Evaluating the Influence of Hydrophobic Nano-Silica on Cement Mixtures for Corrosion-Resistant Concrete in Green Building and Sustainable Urban Development

Round 1

Reviewer 1 Report

This work explains Evaluation of the Influence of Hydrophobic Nano-Silica on  Cement Mixtures for Corrosion-Resistant Concrete in Green  Building and Sustainable Urban Development. The title well suited to the  aim and scope of the journal Sustainability.

The Comments are as follows.

(i) The Research background, Problem statement, Significance and impact of the work are are to be included in the Abstract.

(ii) The line “Concrete is the most widely used construction material in the world due to the benefits it offers compared to other materials in civil engineering works” need to be cited. Some relevant works are found below

https://doi.org/10.1504/IJESD.2019.099491

https://doi.org/10.3390/su151410986

https://doi.org/10.1016/B978-0-12-821730-6.00031-0

(iii) Number of  small paragraphs are there in Introduction Section. Merge these paragrapgh wherever necessary.

(iv) State the novelty of your work in the introduction section.

(v) Theoretical Framework is vague. Reduce the contents

(vi) In section 3.3.3., remove the numbering 1., 2., 3., etc. Instead provide bulletin points.

(vii) Explain the results using bar chart/Line chart also.

(viii) Your results needs to be compared with existing literatures.

(ix) Figure 3, 4 need to be replaced with a clear graph. The legends n the current figures are not clearly visible.

After carrying out a thorough peer review, It is recommended to do major change.

Author Response

Dear respected reviewer.

• All the mentioned suggestions tried to be applied
• I added all three 3 papers modified the text, and changed some parts
• The bar chart is considered in another paper submitted to this special issue. so I am afraid using it here cause plagiarism.
• All graphs change with the visible one.

Thank you for your constructive comments

Author Response File: Author Response.pdf

Reviewer 2 Report

The lack of elaboration on the experimental design justifies the manuscript's rejection for publication. It is suggested that the authors include all necessary information for a scientific work, such as material characterization, experimental procedures, and a comprehensive and detailed discussion of the results. Specific comments are highlighted below:

1)      Review the formatting of the entire manuscript! There are different spacings and styles. Standardize according to the journal's formatting.

 

2)      “This research project investigates the impact of substituting hydrophobic nano-silica particles for 2% of the cement weight in high-strength concrete mixes.” Include a sentence at the beginning of the abstract highlighting the novelty of the research.

 

 

3)      “The concrete designs feature a high strength of 42 MPa, and the hydrophilic nano-silica particles undergo functionalization processes to obtain hydrophobic properties.” Why are these properties interesting for concretes? It is important to clarify this in the manuscript.

 

4)      “The research findings reveal 25 that concrete containing nano-silica particles demonstrates improved physical-mechanical properties compared to other mixes” Incorporate some quantitative values regarding the enhancements in the properties.

 

 

5)      “suggests a direct influence of nano-silica on 29 the corrosion phenomenon.” Possibly, this is associated with the improved refinement of pores and greater matrix compaction.

 

6)      “However, nano-silica particles are functionalized to have a high level of hydrophobicity in order to maximize their efficacy [7].” Effectiveness in what sense? On the other hand, do hydrophobic properties hinder dispersion in the matrix? This issue needs to be contextualized in the introduction.

 

7)      “One of the key advantages of incorporating hydrophobic nano-silica is its ability to 52 mitigate the ingress of harmful elements, such as chloride and carbonate ions, into the 53 concrete microstructure [9].” Explain the mechanism.

 

8)      “…inclusion of nano-silica polydimethylsiloxane (PDMSO)…” it is not clear what PDMSO means.

 

9)      “A large number of previous studies have shown that the addition of nano-silica particles to concrete mixes causes changes in the microstructure of the concrete” Mention these studies.

 

10)   There is a significant body of research on the incorporation of nanosilica in cementitious matrices. What sets this study apart from existing ones? A table showcasing existing studies would help emphasize the novelty of the research.

 

11)   Tables are not mentioned in the text! Please review the entire manuscript.

 

12)   “…which are specified in national and international standards…” Review the formatting of the cited references.

 

13)   “The properties that must be verified are…” The lack of detailed experimental procedure in a scientific work is unacceptable. Merely naming the tests and properties is not sufficient.

 

14)   No references are cited in the results discussion to compare the obtained results with those reported in the literature.

Author Response

Dear respective reviewer
based on your constructive comments. I tried to modify the paper and reply to all questions as best as possible

Thank you for your attitude.

 

• Review the formatting of the entire manuscript! There are different spacings and styles. Standardize according to the journal's formatting.

Based on the instructions for authors (https://www.mdpi.com/journal/sustainability/instructions) there is not any specific formatting for submission. But all the citations and references have been updated by EndNode software based on the provided MDPI style

• “This research project investigates the impact of substituting hydrophobic nano-silica particles for 2% of the cement weight in high-strength concrete mixes.” Include a sentence at the beginning of the abstract highlighting the novelty of the research.

A paragraph has been added to the end of the introduction. I did this based on the suggestion of 2 other respected reviewers.

• “The concrete designs feature a high strength of 42 MPa, and the hydrophilic nano-silica particles undergo functionalization processes to obtain hydrophobic properties.” Why are these properties interesting for concretes? It is important to clarify this in the manuscript.

Yes, the following parts of the text answer the question of why the mentioned properties are interesting for concretes:

Hydrophobic Nano-Silica and Corrosion Resistance:

The text explains that hydrophobic nano-silica particles have been incorporated into concrete mixes to enhance corrosion resistance. These particles undergo functionalization processes to become hydrophobic, which means they repel water. This hydrophobic property of nano-silica is particularly beneficial for concrete because it reduces water absorption in hardened concrete. As a result, concrete with hydrophobic nano-silica responds better to the corrosion phenomenon, prevents deterioration, and provides greater durability to structures. This property is important for countering the corrosion process and ensuring the longevity of concrete structures.

Influence on Water Absorption and Durability:

The text further explains that one of the key advantages of incorporating hydrophobic nano-silica in concrete is its ability to mitigate the ingress of harmful elements, such as chloride and carbonate ions, into the concrete microstructure. These ions are known for compromising the protective barrier between steel reinforcement and concrete, leading to the corrosion process. The hydrophobicity of nano-silica doesn't obstruct the passage of these ions but acts as an extra layer of defense, preventing water from diffusing through the microstructure of the concrete. This property contributes to improved durability by reducing transport properties against erosion, abrasion resistance, carbonation, and chloride ion attack.

Improved Mechanical Properties and Strength:

Nano-silica, despite being hydrophobic, still enhances the mechanical properties of concrete. It reacts with cement during the hydration process, thereby increasing the mechanical strength of the resulting concrete. Additionally, the presence of nano-silica in concrete contributes to improved durability by reducing transport properties against various forms of deterioration. The text also mentions that the mixture with 2% nano-silica PDMSO achieves the designed mechanical strengths and has good behavior under the electrochemical corrosion process.

Nano-Silica's Impact on Structural Integrity:

The text emphasizes that the incorporation of hydrophobic nano-silica in cement mixtures offers a promising avenue for developing corrosion-resistant concrete. By improving mechanical properties, reducing water absorption, and enhancing durability, nano-silica provides a valuable solution to counteract the corrosion phenomenon and ensure the longevity of structures. This suggests that the properties of hydrophobic nano-silica are essential for maintaining the structural integrity of concrete over time, especially in challenging environmental conditions.

• “The research findings reveal that concrete containing nano-silica particles demonstrates improved physical-mechanical properties compared to other mixes” Incorporate some quantitative values regarding the enhancements in the properties. 

Added to the abstract

5)      “suggests a direct influence of nano-silica on the corrosion phenomenon.” Possibly, this is associated with the improved refinement of pores and greater matrix compaction.

 Yes, because nano-silica's hydrophobic properties result in reduced pore connectivity and a denser matrix, thereby inhibiting the ingress of corrosive agents and enhancing the resistance to corrosion.

“However, nano-silica particles are functionalized to have a high level of hydrophobicity in order to maximize their efficacy [7].” Effectiveness in what sense? On the other hand, do hydrophobic properties hinder dispersion in the matrix? This issue needs to be contextualized in the introduction.

The term "effectiveness" refers to achieving the desired hydrophobic properties for enhanced performance.

While hydrophobic properties are desired for improved performance, they can potentially hinder dispersion in the matrix due to agglomeration tendencies caused by reduced affinity to polar components.

Thank you for your attitude to this part. I added an explanation in the introduction for this part

7)      “One of the key advantages of incorporating hydrophobic nano-silica is its ability to mitigate the ingress of harmful elements, such as chloride and carbonate ions, into the concrete microstructure.” Explain the mechanism.

      I modified the sentence in the text.

8)      “…inclusion of nano-silica polydimethylsiloxane (PDMSO)…” it is not clear what PDMSO means.

 PDMSO is an abbreviation for polydimethylsiloxane

9)      “A large number of previous studies have shown that the addition of nano-silica particles to concrete mixes causes changes in the microstructure of the concrete” Mention these studies.

 Has been added based on your suggestion

10)   There is a significant body of research on the incorporation of nanosilica in cementitious matrices. What sets this study apart from existing ones? A table showcasing existing studies would help emphasize the novelty of the research.

11)   Tables are not mentioned in the text! Please review the entire manuscript.

 Revised

12)   “…which are specified in national and international standards…” Review the formatting of the cited references.

I used endknot to reformat all references and citation

13)   “The properties that must be verified are…” The lack of detailed experimental procedures in a scientific work is unacceptable. Merely naming the tests and properties is not sufficient.

This portion of the text was removed due to the lack of references and extra explanation based on the suggestion of other respected reviewers.

14)   No references are cited in the discussion of the results to compare the obtained results with those reported in the literature.

It is entirely true that results need to be discussed concerning previous literary achievements. However, in this paper, the procedure of other researchers has been adopted, while the magnitudes of the additives are completely different. As a result, the comparison for this specific experiment does not appear coherent to the author. However, another paper submitted to this special issue was reviewed by comparing the results to those of previously published reports.

Author Response File: Author Response.pdf

Reviewer 3 Report

Table 2. What is the unit here? Tables in general need improved readability.

Conclusions mention decreased workability with ns addition but this was not really mentioned earlier. Not part of conclusions if it is already solved before this.

Overall the paper is interesting and the experiments well designed, but it is not easy to understand from the manuscript what are the real pros and cons of these additives. The manuscript, especially conclusions, should be rewritten to clarify this.

 

Mostly quite understandable but I would advise a proofreading by a native to correct clumsy mistakes like line 150 where properties against abrasion resistance are discussed.

Mostly quite understandable but I would advise a proofreading by a native to correct clumsy mistakes like line 150 where properties against abrasion resistance are discussed.

Author Response

thank you for your attitude,
The specimens are cylindrical 20 cm in height and 10 cm in diameter. so the weight of the concrete is approximately ~3.5 Kg
So the unit is Kg for each value in table 0.39 + 1 + 0.84 + 1.26 = 3.49
I added this to the table in the revised version.

we tried to improve the text and modified the obvious grammar mistakes.

Reviewer 4 Report

Thank you for submitting the article. I carefully read the text and did not identify any issues. The content was clear and easy to follow.

Author Response

Dear respected reviewer

Thank you for your encouraging message.

Yours sincerely

Round 2

Reviewer 1 Report

Comments are addressed

Author Response

Thank you for your comments

Reviewer 2 Report

No comments from the first round of review were incorporated into the manuscript. I suggest rejecting it.

Author Response

Please see attached.

Author Response File: Author Response.docx