Research on the Rheological Properties and Anti-Aging Mechanism of Paper-Black-Liquor-Modified Bitumen

Round 1

Reviewer 1 Report

Please revise and correct punctuation along the text.

Please consider to reduce Aims and Scope Section and be more punctual in your ideas.

The authors need to include in-text references to Figures and Tables. 

Figures 5 to 11 are not needed, I recommend removing them.

Lines 297 to 304: Please consider to remove. The authors are only repeating in text what is shown in Table 2.

Lines 305 to 307: Please show a FTIR spectra for an easier comparison.

Line 310: TGA does not provide information regarding composition, please correct.

Section 3.1.2: Please use scientific references to support the observations and discussion.

Please discuss more about the resulting pH of black liquor. Can that affect an adequate incorporation of it into binder? why? 

The authors discuss about the environmental problem that represents black liquor, but they also concentrate (reduce) it to obtain a material that is easier to work with. How do the authors ensure that such treatment is not causing other volatile organics to disperse in the air, etc? Plase explain.

The authors consider black liquor to be composed of lignin only (or mainly). I can understand that in terms of simplicity, but it is neccessary that, being this a Sustainability and Environmental Journal, for the authors to be sure of which product are using as a modifier (composition) and to clarify that such a punctual use might be ok of a while, but it has to be considered from the beginning how it might affect (environmentally speaking) a future extraction/reuse of mixture (RAP). Does the liquor contain more hazardous chemicals? This is not clear from what it is presented. I strongly recommend to include a disclaimer that clarifies this.  

Conclusion 4: Please be careful, this would be true only if tested in asphalt mixture (or similar, such as surface treatments). I sugest to include a recommendation to focus future research in asphalt mixture (etc).

 

 

 

 

 

Editing is needed.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

1.       This sentence "In the field of waste recycling, the paper industry has been the focus of attention. 2019, the global production of paper and paperboard achieved 404 million tons, while China, as the global paper center, the production and consumption of paper and paperboard in 2019 reached 107.65 million tons and 107.04 million tons, is expected to continue to maintain the growth trend in the future." in lines on 2 pages, it is necessary to modifite to know exactly what amounts describe what.

2.       I suggest that the chapter Aims and scope be called 2. Experimental part.

3.       The name of Figure 2 should be replaced by the correct name of the figure.

4.       For Figure 3, it is recommended to measure the spectrophotometric values of the colors of the litmus paper and the pH control chart and to write them on the pictures, since the exact color experience cannot be seen through displays and on hardprints.

5.       Please do a check of this sentence on page 5 in line 157: “The bitumen used in this experiment was 70# base bitumen produced by SK Group in Korea and supplied by Yunnan bitumen Reserve and Guarantee Centre in China.”

6.       Throughout the paper, figures must be announced in the text and an explanation given as to why they are shown.

7.       In lines 219 -224 - Irrecoverable flexibility difference, initial strain, strain at the end of each loading cycle  and irrecoverable creep flexibility must be correctly indicated in the text with indexes and as well in equations.

8.       The same situation in the lines from 236 to 256, check the labels and whether they have correctly written indexes in the equations in the explanations of the equations.

9.       A sentence in a line 216 on 8 page must be written with a colon. “In this study, the three indices of irrecoverable creep flexibility (Jnr), recovery rate 216 (R) and irrecoverable flexibility difference (Jnr-diff) were used to evaluate the permanent 217 deformation resistance of the paper black liquor modified bitumen.”

10.   Check the name from Figure 10. and explain how black liquor is applied to potassium bromide plates.

11.   Throughout the entire paper, it is necessary to check exponents on the label and on the units.

12.   Results of infrared spectroscopy - must be supported by literature and what conclusions/definitions were drawn. This sentence must also be supported by literature "In summary, this study concludes that the organic matter contained in the paper black liquor in large quantities is lignin, and the lignin of this species is dominated by the guaiac-based monomer structure."

13.   During the research it is necessary to support the obtained results with literature as much as possible.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Article "Research on the rheological properties and anti-aging mechanism of paper black liquor modified bitumen" is devoted to the study of bitumen binders with improved properties. The following questions and comments were found during the study of this article:

1) There are few references to literature sources in the introduction. For example, more detail can be provided on bio-bitumens (10.1016/j.conbuildmat.2018.06.118), bitumen binder modifiers (10.1016/j.conbuildmat.2022.127946, 10.1016/j.conbuildmat.2022.129919), characteristics and applications of paper black liquor, and so on.

2) There are a small number of typographical errors and mistakes. What is the reason why "bitumen" is written with lowercase or capital letter? Figure 4 - typo, «g» slipped on the picture. Line 24 and 60 - no dota. Lines 51 and 52 are the same beginning of sentences. There are a number of other errors

3) For a complete description of the characteristics of bitumen binders it is necessary to give their viscosities at 25, 135 and 180 °С both for the initial unmodified and for all obtained mixtures. In addition, an important parameter determining the high-temperature behavior of the binder is the rutting factor, so it is necessary to give its dependence on temperature.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thanks for taking care of our recommendations to improve your paper.

Regards.

Reviewer 3 Report

All necessary changes have been made, so the article can be published in the current edition.