PSI - Issue 64

H. Varela et al. / Procedia Structural Integrity 64 (2024) 1427–1434 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 7. Compressive and flexural strength of conventional and 3DP specimens.

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4. Conclusions An experimental study on rheology, printability, and hardened properties of sisal fibers (SF) reinforced 3D printable (3DP) mortars for architectural applications was presented. Two length of SF (13 and 6.5mm) and three volumetric fractions (VF) (0.5, 1, and 1.5%) were considered. The experimental results of conventionally casted and 3DP specimens were compared. The main findings of the study are summarized next: • Flow table test (FTT) and cone-penetration test (CPT) were useful methods to characterize rheology of printable SF mortars. Besides, these methods showed a good correlation between their measured parameters. FTT was a little more precise than CPT, showing higher differences between mixtures studied due to mortar consistency used. • All mixtures were extruded with a manual extruder system without problems. However, robotic 3D printer showed some issues in mixtures with higher amounts of SF (more than 1%), as pumping blockage. Printing process produced the alignment of fibers inside the printed filament. • The addition of fibers and 3DP process affected the physical and mechanical properties of mortar, due to the effect of fibers and the alignment produced by extrusion, respectively. • 3DP specimens and those with low VF of fibers (0.5 %) presented lower open porosity and apparent density. • Only the highest VF of SF (1.5 %) showed larger capillary water absorption index ( i ) than the reference mortar in conventional specimens, although all mixtures presented a similar behavior in 3DP specimens. • The addition of fibers and 3DP process reduced mortar compressive strength. However, the use of fibers and the alignment due to extrusion improved mortar flexural strength development, particularly flexural strength remaining after first crack. Acknowledgements The authors acknowledge with thanks the international research mobility of Dr. Hugo Varela at the Federal University of Rio de Janeiro funded by the Project: GA-101086440 — BEST of the Marie Skłodowska -Curie actions - Staff Exchanges call HORIZON-MSCA-2021-SE-01, funded by the European Union, and the Grant for training of Lecturers (FPU-UAH 2019) funded by Universidad de Alcala. References

Bohuchval, M., Sonebi, M., Amziane, S., Perrot, A., 2020. Effect of metakaolin and natural fibres on three - dimensional printing mortar. Proceedings of the Institution of Civil Engineers – Construction Materials, (2020). https://doi.org/10.1680/jcoma.20.00009.