Laboratory Performance Evaluation of Hot-Mix Asphalt Mixtures with Different Design Parameters
Round 1
Reviewer 1 Report
This manuscript investigates the effect of aggregate gradation, Ndes and asphalt type on the performance of HMAs. Seven different combinations of aggregate gradation, Ndes and asphalt type were evaluated. The subject is worthy of investigation and is appropriate and focused well on the Journal’s scope. In general, the analysis is well conducted and the findings are interesting and valuable. However the reviewer believes that the manuscript needs minor changes as for the following comments.
- Line 46, please explain the meaning of the symbol FM300 (fineness modulus)
- Line 68 please replace “also need to been” with “also need to be”
- In section 1, Introduction", references DOI: 10.1163/157361106776240761 is suggested in order to explain the importance of the mixture’s performance characterization.
- Table 1, please explain the criterion followed in the definition of the seven groups
- Lines 145 and 148, replace εB with εB
- Line 158 Equation (4) is missed
- Line 159, description of the symbols in equation (3) is needed
- Section Summary and Conclusion. Improve the section by specifying how the results can be used. Authors are suggested to provide to readers and practitioners some useful indications.
Author Response
Dear Reviewer:
On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Laboratory Performance Evaluation of Hot-mix Asphalt Mixtures with Different Design Parameters”. (No. applsci-777423).
We have studied the comments carefully and have made revision which marked in red in the paper. We have tried our best to revise our manuscript according to the comments. We took into account of your comment, the main corrections in the paper and the responds to your comments are as following:
Responds to the reviewer’s comments:
Reviewer #1:
1. Line 46, please explain the meaning of the symbol FM300 (fineness modulus).
Response: Modified.
- Line 68 please replace “also need to been” with “also need to be”.
Response: Modified.
- In section 1, Introduction", references DOI: 10.1163/157361106776240761 is suggested in order to explain the importance of the mixture’s performance characterization.
Response: Thanks for your suggestion, and this reference has been added.
- Table 1, please explain the criterion followed in the definition of the seven groups.
Response: We need to balance the experimental combinations and limited materials, therefore seven different combinations including vary value of design parameters were conducted and analyzed. Some meaningful phenomenon and conclusions were then obtained based on these seven groups.
- Lines 145 and 148, replace εB with εB.
Response: Modified.
- Line 158 Equation (4) is missed.
Response: Modified.
- Line 159, description of the symbols in equation (3) is needed.
Response: Modified.
- Section Summary and Conclusion. Improve the section by specifying how the results can be used. Authors are suggested to provide to readers and practitioners some useful indications.
Response: Modified. Thanks for your suggestion, and several useful indications have been added in the section of summary and conclusion.
We have checked the manuscript and revised it in detail according to the comments. We submit there the revised manuscript as well as a list of changes, and some minor errors have been modified in the paper which does not list above.
We would like to express our great appreciation to you for comments on our paper. If you have any question about this paper, please don’t hesitate to let me know.
Author Response File: 
Author Response.doc
Reviewer 2 Report
In the first line of abstract, asphalt type is assumed as parameter. It should be noted that the parameter is quantifiable, while the asphalt type is a general term to call material. I recommend to replace with variable, i.e., the aggregate gradations and binder type are variables that affects mix design of HMA.
It is not necessary to show aggregate size distribution through gradation curve (Fig 2) and table 2. It is recommended to use either table or the curve.
Regarding UPST, the authors followed the specific standard? If yes, provide the details of standard. If it is a local standard, that is ok. Just provide standard number for further evaluation.
The authors did not discuss about optimum performance of group shown in the Table 3. It means that the authors can propose each group for a specific utility condition. It is obvious that it would not be realistic to design a mix shows a satisfying performance in UPST, UCMT, fatigue, rutting and UCT.
It seems that the authors try to use superpave mix design procedure associated with balanced mix design method for the evaluations of the mix groups. Although all the requirements of BMD were not respected, it is recommend to explain about it in the section of introduction.
Author Response
Dear Reviewer:
On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Laboratory Performance Evaluation of Hot-mix Asphalt Mixtures with Different Design Parameters”. (No. applsci-777423).
We have studied the comments carefully and have made revision which marked in red in the paper. We have tried our best to revise our manuscript according to the comments. We took into account of your comment, the main corrections in the paper and the responds to the your comments are as following:
Responds to the reviewer’s comments:
Reviewer #2:
- In the first line of abstract, asphalt type is assumed as parameter. It should be noted that the parameter is quantifiable, while the asphalt type is a general term to call material. I recommend to replace with variable, i.e., the aggregate gradations and binder type are variables that affects mix design of HMA.
Response: Thanks for your suggestion and modified.
- It is not necessary to show aggregate size distribution through gradation curve (Fig 2) and table 2. It is recommended to use either table or the curve.
Response: Accept and modified.
- Regarding UPST, the authors followed the specific standard? If yes, provide the details of standard. If it is a local standard, that is ok. Just provide standard number for further evaluation.
Response: Modified. The UPST was followed the specific standard of “ Ministry of Communications of China. (2017). Specifications for design of highway Asphalt Pavement: JTG D50-2017, China communication press (in Chinese), Beijing ”.
- The authors did not discuss about optimum performance of group shown in the Table 3. It means that the authors can propose each group for a specific utility condition. It is obvious that it would not be realistic to design a mix shows a satisfying performance in UPST, UCMT, fatigue, rutting and UCT.
Response: Thanks for your comment. The satisfying performance of HMAs, in our opinion, should be defined as the resistance of HMAs can perform equal or even better than the pavement requirements. Therefore, the experimental groups in Table 3 were not designed for choosing an optimum combination, but for providing more possibilities to the design of HMAs. It can be seen that compared with traditional methods, more design combinations can be used to achieve the expected performance, and thus the flexibility in the design of HMAs was improved.
- It seems that the authors try to use superpave mix design procedure associated with balanced mix design method for the evaluations of the mix groups. Although all the requirements of BMD were not respected, it is recommend to explain about it in the section of introduction.
Response: Modified. The balanced mix design (BMD) is mainly to balance the high temperature (HWTD) and fatigue performance (Overlay Test), which is effective but only in terms of materials. Our paper focuses on the balance of materials and pavement requirements, which is performance balanced mix design (PBMD). We found that more possibilities can be provided to meet the pavement requirements. Several references about PBMD have been added in the section of introduction.
We have checked the manuscript and revised it in detail according to the comments. We submit there the revised manuscript as well as a list of changes, and some minor errors have been modified in the paper which does not list above.We would like to express our great appreciation to you for comments on our paper.
Author Response File: Author Response.doc
Reviewer 3 Report
I have read this manuscript with a great interest, however, I do not think the authors did enough investigation to make a sound conclusion. Authors have selected just 7 groups out of 27 possible experimental groups. I do not see any statistical investigation in this manuscript to make a strong conclusion. Some detailed comments are outlined below.
L44, You should spell out all acronyms at the first usage. National Cooperative Highway Research Program (NCHRP)
L47, it should be Rutting resistance.
Figure 1, This graph does not show the seven designed groups. Why 7 combinations were selected. The maximum combination can be 27 (3*3*3). This is a cherry picking!
Figure 2, You need some explanation for AC-16 as well as a reference.
Figure 4, Y-axis on the right side needs a legend in all figures. You also need to include a & b on the graph.
Author Response
Dear Reviewer:
On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Laboratory Performance Evaluation of Hot-mix Asphalt Mixtures with Different Design Parameters”. (No. applsci-777423).
We have studied the comments carefully and have made revision which marked in red in the paper. We have tried our best to revise our manuscript according to the comments. We took into account of your comment, the main corrections in the paper and the responds to the your comments are as following:
Responds to the reviewer’s comments:
Reviewer #3:
- L44, You should spell out all acronyms at the first usage. National Cooperative Highway Research Program (NCHRP).
Response: Modified.
- L47, it should be Rutting resistance.
Response: Modified.
- Figure 1, This graph does not show the seven designed groups. Why 7 combinations were selected. The maximum combination can be 27 (3*3*3). This is a cherry picking!
Response: Thanks for your comment. This experiment was originally intended to use an orthogonal design, however due to the limited materials, finally these seven combinations were systematically conducted. Our conclusions are all based on these seven groups of experiments. Some interesting and meaningful phenomenon were discovered. These three design parameters can complement with each other in the performance of HMAs. What’s more, several combinations show even better comprehensive performance than traditional one, such as the combination of hard asphalt and low Ndes. In addition, Under the combination of design parameters, more design possibilities can be obtained to achieve the expected performance compared with traditional methods, and thus the flexibility in the design of HMAs was further improved.
- Figure 2, You need some explanation for AC-16 as well as a reference.
Response: Modified. The aggregate gradation of AC16 was frequently adopted in the asphalt pavement projects in China. Therefore, it was considered in our research.
- Figure 4, Y-axis on the right side needs a legend in all figures. You also need to include a & b on the graph.
Response: Modified.
We have checked the manuscript and revised it in detail according to the comments. We submit there the revised manuscript as well as a list of changes, and some minor errors have been modified in the paper which does not list above.We would like to express our great appreciation to you for comments on our paper.
Author Response File: Author Response.doc
Round 2
Reviewer 2 Report
The authors addressed the comments properly. I recommend to publish.
Reviewer 3 Report
n/a
