Utilisation of Waste-Based Geopolymer in Asphalt Pavement Modification and Construction—A Review

Round 1

Reviewer 1 Report

This paper shows a good review of Geopolymer in Asphalt, there are some issues that need to address

- Introduction is written simply, most recent research and innovation in bionanomaterials performances should be reviewed to show the gap of knowledge. The introduction should be extended with recent research papers.

Authors can cite the following work in the introduction which is closely related to their work and recently reported:

- "Strength and microstructural study of recycled asphalt pavement: Slag geopolymer as a pavement base material." Journal of Materials in Civil Engineering 30, no. 8 (2018): 04018177.

- "Warm mix asphalt technology: An up to date review." Journal of Cleaner Production (2020): 122128

what makes this review different from the other and from the most recent ones?

The future plan or future Geopolymer in Asphalt development direction needs to be addressed.

There are some grammatical errors, please carefully check the whole manuscript.

Author Response

Thank you for giving me the opportunity to submit a revised with major correction of my manuscript titled Utilization of Waste-Based Geopolymer in Asphalt Pavement Modification and Construction; A Review to sustainability; we here and wherever applicable throughout appreciate the time and effort that you and the reviewers have dedicated to providing your valuable feedback on my manuscript. Furthermore, we are grateful to the reviewers for their insightful comments on my review paper. Hence,  we have been able to incorporate changes to reflect most of the reviewers' suggestions. We have highlighted the changes with blue and response to the manuscript's comments end of the manuscript based on the reviewer's comments.

Author Response File: Author Response.docx

Reviewer 2 Report

Thank you for submitting your work for consideration for publication.  In this manuscript, the authors have performed a nice literature review of the use of geopolymers in asphalt binders. However, there are still some points which require correction/addition before the manuscript can be published.  Please see my comments below:

1. Line 40 - Which "inorganic" binder?  Asphalt is derived from fossil fuels and other organic sources.
2. Lines 53 - 62 - This part is not well organized, along with other parts of the introduction.  The authors jump between specific details and major overarching points.  I suggest to revise this introduction.
3. Figure 1 - Are these all geopolymer studies or only those related to asphalt?  The vast majority of this material is in Portland cement concrete replacement so if it's the latter, most of these studies would not be relevant.
4. Line 101 - Do the authors mean Figure 3?
5. Figure 6 - This figure is not legible and needs to be revised.
6. Section 3.3 - This section is quite light- has no one done any study other than high temperature?  If so, other studies at low/intermediate temperature must be considered.
7. Figure 12 - Which investigation is this from?
8. Lines 452 - 454 - This is simply not true, by far the biggest energy consumption requirement from a pavement life cycle perspective is the use phase.
9. This entire table must be revised to include sources.  Where is this information from?
10. Section 6 - What about other materials besides the fly ash based geopolymers?  How do these impact cost?
11. Overall, the authors are also missing discussion of storage stability/blending compatibility which is absolutely critical for using materials like these.  It must be discussed in detail of any review of a particulate modifier/additive.

Author Response

Thank you for giving me the opportunity to submit a revised with major correction of my manuscript titled Utilization of Waste-Based Geopolymer in Asphalt Pavement Modification and Construction; A Review to sustainability; we here and wherever applicable throughout appreciate the time and effort that you and the reviewers have dedicated to providing your valuable feedback on my manuscript. Furthermore, we are grateful to the reviewers for their insightful comments on my review paper. Hence,  we have been able to incorporate changes to reflect most of the reviewers' suggestions. We have highlighted the changes with blue and response to the manuscript's comments end of the manuscript based on the reviewer's comments.

Round 2

Reviewer 1 Report

Title: Utilization of Waste-Based Geopolymer in Asphalt Pavement Modification and Construction; A Review

In this revised manuscript, the Authors have made corrections according to referee comments. In my opinion, the manuscript in current form could be considered for acceptance. 

Author Response

Thank you for your positive, fruitful comments and suggestions, which have improved our manuscript's quality.

Reviewer 2 Report

Thank you for the resubmission. Overall, the changes are mostly satisfactory but the English grammar in the revised sections must be corrected as there were many errors.

Author Response

Thank you for your positive, fruitful comments and suggestions, which have improved our manuscript's quality. Moreover, we have fixed the manuscript and proofreading the paper to eliminate all such errors and attached with proofread invoice.