Feasibility of Using Combustion-Based Methods to Quantify Saline-Based Anti-Stripping Agent in Modified Asphalt Binders

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Thanks for addressing the comments successfully 

Its fine

Reviewer 2 Report (Previous Reviewer 3)

After having read the authors' responses and the revised version of the manuscript, I consdier that the authors have adequately completed the article and that it can be published without further modifications.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This manuscript presents a valuable contribution to the field of pavement materials, addressing a critical gap in the quantification of anti-stripping agents in asphalt binders. The research is well-conceived and executed, with findings that have clear practical implications. However, further clarification and expansion in certain areas could enhance the manuscript's impact and usefulness to the field.

1-   The abstract provides an adequate level of technical detail for the reader to understand the research's scope and the methods applied, including heat combustion tests and residue analysis. This helps in setting the stage for the reader's expectations on the depth of the study.

2-   In table 1 page (3) please remove (RTFO) before PAV

3-   In page 4, the addition dosage of Zycotherm is it 0.05% ? that mean for 50 gm asphalt cement is it 0.025 gm, please check the addition dosage. Cite references if there is.

4-   In page 5, there is no need to detailed discussion of some technical issues (like , This study utilized two different sizes of the NCAT Asphalt Content Furnace, a 197 product developed by Thermo Fisher Scientific firm, for inquiry purposes. The use of 198 these furnaces was required due to limited space, which made the smaller oven unable 199 to efficiently oxidize the bigger 20g sample. Therefore, the ignition process for the bigger 200 sample was carried out in a two-stage fashion. Firstly, the sample was subjected to in-201 cineration in the larger oven, and then it experienced oxidation in the smaller oven.)

5-   In page 7, SEM technique is well known , also there is no need for figure 4

6-   Please re-produce figures 5,6 and 7

7-   In page 11, give more interpretation for SEM results existed in figure 9

8-   In page 15, instead of discussion state the main conclusions please.

9-   You can get benefit from the following references (https://doi.org/10.1155/2018/3109435) and (https://doi.org/10.3390/coatings12121895)

some improvements are required to enhance the academic presentation of this manuscript 

Author Response

Thank you for all the comments.  It was helpful. And I tried to reply and revise the manuscript accordingly. 

Author Response File: Author Response.pdf

Reviewer 2 Report

The reason for selecting the experiments used in this manuscript is unclear and the reported heat combustion decrease of 1.34 and 1.72% for 0.05% and 0.1% Zychotherm modified binder cannot be considered meaningful for evaluating the percentage of the utilized anti-striping. In this regard, some major comments are briefly mentioned in the following:

1. It is impossible to conduct such a study only using one type of neat bitumen.

2. The results presented in Figure 6 and Figure 7 are not meaningful as the results are very close and it is highly dependent on the type of neat bitumen. Therefore, one cannot conclude that if the heat combustion decreases by 1.73%, then there is 0.1% of zychotherm within the sample.

3. The bullet points presented in the conclusion section are not informative.

4. How did the authors read reference#25 while it is a thesis written in Persian?

The English writing of the present manuscript should be polished.

Author Response

Thank you for your comments and time. I tried to revise it accordingly. Again it is a feasibility study and needs to add a more comprehensive test to finalize. Thanks.

Author Response File: Author Response.pdf

Reviewer 3 Report

The article presents a topic of interest for the field of asphalt paving and can be useful, both for the highway administration and for research groups.

In this reader's opinion, the document is written with great care and the introduction clearly argues the reasons for the proposed study. There is no doubt about the innovation represented by the introduction of nanotechnologies in the field of adhesion promoters for asphalt mixtures.

I would like to ask the authors if test standards have been followed for the use of the calorimeter and the ignition oven.

Regarding the change in the sample weight: Could using a sample of less than 20 grams in the ignition oven affect the result?

Figure 5: It is recommended to add legends to the figure.

Figures 6 and 7: if 5 samples were analyzed, could you comment on the standard deviation of the results obtained, or indicate them in the figures?

Line 290: This line could be complemented with some explanation. Where do the values ​​mentioned for optimal combustion efficiency come from?

Author Response

Thank you for all of your comments. It helped us a lot to reshape the manuscript. I try to revise the paper accordingly. Thanks.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

None of my comments are addressed, especially the introductory explanation about the problem statement. Therefore, I must reject this paper.

It should be improved.

Author Response

Addressing the major comments from the reviewer involves clarifying the methodology and justifying the results of your research on the detection method for Zycotherm in modified asphalt binders. Here are the responses to the reviewer's comments:

1. Agreed, thanks for the comment. It would be better to increase the sample size of different binder types and grades. There should be some research to be done. This is again a feasibility study. Also, the materials were provided by the Georgia Department of Transportation (GDOT) so we did not have any choice but to make more samples with other grades of bitumen. But even if we use the different binder the result will be the same. As we quantify the percentage of Zuchotherm residue after ignition which will be the same for different grades of asphalt binder along with the source of binder.

2. This is a feasibility study and a heat combustion test was a part of the study. The SEM-EDX test and the residue weight from the ignition support more in concern of detecting Zycotherm. The heat combustion value was indicated that the different percentage of Zycotherm dosage creates different results.

3. We rearranged the conclusions section and tried to make it more informative. I added the conclusion part here for your reference.

Conclusion

The purpose of this research was to investigate whether or not it would be possible to create a detection method that would be able to measure the amount of siloxane-based anti-stripping liquid agents, more especially Zycotherm, that are present in modified asphalt binders. Following are some conclusions that can be drawn from the various results of the tests that were conducted:

1. The study makes a feasible combustion-based detection method for quantifying siloxane-based anti-stripping agent (Zycotherm) concentrations in modified asphalt binders. This method, leveraging heat combustion and ignition processes, demonstrated the capability to closely measure low doses (0.05% and 0.1%) of Zycotherm, showcasing its potential for practical application in quality control and quality assurance processes in asphalt binder modification.

2. Incorporation of Zycotherm into asphalt binders resulted in a measurable decrease in heat combustion values, with reductions of 1.34% and 1.72% for 0.05% and 0.1% Zycotherm modified binders, respectively. This finding indicates that Zycotherm, even in minimal concentrations, can significantly affect the combustion characteristics of asphalt binders, suggesting a chemical interaction that alters the binder's thermal properties.

3. The study revealed that Zycotherm-modified asphalt binders leave a distinguishable yellowish residue after burning and ignition processes, contrasting with the dark black residue of unmodified binders. This observation not only supports the method's effectiveness in detecting Zycotherm presence but also offers a simple, visual means of preliminary assessment before quantitative analysis.

4. A direct, nearly proportional relationship was established between the amount of Zycotherm and the mass of silica residue. This correlation under-scores the principle that the quantity of silica residue, resulting from the combustion of siloxane-based additives, can serve as a reliable indicator of the Zycotherm content in modified asphalt binders.

4. We remove that reference. Sorry for the inconvenience.

Author Response File: Author Response.pdf