**5. Conclusions**

Based on the above discussion of the research results, several conclusions can be drawn to summarize the research work:


**Author Contributions:** Conceptualization, M.Ł. and A.B.; methodology, M.Ł. and A.B.; investigation, A.B., K.P. and P.B.; resources, A.B.; writing—original draft preparation, A.B.; writing—review and editing, A.B., K.P., P.B. and M.Ł.; supervision, A.B. and M.Ł.; funding acquisition, M.Ł. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by the National Center for Research and Development in Poland under grant: M-ERA.NET3/2021/70/GEOSUMAT/2022 "Materials for Circular Economy—Industrial Waste Based Geopolymers Composites with Hybrid Reinforcement" under M-ERA.NET 3 Call 2021.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** Special thanks go to Joanna Marczyk, who performed the phase analysis studies of the base material. Publication cost of this paper was covered with funds from the Polish National Agency for Academic Exchange (NAWA): "MATBUD'2023—Developing international scientific cooperation in the field of building materials engineering" BPI/WTP/2021/1/00002, MATBUD'2023.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

#### **References**


**Disclaimer/Publisher's Note:** The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.
