Combined additive manufacturing processes for reinforced concrete elements

增材制造技术可以自动化生产几乎任何形状和使用各种材料的组件。作为建筑行业的一个感兴趣的问题，许多研究项目都集中在无钢筋混凝土构件的生产上。特别是近年来，许多著名的项目已经证明了增材制造技术在建筑行业的潜力。这种创新制造方法的下一步发展是静态相关组件的制造。在这种情况下，为了传递荷载产生的拉力以及确保静态相关混凝土构件的延性破坏行为，加固元件的集成是不可缺少的。在集成增强元件时，该工艺一方面必须保证增材制造方法的灵活性和效率，另一方面必须保证增强材料的有效利用。因此，有必要开发组合制造方法，在获得设计自由的同时提供与周围材料的适当结合。提交的研究项目的目的是对组合增材制造技术进行基础研究和探索性比较评估，以将钢筋元件自动集成到混凝土构件的增材制造过程中。到目前为止，研究状况仍处于起步阶段，大量的技术竞争对手是同时对几种技术进行调查的动机，目的是进行评估。有几种类型的勘探技术，这些技术是在实验室规模上同时开发和研究的。在此基础上，通过实验确定与生产相关的特性值（例如生产率）以及部件特性（例如强度），并在矩阵式概览中进行比较。对基础研究的需求源于有趣的增强方法与材料高效增材制造技术的高度组合多样性，以及对这些技术组合的实验评估，这些技术组合到目前为止尚未被研究。作为混凝土基质增材制造的技术方法，将考虑两种工艺：a）挤出沉积3D打印和B）喷射混凝土3D打印。对于增强元件的生产，a）纤维粗纱的沉积，B）借助于附加焊接工艺的钢筋的生产和c）机器人支持的短钢筋的插入被比较地检查。由于生产自动化领域的跨学科合作（K。Dröder），组件结构设计（H. Kloft）和材料科学（D. Lowke），使所需的跨域研究成为可能。

Additive manufacturing techniques enable the automated production of components of almost any shape and using various materials. As a matter of interest in construction industry, many research projects have focused on the production of unreinforced concrete components. In particular, in recent years numerous prestigious objects have demonstrated the potential of additive manufac-turing techniques for the construction industry.The next step in the development of this innovative manufacturing method is the fabrication of statically relevant components. In this context the integration of reinforcement elements is indis-pensable in order to transfer tensile forces arising from the load as well as to ensure ductile failure behaviour of statically relevant concrete components. When integrating reinforcement elements, the process must guarantee the flexibility and efficiency of additive manufacturing methods on the one hand and the effective exploitation of the reinforcement on the other hand. Hence, there is the need for developing combined manufacturing methods, which receive the freedom of design and provide a proper bond with the surrounding material at the same time.The aim of the submitted research project is the fundamental investigation and explorative-comparative assessment of combined additive manufacturing technologies for the automated integration of reinforcement elements into the additive manufacturing process of concrete components. Until now the state of research is still at the beginning and the large number of technology competitors is the motivation of simultaneous investigation on several technologies with the aim of an evaluation. There are several types of technologies for the exploration, which are developed and investigated simultaneously and experimentally on a laboratory scale. Based on that, production-related characteristic values (e.g. productivity) as well as component characteristics (e.g. strength) are determined experimentally and compared in a matrix-like overview. The need for fundamental research derives from the high combinatorial diversity of interesting reinforcement approaches with material efficient additive manufacturing techniques as well as the experimental evaluation of these technology combinations, which haven’t been investigated until now. As a technology method for the additive manufacturing of the concrete matrix two processes will be considered: a) extrusion-deposition 3D printing and b) Shotcrete 3D printing. For the production of reinforcement elements, a) the deposition of fibre rovings, b) the production of steel bars by means of an additive welding process and c) the robot-supported insertion of short reinforcement bars are comparatively examined. Due to the interdisciplinary cooperation in the fields of production automation (K. Dröder), design of component structure (H. Kloft) and materials science (D. Lowke), the required cross-domain research is enabled.