Rheology properties and future trend of 3D printing concrete: State of the art review

3D printing technology has emerged as a major trend in the current development of the construction industry due to its ability to save materials, time, and labor, while enabling rapid construction. However, due to the lack of rigid formwork for support, 3D printing concrete faces challenges in controlling the flow of fresh concrete and the dimensions after curing. Therefore, controlling the rheological properties to ensure the integrity and basic mechanical properties of 3D printing structures has become a key focus for the advancement. This paper employs bibliometric analysis to review relevant literature from the past decade and discusses various factors influencing the rheological properties of 3D printing concrete. First, a series of rheological models proposed by previous studies are examined and compared. Next, the impact of rheological properties on key factors such as pumpability, extrudability, buildability, and open time is discussed, along with an analysis of the various factors that affect these properties. Finally, the experimental methods and standards for assessing rheological properties are compared and summarized, with predictions made regarding the future development prospects and trends for 3D printing concrete. In general, research on the rheological properties of 3D printing concrete and the development of environmentally friendly materials have become key future development directions and research hotspots. To better ensure the calculation and evaluation of rheological properties, the development of appropriate rheological models and rheometers is essential. At the same time, optimizing material mix ratios and incorporating suitable additives can better control the rheological properties and printability. Finally, as the development of rheological, it is crucial to further improve national standards and experimental methods to enhance consistency and reliability in 3D printing concrete applications.