# Cow Dung Ash in Mortar: An Experimental Study
## 4 Conclusions  
This research explored the potential use of cow dung ash (CDA) as a supplementary cementitious material by investigating its physical and chemical properties. The study also investigated how CDA in varying proportions (5%, 10%, 15%, 20%, 25%, and 30%) affects the workability, hardened, and microstructural properties of mortar. Based on the results obtained from the study, the following conclusions can be drawn:  
* The oxide composition of CDA meets ASTM C150/C150M requirements for cement and is almost similar to that of ordinary Portland cement. However, OPC contains greater amounts of the major oxides of CaO and SiO\({}_{2}\) in comparison to CDA.
* As the percentage of CDA increases in the mortar mix, its workability decreases. Compared to the control mortar, the mortar mixes containing CDA exhibit reduced slump flow. The mortar containing 15% CDA satisfies the slump flow requirements outlined in the ASTM C1437 standard.
* When CDA was utilized beyond 5%, the water absorption of the mortar samples considerably increased due to the porous nature and significant presence of organic compounds that were not effectively removed. As a result, all of the density, homogeneity, and compressive strength of the mortar were negatively impacted. Although the use of CDA as a replacement for OPC resulted in a decrease in compressive strength, the reduction was not considered significant for up to a 15% substitution, as observed at the age of 56 days.
* The compressive strength of mortar specimens is not significantly affected by sulfate attack when containing up to 10% CDA, indicating that these specimens can withstand such an attack with only negligible reduction in strength.
* Mortar mixes containing 10%, 20%, and 30% CDA were found to exhibit thermal stability when exposed to temperatures ranging from 500\({}^{\circ}\)C to 600 \({}^{\circ}\)C. The FTIR analysis revealed the presence of unreacted particles and a wide-stretched C-S-H gel in the mortar samples.
* While the effect of CDA on the properties of mortar can differ across different tests, replacing OPC with up to 10% CDA can serve as a viable substitute for cementitious materials in mortar production. Adopting CDA as a supplementary cementitious material may offer a sustainable and eco-friendly approach that delivers advantages for both the environment and the construction sector.  
Figure 11: FTIR spectra of paste from a control and CDA-containing mortar cured for 28 days.  
* The study has demonstrated the potential of CDA as a promising option for partial replacement of cement. However, further investigations are needed to explore the possible synergistic effects of combining CDA with other supplementary cementitious materials (SCMs), with or without an alkali activator. Such investigations can help to identify the most effective combinations that can lead to improved mechanical properties and durability, as well as sustainable solutions in the cement industry.  
Conceptualization, M.A.W. and M.D.Y.; methodology, M.A.W.; software, M.A.W. and W.Z.T.; validation, M.D.Y., W.Z.T. and B.Z.H.; formal analysis, M.A.W.; investigation, M.A.W.; resources, M.D.Y.; data curation, W.Z.T.; writing--original draft preparation, M.A.W. and B.Z.H.; writing--review and editing, W.Z.T.; visualization, B.Z.H.; supervision, M.D.Y.; project administration, M.D.Y.; funding acquisition, M.D.Y. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data supporting the findings of this study are available upon request.  
The authors declare no conflict of interest.