Factors Affecting Flowability and Rheological Behavior of 3D Printed Concrete (2026-01)¶

3D printed concrete (3DPC) has emerged as a transformative technology, offering significant advantages through digitization, automation, and intelligent fabrication. However, its effectiveness largely depends on fresh-state properties such as flowability for smooth extrusion and sufficient buildability to retain shape after deposition. This paper presents a comprehensive literature review and bibliometric analysis of 3DPC, utilizing VOSviewer to analyze key academic publications. The study evaluates critical material parameters, including aggregates, cement types, binder ratios, supplementary cementitious materials (SCMs), fiber types and dosages, chemical admixtures, temperature, and waste materials, which influence fresh-state characteristics such as rheological properties, flowability, and printing properties. Additionally, the paper addresses mechanical, durability, and key printing properties, along with cost and market predictions, future challenges, and research directions. The findings indicate that the flowability of SCMs, superplasticizers (SPs), viscosity-modifying agents (VMAs), and fibers strongly correlates with both static and dynamic yield stress, where higher static yield stress enhances layer stability during printing. Incorporating nanomaterials, fibers, and chemical admixtures further improves mechanical performance. Durability is also significantly influenced by the types and combinations of additives used, with air-entraining agents (AEAs) and SCMs improving freeze-thaw resistance, while blends of Metakaolin (MK), silica fume (SF), and fibers effectively manage carbonation and chloride penetration. Additionally, to ensure stable extrusion and adequate interlayer bonding, it is recommended to maintain a D/dmax greater than 3.3. This review provides insights into material selection, mix design optimization, and process control, providing valuable insights for researchers and practitioners in the field of 3DPC industry.