Integrating Reinforcement with 3D Concrete Printing (2022-06)¶

3DConcrete Printing (3DCP) is a technology that recently has attracted the attention of both academia and industry. The technology offers an increased design flexibility and has been used at various scales, e.g. from furniture to bridges and houses.One ofthe current challenges in 3DCP is to produce load bearing structures in a single process, i.e. reinforced elements as part of 3DCP process. This is because the integration of vertical reinforcement during the printing process is not trivial. Although few reinforcement methods have been studied, a robust and efficient 3DCP reinforcement solution is yet to be coined. To support these studies in finding a reinforcement solution fit for 3DCP, while limiting experimental efforts, we offer a computational fluid dynamics (CFD) model that simulate concrete flow around rebars. The numerical model applies 1) an elasto-visco-plastic constitutive law to mimic the flow behavior of the concrete and 2) the volume of fluid method to track the free surface of the concrete. To validate the proposed model, 3DCP experiments are carried out by printing around horizontal and vertical rebars. The rheological behavior of the concrete is characterized on a rheometer using a vane-in-cup measuring system, and such data is included in the CFD model. The experimental and numerical results agree relatively well; providing a new venue for identifying printing strategies that ensures a good bonding between concrete and reinforcement.