Experimental Study on Engineering Characteristics of High-Speed Railway Subgrade Filler in Island Permafrost Regions
Round 1
Reviewer 1 Report
This review report has been removed from the review record as it did not conform with MDPI’s standards (https://www.mdpi.com/reviewers#_bookmark11).
Reviewer 2 Report (New Reviewer)
The review is provided in the attached file.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 3 Report (New Reviewer)
Dear Authors,
The manuscript explains the experimental study on engineering characteristics of highspeed railway subgrade filler in the Island permafrost region which is attractive to the readers; however, to better organize the paper, the following correction would be suggested:
1) Over 65% of the references cited in the text are older than 2017, so it's highly recommended to use recent relevant research.
2) Section 2, testing should be taken under the standards. This could be a national code or international like BS or ASTM. The authors are asked to refer to the standard method for each test.
2) Section 2, why the authors selected the constant head permeability test, why the material may subject to various groundwater levels regarding the weather condition in that area.
3) Results and discussion is not presented well. For example, no detailed explanation is provided on how the 3% modifier affected the permeability, while it has no significant effect on the frost/heave rate during the time. Such a scientific paper needs to go more in-depth to explain qualitative as well as quantitative of results.
4) The freeze-thaw cycles show a significant change in compressive strength while using the cement without modifiers, however, no explanation is provided throughout the discussion.
5) The authors are encouraged to perform some insitu tests like Plate Load Test to verify if the stabilization expected from the lab results is taken place when working at the site.
6) The conclusion should revise based on comments 4 and 5.
7) The paper should check by a technical native English speaker.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Paper presents interesting study, but with limited test conducted and lack of comprehensive discussion of obtained results. Materials and methods are correctly presented, bud none of the important parameters of used modifier are shown. Presented results are somewhat expected, therefore a thorough discussion of the impact of used modifier is missing. Discussion section should be thoroughly rewritten, citing relevant previous studies that support here presented (and expected) results. Presented conclusions are too general and their relevance is questionable since statistical analysis is not presented. Generally, results of cement mixture are trivial and not worth commenting. The only novelty within this research could be used modifier but its influence on material behavior is not clearly presented and discussed. The relevance of the presented results is questionable, given that no basic statistical analysis was performed in terms of at least stating the number of tested samples and the standard deviation of the results obtained, nor any other statistical analysis.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Authors present experimental studies on the effect of modification on fillers for practical application in high-speed railway under permafrost conditions. The work is interesting, and it falls within the scope of the journal. The application here is obvious. However, my main complain is on using just three different realization to conduct the test studies: pure, cement-improved and cement/modifier-improved systems with only one percentage studied for the latter cases.
) As written above while the work is interesting authors pick only three realizations. Why they have chosen just a 5% cement load and a 3% modifier one? Given the analyzed impact it would be interesting if the authors could present test results by employing different loads. In any case authors should discuss in detail why they have picked these specific loads in their studies.
) Error bars should be added in all figure data.
) Frost heave modifier is first mentioned in line 103 but in a very vague way. More details are provided but much later (line 161). This later description should be moved as early as possible.
) Symbol mapping should be consistent (square -> pure, circle -> cement, diamond -> cement+modifier). In Figures 8 and 9 it changes as there are just two curves.
) Line 146: “The test aims … filler”. This sentence is repetition of one encountered previously.
) the manuscript requires careful editing with respect to syntax and grammar. Some phrases and instances are not clear and they have to be re-stated. Some examples:
Line 26: “will provide references”, do the authors mean “can serve as a technical reference”? Then “disease” has which meaning here?
“clean” could be changed to “pure” in all instances including figure captions.
Line 92: “super particle size particles” -> “super-sized particles”. The whole meaning of sentence “The filler …. piece” is unclear.
Line 161: “is applying” -> “is being applied”.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for presenting interesting study and making some changes to your work. However, made changes did not significantly improved the quality of your paper. I understand that results are applied for intellectual property protection so I advise you to wait for completion of that process so you will be able to publish your results. Or you can try publishing paper in this form in some other journal since for the journal of this rank you should be able to provide more detailed analyses of obtained results and discussion of chemical and mechanical processes made by used modifier.
Reviewer 2 Report
The authors have revised the manuscript, some parts have been significantly improved however the mail flaw of the present analysis remains. The data study appears too limited with respet to both system realizations studied and the corresponding parametric analysis.
It is very clear that the manuscript can benefit immensely but including more experimental results. Thus, I cannot recommend publication of the present manuscript at this current state.
