Preparation and Properties of SBS/REOB-Modified Rejuvenated Asphalt

Round 1

Reviewer 1 Report

Manuscript Title: Preparation and Properties of SBS/REOB-modified Recycled Asphalt

 

General comments:

Authors conducted a lot of tests to the topic, which is sufficient and great. However, there is too many nonstandard terms, and the experiment was not properly designed. Please have a proficient English user to proof-read it. I suggest MAJOR revision.

 

Specific comments:

1. Abstract.

--- The first sentence, “In order to s… asphaltthe orthogonal test”, please recheck whether it should be “asphalt, the”. Please recheck the whole work for avoiding such mistakes.

--- What does REOB means? It should be the full name when it first appears.

---Authors introduced too much on the test results in abstract, the research background was missed.

2. Introduction.

---waste asphalt mixture (RAP). This is wrong, it should be recycled asphalt pavement (RAP).

---machine Recycled engine. Please recheck the capital.

---I understand that the author used the SBS to improve the performance of REOB recycled asphalt. However, to my best knowledge, the most of China’s high-grade highway was originally built with SBS asphalt (at least the wearing and binder course), thereby the RAP collected from these roads were recycled SBS asphalt pavement. As such, the modification method of this work could never be considered for using in engineering project. Please explain. In addition, even the RAP used the conventional binder (without SBS), after recycled by REOB, which is necessary, I doubt any contractors would like to spend more cost on modify the REOB recycled asphalt using SBS considering the extra materials cost, not to mention the extra equipment and transport.

4. 2.2. Waste Oil Residue (REOB). If you decide to call the REOB “recycled engine oil bot-tom”, then keep it consistent throughout the manuscript.
5. (1) Simulated aging test of base asphalt. It has a principle to produce the aged asphalt using PAV, TFOT and RTFOT, I suppose authors used the TFOT, please include the technical specification to support the 160°C, and 48 h was correctly used.
6. Fig.2. The Fig.2 shows the most significant issue of this work. Authors mixed the SBS, REOB, and aged asphalt to produce the modified asphalt. However, if the aged asphalt was covered on the RAP, how does the method in Fig.2 works？You can not separate aged asphalt from RAP first and then conduct the modification, it never going to happen in engineering projects. On the other hand, if the SBS and REOB are mixing with RAP rather than aged asphalt, then the processes could be completely different, the dry-method should be used.
7. Fig.3 is unnecessary since the fluorescence microscope is a well-known test.
8. 4.2. Dynamic Shear Rheological Test.

---Was there any aged asphalt in sample of 4.5%SBS, 4.5%SBS+9%REOB, 9%REOB? From the results, aged asphalt was added, but it should be clearly shown in figures.

---Why aged asphalt alone was not included in test?

9. 4.3. Rheological Test of Low-Temperature Bent Beam. Please recheck if the word “bent” was right, I think it should be bending.
10. Table 10. Why these 7 samples are completely different with that of DSR test, and why the aged asphalt in BBR was PAV aged, which is different with the previous.
11. Fig.7 (d), there is an irrelevant image named “books-BBR”.
12. Fig.8. the subtitle of each image was confused.

 

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The article presents a large amount of interesting and useful research aimed at the possibility of efficient disposal of industrial waste.
However, there are a number of the following minor remarks that allow improving the understanding of the main idea of ​​the article and the results obtained:
1. Table 2. What does "RA-1 Regenerant" term mean? There is no description in the text of the article. Please explain what "RA-1 Regenerant" is used for in the study.
2. Table 3. The value of the "Structure" parameter should be given in English.
3. Table 4. It is recommended to explain what was used in the article as a stabilizer of SBS-modified asphalt.
4. On Figure 2 there is no designation of steps a, b, c, which are described in the text of the article before the Figure. It is recommended to add the missing symbols.
5. Section 4.3 "Rheological Test of Low-Temperature Bent Beam". The text of the article contains the abbreviations "TFOT" and "PAV", which are recommended to be deciphered
6. Table 10, Figure 7. It is recommended to decipher the abbreviation "BBR". 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

This paper analyses the feasibility of combining SBS and a waste machine Recycled engine oil bot-tom (REOB) to modify a recycled asphalt after aging in the laboratory.

The topic presents evident applicative interest to the readers of Applied sciences, the experimental work is well conceived and conducted, data interpretation is reliable and referencing is appropriate. In general some findings of this research is valuable, however some modifications need to be done to enhance the quality of the paper that are as follows:

ABSTRACT

• The term REOB must be defined in the abstract. In addition the comment “In order to study the improvement effect of an SBS modifier on REOB recycled asphaltthe orthogonal test was adopted to optimize the blending and” should be clarified and rewritten

EXPERIMENTAL

• Extra details about the selected Stabilizer needs to be reported: chemical composition and technical data
• Normative used for standard tests must be included.

RESULTS

• Logarithmic scales are preferred for G* (fig 4 ) and rutting factor (fig 5)
• Experimental conditions chosen for frequency sweep tests are not the best option, since the number of points have been selected in a linear scale (Figure 6) and then the points of the graph are crowded together at high frequencies.
• Reference asphalt should be include in Fig 6
• In section 4.1.1 Authors claim “the rut-ting factor G*/sinδ was similar to the complex modulus G*:” This is an oversimplified assertion since this only happens when δ tends tom 90º
• Fig 6. Only 2 samples are
• Non-standard nomenclature is used along the paper: Exaples
  • Low-Temperature Bent Beam must be bending beam
  • The temperature in figures must be Temperature
• In my opinion REOB can be considered a rejuvenating agent

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thank authors for carefully addressing my comments, it can be accepted for publication after this revision. Congrates!

The following publications may help to improve the scope of literature review, please consider.

10.1016/j.cscm.2022.e00961

10.1016/j.conbuildmat.2021.122389