Life Cycle Assessment of Natural Zeolite-Based Warm Mix Asphalt and Reclaimed Asphalt Pavement

Round 1

Reviewer 1 Report

Section 2.1: The functional unit should make sure that all the investigated scenarios have the same function. That is, that all the six types of asphalt mixtures can result in the same service life of the pavement surface. Only in this case, it is fair to analyze 1 ton of asphalt mixtures for all the scenarios. There is lack of such explanation or assumption in Section 2.1. If the calculation of ESN in Section 2.4 can demonstrate the same service life of different scenarios, it should also be mentioned in Section 2.1.

Line 117: “the limits of the system” is not an appropriate terminology, it should be “the system boundary”. Same for the caption of Figure 1.

Line 123: “useful life periods” should be “service life”

Section 2.2: The authors presented the mass of raw materials and energy demand of asphalt mixing (Table 1-3). However, there is lack of database information regarding the productions of raw materials. What is the database (ecoinvent, GaBi, or others) used to describe the input and output for producing gravel, sand, filler, additives, and binder? If the database is confidential, it should be mentioned in this section. Otherwise, the names of datasets for each raw material (e.g. "Gravel, crushed CH| production | Cut-off, U" if the database is ecoinvent) should be listed in main paper or supporting information.

Table 1: the size information of RAP and the amount of Evotherm should be included

Section 2.4: the daily average traffic load (e.g. in ESAL) and the yearly average temperature of the test section should be mentioned;

Figure 4: the productions of gravel, binder, and additives also consume fuels and electricity. To avoid misleading, the authors should emphasize in the figure that the legend “fuel and electricity” is only for the asphalt mixing. Same for Figure 5.

Line 343: the ESN results should be presented in a new section instead of Section 3.2.

There is lack of section discussing the potential uncertainties. E.g. what are the processes or datasets that were not considered but can affect the final results? Which datasets can be improved in terms of data quality?

Author Response

The authors would like to thank the reviewers for their constructive comments, which have helped to improve our article. Below we explain the improvements we have made to the manuscript (in blue) based on each of the comments they have made.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors

The objective  of this research was to extant and associate through a life cycle valuation using a "cradle-to-gate"  method of different kinds of asphalt mixtures considered for similar performance, hot mix asphalt (HMA) as a control sample, and warm mix asphalt (WMA) using usual zeolite, Evotherm® and  reclaimed asphalt material (RAP) in, unlike quantities. However, it is a good article that performed the analysis with special software, and its field data is little,  and numerical analysis and the number of software runs are small,  It requires a lot of effort and fundamental consideration until final acceptance.

-The number of keywords is high, up to 5 and very technical and specialized words should be chosen.

-Authors should explain more about the specifications of this software.[SimaPro 9 software, ReCiPe method version 1.11].

-The last two columns of the table[Table 2. Temperatures used to quantify] the numbers in it are repeated. Delete these two columns. And its numbers should be explained in the text

-The figure [Figure 3. Contribution..] and other diagrams do not need to start with zero,for a better comparison of differences, the origin of the vertical axis should be of a larger number.

-Data and analysis are few. Authors are recommended to review more data or more projects.

-The authors refer to similar data, methods and methods that can be used in other countries, in other words, the results of this research can be used internationally.

 Thanks

 

Author Response

The authors would like to thank the reviewers for their constructive comments, which have helped to improve our article. Below we explain the improvements we have made to the manuscript (in blue) based on each of the comments they have made.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear responsible author

Thanks for your effort and thorough correction

best wishes