# Marble and Glass Waste Powder in Cement Mortar
## 4 Conclusions  
The main objective of this research was to study the effects of partially replacing cement with MGWP on the fresh, hardened, durability, and microstructure properties of mortar, as well as material characterization. The following conclusions were drawn from this study based on the objectives and results provided using MGWP as a partial replacement for cement:  
* Glass waste powder is classified as a Class N pozzolanic material according to ASTM C618. Marble waste powder, on the other hand, does not meet the requirements specified in the ASTM standard.
* The workability of the mortar increased as the percentage of MGWP increased to replace cement because of the non-absorbent and smooth behavior of GWP.
* The compressive strength, density, and ultrasonic pulse velocity improve with up to 15% replacement of cement with marble and glass waste powder compared to control mixes over a period of 91 days. The maximum compressive strength is observed with a 10% replacement compared to control mixes.
* Related to durability, adding MGWP in mortar production reduces the loss of compressive strength by up to 15%, with the minimum loss observed at a 10% replacement. The porosity and water absorption of the mortar were improved with up to a 15% MGWP replacement.
* The SEM results demonstrated that mortar containing 10% MGWP is denser and has a more compact morphology as a result of additional C-S-H gel formation compared to the control mixes. Additionally, the TGA-DTA results showed that the total mass loss at 28 days is less than at 7 days, with the minimum mass loss determined at 10% MGWP.
* The more intense and broader bandwidth polymerization of C-S-H is observed at 28 days than 7 days compared to control mixes, as can be seen in FT-IR results.
* Using MGWP as a partial replacement for cement enhances the performance of mortar--improving its strength and durability--but also contributes to reducing cement costs and supports environmentally sustainable practices by lowering carbon emissions associated with cement production.  
Figure 17: Correlation of MGWP mortar properties at curing age of 56 days.  
**Author Contributions:** Conceptualization, M.Y.A. and M.D.Y.; methodology, M.Y.A., M.D.Y. and W.M.N.; software, M.Y.A. and M.D.N.; validation, M.D.Y., W.M.N. and W.Z.T.; formal analysis, M.Y.A. and W.M.N.; investigation, M.Y.A. and M.D.N.; resources, M.D.Y.; data curation, M.Y.A.; writing--original draft preparation, M.Y.A. and W.M.N.; writing--review and editing, M.D.Y. and W.Z.T.; visualization, M.D.Y. and W.Z.T.; supervision, W.M.N. and M.D.Y.; funding acquisition, W.Z.T. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors wish to express their sincere gratitude to the Faculty of Civil and Water Resources and the Faculty of Chemical and Food Engineering at Bahir Dar University for their valuable support during the laboratory testing. Special thanks are also extended to Adama Science and Technology University and the Ethiopian Geological Survey Institute for their invaluable assistance throughout the experiments.  
The authors declare no conflicts of interest.