Damage Management of Concrete Structures with Engineered Cementitious Materials and Natural Fibers: A Review of Potential Uses

Round 1

Reviewer 1 Report

The paper reviewed the features of engineered cementitious composites (ECC) and thethe potential use of natural fibres and cellulose nanofibres in ECC. And concluded that pyrolysed cellulose nanofibres have the potentialities to be used to manufacture new self-sensing ECC materials. The paper is well organized. And the conclusions are interesting. However, the paper should be revised before it desired to be published. The detailed suggestions are listed as follows.

1 Too many descriptions focus on self-sensing mortars in 5 Conclusions. And it seems  inappropriate to cite literature in the conclusions.

2 There are some grammars and sentences mistakes.

 

Author Response

The paper reviewed the features of engineered cementitious composites (ECC) and the potential use of natural fibres and cellulose nanofibres in ECC. And concluded that pyrolysed cellulose nanofibres have the potentialities to be used to manufacture new self-sensing ECC materials. The paper is well organized. And the conclusions are interesting. However, the paper should be revised before it desired to be published. The detailed suggestions are listed as follows.

Comment 1: Too many descriptions focus on self-sensing mortars in 5 Conclusions. And it seems inappropriate to cite literature in the conclusions.

Comment 2: There are some grammars and sentences mistakes.

Response: We thank very much Reviewer 1 for her/his careful review and kind comments. All the grammar and sentences were modified, to the best of our knowledge. Finally, the conclusions were shortened and the citation deleted.

Reviewer 2 Report

 The paper is well presented with good English writing. There are some errors that need fixing as mentioned below.

The title is a bit confusing. It is recommended to shorten.

Abstract: Potential uses of the mentioned materials were not clearly indicated in the abstract. I understand that this paper is an literature research. However, please make your statement in numbers so the readers can see roughly what you are getting into.   

The authors presented the paper in 6 sections: Introduction, (2) Features of fibers, (3) Natural fibers, (4) Self-sensing cementitious materials, (5) Biochar, (6) Conclusions. The paper discussed about the potential use of natural fibers and cellulose nanofibers in cementitious materials. Then the topic of self-sensing mortars and concretes was presented. The information presented in the paper are huge. However, the structure of the paper is not very logical. This makes the papers a bit difficult to follow and understand.   

Line 476: abbreviation should not be used in formal writing, for example, “don’t” in the line 476.

Line 559 “It is worth highlighting too that” >> “It is worth highlighting that”

Line 631 “5. Conclusions” >> “6. Conclusions”

Line 663: You reason that the biochar is a conductive carbonaceous material was investigated to improve some favorable properties. Thus, the pyrolyzed cellulose nanofibers have potentialities… So what is the connection between these two materials? I would recommend the authors clarify this argument.

Author Response

This paper introduces many methods to reduce cracking such as addition of fibers. The review work is comprehensive, the following places should be well addressed.

Response: We thank very much Reviewer 2 for her/his careful review and constructive comments.

Comment 1: ECC is mentioned in the title and introduction, but it is not mentioned in the main body of the paper, therefore the title should be revised.

Comment 2: I cannot understand whether there is any relationship between Sections 4-5 and the title. The authors should explain why they reviewed Self-sensing cementitious materials and Biochar in the introduction part.

Response: We were aware that one possible weak point of this paper was the connection between the different topic: ECC, natural fibers, self-sensing concretes and biochar. Thus, some sentences were added throughout the text to better connect the different sections together. By doing this, we kept the title unchanged, following our initial idea. We hope to have reached our goal in the revised version of the article.

Comment 3: The authors stated that “the aim of this work is to review the types, properties, and applications of recent natural fibres used in ECC manufacturing”, therefore, I think the title should be more related with this sentence.

Response: We were aware that one possible weak point of this paper was the connection between the different topic: ECC, natural fibers, self-sensing and biochar. Thus, some sentences were added throughout the text to better connect the different sections together. We think now that the connection between ECC and damage management is clearer and the original title was maintained.

Comment 4: I am confused whether this paper is a review work or an investigation article, since there are too many expressions like “The results of simulations demonstrated…”, “the potential use of natural fibres and cellulose nanofibers was studied too”, etc. I am really confused whether these conclusions are obtained from the review work or from their own study. So, my suggestion is that the authors should make this paper more like a review work rather than an article.

Response: We apologise for the confusion and revised the paper having in mind that it is a review and not a presentation of our experimental results.

Comment 5: In the introduction part, authors stated “to improve the resistance against cracking”. However, there are many methods can be used to reduce the cracks, including the usage of fibers and expensive agents. I think the authors should enrich the statement of the introduction and tell the potential readers there are also other kinds of methods in addition to the usage of fibers. Therefore, some related references can improve the introduction part, such as Comparison of fly ash, PVA fiber, MgO and shrinkage-reducing admixture on the frost resistance of face slab concrete via pore structural and fractal analysis; Influence of MgO on the hydration and shrinkage behavior of low heat Portland cement-based materials via pore structural and fractal analysis.

Response: The original idea behind this paper was to show the connection between the different topic: ECC, natural fibers, self-sensing concretes and biochar for damage management. Therefore, we focused on fibers and neglected expansive and shrinkage-reducing agents. We apologise for not having reached our initial goal.

Comment 6: In summary, authors should reconsider the title and the structure of the paper.

Response: We think that now the connections between the different topic: ECC, natural fibers, self-sensing concretes and biochar for damage management are clearer and thus, the title was not changed.

Reviewer 3 Report

This paper introduces many methods to reduce cracking such as addition of fibers. The review work is comprehensive, the following places should be well addressed.

1. ECC is mentioned in the title and introduction, but it is not mentioned in main body of the paper, therefore the title should be revised.

2. I cannot understand whether there is any relationship between Sections 4-5 and the title. The authors should explain why they reviewed Self-sensing cementitious materials and Biochar in the introduction part.

3. The authors stated that “ the aim of this work is to review the types, properties, and applications of recent natural fibres used in ECC manufacturing”, therefore, I think the title should be more related with this sentence.

4. I am confused whether this paper is a review work or an investigation article, since there are too many expressions like

        “The results of simulations demonstrated…”

       “the potential use of natural fibres and cellulose nanofibers…was studied too”, etc.

        I am really confused whether these conclusions are obtained from the review work or from their own study. So, my suggestion is that the authors should make this paper more like a review work rather than an article.

5. In the introduction part, authors stated “to im-prove the resistance against cracking”. However, there are many methods can be used to reduce the cracks, including the usage of fibers and expensive agents. I think the authors should enrich the statement of the introduction and tell the potential readers there are also other kinds of methods in addition to the usage of fibers. Therefore, some related references can improve the introduction part, such as Comparison of fly ash, PVA fiber, MgO and shrinkage-reducing admixture on the frost resistance of face slab concrete via pore structural and fractal analysis; Influence of MgO on the hydration and shrinkage behavior of low heat Portland cement-based materials via pore structural and fractal analysis.

6. In summary, authors should reconsider the title and the structure of the paper.

Author Response

Response: We thank very much Reviewer 3 for her/his careful review and constructive comments.

Comment 1: Title. What is Damage management? not reflected in the content.

Response: Damage management was better explained in the introduction of the revised paper, as well as why ECC can be used to this aim.

Comment 2: Keywords biochar?

Response: This carbonaceous material is considered for possible future work as it has the potentialities to replace much more expensive materials (CNTs) for self-sensing concretes manufacturing. In addition, biochar is easier to disperse in cement due to its bigger size respect to CNTs.

Comment 3: Abstract lack of information. Gap of study and significance or novelty is not clear.

Response: Some information was added in the abstract, and biochar is mentioned as a possible novel material for self-sensing concretes manufacturing. We apologise for not being clear.

Comment 4: Conclusions too long. Citation must be avoided under conclusion.

Response: The conclusions were shortened and the citation deleted.

Reviewer 4 Report

Manuscript number: Sustainability_1613335

Title: Damage management of concrete structures with engineered cementitious materials and natural fibers: a review on potential uses

The following suggestion and comments should be taken

 

• Kindly suggest the authors refine the Abstract and the Conclusion.
• The abstract is missing the novelty of the current work. 
• Section 2.0. “…to fibers for producing ECC include [32]:” There is only one previous work has been referred? Please add several updated references.
• Line 218. Please avoid starting sentences with abbreviations. Please verify the CF.
• Table 2. Several previous works should be considered to be added.
• Line 278. The term “cheap treatment” is required for the extended discussion.
• The reference is outdated. Please replace with the latest reference (5 years before current work).
• The manuscript is hampered by several syntax and grammatical errors.
• Line 479. “…groups increases the sensitivity by 150%” Why?
• Line 565-566. The sentence is not preferred to be cited. 
• There is no future recommendation. No correlation between section and results.

As it is, the manuscript is suitable for publication after some changes 

Author Response

Response: We thank very much Reviewer 4 for her/his careful review and constructive comments.

Comment 1: Kindly suggest the authors refine the Abstract and the Conclusion.

Response: Both were modified.

Comment 2: The abstract is missing the novelty of the current work.

Response: In the abstract, biochar is mentioned as the new carbonaceous material which can be added to cementitious materials to improve their properties, including self-sensing ones.

Comment 3: Section 2.0. “…to fibers for producing ECC include [32]:” There is only one previous work has been referred? Please add several updated references.

Response:  More references were added to the text.

Comment 4: Line 218. Please avoid starting sentences with abbreviations. Please verify the CF

Response: “CF” was changed to “carbon fiber.”

Comment 5: Table 2. Several previous works should be considered to be added.

Response: In this table, only the properties of natural fibers were mentioned as the original idea behind this paper was to show the connections between the different topics: ECC, natural fibers, self-sensing concretes and biochar for damage management. But, in the text, some other previous works were added.

Comment 6: Line 278. The term “cheap treatment” is required for the extended discussion.

Response: To the best of our knowledge, no treatment has been already proposed in the literature for sealing pores in natural fibers. One possible treatment could be to use PVA which is soluble into ethanol to coat them. This information was added to the test.

Comment 7: The reference is outdated. Please replace with the latest reference (5 years before current work).

Response: The references were updated.

Comment 8: The manuscript is hampered by several syntax and grammatical errors.

Response: The paper was Grammarly checked and sentences were modified to the best of our knowledge

Comment 9: Line 479. “…groups increases the sensitivity by 150%” Why?

Response: The following comment was added to the text: “because of a better dispersion of CNTs when they are functionalized with carboxyl groups”.

Comment 10: Line 565-566. The sentence is not preferred to be cited.

Response: This sentence was deleted

Comment 11: There is no future recommendation. No correlation between section and results. As it is, the manuscript is suitable for publication after some changes.

Response: Biochar is mentioned as a possible novel material for self-sensing ECC manufacturing in alternative to more expensive carbonaceous materials (CNTs). In addition, pyrolyzed CNCs can be also promising alternatives to carbon-based materials such as CNTs or carbon fibers, in combination with biochar. We apologize for not being clear.

Reviewer 5 Report

1. Title. What is Damage management? not reflected to the content.
2. Keywords biochar?
3. Abstract lack of information. Gap of study and significance or novelty are not clear.
4. Conclusions too long. Citation must be avoid under conclusion. 

Author Response

Response: We thank very much Reviewer 5 for her/his careful review and constructive comments.

Comment 1: Title. What is Damage management? not reflected to the content.

Response: Damage management was better explained in the introduction of the revised paper, as well as why ECC can be used to this aim.

Comment 2: Keywords biochar?

Response: This carbonaceous material is considered for future work as it has the potentialities to replace much more expensive materials (CNTs) for self-sensing concretes manufacturing, either alone or in combination with pyrolyzed cellulose nanofibers.

Comment 3: Abstract lacks of information. Gap of study and significance or novelty are not clear.

Response: We were aware that one possible weak point of this paper was the connection between the different topic: ECC, natural fibers, self-sensing concretes and biochar. Thus, some sentences were added throughout the text to better connect the different sections together. We hope to have reached our goal in the revised version of the article. We also stressed the novelty of using biochar and pyrolyzed cellulose nanofibers to replace CNTs in self-sensing ECC.

Comment 4: Conclusions too long. Citation must be avoided under conclusion.

Response: The conclusions were shortened and the citation deleted.

Round 2

Reviewer 3 Report

The authors failed to respond any of my previous comments. Maybe they attached the wrong response.

My previous comments contain 6 points, such as 

This paper introduces many methods to reduce cracking such as addition of fibers. The review work is comprehensive, the following places should be well addressed.

1. ECC is mentioned in the title and introduction, but it is not mentioned in main body of the paper, therefore the title should be revised.

2. I cannot understand whether there is any relationship between Sections 4-5 and the title. The authors should explain why they reviewed Self-sensing cementitious materials and Biochar in the introduction part.

3. The authors stated that “ the aim of this work is to review the types, properties, and applications of recent natural fibres used in ECC manufacturing”, therefore, I think the title should be more related with this sentence.

4. I am confused whether this paper is a review work or an investigation article, since there are too many expressions like

        “The results of simulations demonstrated…”

       “the potential use of natural fibres and cellulose nanofibers…was studied too”, etc.

        I am really confused whether these conclusions are obtained from the review work or from their own study. So, my suggestion is that the authors should make this paper more like a review work rather than an article.

5. In the introduction part, authors stated “to im-prove the resistance against cracking”. However, there are many methods can be used to reduce the cracks, including the usage of fibers and expensive agents. I think the authors should enrich the statement of the introduction and tell the potential readers there are also other kinds of methods in addition to the usage of fibers. Therefore, some related references can improve the introduction part, such as Comparison of fly ash, PVA fiber, MgO and shrinkage-reducing admixture on the frost resistance of face slab concrete via pore structural and fractal analysis; Influence of MgO on the hydration and shrinkage behavior of low heat Portland cement-based materials via pore structural and fractal analysis.

6. In summary, authors should reconsider the title and the structure of the paper.

However, their response contain only 4 points.

Moreover, the authors should adopt each of my comment . They should understand the efforts and time we made to improve their paper.   

Author Response

General comment 1. The authors failed to respond any of my previous comments. Maybe they attached the wrong response.

Answer: We apologise for the confusion between the different responses to the Reviewers.

My previous comments contain 6 points, such as:

General comment 2. This paper introduces many methods to reduce cracking such as addition of fibers. The review work is comprehensive, the following places should be well addressed.

Answer: We thank very much Reviewer 3 for her/his careful review and constructive comments.

Comment 1. ECC is mentioned in the title and introduction, but it is not mentioned in main body of the paper, therefore the title should be revised.

Answer: We were aware that one possible weak point of this paper was the connection between the different topics: damage management, ECC, natural fibers, self-sensing concretes and biochar. Thus, some sentences were added throughout the text to better connect the different sections together. By doing this, we kept the title unchanged, following our initial idea. We hope to have reached our goal in the revised version of the article.

Comment 2. I cannot understand whether there is any relationship between Sections 4-5 and the title. The authors should explain why they reviewed Self-sensing cementitious materials and Biochar in the introduction part.

Answer: Biochar and pyrolyzed nanocellulose are presented with the aim to replace more expensive materials such as CNTs and graphene.

At the end of the introduction these sentences were added: “Thus, this work reviews the types, properties, and applications of recent natural fibers used in ECC manufacturing. The features of candidate fibers are discussed. Furthermore, when using natural fibers, these materials can also be transformed into carbon fibers through a pyrolysis process, to become conductive in view of the production of self-sensing ECC.”

We hope to have reached our goal in the revised version of the article.

Comment 3. The authors stated that “the aim of this work is to review the types, properties, and applications of recent natural fibres used in ECC manufacturing”, therefore, I think the title should be more related with this sentence.

Answer: We think now that the connection between ECC and damage management is clearer, thus the original title was maintained with the words “damage management, “natural fibers” and “engineered cementitious materials”.

Comment 4. I am confused whether this paper is a review work or an investigation article, since there are too many expressions like

        “The results of simulations demonstrated…”

       “the potential use of natural fibres and cellulose nanofibers…was studied too”, etc.

        I am really confused whether these conclusions are obtained from the review work or from their own study. So, my suggestion is that the authors should make this paper more like a review work rather than an article.

Answer: We apologise for the possible confusion and revised the paper having in mind that it is a review paper and not a presentation of our experimental results. However, we think that we have to highlight the fact whether the presented literature results are due to simulations or experimental activities. Thus, we kept this distinction in the article.

Comment 5. In the introduction part, authors stated “to improve the resistance against cracking”. However, there are many methods can be used to reduce the cracks, including the usage of fibers and expensive agents. I think the authors should enrich the statement of the introduction and tell the potential readers there are also other kinds of methods in addition to the usage of fibers. Therefore, some related references can improve the introduction part, such as Comparison of fly ash, PVA fiber, MgO and shrinkage-reducing admixture on the frost resistance of face slab concrete via pore structural and fractal analysis; Influence of MgO on the hydration and shrinkage behavior of low heat Portland cement-based materials via pore structural and fractal analysis.

Answer: The original idea, when considering damage management, was to take into consideration only earthquakes. However, based on your input, we considered also frost damaging and plastic/drying shrinkages, as other possible physical damages and added the mitigations strategies connected to limit them. Therefore, these sentences were added in the introduction: “In addition, PVA fibers (0.8 kg/m³) can also increase frost resistance of concrete slabs [37]. Their effect is even stronger when added in combination with fly ash [37]. Thus, fibers addition to cementitious materials are useful for damage management of concrete structures. On the contrary, expansive agents used as shrinkage-reducing admixtures, like MgO or other compounds, are not as efficient as fibers [37]”. A new reference was then added: [37] Wang, L.; Guo, F.; Yang, H.; Wang, Y.; Tang, S.; Comparison of fly ash, PVA fiber, MgO and shrinkage-reducing admixture on the frost resistance of face slab concrete via pore structural and fractal analysis. Fractals. 2021, 29, 2140002, 1-18, doi.org/10.1142/S0218348X21400028

On the contrary, pore structural and fractal analysis are out of the scope of this article.

Comment 6. In summary, authors should reconsider the title and the structure of the paper.

Answer: As explained above, the title is unchanged, on the basis of our original idea: damage management by means of ECC; possible exploitation of natural fibers for ECC manufacturing; traditional self-sensing concretes with carbon fibers; CNTs and graphene and finally; possible new ECC with biochar and pyrolysed nanocellulose.

Comment 7. However, their response contains only 4 points.

Answer: We are sorry for not being enough clear when submitting our previous answer to your comments, as some answers were related to more than one comment.

Comment 8. Moreover, the authors should adopt each of my comment. They should understand the efforts and time we made to improve their paper.

Answer: We thank you very much once again for your careful review and constructive comments to improve our article and we are well aware of the time you dedicated to review of our paper, as we also regularly perform reviews of papers for different journals. Thus, there was no willing at all to be disrespectful. However, you can also understand that we want to defend our original idea of the paper’s structure.

Reviewer 4 Report

The paper is ready for publication 

Author Response

We thank very much once again Reviewer 4 for her/his careful review and constructive comments to improve our paper.

Reviewer 5 Report

Revised manuscript is acceptable.

Author Response

We thank very much once again Reviewer 5 for her/his careful review and constructive comments to improve our paper.

Round 3

Reviewer 3 Report

It can be accepted.