Mechanical and thermal behavior of a polypropylene geogrid exposed to installation damage and chemical Aggression

This experimental study examines the impact of installation damage and chemical degradation on the mechanical and thermal properties of a polypropylene geogrid. Two protocols were employed: a chemical degradation test involving immersion in a sulfuric acid solution at 80 ± 2°C, and an installation damage test conducted on site. The damage incurred by the geogrid following the degradation tests was evaluated by monitoring the evolution of its mechanical behavior, specifically the secant stiffness modulus at various strains, using a tensile test. Additionally, a differential scanning calorimetry analysis was performed to assess changes in the melting rate of the polypropylene. The results demonstrate that prolonged exposure to an acidic environment leads to a marked reduction in the material’s stiffness, especially at higher strain levels, which reflects a significant degradation of its long-term mechanical performance. Although the effects of installation damage are comparatively less pronounced, they still contribute to a decrease in stiffness modulus. This suggests that the material exhibits greater sensitivity to chemical degradation than to mechanical damage. From a thermal standpoint, an increase in the melting rate during the first three months of immersion, reaching up to 35.61%, followed by a significant decrease after extended exposure, dropping to 27.32%.