## 4 Conclusions  
This study aimed to evaluate the mechanical performance, chemical stability, and reinforcement potential of 3D-printed materials, including PLA, ABS, and electrical ESD PLA, in concrete and NaOH mediums. The results provided insights into both the strengths and limitations of these materials, paving the way for advancements in sustainable construction. The following conclusions align with the research objectives and summarize the key observations. The conclusions regarding mechanical performance under load are as follows:  
* Unreinforced concrete specimens demonstrated unexpectedly higher load-bearing capacity than reinforced counterparts in specific cases, challenging the assumption of universal reinforcement benefits;
* Electrical ESD PLA emerged as the most promising reinforcement material, exhibiting superior post-failure load-bearing capacity and minimal degradation in high-pH environments;
* Observations under mechanical loading revealed faster and more extensive white precipitate formation in specimens subjected to lower loads, suggesting a connection between load resistance and chemical stability. The conclusions regarding chemical stability in NaOH and concrete mediums are as follows:
* Dissolution tests confirmed that the white substance that formed as a solid deposit, resembling powder, originated from chemical reactions involving PLA-based materials in high-pH environments rather than from lime in the concrete;
* PLA and ABS materials showed susceptibility to slow degradation in NaOH solutions, leading to reduced long-term structural stability;
* pH measurements indicated that NaOH interacted chemically with PLA-based and ABS materials, further emphasizing the need for reinforcement materials resistant to high-pH degradation. The conclusions regarding the evaluation of diverse materials for reinforcement potential are as follows:  
* Electrical ESD PLA demonstrated high chemical stability and strong mechanical performance, making it a viable candidate for sustainable construction applications;
* Alternative materials like PET-G and PCTG, along with surface treatments, were identified as potential solutions to mitigate the drawbacks of PLA-based reinforcements while retaining their benefits. The limitations identified in this research highlight the challenges of using PLA materials for reinforced concrete applications. PLA's inherent thermal and hydrolytic instability, combined with its thermal expansion mismatch with traditional construction materials, restricts its long-term durability. Additionally, its vulnerability to degradation in alkaline environments further complicates its use in demanding applications, such as bridges or outdoor concrete structures exposed to moisture and temperature fluctuations. While combining PLA with other materials has shown a potential to mitigate some of these issues,further research is essential to fully address these limitations. Advancing material optimization and exploring the chemical interactions between PLA and concrete will be critical for realizing PLA's potential as a sustainable and reliable alternative for reinforcement. ABS filaments were chosen as the reference material in this study because of their established use in engineering and 3D printing, where their high impact resistance, stiffness, and recyclability make them a reliable standard for comparison. PLA filaments, in contrast, were examined as a more environmentally friendly option, offering advantages in printability and reduced ecological footprint. The goal was to assess whether PLA, despite its challenges with thermal and hydrolytic stability, could meet the mechanical and chemical requirements for reinforcing concrete. By evaluating PLA against ABS, the study aimed to identify materials that could combine sustainability with the performance needed for structural applications. Future research should focus on addressing the chemical stability challenges observed in PLA and ABS materials to enhance their long-term applicability in reinforced concrete structures.