Study of the Mechanical Properties and Water Stability of Microbially Cured, Coir-Fiber-Reinforced Clay Soil
Round 1
Reviewer 1 Report (Previous Reviewer 1)
The manuscript is improved from the previous version. However, some of the main complaints by several reviewers are not fulfilled.
The main remark is that the obtained results are not compared to the literature nor discussed in a scientifically acceptable manner. Section 2 (Materials and methods) contains only one reference. Section 3 (Discussion) contains only 5 references. The authors need to read more papers to see that every experimental methodology, formulae, every result must be referenced and/or discussed.
Also, another issue is that the references list containing only local authors does not give a wide picture on the similar research in the world.
The paper containing 20 pages is not too lenghty, so the argumenting about that is not an excuse to not give the full information on the study (see previous reviews).
There are still unfinished sentences in the text.
There are still unfinished sentences.
Author Response
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Author Response.pdf
Reviewer 2 Report (Previous Reviewer 2)
The aim of the study is to facilitate engineering applications of MICP, the bacillus pasteurii liquid was mixed with coconut-fiber-reinforced soil using the mixing method, and the microbial solidification test was carried out on the reinforced clayey soil with fiber contents of 0, 0.2%, 0.4%, and 0.6% (mass ratio). The results are interesting and useful for the industry. The paper can be accepted after the minor change.
1. The fiber used in the experiment is coconut shell fiber. What are the advantages compared with synthetic fiber ?
2. There are many kinds of natural fibers, such as palm fiber, why choose coconut shell fiber ?
3. Calcium source in cementing solution In addition to CaCl2, is there any other replaceable calcium source ?
4. The size and position of some pictures in the article need to be adjusted, as shown in Figure 1. Please modify them according to the format requirements
5. Table 2 contains redundant empty lines, which need to be modified according to format requirements.
6. In Section 3.1 (1) Stress-Strain relationship, the analysis corresponding to "It can be seen from Fig.11" should be corresponding to FIG. 12 instead of FIG.11. Please modify it.
n/a
Author Response
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Reviewer 3 Report (Previous Reviewer 3)
Surveying of topic with alternate additives and ground improvement methods should be more detailed, discussed and criticized. The chemistry of sample in internal mechanism and its evaluations with chemical bonds, elements and reactions should be added and crtically considered with advantages and disadvantages ways with alternate methods such as grout, lime, differenr fiber, etc. For refernces of criticisms and comparisons the following are recommended:
"GÜLLÜ, Hamza; YETIM, Mehmet Emin; GÜLLÜ BACAK, Elif, Effect of using nano-silica on the rheological, fresh and strength characteristics of cement-based grout for grouting columns. Journal of Building Engineering, 2023, 107100.
"Güllü, H., Al Nuaimi, M. M., & Aytek, A. (2021). Rheological and strength performances of cold-bonded geopolymer made from limestone dust and bottom ash for grouting and deep mixing. Bulletin of Engineering Geology and the Environment, 80, 1103-1123."
Extensive improvement is needed. See report above please
Author Response
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Reviewer 4 Report (Previous Reviewer 4)
SUMMARY
The article submitted for review is relevant. An experimental study on the mechanical properties and water stability of microbially-cured, coir-fiber-reinforced clay soil was carried out. The relevance of the study lies in the need to use environmentally friendly methods of strengthening soils, stabilizing them using new approaches and methods. The authors presented a new method that allows solving engineering problems and contributes to greening. They presented an interesting methodology and obtained a number of important results. Thus, having benefited from the combination of calcium carbonate precipitation and fiber reinforcement technologies, significant improvements have been obtained to improve the safety of engineering structures. Thus, the reviewer believes that the article is interesting and relevant. The reviewer supports the article, but considers it necessary to correct a number of comments, they are listed below.
COMMENTS
1. The authors indicate in the title that these are experimental soil studies. Maybe the authors should remove the word "experimental" from the title to increase the significance of the article. Otherwise, it may seem that in this article only laboratory experiments were carried out, although the authors also analyzed the results, as well as SEM analysis using microscopy, and in general, data processing also plays a big role. It is recommended to remove the word "experimental" from the title.
2. The abstract is not entirely successful. The authors immediately report scientific novelty, but do not say what scientific problem they faced. The scientific problem should be formulated at the beginning of the abstract.
3. The conclusions at the end of the abstract should be stated in a slightly different form so that the quantitative characteristic of the result completes the abstract. The authors first have a quantitative characteristic of the result, and then a qualitative one, this is not entirely true. All numbers and values should be at the end of the abstract.
4. In the "Introduction" section, the authors provide a literature review. But here the reviewer notices that it is rather superficial and shallow. The authors should work on a literature review, in particular, an interesting direction is the use of plant fibers: coconut, sisal and other types in heavy and cellular concrete. That is, the authors should report what work was done on other materials with reinforcement with coconut fibers and sisal fibers. It is recommended to pay attention to cellular concrete and heavy concrete. Also, authors are invited to add 8-10 references on this topic. Also, the authors should pay more attention to the work related to the saturation of concrete with microorganisms. The fact is that building soil or concrete, as well as other building materials, are composites that can be improved by using microorganisms in them. The authors should mention this and not focus their attention only on soils. This will make it possible to give this method a multifunctional meaning and expand the engineering task of the authors.
5. In section 2 "Experimental Materials" I would like to wish the authors to provide photographs in a higher quality and possibly justify the choice of materials in a little more detail.
6. There are comments on the figure 2. This photo is made in poor quality.
7. Figure 3 looks interesting but is poorly described in the text.
8. The graphs presented in figures 4-7 need more detailed interpretation.
9. The graph in Figure 8 looks not very informative. The same remarks apply to numerous graphs in the further presentation of section 3.
10. Section 3 also presents microstructural analyzes using the SEM method. I would like to see a more detailed interpretation of the SEM analyzes presented. I would like to understand how the authors see the phase boundary between the soil and the fiber, whether any fibers undergo deformations when working in the soil under various loads, and how the authors can describe the ways the fibers are distributed in the soil from the point of view of SEM analysis. Here, a very important point is to pay attention to the forces that the fibers perceive in the reinforced soil, as well as microcracking at the phase boundary and fixing or anchoring these fibers in the soil body. The authors are encouraged to provide a detailed comparison of the model they obtained in the course of this experiment at the micro level with the model of the operation of such fibers in other composites, for example, in concrete. That is, how a soil reinforced with fibers and having stabilizing additives performs under load, as it relates to other composites reinforced and formulated in the same way. For example, to make a comparison between soil and heavy concrete or soil and cellular concrete, which will be more comparable in terms of fiber pulling forces or phase boundaries due to the high porosity of cellular concrete reinforced with coconut fibers or sisal fibers. Such a discussion, added to the text, will help to better compare the result obtained with the results of other authors and improve the scientific idea and quality of the article.
11. The conclusions presented by the authors should be specified in terms of the scientific result obtained, the prospects for the development of the study and the scope of this result. The list of 28 references is very small. It should be supplemented with another 15-20 points.
In general, the reviewer believes that the article is done at a high level, and after correcting the comments, the reviewer would like to take a look at this article again. The article should be supplemented in terms of comments and submitted to the reviewer for another review. General note: major revisions.
Comments for author File: Comments.pdf
English language test and minor correction required.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report (Previous Reviewer 3)
Authors have not taken care reviewer's recommendations. Reject.
Authors have not taken care reviewer's recommendations. Reject.
Reviewer 4 Report (Previous Reviewer 4)
The authors revised the manuscript well. The comments have been corrected and the manuscript is ready for publication.
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
- The study shows an approach to soil reinforcing activities by using coir-fiber and microbial activity to precipitat carbonates. However, there are serious English and scientific writing deficiencies. Besides, the discussion is lacking references. The soil needs to be better defined to enable other authors understand and compare the results. The novelty is not clear. Some specific comments follow.
- The second sentence in the abstract section needs refinement to send the message effectively and shortly.
- Is it neccessary to mention "the mixing method" in the text? ("the microbial liquid was mixed with coconut-fiber-reinforced soil using the mixing method"), and also in section 2.2? If you keep the expression, then it needs a further explanation. Is any specific mixing method used?
- Keep the sentences as short and as clear as possible. The third sentence in the abstract, for example, is too long. Check the whole text.
- Please, avoid using the same phrases in one sentence, like here: "The shear strength of clayey soil was effectively improved by using MICP technology, with coconut-fiber reinforcement, and the shear strength first increased and then decreased with the increase in the fiber content." "The combination of MICP technology and fiber reinforcement technology achieved...". "Fiber reinforcement technology is a new type of soil reinforcement technology; the..." "They determined the influence of the optimal amount of reinforcement and the reinforcement method on the reinforcement effect." Improving the whole text in this manner is strongly advised. This way, the text is very hard to read.
- The abstract needs an explanation of how were the important properties of soil improved by coir-fiber and bacteria. Also, define which bacteria is used.
- All the claims in the text need a refernce, such as the whole paragraph in the Introduction section. Check the complete manuscript.
- It is not clear from the text whether anyone in the world used the combinataon of fibres and microorganisms to strengthen the soil. More literature may be needed.
- Using the personal pronouns is avoided in scientific text. Check the whole text.
- Is the region from which the soil was samplesd near the Yellow river, and why is it then mentioned in the first sentece in the Introduction section?
- Some sentences are too short and they are not very well formulated in literary terms, like this one: "They are also low cost, etc."
- Where the coconut shell finer used came from? How were its physical properties obtained? Also, a description of soil testing methods is missing.
- Please, make sure to have all standards listed in the references section (like, for example, GB/T 50123-2019).
- Figure 1 is missing, and however, it seems it is not neccessary for the work.
- PLease, remove the text in Chinese from the figures.
- The confining pressure written in the graphs is lacking the units and need an empty space after the number. ("50confining pressure").
- The text like "From the figure, it can be seen that..." must be deleted from text, just keep writing your conclusions and be specific.
- The whole discussion must be confronted and/or confirmed by other studies.
- It seems some figures repeat the results, this is to be avoided.
- The study does not present the relevant results of the soil, which are very important. Chemical, mineralogical and granulometry analyses are needed.
English contains too many repeated phrases, usage of personal pronouns and an unneccessary text.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The aim of this study is to facilitate engineering applications, the microbial liquid was mixed with coconut-fiber-reinforced soil using the mixing method, and the microbial solidification test was carried out on the reinforced clay with fiber contents. The performance is good. Some minor questions before the acceptance.
1. The article has a few grammatical problems.
2. The annotation in picture 3 in section 3.1 of the article is not changed to English.
3. The picture of TSZ-2 automatic triaxial instrument in picture 1 of the article is missing, please check and supplement.
4. Part of section 2.1Test materials in the article states that "1mol/L NaOH solution is used to adjust the PH value of the medium to 7.3, which presents an alkaline state". However, the pH value of the culture medium of Bacillus pasteurii (ATCC11859) is generally about 9.0, please explain the reason for setting the pH value to 7.3 in the test.
5. It is recommended to describe more about the ' coconut shell fiber ' used in the experiment, which can supplement the picture to give the reader a more intuitive impression.
Good in English
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The study needs extensive revision for novelty in the points of criticsims and material ability:
1) Some workability characteristics in shear stress and viscosity of fiber effects should be considered in comparsion and criticisim with alternate additives:
*Güllü, H., Al Nuaimi, M.M.D. & Aytek, A. Rheological and strength performances of cold-bonded geopolymer made from limestone dust and bottom ash for grouting and deep mixing. Bull Eng Geol Environ (2021). https://doi.org/10.1007/s10064-020-01998-2
2. The microsturcure effects of fiber with alternate additives should be compared. In the poÅŸnt of nano-effecscts should be more pronunced and workability should also tested:
*Effect of using nano-silica on the rheological, fresh and strength characteristics of cement-based grout for grouting columns.https://doi.org/10.1016/j.jobe.2023.107100
Should be improved
Author Response
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Reviewer 4 Report
SUMMARY
The article submitted for review is relevant. The authors conducted an experimental study of the mechanical properties and water stability of microbially cured, coir-fiber-reinforced clay soil. The scientific novelty of the research is the development of a new method of soil consolidation. The authors described the essence of the method, which consists in reinforcing the treatment of cohesive soil using microbial-induced calcium carbonate precipitation (MICP), with fiber reinforcement, which improves the mechanical properties and water resistance of the soil. Using different dosages of coconut fiber, the authors examined clay soils for non-drainage triaxial compaction, calcium carbonate content, and a disintegration test in combination with SEM microscope image analysis to compare and analyze the mechanical properties and water resistance of clay soils. The authors have carried out important and completed experimental studies, and have obtained effective results in improving the shear strength of clay soil, increasing the adhesion force, reducing the disintegration rate, and increasing the precipitation and yield of calcium carbonate. All these results made it possible to confirm the effectiveness of the method proposed by the authors for improving the safety of engineering structures. Thus, the study of the authors is quite interesting and useful from the point of view of scientific and practical significance. At the same time, there are some comments that need to be corrected. They are presented below.
COMMENTS
1. The period after the title of the article is redundant. Should be removed.
2. There is no description of the research problem at the beginning of the abstract. Need to be supplemented.
3. The abstract lacks a clearly formulated purpose of the study. Need to be added.
4. In paragraph (1) in the abstract, it is not clear how much the shear strength of the clay soil has been improved. A quantification of said improvement should be added.
5. The keyword "microstructure" is recommended to be deleted. It clearly falls out of the list of other keywords.
6. The authors should supplement the transition between the literature review and the purpose and tasks of the study with the formulation of the scientific novelty of this study. I would like to see in the manuscript what problem the authors solved with their research and what scientific deficit they filled.
7. At the end of the "Introduction" section, there are no clearly formulated purpose and tasks of the study. Need to be supplemented.
8. There are very few references (15) in section 1 for such a topic as soil consolidation. It would be necessary to expand their number to 22-25 in order to more clearly highlight the scientific novelty of the study.
9. The title of section two is recommended to be simplified, since the word “experimental” is repeated twice in it. For example, you can change it to "Experimental materials and Methods" or, more simply, "Materials and Methods".
10. After mentioning all materials and equipment in section 2, a link or information about the supplier/manufacturer, city and country should be given.
11. There is no mention in the text of Figure 11. It is necessary to add it before the figure, and also analyze the specified figure in detail. The same applies to Figure 15 (SEM).
12. It is necessary to strengthen the discussion of the obtained results in terms of their comparison with the results obtained earlier in other works of the authors and other authors.
13. The conclusions should be supplemented with information about the practical significance of the results obtained and the prospects for further research in this direction.
14. The list of references contains only 18 items, which is very small for such studies published in the world's leading scientific journals. "References" should be strengthened with another 10-15 references to the literature.
15. There are misprints in the article, in many places there are no necessary spaces, capital letters, there are extra spaces in the text, and the like. It is necessary to proofread the text of the manuscript again and correct the shortcomings. Some correction of the English language of the manuscript is also needed.
16. The general remark on the article is as follows. The article is interesting and relevant. At the same time, the article has a number of shortcomings that the reviewer listed, and they need to be corrected. The article needs some revision, after which it must be resubmitted for review.
Comments for author File: Comments.pdf
Proofreading of the text and minor edits of the English language are required.
Author Response
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