Biopolymer Geogrids for Geotechnics

Abstract

This study focused on the mechanical characterisation of 3D printed biopolymer geogrids for civil and geotechnical engineering applications. The polylactic acid specimens were designed based on first-order similitude conditions and were produced by fused deposition modelling techniques. An experimental programme was carried out to investigate the mechanical behaviour of 1:2 scale model geogrids undergoing tensile loading conditions, in order to explore their use in soil reinforcement and stabilisation of geomaterials. The secant stiffness at 2.0% of strain and the ultimate tensile strength were used for this purpose. The results showed an average tensile strength of 4.5 ± 0.5 kN/m, which is in good agreement with that of fossil oil-derived polymer prototypes, while presenting a significantly lower elongation at failure. The printing process appeared stable and replicable. The influence of degradation on the tensile properties of 3D printed polylactic acid geogrids over time still needs to be studied.


Keywords: geogrid, additive manufacturing, biopolymer, tensile strength, geotechnics

References
[1] NP EN ISO 10318-1:2016. Geossintéticos; Parte 1: Termos e definições (ISO 10318- 1:2015). Instituto Português da Qualidade, 2016.

[2] Vertematti JC. Brazilian manual of geosynthetics. Brazilian Association of Nonwoven and Technical Fabrics Industries; São Paulo, Brazil,2004.

[3] Walsh AT. Multi-axial grid or mesh structures with high aspect ratio ribs. United States patent. US 11,149,386. 31th January, 2017. Available from: https://patft.uspto.gov/netahtml/PTO/

[4] Cislaghi A, Sala P, Borgonovo G, Gandolfi C, Bischetti GB. Towards more sustainable materials for geo-environmental engineering: The case of geogrids. Sustainability. 2021;13(5):2585. https://doi.org/10.3390/su13052585

[5] Viswanadham BVS, König D. Studies on scaling and instrumentation of a geogrid. Geotextiles and Geomembranes. 2004;22(5):307–328. https://doi.org/10.1016/s0266-1144(03)00045-1

[6] Stathas D, Wang JP, Ling HI. Model geogrids and 3D printing. Geotextiles and Geomembranes. 2017;45(6):688–696. https://doi.org/10.1016/j.geotexmem.2017.07

[7] Wang S, Ma Y, Deng Z, Zhang S, Cai J. Effects of fused deposition modeling process parameters on tensile, dynamic mechanical properties of 3D printed polylactic acid materials. Polymer Testing. 2020;86:106483. https://doi.org/10.1016/j.polymertesting.2020.106483

[8] Oliveira G, Falorca I. Stress-strain relationship in homogeneous and two-layered triaxial test specimens. KnE Engineering. 2020;5(5):88-99. https://doi.org/10.18502/keg.v5i5.6923

[9] NP EN ISO 10319:2016. Geossintéticos: Ensaios de tração em tiras largas (ISO 10319:2015). Instituto Português da Qualidade, 2016.