Evaluation of 3D-printed model geogrids and composite geosynthetics made from recycled plastics: Bridging laboratory insights with field performance

Over the past few decades, use of geosynthetics has become increasingly common in civil and environmental projects due to their wide range of functions, including stabilization, filtration, separation, and drainage. Meanwhile, the growing volume of plastic waste presents significant environmental challenges such as overflowing landfills, harmful emissions from incineration, and soil pollution. Utilizing recycled plastic for geosynthetic production offers a sustainable solution by reducing reliance on landfills and incineration, thereby mitigating the associated environmental impact of plastic waste. In this paper, innovative and sustainable approaches for stabilizing unpaved roads are examined. The study involves modeling, design, and production of 3D-printed model geogrids made from recycled polyethylene terephthalate (PET) using a material extrusion 3D printer to create 1:10 scale prototypes, as well as evaluation of their tensile strength through laboratory tests conducted in accordance with ASTM standards. It also investigates field implementation and performance evaluation of an unpaved road stabilized with a new type of composite geosynthetic made from recycled plastic and compares to a similar conventional composite geosynthetic made from virgin plastic—both developed by the geosynthetics industry—and a non-stabilized control test section. This comparison is made through a series of dynamic cone penetrometer (DCP), lightweight deflectometer (LWD), field California Bearing Ratio (CBR) tests, in-situ testing, and visual inspections. The results indicate that composite geosynthetics made from both recycled and virgin plastics show promise in soil stabilization by increasing bearing capacity, strength, and stiffness, while reducing rutting, deformation, and granular base thickness.