TRR Project A03: Near-Nozzle Mixing for Functionally Graded 3D Concrete Printing

Project A03 is part of the Collaborative Research Centre TRR 277 “Additive Manufacturing in Construction (AMC)” and focuses on the development of advanced extrusion-based 3D concrete printing technologies. The project addresses one of the key limitations of conventional extrusion-based 3D concrete printing: the conflict between pumpability and buildability. Conventional systems require fresh concrete or mortar to be transported over relatively long distances before reaching the printing nozzle, which restricts the use of stiff mixtures, large aggregates, lightweight aggregates, and other pressure-sensitive materials.

To overcome these limitations, Project A03 develops the Near-Nozzle Binder-Aggregate Mixing (NNBAM) concept. In this approach, a pumpable cementitious paste is transported separately to the print head, where aggregates are continuously dosed and mixed immediately before extrusion. The system enables the production of different printable materials, including natural-sand mortar, lightweight mortar, and recycled-aggregate mortar. More importantly, the material composition can be modified during printing, enabling the fabrication of functionally graded concrete (FGC) with spatially varying density, stiffness, strength, and other material properties.

Ultimately, Project A03 aims to establish a flexible manufacturing strategy in which material is placed according to local structural and functional requirements. By combining additive manufacturing with controlled material grading, the project seeks to reduce material consumption and component weight while maintaining required structural performance, contributing to more resource-efficient and sustainable concrete construction.

Finanzierung und Unterstützung

Dieses Projekt wird von der Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) finanziert – project number 414265976. 

Für die finanzielle Unterstützung möchten wir uns an dieser Stelle bedanken.