduction. Full sections offered the highest moment capacity but with high material consumption and a brittle failure mode. H sections offered a balance between moment capacity, material efficiency, and ductile failure, making them suitable for specific applications. However, T and U sections showed reduced moment capacity, likely due to delamination between layers. This research emphasizes the importance of material optimization, strategic reinforcement, and tailored cross-sectional design to achieve superior flexural performance and efficient material usage in 3D printed concrete structures.