Evaluating the Effect of Glass and Carbon Fiber Mesh on 3D-Printed Concrete Performance.

Additive manufacturing of concrete offers reduced waste, faster construction, and design freedom, yet effective reinforcement integration remains a major challenge due to weak interlayer bonding and anisotropy. Most prior studies focus on vertical reinforcement, short fibers, or metallic systems, achieving modest flexural improvements (15-60%). This study evaluates horizontal continuous reinforcement using glass fiber mesh and two carbon fiber meshes (ARMO-mesh 200/200 and 500/500) integrated during 3D printing. The methods include extrusion-based printing of small (four-layer) and beam-like (eight-layer) specimens, both printed and cast, followed by three-point flexural and compression tests at 7 and 28 days under vertical and horizontal loading. The results show that ARMO-mesh 500/500 significantly enhances flexural strength-up to 100% over unreinforced controls (e.g., 24.4 kNm vs. 12.2 kNm in small specimens at 28 days) and ~60% over ARMO-mesh 200/200, while glass mesh provides only marginal gains (~12%). Carbon meshes also improve post-cracking toughness and apparent interlayer cohesion. A pronounced size effect reduces nominal strength in larger specimens. These findings demonstrate that wide-format porous carbon meshes offer a scalable, corrosion-resistant solution for load-bearing 3D-printed concrete elements, advancing automated digital construction.