## 4 Conclusions  
The present study provides important insights into the degradation of GFRP pipes under varying environmental conditions, with a particular focus on the impact of the temperature and corrosive agents. The findings demonstrate that GFRP pipes are highly  
Figure 14: Interaction plots for the following: (**a**) tensile strength; (**b**) tensile modulus; (**c**) Poisson’s ratio.  
susceptible to mechanical degradation when exposed to elevated temperatures and aggressive environments like saltwater and alkaline solutions. Exposure to saltwater causes a significant decrease in the ultimate tensile strength (UTS) and elastic modulus as the temperature rises, with a notable reduction at 50 \({}^{\circ}\)C. This leads to diminished resistance to deformation, reduced stiffness, and lower ductility, making the material more brittle. Similarly, this study shows that alkaline environments, particularly at high temperatures, result in even more severe degradation of GFRP, significantly reducing both the strength and stiffness.  
In contrast, exposure to air at 50 \({}^{\circ}\)C results in only moderate reductions in the UTS and elastic modulus, with the Poisson's ratio remaining relatively stable. This suggests that, in the absence of corrosive agents, GFRP pipes retain much of their stiffness and ductility, even at elevated temperatures. These results highlight the importance of considering environmental factors such as the pH and the composition of the environment when assessing the long-term durability of GFRP pipes.  
This study also emphasizes that combined environmental factors, especially the temperature and solution type, have a synergistic effect on the mechanical degradation of GFRP pipes. Exposure to both saltwater and alkaline environments at elevated temperatures proves to be more detrimental than exposure to individual factors alone.  
While this study provides valuable insights, there are limitations. The experimental setup focused primarily on saltwater, alkaline solutions, and air, excluding other potentially aggressive environments, such as acidic solutions. Additionally, only short-term exposure was considered, and the effects of prolonged exposure remain unclear. Variations in manufacturing processes and material formulations could further influence GFRP pipe performance, meaning the results may not be universally applicable to all types of GFRP materials.  
Future research should expand on these findings by investigating a broader range of environmental conditions, including acidic environments and varying concentrations of saltwater and alkaline solutions. Long-term exposure studies will be essential to understanding the degradation mechanisms in real-world applications. Moreover, incorporating other loadings, such as cyclic loading, could offer a more comprehensive view of GFRP performance under practical conditions. Further exploration of GFRP formulations, resin types, and fiber orientations will deepen the understanding of how material composition influences degradation under environmental and thermal loads.  
Conceptualization, A.D. and M.T.; methodology, M.T., A.D., G.L. and A.I.P., software G.L., validation, M.T., A.D., G.L. and A.I.P.; formal analysis, G.L. and M.T.; investigation, M.T., A.D., G.L. and A.I.P.; resources, M.T., A.D., G.L. and A.I.P.; data curation, M.T., A.D., G.L. and A.I.P.; writing--M.T., A.D., G.L. and A.I.P.; writing--review and editing M.T., A.D., G.L. and A.I.P.; visualization M.T.; supervision, M.T.; project administration, M.T.; funding acquisition, M.T., A.D. and A.I.P. All authors have read and agreed to the published version of the manuscript. This research received no external funding.  
Not applicable.  
Data availability Statement: Data are contained within the article.  
The authors declare no conflicts of interest.