The Effect of Viscosity-Modifying Admixture on the Extrudability of Limestone and Calcined Clay-Based Cementitious Material for Extrusion-Based 3D Concrete Printing

Materials

Fred Veer¹  Oğuzhan Çopuroğlu²  Stefan Chaves Figueiredo²  Yu Chen²  Erik Schlangen²  Çağlar Yalçinkaya² 

[1] Faculty of Architecture and the Built Environment, Delft University of Technology, 2628 BL Delft, The Netherlands;Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2628 CN Delft, The Netherlands;

关键词: extrudability;    ram extruder;    limestone and calcined clay;    extrusion-based 3D concrete printing;    viscosity-modifying admixture;   

DOI  :  10.3390/ma12091374

来源: DOAJ

【 摘 要 】

To investigate the effects of viscosity-modifying admixture (VMA) on the extrudability of limestone and calcined clay-based cementitious materials, three mix designs with different dosages of VMA were proposed in this study. The ram extrusion was utilized as an extrusion model for exploring the fresh properties of printable materials. Two methods were used, based on the ram extruder setup—(a) extruding materials with the same extrusion speed at different rest times to determine how the pressure changes with time; (b) extruding materials with different extrusion speeds at the same rest time to investigate the material flow parameters using the Basterfield et al. model. The main findings of this study could be summarized as—(1) the extrusion pressure of all mix designs exhibited an increasing trend with time. At the same tested age, the extrusion pressure under 0.25 mm/s of piston speed was increased and the shape retention of the extruded filaments was enhanced by increasing the dosage of VMA; (2) the correlation between the experimental results and the Basterfield et al. model was excellent (R-squared value: 0.99). The mixture with a higher content of VMA showed an increased elongational yield stress, flow consistency, and shear yield stress.

【 授权许可】

Unknown