3D concrete printing using computational fluid dynamics: Modeling of material extrusion with slip boundaries

Khalid El Abbaoui*, Issam Al Korachi, Mostapha El Jai, Berin Šeta, Md Tusher Mollah*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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This paper investigates the role of slip boundary conditions in computational fluid dynamics modeling of material extrusion and layer deposition during 3D concrete printing. The mortar flow governed by the Navier-Stokes equations was simulated for two different slip boundary conditions at the extrusion nozzle wall: no-slip and free-slip. The simulations were conducted with two constitutive models: a generalized Newtonian fluid model and an elasto-viscoplastic fluid model. The cross-sectional shapes of up to three printed layers were compared to the experimental results from literature for different geometrical- and speed-ratios. The results reveal that employing free-slip boundary conditions at the extrusion nozzle wall improves layer-mimicking quality for both constitutive models, indicating the presence and importance of a lubricating layer of fine particles at the concrete-solid wall interface. This enhanced performance is primarily due to the observed decrease in extrusion pressure that minimizes layer height- and width-deviations compared to the experimental prints. Furthermore, the free-slip boundary conditions play an important role in predicting the multilayer prints, its deformation and groove shapes.
Original languageEnglish
JournalJournal of Manufacturing Processes
Pages (from-to)448-459
Publication statusPublished - 2024


  • 3D concrete printing
  • Computational fluid dynamics
  • Cross-sectional shapes
  • Elasto-viscoplastic fluid model
  • Generalized Newtonian fluid model
  • Slip boundary conditions


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