**4. Conclusions and Summary**

Waste management has gained great importance due to the increase in the amount of waste. The reuse or recycling approach of these waste products, especially in the construction sector, has become a more attractive option. In this study, the applicability of waste glass on concrete production was investigated by considering two different conditions, i.e., replacing cement with waste glass powder and replacing cement, fine and coarse aggregate with waste glasses. A series of tests were conducted on concrete samples produced with different amounts of waste glass to determine engineering properties both in the fresh and hardened cases. In the fresh case of concrete, workability and slump properties were explored. In the case of hardened concrete, compression strength, splitting tensile strength, and flexural strength of the produced test specimens were investigated. These properties were then compared with those of plain concrete. Then, SEM analysis was carried out to explore the interaction between glass powder, cement, and aggregates. Furthermore, practical equations were developed to identify the compressive strength, splitting tensile strength, and flexure strength of concrete produced with WGP. Based on our study, the following conclusions can be drawn:


In this study, it was observed that waste glass can be used as a partial cement substitute, or as cement, fine and coarse aggregate in concrete. Optimum waste glass dosage has also been identified for design purposes. However, lower strength values were observed when waste glass was used as a partial replacement for cement. The current study defines waste glass as suitable, reachable in large amounts, a local eco-material, cheap, that can be selected for concrete construction, in a point of view between economically and environmentally responsive. To mitigate this shortcoming, future studies will concentrate on the use of waste glass with other recycling fibers.

**Author Contributions:** Conceptualization, Y.O.Ö. and D.D.B.-N.; methodology, Y.O.Ö. and D.D.B.-N.; data curation, Ö.Z., M.K., D.P.B.-N. and Y.O.Ö.; investigation, A.˙ I.Ç., Y.O.Ö., Ö.Z., M.K.; writing original draft preparation, A.˙ I.Ç., Y.O.Ö., Ö.Z., S.Q., J.A., D.D.B.-N. and D.P.B.-N.; writing—review and editing, Y.O.Ö., Ö.Z., M.K., S.Q., J.A., D.D.B.-N. and D.P.B.-N.; funding acquisition, D.D.B.-N. and D.P.B.-N. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by Gheorghe Asachi Technical University of Ia¸si—TUIASI-Romania, Scientific Research Funds, FCSU-2022.

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

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** This paper was financially supported by the Project "Network of excellence in applied research and innovation for doctoral and postdoctoral programs"/InoHubDoc, project co-funded by the European Social Fund financing agreement no. POCU/993/6/13/153437. This paper was also supported by "Gheorghe Asachi" Technical University from Ia¸si (TUIASI), through the Project "Performance and excellence in postdoctoral research 2022".

**Conflicts of Interest:** The authors declare no conflict of interest.

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