Review Reports - Recycled Plastics in Asphalt Mixtures: A Systematic Review of Mechanical Performance, Environmental Impact and Practical Implementation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors of this paper have systematically reviewed and evaluated the application of plastics in asphalt mixtures, with a focus on their impacts on mechanical performance and environmental benefits. The results confirm the critical roles of plastic type, mixing method, and local conditions in optimizing the performance of asphalt mixtures. The discussion is clear, and the research objectives are well-defined. However, there are still certain issues in the manuscript, and it is recommended to be accepted after careful revision:

The use of figures should be emphasized in the review. Replacing tables with figures can better enhance the readability of the review.
Abbreviations in the paper (e.g., PP) should be annotated when they first appear in the main text, and the abbreviations can be used directly thereafter.
The quality of Figure 4 is too low (e.g., the font size is too small), and it can be revised.
The conclusions should be summarized point by point, and the writing of the conclusions should correspond to the research content above.
I believe that the structural arrangement and discussion logic of the paper can be appropriately optimized.
Why are the fonts in the tables not unified, for example, Table 13?
Abbreviations that appear for the first time in the abstract should also be given their full names. Of course, the definition of abbreviations should be carefully checked in accordance with the journal's requirements.
There is still a lack of content concerning existing technical challenges and future prospects. For instance, the analysis of the durability performance of asphalt and its mixtures, and even the development of recycling technologies, have not been effectively addressed. Additionally, the impact of existing technical challenges and future prospects on the review is of crucial importance, and we recommend that this part be written as a separate chapter with points listed.

Author Response

1. The use of figures should be emphasized in the review. Replacing tables with figures can better enhance the readability of the review.

Response:

After reviewing all the tables, we determined that the information they contained was not suitable for representation in graphs or diagrams without loss of detail. Therefore, they were kept in a tabular format, ensuring clarity and compliance with journal standards.

2. Abbreviations in the paper (e.g., PP) should be annotated when they first appear in the main text, and the abbreviations can be used directly thereafter.

Response:

All abbreviations in the manuscript were reviewed and defined the first time they appeared, both in the abstract and in the body of the text, maintaining consistent usage throughout the document.

3. The quality of Figure 4 is too low (e.g., the font size is too small), and it can be revised.

Response:

Figure 4 has been redesigned with higher resolution, optimized font size, and layout improvements for easier reading.

4. The conclusions should be summarized point by point, and the writing of the conclusions should correspond to the research content above.

Response:

The conclusions section was rewritten in bullet point format, summarizing each key finding and ensuring its direct correspondence with the discussion presented.

5. I believe that the structural arrangement and discussion logic of the paper can be appropriately optimized.

Response:

The discussion section was restructured into a logical order (plastic type → mixing method → mechanical properties → environmental impact), clear subheadings were added, and transitions between subtopics were improved.

6. Why are the fonts in the tables not unified, for example, Table 13?

Response:

All tables were reviewed to unify font type, size, and style, applying the typographic standards established by the journal.

7. Abbreviations that appear for the first time in the abstract should also be given their full names. Of course, the definition of abbreviations should be carefully checked in accordance with the journal's requirements.

Response:

The definition of all abbreviations was checked and corrected the first time they appeared, both in the abstract and in the text, in compliance with the journal's editorial standards.

8. There is still a lack of content concerning existing technical challenges and future prospects. For instance, the analysis of the durability performance of asphalt and its mixtures, and even the development of recycling technologies, have not been effectively addressed. Additionally, the impact of existing technical challenges and future prospects on the review is of crucial importance, and we recommend that this part be written as a separate chapter with points listed.

Response:

A new section on technical challenges and future prospects was added to the discussion section, addressing durability, long-term performance, technological limitations, and regulatory acceptance. Future research directions were also outlined, including improvements in recycling technologies, characterization methodologies, and optimization of mixing methods, considering their impact on the use of plastics in asphalt mixtures.

We appreciate your feedback on how to improve this article. We also inform you that an extensive review of the English language has been conducted.

Reviewer 2 Report

Comments and Suggestions for Authors

General comments:

The manuscript brings a systematic review about the effects of recycled plastic incorporation into asphalt mixtures. This is a relevant topic and the manuscript is well-written; however, I come away with some considerations that need to be addressed to improve the quality of the manuscript.

Specific comments:

Line 68: This line continues the reasoning of the previous paragraph. Thus, merge this paragraph with the previous one.

Line 82: What about rigid pavement? Explain this type of pavement first and then you can proceed with the flexible pavement.

Line 148: Is Google Scholar a reliable database?

Line 163: You must include studies published in 2024.

Section 3: This section deserves better sectioning. For instance, in 3.3 and 3.4 should be subsections from 3.2. Also, you could make a flowchart summarizing the sections detailed.

Section 3.5: You label the further subsections with abbreviations; however, it would be more suitable if you write the name of the polymer and then insert the abbreviation in parenthesis. For instance: 3.5.1 Polyethylene Terephthalate (PET).

Line 382: Extreme weather conditions regard warm or cold climate, or both?

Section 4: Discussion is about bringing a new perspective about the theme, but sometimes it seems you are drawing the conclusions. Revise from line 492 onward to eliminate unnecessary considerations.

Author Response

General comments:

Specific comments:

1. Line 68: This line continues the reasoning of the previous paragraph. Thus, merge this paragraph with the previous one.

Response:

The paragraph mentioned on line 68 was merged with the previous one to maintain consistency in the presentation of ideas.

2. Line 82: What about rigid pavement? Explain this type of pavement first and then you can proceed with the flexible pavement.

Response:

A brief mention was added to the general classification of pavements, including rigid pavements, clarifying that the focus of this study is exclusively on flexible pavements (asphalt mixtures) and that rigid pavements were not considered in the analysis.

3. Line 148: Is Google Scholar a reliable database?

Response:

It was clarified in the text that Google Scholar was used only as a support tool to expand the search, and that the main databases were Scopus and Web of Science , guaranteeing the quality and validity of the sources used.

4. Line 163: You must include studies published in 2024.

Response:

The study covers only the period 2012–2023, so no studies from 2024 were included. This time range was maintained to ensure consistency with the search and selection criteria established in the methodology. However, articles from 2024 and 2025 were included in other sections of the study.

5. Section 3: This section deserves better sectioning. For instance, in 3.3 and 3.4 should be subsections from 3.2. Also, you could make a flowchart summarizing the sections detailed.

Response:

Section 3 was restructured, eliminating redundant sections and unifying the content into a single section entitled “ Ways of incorporating plastic into asphalt mixtures”, to improve the coherence and clarity of the presentation.

6. Section 3.5: You label the further subsections with abbreviations; however, it would be more suitable if you write the name of the polymer and then insert the abbreviation in parenthesis. For instance: 3.5.1 Polyethylene Terephthalate (PET).

Response:

The titles of all subsections in Section 3.5 were modified to write the full polymer name followed by the abbreviation in parentheses, as suggested.

7. Line 382: Extreme weather conditions regard warm or cold climate, or both?

Response:

The wording of the aforementioned line has been revised to specify whether the reference to extreme weather conditions refers to hot, cold, or both climates.

8. Section 4: Discussion is about bringing a new perspective about the theme, but sometimes it seems you are drawing the conclusions. Revise from line 492 onward to eliminate unnecessary considerations.

Response:

The discussion section was revised, starting at line 492, removing or moving any definitive statements to the conclusions section to ensure that the discussion focuses exclusively on the analysis and interpretation of the results.

Reviewer 3 Report

Comments and Suggestions for Authors

What does the research address the main question?

The paper is a literature review on plastic utilization (recyclability) in asphalt mixtures.

What parts do you consider original or relevant to the field? What specific gap in the field does the paper address?

No originality is detected in the article; it only addresses mechanical properties, and the topic of "environmental impacts" mentioned in the title is presented as an existing gap, without adding any additional information.

What does it add to the subject area compared with other published works?

There is no contribution to the field.

What specific improvements should the authors consider regarding the methodology?

Considering the limited data on environmental and economic impacts, authors should approach these data in a manner that ensures a meaningful contribution to the field.

Are the conclusions consistent with the evidence and arguments presented? Were all the main questions posed addressed? By which specific experiments?

The conclusion is poor. The main question is not satisfactory.

Are the references appropriate?

For review literature, yes, but not the paper.

Any additional comments on the tables and figures and the quality of the data.

I suggest that the authors change the title of the article. They should delve deeper into the environmental and economic impacts to further enrich the work and contribute to the topic.

This article presents a systematic review of the literatura on the incorporation of recycled plastics into HMA and WMA with a focus on their effects on mechanical performance and environmental impact.

However, as mentioned by the authors, there is a need for studies on economic and environmental impacts. In this sense, I believe that the title should be corrected by excluding the term "environmental impact" due the lack of data.

Given the above, there is a limitation of the research that does not present significant data to scientific community and it is limited to analyses of mechanical performance already published in a few papers.

I suggest that the authors carry out a deeper study and address significant data on the environmental and economic impacts of the use of recycled plastic in asphalt mixtures in order to contribute to future studies.

Author Response

What does the research address the main question?

The paper is a literature review on plastic utilization (recyclability) in asphalt mixtures.

Response:

We appreciate the comment. The research question was explicitly incorporated into the introduction to clarify the central objective of the study, directly responding to the reviewer's recommendation.

What parts do you consider original or relevant to the field? What specific gap in the field does the paper address?

Response:

We appreciate your feedback. We have revised and strengthened the discussion on environmental impacts, incorporating a critical analysis of the limitations found in the literature and highlighting important gaps. We have also emphasized that the original contribution of this review lies in the comparative systematization of plastic types and incorporation methods in HMA and WMA, considering both mechanical properties and environmental implications, which provides a solid foundation for future research and practical applications

What does it add to the subject area compared with other published works?

There is no contribution to the field.

Response:

We appreciate your comment. While we agree that the available empirical studies are limited, we believe this manuscript's contribution lies in the systematization and critical analysis of existing information, identifying relevant gaps and proposing concrete lines of future research. We have strengthened the introduction and conclusions to make this contribution explicit, highlighting how the review can serve as a reference for the development of technical standards and guide subsequent research on the use of recycled plastics in HMA and WMA asphalt mixtures

What specific improvements should the authors consider regarding the methodology?

Considering the limited data on environmental and economic impacts, authors should approach these data in a manner that ensures a meaningful contribution to the field.

Response:

We appreciate the reviewer's valuable comment. While this review summarizes the general environmental implications reported in the literature, detailed life cycle assessment (LCA) studies, emissions quantification, and economic analyses were beyond the scope of this work. Future studies can and should address these aspects using standardized methodologies to ensure comparability and provide a more comprehensive assessment of the environmental and economic performance of asphalt mixtures with recycled plastics.

Are the conclusions consistent with the evidence and arguments presented? Were all the main questions posed addressed? By which specific experiments?

The conclusion is poor. The main question is not satisfactory.

Response:

We appreciate the feedback. The conclusions were rewritten in a clear bulleted format, aligned with the stated objectives and supported by the evidence presented in the discussion, directly addressing the study's main question.

Are the references appropriate?

For review literature, yes, but not the paper.

Response:

We appreciate the valuable comment. We recognize that, while the primary focus of this paper does not include a detailed economic analysis, we have expanded the treatment of environmental impact in the Introduction, Discussion, and Conclusion, incorporating additional references that strengthen this section. We believe these modifications improve the alignment between the literature used and the study's objectives, while remaining consistent with the original scope of the review.

Any additional comments on the tables and figures and the quality of the data.

I suggest that the authors change the title of the article. They should delve deeper into the environmental and economic impacts to further enrich the work and contribute to the topic.

This article presents a systematic review of the literature on the incorporation of recycled plastics into HMA and WMA with a focus on their effects on mechanical performance and environmental impact.

Response:

We appreciate the reviewer's comment. We respectfully consider that the inclusion of the term “environmental impact” in the title remains appropriate, as the manuscript synthesizes and critically discusses the environmental considerations reported in the literature regarding the use of recycled plastics in HMA and WMA. While we acknowledge that detailed quantitative analyzes—such as life cycle assessment or economic evaluations—were beyond the scope of this review, the paper incorporates qualitative and comparative insights from previous studies, which provide a foundation for understanding the environmental dimension of the topic. In response to the suggestion, we have expanded the discussion in the Introduction, Discussion, and Conclusion to make these contributions more explicit and to highlight research gaps where future work can address comprehensive environmental and economic assessments. We believe that, by systematizing the current knowledge and identifying these gaps, the manuscript offers a valuable reference for both the scientific community and the development of future technical guidelines in the field.

We appreciate your feedback on how to improve this article. We also inform you that an extensive review of the English language has been conducted.

Reviewer 4 Report

Comments and Suggestions for Authors

The paper reviews the use of plastic in asphalt mixtures. It is well-organized and a clear search methodology has been followed. For further amendments, the authors are requested to revise according to the following issues:

1_ The liaison between the 1^st and the 2^nd introductory paragraphs is ambiguous, what is the liaison between the 6% of road occupation and the amount of waste plastic. Please reassess the cohesion at this point.

2_ Please enhance the justification of reviewing the use of plastic in asphalt. Highlight about the sparsity of waste plastic worldwide, the different level of recycling maturity, the absence of legislative protocols, etc. You may see and cite other similar studies, e.g., https://doi.org/10.3390/futuretransp5020067

3_ Are there any references to support the use of figure 1? Or even references from where the figure was adapted?

4_ Please specify the rate at which each plastic waste particle is most often used in asphalt mix production using a figure or other way.

5_ For subsection 3.3, you may tabulate the differences of wet and dry processing methods.

6_ You may split section 5 in two subsections, “main remarks”, where your findings and remarks are summarized, and “future prospects”, where you will define the areas, you think future research will focus on.

7_ Please add an abbreviation list at the end of the paper (before the references).

Author Response

Response:

The introduction was revised and rewritten to clarify the relationship between road length and the generation/management of plastic waste in the road context.

Response:

The justification was expanded with information on the varying availability of plastic waste by region, as well as differences in recycling technologies and policies. The suggested reference and other references supporting this section were also included.

3_ Are there any references to support the use of figure 1? Or even references from where the figure was adapted?

Response:

The origin of the figure was reviewed, and the corresponding reference was added, indicating that it was prepared by the authors based on specific sources.

4_ Please specify the rate at which each plastic waste particle is most often used in asphalt mix production using a figure or other way.

Response:

The requested information was already included in the original manuscript, where the most commonly used types of plastics in asphalt mixtures are presented in Figure 5 and Table 15.

5_ For subsection 3.3, you may tabulate the differences of wet and dry processing methods.

Response:

The comparison between hot and cold methods was already included in the original manuscript through Table 14, which presents their advantages, disadvantages, characteristics, and applications.

Response:

The reviewer's suggestion was addressed by dividing section 5 into two subsections: Main observations, which presents a summary of findings and analysis in a clear and concise bullet point format, and Future perspectives, which describes possible lines of research and recommendations derived from the study.

7_ Please add an abbreviation list at the end of the paper (before the references).

Response:

A list of abbreviations was added at the end of the manuscript, before the references section. This list includes all the acronyms used in the text along with their full definitions, ensuring consistency and correspondence with the abbreviations mentioned throughout the document.

We appreciate your feedback on how to improve this article. We also inform you that an extensive review of the English language has been conducted.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Author Response

We sincerely thank you for your observations, which contributed to improving the quality of our manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors responded satisfactorily to my comments. Now the manuscript is adequate to be published.

Author Response

We sincerely thank you for your observations, which contributed to improving the quality of our manuscript.

Reviewer 3 Report

Comments and Suggestions for Authors

Congratulations the authors for theirs effort in improving the article, but

I did not detected any original parts in the work.
I do not detect anything that will add to the subject area

Author Response

Congratulations the authors for theirs effort in improving the article, but

I did not detected any original parts in the work.
I do not detect anything that will add to the subject area

Response:

We appreciate the reviewer’s comments. We respectfully submit that our manuscript is original and provides added value to the subject area. Unlike previous reviews, which are limited to specific aspects such as Marshall properties, fatigue and rutting performance, or life cycle analysis, our work integrates mechanical performance, environmental considerations, and practical implementation into a single framework. Moreover, we applied a systematic PRISMA/ScR methodology with bias assessment, screened over 7,000 records from multiple databases (2012–2023), and selected the most relevant studies. Finally, beyond summarizing existing findings, we provide practical guidance by identifying the most effective combinations of plastics, incorporation methods, and asphalt mixtures, which we believe constitutes a meaningful contribution for both researchers and practitioners.

Main Advantages and Originalities of Our Article

Holistic scope: Combines mechanical performance, environmental considerations, and practical implementation.
Rigorous methodology: First to apply PRISMA/ScR with bias assessment in this field.
Broader coverage: Screening of 7,441 records across four databases (Google Scholar, Scopus, EBSCO, Web of Science), with a final dataset of 39 studies (2012–2023).
Practical orientation: Provides guidance on which plastic types and incorporation methods are most effective (e.g., PET in HMA with the dry method, LDPE in WMA with the wet method).
Contribution to the field: Establishes a clear and updated state of the art, offering a reference for researchers, engineers, and policymakers.

To emphasize the originality and contributions of this article, the following table presents an analysis of different reviews addressing similar themes:

No.	Tittle	Authors	Objective	Methodology	Data base	Variants	Date
1	Repurposing waste plastics into cleaner asphalt pavement materials: A critical literature review	Shenghua Wu, Luke Montalvo	To critically review the feasibility of repurposing waste plastics into asphalt pavements, evaluating engineering performance, economic benefits, and environmental impact reduction.	Literature review: collection, analysis, and comparison of previous studies on different types of recycled plastics applied to asphalt.	ScienceDirect (Journal of Cleaner Production, Elsevier)	Plastic types analyzed: PET, HDPE, PVC, LDPE, PP, PS, ABS, EVA, PU, PC. Methods studied: dry vs. wet incorporation, compatibility, mechanical performance, environmental and economic benefits.	September 28, 2020 (online publication date)
2	Incorporation of plastic waste into road pavements: A systematic literature review on the fatigue and rutting performances	Josué Cardoso, Adelino Ferreira, Arminda Almeida, João Santos	To systematically review the incorporation of plastic waste into asphalt mixtures, focusing specifically on its impact on fatigue and rutting performance.	Systematic literature review following the PRISMA 2020 methodology: advanced searches in Scopus and Web of Science (May 31, 2023), screening, eligibility criteria, and dataset of 49 selected studies.	Scopus and Web of Science	Plastic types reviewed: PET, LDPE, HDPE, PE, PP, PVC, ABS, and polymeric compounds. Mixing methods: dry and wet processes. Asphalt mixture types: dense-graded, gap-graded (SMA, SDA, BBTM), and open-graded (PA). Tests analyzed: fatigue (Four-point Bending, Indirect Tensile Fatigue, Semi-circular Bending, etc.) and rutting (Wheel Tracking, Hamburg Wheel Tracking, Dynamic Creep, etc.)	May 31, 2023 (systematic search date); Accepted September 18, 2023; Published online September 30, 2023
3	The use of plastic waste in asphalt: A critical review on asphalt mix design and Marshall properties	Soheil Heydari, Ailar Hajimohammadi, Nioushasadat Haji Seyed Javadi, Nasser Khalili	To critically review the effects of incorporating plastic waste into asphalt mixes, with a focus on mix design optimization and Marshall properties (Stability, Flow, Air Voids, MQ).	Novel critical literature review of 346 publications. Data on Marshall test results were extracted directly or from graphs (using Engauge Digitizer), then categorized and re-analyzed. Trends and conflicts were highlighted through graphical comparisons, focusing on Optimum Binder Content (OBC) and Optimum Polymer Content (OPC).	ScienceDirect (Construction and Building Materials, Elsevier)	Plastics studied: LDPE, HDPE, PET, PP, PVC, PE, PTP, EVA, ABS, plus crumb rubber (CR). Processes: dry and wet incorporation methods. Key properties: Marshall Stability, Flow, Air Voids, Marshall Quotient (MQ), Stiffness, Fatigue, Rutting.	Accepted October 4, 2021; Published online October 13, 2021
4	Closing the Loop: Harnessing waste plastics for sustainable asphalt mixtures – A comprehensive review	Prabin Kumar Ashish, Anand Sreeram, Xiong Xu, Pavan Chandrasekar, Ajayshankar Jagadeesh, Dheeraj Adwani, Rabindra Kumar Padhan	To provide a comprehensive review on the use of waste plastics in asphalt mixtures, addressing not only mechanical performance but also environmental concerns, life cycle assessment (LCA), economic feasibility, and global field trials.	Systematic critical review of literature and global field projects. Covered: (a) classification of plastics (thermoplastics vs thermosets), (b) recycling/processing methods (mechanical, chemical, chemolysis), (c) wet vs. dry incorporation, (d) mechanical properties (rutting, fatigue, ITS, Marshall Stability), (e) environmental impacts (fumes, microplastics, leachates), (f) LCA and cost analyses, and (g) international case studies.	ScienceDirect (Construction and Building Materials, Elsevier)	Plastics: Thermoplastics (PE, PP, PET, PS, PVC, PC, ABS) and Thermosets (PU, Epoxy Resins). Processes: Wet mixing, Dry mixing, Chemical treatments (glycolysis, aminolysis). Properties: Stiffness, Fatigue, Rutting, ITS, Marshall Stability, Environmental emissions, LCA. Field trials: India, UK, USA, Australia, New Zealand, Pakistan, China, South Africa, Indonesia.	Received January 16, 2023; Accepted August 2, 2023; Published online August 7, 2023

This article:

No.

Tittle

Authors

Objective

Methodology

Data base

Variants

Date

Recycled Plastics in Asphalt Mixtures: A Systematic Review of Mechanical Performance, Environmental Impact and Practical Implementation

Julio Calderón-Ramírez, David Sepúlveda-Valdez, Leonel García, Marcelo Lomelí-Banda, Carlos Salazar-Briones, Marco Montoya-Alcaraz

To systematically review the mechanical performance, environmental impacts, and practical implementation of incorporating recycled plastics into Hot Mix Asphalt (HMA) and Warm Mix Asphalt (WMA). To determine which type of recycled plastic and incorporation method provide the best balance between mechanical durability and sustainability.

Systematic Review using PRISMA/ScR methodology. Screening of 7,441 records (2012–2023) across multiple databases (Google Scholar, Scopus, EBSCO, Web of Science). After duplicates and filters, 39 studies were analyzed. Included bias assessment, data extraction, and comparative analysis of plastic types (PET, LDPE, PP, HDPE), incorporation methods (dry, wet, pyrolysis), and asphalt grades (HMA/WMA).

Google Scholar, Scopus, EBSCO, Web of Science

Plastics: PET, LDPE, PP, HDPE, PVC, PS, EVA, ABS, PC, PU. Methods: Dry, Wet, Pyrolysis. Mixes: HMA, WMA. Performance parameters: stiffness, fatigue, rutting, thermal cracking, moisture resistance, viscosity. Environmental aspects: CO₂ reduction, energy savings, landfill diversion, microplastic immobilization.

2012–2023 (search conducted with PRISMA/ScR, cutoff at 2023)

Reviewer 4 Report

Comments and Suggestions for Authors

My concerns were partially addressed. Please specify in your replies the exact line numbering that reflects the answers to the points raised to you. This expedites the re-review procedures.

Author Response

My concerns were partially addressed. Please specify in your replies the exact line numbering that reflects the answers to the points raised to you. This expedites the re-review procedures.

Response:

We sincerely thank you for your observations. In this revised version of the manuscript, we have carefully revisited your comments to ensure that they are fully addressed. Following your request, we now provide the exact line numbers where each modification can be found, which we hope will facilitate the re-review process.

1. The liaison between the 1st and the 2nd introductory paragraphs is ambiguous, what is the liaison between the 6% of road occupation and the amount of waste plastic. Please reassess the cohesion at this point.

Response:

The introduction was reorganized to clarify the relationship between road network expansion and the generation/management of plastic waste in the road context. Additionally, a new paragraph was included to explain how road infrastructure influences plastic production and management, thereby strengthening coherence between both sections. (Page 2, lines 42–46).

2. Please enhance the justification of reviewing the use of plastic in asphalt. Highlight about the sparsity of waste plastic worldwide, the different level of recycling maturity, the absence of legislative protocols, etc. You may see and cite other similar studies, e.g., https://doi.org/10.3390/futuretransp5020067

Response:

The justification was expanded by including information on the variable availability of plastic waste across different regions, as well as differences in recycling technologies and policies worldwide. Moreover, the suggested reference (https://doi.org/10.3390/futuretransp5020067) was incorporated, along with other related sources, to reinforce this section. ( Page 2, Lines 46-50).

3. Are there any references to support the use of figure 1? Or even references from where the figure was adapted?

Response:

The origin of the figure was verified, and the corresponding reference was added. It was specified that the figure was prepared by the authors based on specific sources, ensuring transparency and proper citation. ( Page 4, line 130, Reference [38]).
4. Please specify the rate at which each plastic waste particle is most often used in asphalt mix production using a figure or other way.
Response:
The requested information was already included in the original manuscript. The frequency of use of the main types of plastics (PET, PE, PP, etc.) in asphalt mixtures was highlighted in Figure 5 and Table 16, providing a clear and comprehensive visualization of the data
Page 18, line 471, Figure 5.

Page 18, line 486, Table 16.

5. For subsection 3.3, you may tabulate the differences of wet and dry processing methods

Response:

A comparative table was incorporated in subsection 3.3, summarizing the advantages, limitations, and main characteristics of the dry and wet incorporation methods. This addition facilitates readability and improves the understanding of the section (Page 8, line 274, Table 4).

6. You may split section 5 in two subsections, “main remarks”, where your findings and remarks are summarized, and “future prospects”, where you will define the areas, you think future research will focus on.

Response:

The reviewer’s suggestion was addressed by dividing Section 5 into two subsections: 5.1 Main Findings, which provides a clear and concise summary of the results and analysis; and 5.2 Future Perspectives, where possible research directions and recommendations derived from the study are discussed( Future perspectives: Page 21, lines 588–614).

7. Please add an abbreviation list at the end of the paper (before the references).

Response:

A list of abbreviations with their full definitions was added at the end of the manuscript, before the References section. This addition ensures coherence and consistency with all abbreviations mentioned throughout the text (Page 26, Section 6. Abbreviations, lines 826–837.)