Continuous and adaptable printing path based on transfinite mapping for 3D concrete printing

Abstract

Three-dimensional (3D) concrete printing is an advanced and promising construction method that shows great development potential in the field of construction engineering owing to its highly flexible and intelligent characteristics. The printing path design that is directly related to the 3D printing process is usually limited by the time-dependent rheological properties of concrete composites and the nozzle opening of the print head. Improper path design is liable to disruption, interfacial defects, self-intersection, and even a certain amount of unfilled areas. This paper proposes a flexible and adaptive transfinite mapping method for the path planning of 3D concrete printing by properly mapping a predetermined continuous-type path to the digital model to be printed. This method combines the morphological features of the digital model and path types to achieve a high-quality and high-continuity adaptive printing path. Meanwhile, the relationship between the extrusion process parameters of cementitious composites is experimentally measured and subsequently incorporated into the path design program to realize zero-gap printing by in-process controlling the extrusion parameters. The advantages of this method in adapting to the diversity of morphological features and path types are verified by a set of free-form structures, and the applicability is experimentally validated.