PONE-D-23-40567Research on the expansion, shrinkage characteristics and fracture evolution of red clay stabilised with phosphogypsum under dry-wet cyclesPLOS ONE

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PLOS ONE

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Reviewers' comments:

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: N/A

Reviewer #3: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript used red clay and the waste of phosphogypsum in highway roadbed construction. The author analyzed the influence of phosphogypsum content on the performance of the mixture. The paper has certain engineering reference value. And the structure and methodology of the paper are both reasonable. However, some revisions are suggested based on the following comments.

1. The English grammar needs to be carefully checked and improved throughout the manuscript, e.g. by a professional English language editor. The current version is difficult for readers to comprehend.

2. The abstract needs to be rewritten, listing the main summary findings of this paper.

3. The keywords should be condensed further to accurately reflect the content of the paper.

4. In introduction section, in comparison to existing research, please explain the research objectives and innovations of the paper.

5. In the test section, the flowchart may be included to clearly demonstrate the research scheme of the paper.

6. The author emphasizes "special performance", but I believe the author only studied conventional engineering performance of the mixture of red clay and phosphogypsum. I suggest the author revise it.

7. In Analysis of test results section, some titles require modification to better align with the content discussed, for example, Relationship to compaction, Relationship with cement dosage, etc. are difficult to understand.

8. To enhance the theoretical depth of the paper, I suggest adding some mechanism analysis in the discussion section of the experimental results.

Reviewer #2: This manuscript investigates the expansion, shrinkage, and fracture evolution characteristics of red clay stabilized with phosphogypsum under dry-wet cycles. The authors conducted a thorough experimental study, varying key parameters such as cement dosage, compaction degree, water content, and number of dry-wet cycles. The results show that absolute expansion and shrinkage rates are positively correlated with compaction degree, number of dry-wet cycles, and cement dosage, while negatively correlated with initial moisture content and phosphogypsum dosage. Fracture rate increases with dry-wet cycles and decreases with initial water content, compaction, cement, and phosphogypsum dosage. The authors propose optimal cement and phosphogypsum dosages for roadbed filler. The research methodology is sound, and the findings have practical implications for road engineering. Some areas for improvement include providing more context, clarifying certain methodological details, and discussing limitations.

Comments:

1. The introduction could benefit from more context about the significance and challenges of using red clay as a roadbed material. What specific problems does the high liquid limit and plasticity of red clay pose for road construction?

2. On page 3, the authors mention that phosphogypsum contains toxic elements like arsenic, chromium, and lead. Have the environmental and health risks of using phosphogypsum been adequately addressed?

3. The sentence "From the above, it can be seen that there are certain research results on the strength and deformation of phosphogypsum soils, but there is a lack of research results related to the road performance of phosphogypsum-red clay due to the special characteristics of red clay" on page 3 could be supported with more specific examples of the research gaps.

4. How were the cement dosages of 4%, 6%, and 8% selected? Is there a reason these particular values were chosen?

5. The authors state on page 4 that the radioactivity index of the phosphogypsum is in accordance with GB 6566-2010 standards. It would be helpful to provide the actual radioactivity index values and limits for context.

6. Why was the optimal number of dry-wet cycles proposed to be 7 in this study (page 4)? Is this based on previous research or practical considerations?

7. On page 6, the humidification and drying target moisture contents are mentioned. How were these specific values (optimal +/- 7%) determined?

8. The image processing methodology using PCAS to quantify crack areas is interesting. Have the authors validated this technique against other methods or manual measurements?

9. In Section 3.1, the authors attribute the increase in absolute expansion rate with higher compaction to the increase in hydrophilic minerals. This explanation could be strengthened with more specific evidence or references.

10. The discussion on page 10 about closed pores transforming into connected pores and changes in the microscopic stress-strain field is intriguing. Is there any microstructural analysis that could support these claims?

11. On page 11, it's mentioned that CaO in cement reacts with SiO2 in clay to form hydrated calcium silicate gel. A reference for this reaction would be beneficial.

12. The explanation of phosphogypsum's inhibiting effect on the swelling and deformation of red clay (page 11) could be more detailed. What specific mechanisms are at play?

13. In Section 3.3, the authors discuss the development of horizontal tensile stress in the specimens during drying. Have the authors considered measuring or modeling these stresses directly?

14. On page 14, the authors state that an increase in cement dosage leads to more formation of hydrated calcium silicate and calcium aluminate, which increases tensile strength. This is a key point that warrants more discussion and supportive references.

15. The observation on page 15 that higher initial water content leads to the wrapping of micropores by water film and formation of a monolithic lamellar structure is noteworthy. Are there any microscopic images or previous studies that demonstrate this phenomenon?

16. The fitting equation (4) relating compaction, absolute expansion/shrinkage rate, and fracture rate is a valuable contribution. Have the authors considered the physical meaning behind the coefficients a, b, c, d, and e?

17. In the conclusion, the authors suggest an optimal cement dosage of 6% and phosphogypsum:red clay ratio of 1:1 to 1:2. How do these recommendations compare with current practice or other stabilization methods?

18. The research focuses on the experimental characterization of phosphogypsum-stabilized red clay. Are there any plans for field trials or case studies to validate the findings in real-world conditions?

19. The authors have demonstrated the potential of phosphogypsum for stabilizing red clay. Are there any economic or logistical considerations that could impact the widespread adoption of this technique?

20. While the study provides valuable insights, there are some limitations that could be addressed in future work. For example, the long-term durability and environmental impacts of phosphogypsum-stabilized red clay could be investigated further.

Reviewer #3: Please find the following the comments/suggestion.

1. The presented abstract is very length, it should be to the point and concise. Abstract could be more informative by providing results. I prefer to see some results in the abstract.

2. Please include the latest reference in the section 1. The introduction needs to be more emphasized on the research work with a detailed explanation of the whole process considering past, present and future scope. Please discuss more about the application of image processing in the other branches of engineering.

3. How the present study gives more accurate results than previous studies about the image processing? It needs to be strengthened in terms of recent research in this area with possible research gaps. It is strongly recommended to add a recent literature.

4. Research gaps should be highlighted more clearly and future applications of this study should be added.

5. There is no presentation of figures against the results, please include some graphs for the better understanding of the results.

6. Author use different abbreviation at different places, which confused the reader, Please provide the list of the abbreviation, please use in the start.

7. The manuscript required the proof reading.

8. Please pay attention on the formatting guidelines as per the journal requirement.

9. Please provide more discussion for the section 2, please include more description of the propose method by adding latest references.

10. In the conclusion section, the limitations of this study, suggested improvements of this work, and future directions should be added

The author needs to address the abovementioned points for the betterment of the manuscript.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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PONE-D-23-40567R1Research on the expansion, shrinkage properties and fracture evolution of red clay stabilised with phosphogypsum under dry-wet cyclesPLOS ONE

Dear Dr. Chen,

Thank you for submitting your manuscript to PLOS ONE.  

After careful consideration, we feel that it has satisfied our scientific requirements for publication.

However, our editorial team have significant concerns about the grammar, usage, and overall readability of the manuscript. PLOS ONE requires that published manuscripts use language which is 'clear, correct, and unambiguous', see our criteria for publication at https://journals.plos.org/plosone/s/criteria-for-publication#loc-5. We therefore request that you revise the text to fix the grammatical errors and improve the overall readability of the text.

We suggest you have a fluent English-language speaker thoroughly copyedit your manuscript for language usage, spelling, and grammar. If you do not know anyone who can do this, you may wish to consider employing a professional scientific editing service.

Please note that we will not be able to proceed with publication of your manuscript until the concerns above are addressed.

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Please submit your revised manuscript by Jul 18 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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We look forward to receiving your revised manuscript.

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Hanna Landenmark

Staff Editor, PLOS ONE

on behalf of 

Seyed Sina Mousavi Ojarestaghi

Academic Editor, PLOS ONE

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Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

The authors appropriately enhanced the manuscript based on the reviewers' comments.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: The manuscript (Research on the expansion, shrinkage properties and fracture evolution of red clay stabilised with phosphogypsum under dry-wet cycles) has been well revised and can be processed for the next stage of publication.

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Reviewer #2: Yes: Mahmoud Akeed

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Research on the expansion, shrinkage properties and fracture evolution of red clay stabilised with phosphogypsum under dry-wet cycles

PONE-D-23-40567R2

Dear Dr. Chen,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Jiaolong Ren

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: Now, the manuscript (Research on the expansion, shrinkage properties and fracture evolution of red clay stabilised with phosphogypsum under dry-wet cycles) is ready for the next stage of the publishing process.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

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