Investigation of geofoam used as lightweight fill material under cyclic loads

In this study, the behavior of Geofoam material under repeated loads was examined by employing it as lightweight fill with specific densities and thicknesses in flexible superstructures. For this purpose, poorly graded sandy soil and Geofoam with densities of 16 and 28 kg/m³ and thicknesses of 15, 20, and 30 cm were used. In addition, in some experiments, geosynthetic materials namely geotextile, geogrid, and geocell with two different thicknesses were placed at the soil layer. The repeated load tests were conducted on a large scale in a laboratory setting, after which numerical analyses were performed to compare the experimental and numerical results. The numerical analyses were carried out using finite element modeling with PLAXIS v8.6. The study's outcomes were evaluated in terms of total, permanent, and elastic deformations, Traffic Benefit Ratio (TBR), Wheel Path Reduction Ratio (RDR), and the percentage of elastic deformation. In terms of overall deformations, it was observed that increasing the thickness of the sandy layer led to a reduction in deformations when the Geofoam thickness was kept constant. Regarding the tests with geosynthetics, the most effective application under repeated loads was found when a geocell with a cell height of 10 cm was used. Furthermore, increasing the Geofoam density resulted in an approximate reduction of 3 cm in both total and permanent deformations.