Towards More Sustainable Materials for Geo-Environmental Engineering: The Case of Geogrids

Abstract

Plastic materials are widely used in geotechnical engineering, especially as geosynthetics. The use of plastic-based products involves serious environmental risks caused by their degradation. Innovative research has been focusing on biodegradable polymers of natural origin, especially on poly(lactic acid) (PLA), to reduce the use of plastics. This study aims to explore the potentiality of biopolymers for the production of geogrids, measuring the chemical and mechanical characteristics of raw materials and of prototype samples, similar to those available on the market. First, chemical composition and optical purity were determined by hydrogen nuclear magnetic resonance (1H-NMR) and polarimetry. Furthermore, samples of uniaxial and biaxial geogrids were custom-molded using a professional 3D printer. Mechanical properties were measured both on the filament and on the prototype geogrids. The maximum tensile resistance was 6.76 kN/m for the neat-PLA filament and 10.14 kN/m for uniaxial prototype geogrids produced with PLA-based polymer mixed with titanium dioxide. PLA-based materials showed higher tensile properties than polypropylene (PP), the most common petroleum derivative. Conversely, such biomaterials seem to be more brittle and with scarce elongation rate respect PP. Nonetheless, these results are encouraging and can support the use of PLA-based materials for innovative biodegradable geosynthetics production, especially if used in combination with live plants.

Biopolymer Geogrids for Geotechnics

“…In terms of ultimate tensile strength, model geogrids were characterised by an average tensile strength of 4.5 ± 0.5 kN/m. Similar results were reported by [4]. Table 5 presents the parameter values to be considered with the downscaling of the prototype geogrids with a scale factor of 2 (N = 2) under 1-g conditions for geogrids with 18 mm aperture size.…”

“…To offset the negative impact of using synthetic materials, biopolymer geogrids are increasingly being explored for civil and geotechnical engineering applications. Among the natural-derived and renewable biopolymers, the polylactic acid (PLA) can ensure several advantages in terms of sustainability and eco-compatibility [4]. A common practice in geotechnical research studies is to use physical modelling techniques in order to infer the prototype behaviour.…”

Mechanical and Structural Characterization of Pineapple Leaf Fiber

“…Sustainable green technology developments have been elevated in recent times, especially, in the polymer composite industry [1]. Thus, the focus currently is on the identification and characterization of plant fibers for a variety of applications, including fabrication of scaffolds for tissue regeneration, drug delivery, and prosthetic design [2][3][4].…”

Effect of different forms on geogrid tensile properties based on 3D printing technology

“…They studied the effect of the spacing and height of microbumps on the geomembrane surface on the shear properties of the geomembrane-sand interface. Cislaghi et al 24 fabricated the uniaxial prototype geogrid made of PLA-based polymer mixed with titanium dioxide by 3D printing technology and discussed the potential of biopolymer in the production of geogrids. Nabeel et al 25 manufactured a lightweight porous composite structure with continuous carbon fibers through 3D printing technology, and examined and explored its fracture interface through tensile tests.…”