Research on the Mechanism of Surfactant Warm Mix Asphalt Additive-Based on Molecular Dynamics Simulation
, Mingliang Dong 1,†, Yansheng Yang 3, Jingtao Shi 2,4, Junjie Wang 1, Wenxin Wu 1, Xingchi Zhao 1, Xu Zhou 1 and Chenlong Wang 1Round 1
Reviewer 1 Report
The article entitled "Research on the Mechanism of Surfactant Warm Mix Asphalt Additive Based on Molecular dynamics Simulation Pinhui Zhaoa, Mingliang Donga, Yansheng Yangc, Jingtao Shib,d, Junjie Wanga, Wenxin Wua, Xingchi Zhaoa, Xu Zhoua and Chenlong Wanga deals with the mechanism of adsorbing and lubricating film of base asphalt and WMA on the surface of stone by molecular dynamics (MD) simulation method, and the effect of surfactant WMA additive on the lubrication performance of the shear friction system of “stone-asphalt-stone”.
In that paper has been shown that in the friction system of warm mix asphalt and base asphalt, the shear stress changes differently with the increase of shear rate. The WMA lubricating film remains stable when the shear rate in the range of 10-40m/s, which means the shear stress of the warm mixed asphalt lubricating film is less affected by the shear rate and changes very slowly. The increment of shear rate leads to the increase of temperature in the lubricating film of WMA. With the increase of temperature, the shear stress of the lubricating film of WMA shows a decreasing trend, while the shear stress of the lubricating film of base asphalt shows a trend of first increasing and then decreasing with maximum shear stress.
In my opinion, the conclusions sound good and the paper can be interesting for readers.
The paper can be published as-is, only proofreading is recommended.
Author Response
Thank you very much. Proofreading have been made.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Review of the manuscript ID: coatings-1428051: “Research on the Mechanism of Surfactant Warm Mix Asphalt Additive Based on Molecular dynamics Simulation” submitted for publication in the journal Coatings.
The manuscript ID: coatings-1428051: “Research on the Mechanism of Surfactant Warm Mix Asphalt Additive Based on Molecular dynamics Simulation” is well prepared, written and structured. It deserves publication in Coatings after minor amendments taking into account the comments made below.
- A list of abbreviation is recommended to add to the manuscript to better understand the used abbreviations. For example the abbreviation IMDL in the abstract has not been explained before its use. Most probably it concerns imidazoline, but it is not explained by the authors.
- The sentence in the abstract: “In addition, as the shear stress of the lubricating film of the WMA decreases, while the base asphalt increases first and then decreases with the rise of temperature, demonstrating that the compactability of the mixture does not improve linearly with the increase of temperature.” is not very clear. When the shear stress of the lubricating film of the WMA decreases what of the base asphalt increases, which property? It does not become clear.
- Conclusions: 1) “The WMA lubricating film remains stable when the shear rate in the range of 10-40m/s…” missing the verb to be. It should be like this; “The WMA lubricating film remains stable when the shear rate is in the range of 10-40m/s…”
Author Response
Comment 1: A list of abbreviation is recommended to add to the manuscript to better understand the used abbreviations. For example the abbreviation IMDL in the abstract has not been explained before its use. Most probably it concerns imidazoline, but it is not explained by the authors.
Response: Thank you very much. A list of abbreviation have been add to the manuscript.
Comment 2: The sentence in the abstract: “In addition, as the shear stress of the lubricating film of the WMA decreases, while the base asphalt increases first and then decreases with the rise of temperature, demonstrating that the compactability of the mixture does not improve linearly with the increase of temperature.” is not very clear. When the shear stress of the lubricating film of the WMA decreases what of the base asphalt increases, which property? It does not become clear.
Response: Thank you very much. The sentence was rewritten.
Comment 3:Conclusions: 1) “The WMA lubricating film remains stable when the shear rate in the range of 10-40m/s…” missing the verb to be. It should be like this; “The WMA lubricating film remains stable when the shear rate is in the range of 10-40m/s…”
Response: Thank you for your careful work. This mistakes mentioned above have been corrected in this paper already.
Author Response File: Author Response.pdf
Reviewer 3 Report
Abstract:
All components are present but may need minor writing for readability
The subject matter is original and of general interest.
Remark:
IMDL WMA additive, write this abbreviation fully once.
Introduction:
Minor rewriting is advisable to clarify the aim and hypothesis.
Current references that will be of interest to readers.
Calculation method of MD simulation
Adequately written, although writing could be polished; minor typos/grammar/ punctuation errors Description of procedures needs minor clarification (clearly remediable).
Results and discussion:
- Statements and conclusions are presented but need minor revision to correlate with data and link with goals.
- Study implications and/or limitations are presented but are missing the point (s), which can be addressed.
Remark: do you have any idea to verify the results with an experiment.
Summary and conclusions:
Statements and conclusions are clearly supported by data and are linked to goals
- Study advances knowledge
- The study’s implications and limitations are completely and succinctly presented
Although I am missing a future perspective
Some study implications and/or limitations are missing or not clearly presented.
What about any experimental verification or applications.
Author Response
Comment1:
Abstract:
All components are present but may need minor writing for readability
The subject matter is original and of general interest.
Remark:
IMDL WMA additive, write this abbreviation fully once.
Response: Thank you for your careful work. Done.
Comment2:
Introduction:
Minor rewriting is advisable to clarify the aim and hypothesis.
Current references that will be of interest to readers.
Response: Thank you for your suggestion, it has been modified accordingly.
Comment 3:
Calculation method of MD simulation
Adequately written, although writing could be polished; minor typos/grammar/ punctuation errors Description of procedures needs minor clarification (clearly remediable).
Response: Thank you very much. This section was double-checked and some errors were revised.
Comment 4:
Results and discussion:
- Statements and conclusions are presented but need minor revision to correlate with data and link with goals.
- Study implications and/or limitations are presented but are missing the point (s), which can be addressed.
Remark: do you have any idea to verify the results with an experiment.
Response: Thank you very much. Corresponding changes have been made in the received manuscript based on your suggestions.
Comment 5:
Summary and conclusions:
Statements and conclusions are clearly supported by data and are linked to goals
- Study advances knowledge
- The study’s implications and limitations are completely and succinctly presented
Although I am missing a future perspective
Some study implications and/or limitations are missing or not clearly presented.
What about any experimental verification or applications.
Response: The significance of the study and future prospects are further elucidated in the final part of the conclusion.
Author Response File: Author Response.pdf
Reviewer 4 Report
The manuscript presents the results of the interface lubrication characteristics between asphalt and stone based on the tribological theory and molecular dynamics simulation method. The authors studied the mechanism of adsorbing and lubricating film of base asphalt and additive on the surface of alkaline stone, calcite in this case, considering that asphalt acts as a lubricant during asphalt mixing and compaction. Imidazoline surfactant synthesized by Zhao et al. was adopted as warm mix asphalt additive in the molecular simulation model of lubricating film in this paper.
Two simulation models of stone-asphalt-stone were buildt based on asphalt lubrication film and calcite mineral-matrix being analyzed with Forcite module of the Material Studio software. The action mechanism of warm mix asphalt was studied by investigating shear rate, shear stress, additive distribution and adsorption energy. The molecular model was verified by laboratory results from literature data.
The methods used are well described and the results obtained were analyzed. The results are significant and interpreted appropriately. The approach is appropriate, the methods and working hypotheses are completely presented, the results are fully discussed and well explained. In my opinion the manuscript brings new and interesting data in the field of asphalt materials, and also recommend publication in the journal.
Author Response
Thank you very much.
Author Response File: Author Response.pdf
