Interlayer Reinforcement in Shotcrete-3D-Printing                : The Effect of Accelerator Dosage on the Resulting Bond Behavior of Integrated Reinforcement Bars

Niklas Freund; Dirk Lowke

doi:10.52825/ocp.v1i.72

Authors

Niklas Freund Technische Universität Braunschweig , Institute of Building Materials https://orcid.org/0000-0003-2392-5439
Dirk Lowke Technische Universität Braunschweig , Institute of Building Materials https://orcid.org/0000-0001-8626-918X

DOI:

https://doi.org/10.52825/ocp.v1i.72

Keywords:

Additive Manufacturing in Construction, 3D Concrete Printing, Shotcrete 3D Printing, Interlayer Reinforcement Bars, Pull-out Tests, Micro Level Analysis

Abstract

Additive manufacturing with cement-based materials has recently become increasingly common on construction site. The high degree of freedom in individual geometric shapes, the associated potential for resource-efficient designs, and the high degree of automation could make this technology a milestone in the history of construction industry. Many of the existing manufacturing techniques are initially based on unreinforced concrete. However, for many structural elements, the use of reinforcement is indispensable and therefore the reinforcement integration represents a prerequisite. One promising reinforcement strategy is the use of interlayer reinforcement. This method specifically uses the layered characteristic of the additive manufacturing process by integrating reinforcement between the applied layers. In combination with an adaptive path planning, it is therefore possible to manufacture force-flow-compliant reinforced elements with a minimal increase in process complexity compared to an unreinforced production. However, besides the integration process itself, material-process interactions represent an important research topic. Especially for Shotcrete-3D-Printing, the use of accelerators can significantly change the structural build-up of the applied material and thus effect the bonding ability of the sprayed concrete to the integrated reinforcement element. The present study investigates the effect of accelerator dosage on the bond properties of integrated rebars. The resulting bond is analyzed non-destructively via computed tomography and mechanically by pull-out tests according to RILEM RC6. The results show that the material compaction caused by the sprayed application leads to excellent bond properties. However, by using high accelerator dosages, bond deteriorations can be observed.

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Interlayer Reinforcement in Shotcrete-3D-Printing

The Effect of Accelerator Dosage on the Resulting Bond Behavior of Integrated Reinforcement Bars

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