Effect of Mechanical Properties on Performance of Cold Mix Asphalt with Recycled Aggregates Incorporating Filler Additives

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Line 17: It sounds a bit unusual to express a ratio as 100:0. It would be clearer to use percentages like 100%, 50%, and 0%. In this context, it's advisable to define the percentage as the amount of RAP (Recycled Asphalt Pavement) in CAM (Cement-Asphalt Mortar).

It seems that a specific quantity of RAP enhances performance, while an excessive amount impairs its effectiveness, indicating a threshold. Could you include additional samples, such as those with 75% RAP or higher?

Line 208: Font sizes vary in Figure 8.

RAM in CAM may not offer the same long-term performance and durability as hot mix asphalt, in your study have you considered that?

The resilient modulus of CMA with RAP is much less compared to CM, please add more discussion if it will affect its application in some area, like pavement design. You may want to check what the local mini. MR required.

Comments on the Quality of English Language

It's generally Ok but it's can be improved to simplify some descriptions to make the reader easier to follow.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript investigates the mechanical properties and performance of cold mix asphalt (CMA) incorporating recycled asphalt pavement (RAP) and various filler additives. The experiments are well-designed and the results are clearly presented. Incorporating RAP and fillers like cement and fly ash seem to improve stability, moisture resistance, stiffness and abrasion loss of CMA. Using 50% RAP provides an optimum balance of improved performance without compromising workability. The paper makes a good case for sustainability benefits of reusing RAP in this way. However, the introduction lacks clarity on specific knowledge gaps being addressed. More discussion of limitations and recommendations for future work would strengthen conclusions. Overall this is a solid experimental study demonstrating beneficial reuse of RAP in CMA using locally available materials.

Comments to the authors:

1. The introduction currently focuses heavily on previous literature. Please add 1-2 paragraphs clearly stating the knowledge gaps this study aims to address.
2. On page 3 clarify how the RAP material was selected - why 50% and 100% specifically?
3. On page 5, please provide more details on the source and composition of the fly ash used.
4. In Table 1 please add units for the physical properties.
5. define acronyms when first introduced - e.g. IEC.
6. For Figure 3 XRD results, add labels identifying major peaks in each spectrum.
7. the statement "maximum density achieved for 50R2FA..." seems contradictory to Figure 12 which shows 50R2C as highest. Please clarify or correct.
8. In Figure 15 on page 17, error bars would help assess significance of differences in Marshall Quotient values between mixes.
9. On page 19, provide more justification for selecting the specific MR test temperatures used.
10. Conclusions could be strengthened by adding limitations of current study and recommendations for future work.
11. On page 3, expand discussion of how use of RAP reduces emissions. Cite sources.
12. provide more details on Stabil-road composition and supplier.
13. clarify why cationic vs. other emulsion type was chosen.
14. On page 15, explain the proposed mechanism of improved adhesion with cement additive.
15. states abrasion loss increased for 100% RAP - discuss possible reasons.
16. Conclusions could highlight the broader sustainability implications of reusing RAP.

 

 

Comments on the Quality of English Language

 Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This study is aimed to compare 3 different fillers on cold asphalt mix containing RAP. The study is experimentally comprehensive and has some good outcomes, however, there are some comments need to be addressed carefully:

- The introduction is quite general. pls shorten it and show the knowledge gap more clearly, beside the problem statement. why this study is done!! also, the objectives is very general; pls state it more specifically.

-Since the authors used 3 different fillers, it would be necessary to use a statistical analysis to show which filler provides the best performance.

- in conclusion, it should be stated clearly which filler has higher properties.

- most of references are outdated, pls cite more updated and relevant studies (2019 onward), some suggestions:

 

https://doi.org/10.1007/s42947-022-00216-4

https://doi.org/10.1016/j.conbuildmat.2022.127026

 

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Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Well revised. Can be processed for the next stage of publication.

Reviewer 3 Report

Comments and Suggestions for Authors

No further comments as all my comments were addressed by the authors