Investigating the Ability of Road Specifications to Discriminate the Rutting Behavior of Rubberized Asphalt Mixtures in Italy^†

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Specific comments:

1. There is only one basic index of rutting characteristics in 2.3.1. Is it too few basic indexes to comprehensively evaluate rutting resistance？
2. The evaluation of indirect tensile strength at high temperature is described in section 2.3.1.1. 54℃ is used in the experiment, but the paper also calculates the local air temperature for a week and adopts the highest road temperature for the experiment. What temperature is the final evaluation index based on?
3. The description of CTI is not mentioned in Section 2.3.1, but in the conclusion analysis of Chapter 3, there is an analysis of the experimental results of CTI.
4. The introduction part describes that the main research purpose of this paper is to discriminate the rutting behavior of rubberized asphalt mixtures in Italy However, in subsequent experiments and analyses, only the recommended values given by Italian continental codes are described. The anti-rutting ability of asphalt mixtures is distinguished through experimental data and recommended values, but how to distinguish it is not stated. What are the criteria for distinction?

Format comments:

1. There is no punctuation at the end of 107 lines of the paragraph, 117 acts to separate two paragraphs of the same section, and the other sections are not similar.

2. Table 1 is short and contains only three lines but is spread across pages. It is recommended to adjust it to a single page.

3. The table and figure are recommended to be right-aligned in a unified format.

4. Section 2.2 only have one part in it, it is suggested to remove the subtitle 2.2.1.1; section 2.3.1 is the same, there is only one section below, it is recommended to remove the subtitle 2.3.1.1; 2.3.2.2.1 also has similar problems; similar problems still exist in other parts of the article. Please modify them.

5. Section 2.3.2.2.1 title format is not uniform, some use bold processing.

6. The format of the first paragraph is not aligned in the section 3.1.1.1.

7. Figure 10 has no title, and 454 lines of paragraphs are not capitalized at the beginning.

8. There is no uniform way to refer to charts in the article, such as "Table" "table".

9. Table 2 is mentioned from the introduction and is cited many times in the paper, but Table 2 is located in Chapter 2. It is suggested to change the position of Table 2 to the place where the article was first mentioned.

10. The naming way of small and medium-sized titles in the article is confused, and there are too many grades, even to the five-level titles, it is suggested to reduce as appropriate.

Author Response

The authors are extremely thankful for the careful reading, positive evaluation, and constructive and objective suggestions of the reviewers. Taking worthy suggestions of the reviewer into account, the paper has been carefully revised. All the comments and suggestions made by the reviewer have been incorporated in the revised manuscript. The detailed modifications and responses on a point-by-point basis are listed below. Hope our revisions would be sufficient enough to satisfy your concerns regarding this manuscript.

Please find the attached file of comments and response 

Thanks 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This study investigates the ability of current Italian road specifications to differentiate between the rutting behavior of conventional and rubberized asphalt mixtures. It offers new perspectives and data support for the practical implementation of rubberized asphalt mixtures, which is crucial for enhancing road durability and reducing maintenance costs. The findings highlight the limitations of the current Italian road specifications and propose suggestions for improvement, which are valuable for informing policy development and specification enhancement. However, the reviewer has several comments that the authors should address to enhance the quality of this manuscript.

1. The Introduction should clarify how the existing Italian road research specifications assess the rutting performance of asphalt mixtures and identify any challenges in using them to evaluate rubberized asphalt mixtures.

2. Some statements in the manuscript may appear contradictory: “Currently, technological advancements involve the integration of both synthetic and recycled rubber into traditional asphalt mixes to improve resistance to rutting” and “However, due to the swelling at high temperature, the crumb rubber is less likely to resist permanent deformation”. The conclusion of the study indicates that rubberized asphalt mixture does enhance rutting performance. Please give some explanation.

3. In the specimen preparation section, the authors should elucidate the key differences between the two molding methods regarding the control of compaction energy and target air voids.

4. Various test methods have revealed significant differences in the rutting performance indicators between conventional asphalt mixture and rubberized asphalt mixture, with varying degrees of difference. In the future, how should test indicators be selected to evaluate the anti-rutting performance of rubberized asphalt mixture?

Comments on the Quality of English Language

The writing skill is generally accepted. However, the authors should carefully recheck some expressions.

Author Response

The authors are extremely thankful for the careful reading, positive evaluation, and constructive and objective suggestions of the reviewers. Taking worthy suggestions of the reviewer into account, the paper has been carefully revised. All the comments and suggestions made by the reviewer have been incorporated in the revised manuscript. The detailed modifications and responses on a point-by-point basis are listed below. Hope our revisions would be sufficient enough to satisfy your concerns regarding this manuscript

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

In this research article, the authors have worked on "Investigating the ability of road specifications to discriminate the rutting behaviour of rubberized asphalt mixtures in Italy". The following comments/suggestions need to be incorporated during revision.

1. The title is not clear.
2. Provide related references. Avoid self citatons.

3. Insufficient Literature Review: The article does not provide an adequate review of previous studies on the use of rubberized asphalt mixtures, particularly in the context of Italian road specifications. This lack of context makes it difficult to understand the novelty and significance of the current study.

4. Unclear Justification for ECR Use: The rationale for choosing Engineered Crumb Rubber (ECR) over other potential additives or modifications is unclear. More explanation is needed on why ECR was selected for this study.

5. Methodological Details Missing: The methodology section lacks detailed descriptions of the asphalt mixtures' preparation, testing, and analysis. Specific information on mix design, sample preparation, and testing conditions is crucial for reproducibility.

6. Small Sample Size: The study does not specify the number of specimens tested for each mix type. A larger sample size would enhance the reliability and statistical significance of the findings.

7. Comparative Analysis Limitations: While the study compares ECR-modified asphalt to conventional mixtures, it does not adequately discuss the relative performance of ECR compared to other potential additives or modifications.

8. Lack of Long-Term Performance Data: The study focuses primarily on short-term rutting behaviour without considering long-term durability and performance. Long-term testing and evaluation are necessary to validate the benefits of ECR.

9. Insufficient Discussion of Results: The results section presents data without sufficient explanation or discussion on why certain trends were observed, such as the specific mechanisms by which ECR enhances rutting resistance.

10. Inadequate Environmental Impact Analysis: While the study suggests that ECR can promote sustainability, it does not provide a detailed environmental impact assessment or life cycle analysis to quantify these benefits.

11. Workability Concerns Not Addressed: The impact of adding ECR on the workability and practical application of asphalt mixtures is not discussed. Workability is a critical property for paving materials and should be analyzed.

12. Data Presentation Issues: The data presentation lacks clarity, with missing graphical representations and tables that could help better illustrate the findings and trends observed in the results.

13. Language and Grammar Issues: The manuscript contains numerous grammatical errors and unclear sentences, detracting from the article's readability and professionalism.

14. Conclusions Not Well-Supported: The conclusions drawn from the research are not adequately supported by the data presented. More detailed analysis and discussion are required to substantiate the claims made in the conclusions.

15. Limited Scope of Testing Methods: While the study introduces advanced testing methods like SSR and FN, it does not compare these methods with other widely used performance tests. A broader range of testing methods would provide a more comprehensive evaluation.

16. Statistical Analysis Limitations: The article lacks detailed statistical analysis to validate the findings. More robust statistical methods are needed to confirm the significance of the results.

17. Practical Implications Not Discussed: The study does not adequately address the practical implications of incorporating ECR into road specifications, such as cost considerations, ease of implementation, and potential barriers to adoption.

18. I think the presentation of bar graphs with black and red colour is not good. Try to change the colour.

Addressing these comments would significantly enhance the research article's quality, clarity, and scientific rigour, making it more suitable for publication.

Comments on the Quality of English Language

Minor Editing

Author Response

The authors are extremely thankful for the careful reading, positive evaluation, and constructive and objective suggestions of the reviewers. Taking worthy suggestions of the reviewer into account, the paper has been carefully revised. All the comments and suggestions made by the reviewer have been incorporated in the revised manuscript. The detailed modifications and responses on a point-by-point basis are listed below. Hope our revisions would be sufficient enough to satisfy your concerns regarding this manuscript.

Please find the attached copy of responses

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The research concerns a well-known topic and it is difficult to find elements of novelty. Text is effective, but not clear and well organized. The abstract is correct, contains a summary, key findings, but need revision. 

Comments on the Quality of English Language

Minor editing of English language required

Author Response

The authors are extremely thankful for the careful reading, positive evaluation, and constructive and objective suggestions of the reviewer. Hope our reply would be sufficient enough to satisfy your concerns regarding this manuscript.

Difficulty in finding elements of novelty.

Please see the figure 2 of the research study that 

(Are the current Italian road specifications able to discriminate between conventional and alternative paving materials?)

 The second version of the paper is supposed to be under revisions for more clarity 

Thanks

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

All the comments have been addressed.

Author Response

No further comments have been found.

 

Reviewer 3 Report

Comments and Suggestions for Authors

Quality of the manuscript is improved 

Comments on the Quality of English Language

Minor English editing required 

Author Response

No further comments have been found.

Reviewer 4 Report

Comments and Suggestions for Authors

The article has not undergone any fundamental improvement, so it should still be rejected

Author Response

Since round 1, the authors did not find any specific comments from the reviewer. No further comments have been found in round 2.