Project Details
Projekt
Additive manufacturing of free formed reinforced concrete elements by selective binding with calcium silicate cements
Subject Area
Structural Engineering, Building Informatics and Construction Operation
Construction Material Sciences, Chemistry, Building Physics
Construction Material Sciences, Chemistry, Building Physics
Term
from 2014 to 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 257344691
At present, bionically inspired structural elements with an optimized design can only be produced with great difficulty using conventional manufacturing processes. Additive manufacturing processes (3D printing) which permit a large freedom in choice of geometry present a promising alternative. Although such processes are now state of the art in many areas of production, their application in the construction industry has so far only been considered in a small number of research projects. This research project aims at the development of a new method for the application of additive manufacturing processes in concrete construction. The research focusses on the creation of a basic method for the construction of free form concrete structures and the appropriate necessary materials.The proposed manufacturing process >selective binding< is a 3D printing method in the narrower sense. Thin layers of granular material are selectively bound by local introduction of flowable material to form layer by layer a solid which was previously designed using a computer. Two variants of the method are to be investigated: a) In >wet printing< layers of fine aggregate are applied and selectively bound by point introduction of binder paste. b) In >selective activation< a mixture of aggregate and binder powder is applied and the hydration process activated by introducing water.Up to now researchers have only considered the extrusion process for the additive manufacture of concrete elements. This method has the significant disadvantage that the production of overhanging sections is restricted which severely reduces the freedom of geometric design. In the one published project on selective binding for the production of construction elements, Portland cement is not used as a binder. However on account of its geometric freedom, selective binding has the greatest potential for use in construction. In order to build on the wealth of experience in concrete technology in strength, deformation and durability properties of concrete and ensure the availability of the necessary materials, binders based on calcium silicate are considered in the proposed research project. In addition, first attempts in the production of reinforced concrete elements using 3D printing are planned.The feasibility of the chosen approach has been demonstrated in preliminary tests performed by the applicant. Further fundamental research is needed in order to apply the method of selective binding to produce free form concrete elements with high resolution, dimensional stability, strength and durability at a high construction speed.
DFG Programme
Priority Programmes
