Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors conducted an interesting review article on waste glass-contained UHPC specimens. Although valuable efforts have been conducted by the authors in this study, a major revision is required to enhance the manuscript. Accordingly, please consider the following comments:

- General comments: The authors should specifically emphasize whether they concentrated on recycled glass powders, aggregates, or fibers.

- Plz provide a specific figure to explain the various sections and subsections considered for this review study.

- Various figures were used from the literature. The authors should provide permission from publishers. It is very important.

-  The reviewer recommends not using short paragraphs throughout the manuscript.

- Plz re-check the title: admixture or additives?  

- Plz re-check figure 1: The reviewer recommends to prepare a comparison curves for various literature in a same figure. (for others characteristics also if possible). The reviewer recommends reading following review article as a good example to be followed (https://doi.org/10.1016/j.cemconres.2019.03.013)

- Figures 3 & 4: plz add references.

- Figure 21: plz add a reference.

- The reviewer recommends re-analyzing the literature results to solve the issue of permission. Also, there is missing parts of comparison between characteristics in this study.

- Table 6: please prepare a comparison figure instead of this table to compare the results regarding the waste glass type and dosage affecting the compressive strength of UHPC.

- The reviewer recommends proving specific table (more comprehensive than Table 5) to explain various mix design considered for UHPC mixtures containing waste glass.

 

- Please provide a section to summarize the findings and mention research gaps for being considered by future studies. This section was provided by some review papers such as https://doi.org/10.3390/constrmater1030010. 

Comments on the Quality of English Language

It is OK.

Author Response

Response to Reviewers’ Comments

(Manuscript Number:  sustainability-3031858)

 

Title: A Comprehensive Overview of Recycled Glass as Mineral Admixture for Circular UHPC Solutions.

Journal: Sustainability

Authors: N. Marcela Redondo-Pérez, Jesús D. Redondo-Mosquera, and Joaquín Abellán-García

 

The authors greatly appreciate the Editor’s time in handling the manuscript review. We also thank the reviewers for their constructive comments and valuable suggestions. The manuscript has been revised in light of their suggestions and comments. We are sure that the revised manuscript’s quality is improved. Point-wise, answers to their specific comments/suggestions/queries are as follows.

 

 

Response to Reviewer #1 Comments

 

General Comment. The authors conducted an interesting review article on waste glass-contained UHPC specimens. Although valuable efforts have been conducted by the authors in this study, a major revision is required to enhance the manuscript. Accordingly, please consider the following comments:

Response. The authors are grateful to the reviewer for his encouraging remarks and positive comments. Our pointwise response to the comments is as follows.

General comment: The authors should specifically emphasize whether they concentrated on recycled glass powders, aggregates, or fibers.

Response.

Thank you for your insightful comment. We appreciate your suggestion to clarify the focus of our review. This review article specifically examines the effects of recycled glass powders and sand, as detailed in section "4. The use of waste glass powder in UHPC formulations" and subsections "4.1 GP as supplementary cementitious material" and "4.2 Waste glass as a replacement for QS". In response to your feedback, we have revised the abstract to clearly state it from the beginning of the manuscript.

Comment#1. Plz provide a specific figure to explain the various sections and subsections considered for this review study.

Response. Thank you for your valuable feedback. We appreciate your attention to detail. In response to your comment, we have created a new figure, labeled as “Figure 1,” which outlines the various sections and subsections considered in our review study. Each section and subsection is represented within the figure, enhancing the overall clarity of our paper.

Comment#2. Various figures were used from the literature. The authors should provide permission from publishers. It is very important.

Response. To avoid the need to request permission from publishers, which would extend the review timeline beyond the journal's established deadlines, we have replaced some Figures with similar ones from open-access journals that permit reuse for non-commercial purposes, as outlined by Creative Commons licenses. In cases where suitable open-access alternatives were unavailable, we eliminated those figures and adjusted the text accordingly. After doing this, in the new version of the manuscript, there are 17 of the 23 Figures that were created by the authors based on data obtained from scientific literature. It is clear that those do not need any permission from any publisher.

The rest of the figures, those that have been taken from the scientific literature, are listed below, along with their sources and the link/doi to verify that they are open-access sources with permission to reuse for non-commercial purposes:

Figure 2 (left).

-     Source: doi:10.1016/j.cscm.2023.e01906

-     Type of document: Research paper

-     Journal: Case Studies in Construction Materials

This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

 

Figure 2 (right). (This figure is not the same as in the original manuscript, it was changed to a similar one from an open-access journal).

-     Source: https://doi.org/10.20868/UPM.thesis.66122

-     Type of document: Doctoral thesis

This document is available at the UPM Digital Archive at https://oa.upm.es/66122/. The UPM Digital Archive houses in digital format the academic and scientific documentation (theses, articles, etc.) generated at the institution and makes it accessible through the Internet, within the framework of the Budapest Open Access Initiative and the Berlin Declaration, of which the Polytechnic University of Madrid (UPM by its acronym in Spanish) is a signatory.

 

Figure 3 (a). (This figure is not the same as in the original manuscript, it was changed to a similar one from an open-access journal).

-     Source: doi:10.1016/j.cscm.2024.e03231

-     Type of document: Research paper

-     Journal: Case Studies in Construction Materials

This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

 

Figure 3 (b). (This figure is not the same as in the original manuscript, it was changed to a similar one from an open-access journal).

-     Source: http://doi.org/10.15446/dyna.v87n213.82655

-     Type of document: Research paper

-     Journal: DYNA (Colombia)

This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

 

Figure 6.

-     Source: doi:10.1016/j.cscm.2024.e03231

-     Type of document: Research paper

-     Journal: Case Studies in Construction Materials

This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

 

Figure 7. (This figure has been modified due to another reviewer’s requirement).

-     Source: https://doi.org/10.20868/UPM.thesis.66122.

-     Type of document: Doctoral thesis

This document is available at the UPM Digital Archive at https://oa.upm.es/66122/. The UPM Digital Archive houses in digital format the academic and scientific documentation (theses, articles, etc.) generated at the institution and makes it accessible through the Internet, within the framework of the Budapest Open Access Initiative and the Berlin Declaration, of which the Polytechnic University of Madrid (UPM by its acronym in Spanish) is a signatory.

 

Figure 14. (This figure is not the same as in the original manuscript, it was changed to a similar one from an open-access journal).

-     Source: doi:10.1016/j.cscm.2022.e01308

-     Type of document: Research paper

-     Journal: Case Studies in Construction Materials

This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

 

Figure 15.

-     Source: https://doi.org/10.20868/UPM.thesis.66122.

-     Type of document: Doctoral thesis

This document is available at the UPM Digital Archive at https://oa.upm.es/66122/. The UPM Digital Archive houses in digital format the academic and scientific documentation (theses, articles, etc.) generated at the institution and makes it accessible through the Internet, within the framework of the Budapest Open Access Initiative and the Berlin Declaration, of which the Polytechnic University of Madrid (UPM by its acronym in Spanish) is a signatory.

 

Comment#3. The reviewer recommends not using short paragraphs throughout the manuscript.

Response. In response to your request, we have avoided short paragraphs where possible in the revised manuscript.

Comment#4. Plz re-check the title: admixture or additives? 

Response. Although both expressions are easily found in scientific literature, "mineral admixture" is the term used by ASTM and the most widespread to refer to this type of concrete material. Here is the definition of "Mineral Admixture" from the ASTM: " “Mineral admixtures include any essentially insoluble material other than cement and aggregate, which is used as an ingredient for concrete, and is added to the batch immediately before or during mixing. Mineral admixtures include natural materials, processed natural materials, and artificial materials […]”.

In addition, here are some references that use this term instead of “mineral additives”:

- https://doi.org/10.1007/s42452-020-2533-6

- https://doi.org/10.1016/0008-8846(88)90081-6

- https://doi.org/10.1016/S0958-9465(00)00031-7

- https://doi.org/10.1016/S0008-8846(00)00454-3

- https://doi.org/10.1016/S0008-8846(03)00038-3

Therefore, we strongly believe that mineral admixture is the correct way for the title.

 

Comment#5. - Plz re-check figure 1: The reviewer recommends to prepare a comparison curves for various literature in a same figure. (for others characteristics also if possible). The reviewer recommends reading following review article as a good example to be followed (https://doi.org/10.1016/j.cemconres.2019.03.013)

Response. We sincerely appreciate the valuable input provided by the reviewer. Thank you for recommending the review article titled “A review on concrete fracture energy and effective parameters” by S. Khalilpour, E. BaniAsad, and M. Dehestani (DOI: 10.1016/j.cemconres.2019.03.013). We have carefully considered your feedback, but in this case, it is not possible to follow it. Please note that the primary purpose of Figure 2 (previously labeled as Figure 1), is to illustrate the amorphous nature of recycled soda-lime glass from distinct sources. The presence of sawtooth patterns in the XRD highlights this characteristic effectively. On the other hand, please note that quantitative interpretation of X-ray diffraction graphs for mineral additives can be challenging. Typically, these graphs are presented with peak identification rather than quantitative reports (it can be done, but it is difficult, depending on the database used to analyze the graph, the bias of the technician, and so on. Therefore, the quantitative interpretation of XRD analysis is not usually provided in the research papers). As a result, preparing a direct comparison curve for various literature sources is not feasible.

Instead, we have increased the references of concrete research that present XDR graphs of recycled glass in case any readers would like to review the topic further. Please refer to line 236 of the new version of the manuscript.

Once again, we express our gratitude for the recommended reading, and we have taken steps to enhance the clarity and relevance of our review paper based on your insightful suggestions.

Comment#6. Figures 3 & 4: plz add references.

Response. Thank you for your valuable feedback. We confirm that both figures were created by the authors of this manuscript. However, in accordance with your instructions, we have now incorporated the references from which the information was obtained to create these figures.

Comment#7. Figure 21: plz add a reference.

Response. Thank you for your suggestion. Similar to the previous case, Figure 22 (formerly Figure 21 in the old version of the manuscript) was created by the authors using data from published research. Following your instructions, we have added the appropriate reference to this figure.

Comment#8. The reviewer recommends re-analyzing the literature results to solve the issue of permission. Also, there is missing parts of comparison between characteristics in this study.

Response. We appreciate the reviewer's suggestion to re-analyze the literature results to address the permission issue. We have already resolved this matter in our response to Comment#2. Additionally, we have expanded on the research gaps our review aims to address and highlighted the novelty of our work in relation to the existing literature in the new version of the manuscript. Specifically, we have revised the last paragraph to include a more thorough comparison between the characteristics of our study and previous works. Please see lines 123-130 in the revised manuscript for these updates.

 

Comment#9. Table 6: please prepare a comparison figure instead of this table to compare the results regarding the waste glass type and dosage affecting the compressive strength of UHPC.

Response. We appreciate the reviewer's suggestion to prepare a comparison figure instead of Table 6 to illustrate the effects of waste glass type and dosage on the compressive strength of UHPC. However, we believe that this may not be the most effective approach. The data presented in Table 7 (Table 6 in the previous version of the manuscript) encompasses multiple variables, including maximum size, average size, replacement percentage, compressive strength under standard curing, and compressive strength under thermal curing. Converting this complex information into a figure may make it difficult to interpret. We believe that presenting this data in a table format is clearer and more accessible for readers.

Thank you for your understanding.

 

Comment#10. The reviewer recommends proving specific table (more comprehensive than Table 5) to explain various mix design considered for UHPC mixtures containing waste glass.

Response. Thank you for your valuable feedback. We appreciate your suggestion regarding the inclusion of a more comprehensive table to explain the various mix designs considered for UHPC mixtures containing waste glass.

 

In response, we would like to clarify the comprehensive nature of the information already presented in our manuscript:

 

Table 5 in our manuscript, titled "Reported research utilizing waste glass combined with other mineral admixtures in UHPC formulations," provides detailed information on previous research efforts that incorporate waste glass as a cementitious material in UHPC formulations. This table showcases the diverse approaches and outcomes from existing studies, highlighting the versatility and potential of waste glass in UHPC.

 

Table 7, titled "Results of compressive strength of UHPC with glass sand," presents comprehensive data on the mix designs where waste glass is used as sand. It includes crucial information about the compressive strength of these mixtures, offering insights into their mechanical performance.

 

Table 6 (5 in the old version) is critical to our manuscript as it depicts the mixture proportion in kilograms per cubic meter for a control UHPC dosage, a typical UHPC formulation without alternative cementitious materials, and two optimized UHPC formulations that incorporate waste glass powder in varying sizes. In addition to the mixture proportions, Table 6 provides essential details such as the water-to-binder ratio, slump flow value, and virtual packing density of the mixtures. These parameters are fundamental to understanding the rheological and mechanical properties of the UHPC formulations.

 

Moreover, the data in Table 6 is extensively utilized across multiple subsections of our review article, including:

 

5.1 Rheological properties

5.4.1 Compressive strength

5.4.2 Modulus of Elasticity (MoE)

5.4.3 Ultrasonic pulse velocity

5.5.1 Voids in hardened concrete

5.5.2 Chloride penetration

5.5.3 Initial Surface Absorption

5.5.8 Drying shrinkage

7. Cost implications

Given its integral role in supporting the findings and discussions throughout the manuscript, Table 6 cannot be replaced. However, we recognize the importance of clarity and comprehensiveness. To address your suggestion, we propose enhancing Table 6 by including additional columns or rows, if necessary, to further elaborate on the specific mix designs incorporating waste glass. This enhancement will ensure that all relevant data is presented cohesively, providing a more comprehensive overview without the need to introduce a completely new table.

 

We hope this explanation clarifies the extensive coverage and importance of the existing tables and addresses your concerns effectively. Thank you once again for your insightful feedback.

 

Comment#11. Please provide a section to summarize the findings and mention research gaps for being considered by future studies. This section was provided by some review papers such as https://doi.org/10.3390/constrmater1030010.

Response. We appreciate the reviewer’s suggestion and the reference to "Clay as a Sustainable Binder for Concrete—A Review" by Seyed Sina Mousavi, Chandrasekhar Bhojaraju, and Claudiane Ouellet-Plamondon. Due to the already substantial length of our paper, we have opted not to add a new section. Instead, we have completely rewritten the conclusion section to be more concise and succinct, effectively summarizing the key findings and their implications. Additionally, we have included a final paragraph in the conclusion section to highlight future research directions. This enhancement aims to provide clear and structured guidance for future studies, addressing potential areas for further exploration and development.

 

Reviewer 2 Report

Comments and Suggestions for Authors

This review article is very informative and well-written. After reading the whole manuscript, it is obvious that the authors spent so much time preparing it. The authors did not only report the results from literature but also commented on every single information with valid explanations and strong reasoning. Well-done on this great piece of work. However, some minor comments should be addressed:

1. A very well and informative brief about UHPC has been provided in the introduction section. However, the information about glass waste and its use in concrete is narrow and should be extended (types of glass waste, statistics about its amount in landfill, its effect on concrete... etc.). Some useful information were spotted in section 2, however, the introduction section needs more information like this. Please, refer to the following papers for more information: https://doi.org/10.1016/j.rineng.2022.100790 

2. In section 3.1: What about the color of the glass? Many papers discussed the color of glass and its effect on concrete. For example, the presence of chromium in green glass and its effect on ASR and crack initiation. I am aware that you are discussing UHPC, however, this section is about glass classification in general.

3. In section 3.3: CaO and Na2O contents in glass are important factors that should be considered in this section. Write a little about them and their effect on concrete in this section.

4. Split the images in Figure 2 into (a) and (b) putting the reference for each image separately. Also, clarify the description about Figure 2 (in the text and the caption). Was it used as fine or coarse aggregate?

5. Reference for Figures 3 and 4. Even if you draw them, where did you get the information from?

6. Rice husk ash as a cement partial replacement for UHPC containing waste glass powder showed a reduced workability. Write an explanation for this in section 4.1, providing references.

7. Add a brief section about the practical applications of glass waste in UHPC before the conclusion section.

Author Response

Response to Reviewers’ Comments

(Manuscript Number:  sustainability-3031858)

 

Title: A Comprehensive Overview of Recycled Glass as Mineral Admixture for Circular UHPC Solutions.

Journal: Sustainability

Authors: N. Marcela Redondo-Pérez, Jesús D. Redondo-Mosquera, and Joaquín Abellán-García

 

The authors greatly appreciate the Editor’s time in handling the manuscript review. We also thank the reviewers for their constructive comments and valuable suggestions. The manuscript has been revised in light of their suggestions and comments. We are sure that the revised manuscript’s quality is improved. Point-wise, answers to their specific comments/suggestions/queries are as follows.

 

Response to Reviewer #2 Comments

 

General Comment. This review article is very informative and well-written. After reading the whole manuscript, it is obvious that the authors spent so much time preparing it. The authors did not only report the results from literature but also commented on every single information with valid explanations and strong reasoning. Well-done on this great piece of work. However, some minor comments should be addressed:

Response. The authors are grateful to the reviewer for his encouraging remarks and positive comments. Our pointwise response to the comments is as follows.

Comment#1. A very well and informative brief about UHPC has been provided in the introduction section. However, the information about glass waste and its use in concrete is narrow and should be extended (types of glass waste, statistics about its amount in landfill, its effect on concrete... etc.). Some useful information were spotted in section 2, however, the introduction section needs more information like this. Please, refer to the following papers for more information: https://doi.org/10.1016/j.rineng.2022.100790

Response. Thank you for your insightful comments and recommendations. We have taken your advice and included the recommended article, "Comprehensive investigation of recycled waste glass in concrete using silane treatment for performance improvement" by Feras W. Al-Awabdeh, Mazen J. Al-Kheetan, Yazeed S. Jweihan, Husam Al-Hamaiedeh, and Seyed Hamidreza Ghaffar, in the references of the revised manuscript. This inclusion has allowed us to enhance Section 3.2, "Production."

 

In response to your suggestions, we have also added detailed information on the types of glass waste and recycling statistics in Section 3.2, "Production," and Section 3.1, "Glass Classification."

 

However, it is important to note that UHPC significantly differs from conventional concrete, particularly due to its extensive use of supplementary cementitious materials and its composition, which lacks portlandite and typically uses only micro-sand instead of coarse aggregate. Therefore, our manuscript focuses exclusively on the impact of glass powder (GP) in UHPC. Addressing the effects on conventional concrete would detract from the necessary focus on UHPC. While there is a substantial body of research on the use of glass powder in conventional concrete, studies on its use in UHPC are comparatively limited.

Thank you once again for your valuable suggestions, which have helped enhance the quality and comprehensiveness of our manuscript.

 

Comment#2. In section 3.1: What about the color of the glass? Many papers discussed the color of glass and its effect on concrete. For example, the presence of chromium in green glass and its effect on ASR and crack initiation. I am aware that you are discussing UHPC, however, this section is about glass classification in general.

Response. As per your request, we have added and commented the issues of color in glass. Please, see lines from 194 to 206 as well as new Table 2 in the new version of the manuscript.

Comment#3. In section 3.3: CaO and Na2O contents in glass are important factors that should be considered in this section. Write a little about them and their effect on concrete in this section.

Response. Section 3.4. depicts the chemical reactions of glass powder in UHPC curing. This section highlights the formation of (i) calcium silicate hydrate gel; (ii) calcium aluminate silicate hydrate; and (iii) Alkali-silica gel. In these reactions the oxides you are talking about participate.

Comment#4. Split the images in Figure 2 into (a) and (b) putting the reference for each image separately. Also, clarify the description about Figure 2 (in the text and the caption). Was it used as fine or coarse aggregate? 

Response. Thank you for your detailed feedback. We have split the images in Figure 3 (2 in the old version) into (a) and (b). In addition, we provided separate references for each image. Additionally, we have clarified the description in both the text and the caption. One image represents the material used as a partial cement replacement, while the other shows the material used as a total quartz powder replacement. The latter was also explained in the new version of the manuscript.

Comment#5. Reference for Figures 3 and 4. Even if you draw them, where did you get the information from?

Response. Thank you for your valuable feedback. We confirm that both figures were created by the authors of this manuscript. However, in accordance with your instructions, we have now incorporated the references from which the information was obtained to create these figures.

Comment#6. Rice husk ash as a cement partial replacement for UHPC containing waste glass powder showed a reduced workability. Write an explanation for this in section 4.1, providing references.

Response. Thank you for your valuable feedback. Following your instructions a line was added to explain why RHA particles jeopardize UHPC rheology. References were also added. Please see lines 434-435 of the new version of the manuscript.

Comment#7. Add a brief section about the practical applications of glass waste in UHPC before the conclusion section.

Response. Thank you for your valuable feedback. We appreciate your suggestion to add a brief section about the practical applications of glass waste in UHPC. In response, we would like to highlight that section 8 (8. Case study of a field application) of the manuscript already analyzes a case study of a real application of recycled-glass-UHPC. This section provides detailed insights into the practical implementation and benefits of using recycled glass in UHPC.

Reviewer 3 Report

Comments and Suggestions for Authors

Brief Overview:

This review paper provides an in-depth analysis of the utilization of recycled glass in UHPC, exploring its effects on durability, rheology, and mechanical properties, including compressive, flexural, and tensile strength, as well as costs and carbon footprint implications. The paper effectively underscores the sustainability benefits, cost reductions, and environmental advantages associated with using recycled glass in UHPC formulations.

Issues and Suggestions for Improvement:

1. In the introduction, UHPC with waste glass isn’t be mentioned until line 99 on page 3. The preceding part could be more concise. The discussion on UHPC with waste glass should appear earlier to maintain reader engagement.

2. Ensure the introduction clearly states the research gaps this review aims to address. This can be done by explicitly mentioning the novelty of this review in relation to existing literature.

3. Consider plotting the slump flow in Figure 6 to enable readers make a clearer comparison between two images.

4. Certain sections require more comprehensive referencing. For instance, the sections “5.5.7 Resistance to mechanical abrasion” (page 30, line 1000-1009) and “5.5.9 Resistance to deicing salt scaling” (page 32, line 1042-1057) cite only Ref. 40, and “5.5.8 Drying shrinkage” (page 31, line 1012-1036) cites only Ref. 92. It is advisable to incorporate additional recent studies to enrich these discussions.

5. Considering that the economic benefit of UHPC containing waste glass is one of the main points of this paper, it would be better if the section of ”7. Cost implications” (page 34, line 1125-1137) can be further analyzed.

6. It is recommended that add a section on future research directions at the end of the paper. Highlight areas where further investigation is needed and suggest potential methodologies for future studies.

7. The conclusions section should be more concise and succinct, summarizing the key findings and implications more directly.

8. While the references are comprehensive and relevant, ensure the inclusion of the most recent studies, particularly those published in the last two years, to provide an up-to-date perspective.

Author Response

Response to Reviewers’ Comments

(Manuscript Number:  sustainability-3031858)

 

Title: A Comprehensive Overview of Recycled Glass as Mineral Admixture for Circular UHPC Solutions.

Journal: Sustainability

Authors: N. Marcela Redondo-Pérez, Jesús D. Redondo-Mosquera, and Joaquín Abellán-García

 

The authors greatly appreciate the Editor’s time in handling the manuscript review. We also thank the reviewers for their constructive comments and valuable suggestions. The manuscript has been revised in light of their suggestions and comments. Point-wise, answers to their specific comments/suggestions/queries are as follows.

 

 

Response to Reviewer #3 Comments

 

Brief Overview. This review paper provides an in-depth analysis of the utilization of recycled glass in UHPC, exploring its effects on durability, rheology, and mechanical properties, including compressive, flexural, and tensile strength, as well as costs and carbon footprint implications. The paper effectively underscores the sustainability benefits, cost reductions, and environmental advantages associated with using recycled glass in UHPC formulations.

Response. The authors are grateful to the reviewer for his encouraging remarks and positive comments. Our pointwise response to the comments is as follows.

Comment#1. In the introduction, UHPC with waste glass isn’t be mentioned until line 99 on page 3. The preceding part could be more concise. The discussion on UHPC with waste glass should appear earlier to maintain reader engagement.

Response. Thank you for your valuable feedback. We appreciate your suggestion to mention UHPC with waste glass earlier in the introduction to maintain reader engagement. In the revised manuscript, we have moved the first mention of recycled glass UHPC to line 53 on page 2.

Please, note that the order of the explanations has been carefully structured to maintain the logical flow of the manuscript. First, we discuss the advantages and disadvantages of UHPC, followed by the production and challenges associated with glass waste. This progression leads naturally to how incorporating recycled glass can address both the sustainability and cost issues of UHPC, as well as the landfill storage problems of glass waste. Introducing the concept of recycled glass any earlier would disrupt this logical sequence.

We believe that the approach provided now in the new version of the manuscript provides a clear and coherent narrative that enhances reader understanding and engagement with the topic.

Comment#2. Ensure the introduction clearly states the research gaps this review aims to address. This can be done by explicitly mentioning the novelty of this review in relation to existing literature.

Response. Thank you for your insightful comment. We agree that the introduction should clearly state the research gaps this review aims to address and highlight the novelty of our work on existing literature. To address this, we have revised the last paragraph of the new version of the manuscript. Please, see lines 123-130 of the new version of the manuscript.

 

Comment#3. Consider plotting the slump flow in Figure 6 to enable readers make a clearer comparison between two images.

Response. Thank you for your insightful suggestion. In response to your comment, we have added a plot of the slump flow in Figure 7 (6 in the previous version of the manuscript) indicating the slump value in each case to facilitate a clearer comparison between the two images. This enhancement aims to provide readers with a more comprehensive understanding of the differences in workability of the UHPC mixtures without and with recycled glass.

Comment#4. Certain sections require more comprehensive referencing. For instance, the sections “5.5.7 Resistance to mechanical abrasion” (page 30, line 1000-1009) and “5.5.9 Resistance to deicing salt scaling” (page 32, line 1042-1057) cite only Ref. 40, and “5.5.8 Drying shrinkage” (page 31, line 1012-1036) cites only Ref. 92. It is advisable to incorporate additional recent studies to enrich these discussions. 

Response. Thank you for your valuable feedback. We acknowledge the need for more comprehensive referencing in certain sections. We have incorporated into the new version of the manuscript additional references to enrich the discussions in the sections “5.5.7 Resistance to mechanical abrasion,” “5.5.9 Resistance to deicing salt scaling,” and “5.5.8 Drying shrinkage.” These sections now include multiple references to provide a more robust and thorough review of the topics.

Comment#5. Considering that the economic benefit of UHPC containing waste glass is one of the main points of this paper, it would be better if the section of ”7. Cost implications” (page 34, line 1125-1137) can be further analyzed.

Response. Following your instructions Section 7 has been improved.

Comment#6. It is recommended that add a section on future research directions at the end of the paper. Highlight areas where further investigation is needed and suggest potential methodologies for future studies.

Response. Following your instructions, a last paragraph was added at the end of the conclusion section to indicate future research directions. This addition aims to provide clear and structured future research directions, ensuring that the review addresses potential areas for further exploration and development.

Comment#7. The conclusions section should be more concise and succinct, summarizing the key findings and implications more directly.

Response. According to your request, the conclusion section has been completely rewritten to be more concise and succinct, summarizing the key findings and implications more directly

 

Comment#8. While the references are comprehensive and relevant, ensure the inclusion of the most recent studies, particularly those published in the last two years, to provide an up-to-date perspective.

Response. The references have been thoroughly reviewed. However, as some of the reviewer's comments asked for improved references in specific parts of the manuscript (e.g., comment #4), the final number of references increased to 162.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors appropriately improved the manuscript. 

Comments on the Quality of English Language

It is Ok.

Reviewer 2 Report

Comments and Suggestions for Authors

I recommend the publication of the paper

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript has been revised in detail in response to the review comments and has met the academic standards for publication in this journal.