Calcium Leaching of 3D-Printed Cement Paste Exposed to Ammonium Chloride Solutions
Round 1
Reviewer 1 Report
The article focuses on investigating the calcium leaching of 3D printed cement paste exposed to ammonium chloride solutions. The results found in this paper were very interesting, and it can be accepted for publication. However, before being accepted, it needs some corrections and improvement to be clearer. The comments are the follows:
1. Please revise the lines from 67 to 72. It is repeated two times.
2. The authors can explain the CO2 quantity given in Table 1? The mineralogical composition of cement as well as the AMF should be presented.
3. What analysis was used to determine the workability of cement paste?
4. Why the author did not used the arresting the hydration. Well-known that if the sample was placed in a temperature of 105 °C, this high temperature can have two influences:
- Accelerating the hydration of unreacted cement
- Decomposition of Ettringite or a part of C-S-H.
5. To determine the leaching depth, why author did not used the SEM technique with EDS to have a better precision.
6. Why the authors choose the loading rate of 2.4 KN/s or 144 KN/min. This loading rate has been applied to determining the compressive strength of standard mortar.
7. What formula was used to quantify the portlandite content using the TGA analysis?
8. Particle size distribution of AMF, and FA should be presented.
9. Why the compressive strength of both samples after 28 days of leaching is higher than the compressive strength before the leaching while the porosity increase.
10. The author can provide the XRD of sample in the zone non leached.
11. The porosity, the portlandite content, and the bound chemically water content of zone non leached should be presented.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
General Comments
1. The quality of figures is very bad, for example in Figures 1 and 2 the text cannot be read. In general, quality of Figures, tables and captions should be improved.
2. The authors should check typing errors throughout the manuscript. English style should also be improved.
Technical Comments
1. The description of the work investigated is unclear and it should be improved by adding more details. add a final statement that highlights the importance of this research and its possible potentials. The authors should explain clearly in the abstract what is the novelty of the proposed method and what is the added value in this article? The novelty and presentation? and should be improved and include clear statement about objectives, methodology and findings.
· The literature section is lacking in discussing the mechanical properties of concrete comprising 3D concrete. Please add more literature to this. https://doi.org/10.12989/sem.2023.85.2.275, https://doi.org/10.3390/app13010124, https://doi.org/10.3390/ma15207346
2. Materials and methods: it is recommended to describe the materials used one by one. What are the properties of cement (setting time, specific gravity, consistency etc.)? Properties of fine and coarse aggregate? Granulometric curves for the fine and coarse aggregate? Superplasticizer used, if any? This section is shallow with fewer details and it should be improved. Please introduce a new section to the materials used and discuss everything under this section.
3. I reviewer strongly recommend add the statically model to justify your results accuracy. The current study in lab report.
4. Authors addressed part of the suggestions. However, quantitative analysis work, but authors did not add any of that part of work. The current version of manuscript looks more like a lab report rather than a research paper. I would still suggest authors to add some other analysis results to quantitative study.
5. Novelty needs to be emphasized. The work seems to be a combination of available literature with an experimental arrangement with no proper connection/justification about the reported experimental results.
6. How to ensure the results' accuracy, because this lab report?
7. The conclusion should be more carefully rewritten, summarizing what has been learned and why it is interesting and useful.
The authors should check typing errors throughout the manuscript. English style should also be improved.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
Authors would like to publish an interesting paper entitled "Calcium leaching of 3D printed cement paste exposed to ammonium chloride solutions." Because of their results which contain decreasing in bulk density, increasing in water absorption, calcium leaching anisotropic behavior, XRD observation, DTG-TG analysis, and porosity measurement, I believe that the paper can fill the gap between physical feature and chemical compound in the 3D-printed cement paste subjected to harmful ammonium chloride solution.
Moreover, their results are important in terms of regression coefficient which the authors gave. This relationship among calcium leaching and compressive strength development can open new ways to develop new computing system in terms of AI.
For that reasons I have enumerated above, the journal can put the paper into current archive.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 4 Report
This study was undertaken with the aim of investigating the Calcium leaching of 3D printed cement paste exposed to ammonium chloride solutions. The topic fits the scope of the journal. The Objective of the work is clearly mentioned. Introduction section is explained with background of the study. Materials and Test Method sections elaborate the detailed materials properties and method of experimentation. The detailed discussion with the clear results is presented in Results and discussion section. Conclusion is presented clearly with the main results obtained.
However, the following comments were addressed before taking the decision on the manuscript.
Comments:
· Improve the abstract by following the pattern:
Research background and Problem statement – Objective of investigation –Methodology – Main findings- Recommendation of the research.
· How your work is differs from past similar studies?
· Based on which standards/codes, the mix design was done?
· Includes some more experimental photos.
· Mention the relevant standards/codes followed for various tests done in this work.
· Conclusion: State your research recommendations.
· Mention the scope for future research.
· Include List of abbreviations in the manuscript at last
Overall, This Manuscript needs a minor revision before the acceptance.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
no further comments
