Construction-Scale 3D Printing (2017-06)¶

Building 3D objects in sequential layers is a technique employed by rapid manufacturing processes and allows great design freedom in manufacturing. Scaling up such automated additive fabrication from building small industrial parts to constructing buildings has been challenging for researchers during the recent years. Compared to the traditional construction methods, numerous advantages are offered by a well-developed layer based automated construction process, including architectural design freedom, lower construction cost, superior construction speed, and higher degree of customization. Concrete has been recognized as most viable option as the material to be used with such a process. However, there are several main challenges that yet have to be solved. Obtaining a mixture with high shape stability in the fresh state is among these challenges. Ideally, non-stop printing of successive layers is desired in building a structure, so the total construction time is minimized. In this paper, an experimental investigation of the shape stability of freshly printed concrete layers using a small-scale linear concrete printing setup with remote control capability is outlined. First, longer stoppage time between successive layers is examined to determine the effects on the deformations of fresh printing concrete. Then, heat application is proposed and studied as a measure to improve the shape stability of freshly printed concrete without adding any delay to the construction process. Furthermore, a one-story building is considered and the influence of each scenario on the total construction time is discussed.