Construction and Performance Evaluation of Polyurethane-Bound Porous Rubber Pavement (PRP) Trial Section in the Cold Climate

Round 1

Reviewer 1 Report

The article deals with the important and current problem of assessing the behavior of porous road surfaces made in the PRP technology - polyurethane-bound Porous Rubber Pavement, with different content of components (Stone Aggregate, Rubber Aggregate and Stockmeier Polyurethane Binder) and air voids. The tests were carried out on two specially prepared trial sections. The tests were carried out in real weather conditions of road surfaces - immediately after the trial sections were made, as well as after two weeks and seven months. The test program was comprehensive and consisted of two parts: laboratory testing and field tests on the trial sections. I consider the main weakness of the work is the lack of a clearly defined objectives as well as the lack of generalized conclusions resulting from the analyzes carried out in the research.

Detailed remarks are included in the attached file.

Comments for author File: Comments.pdf

Author Response

1. Comments were made within the manuscript

• All of them are addressed except No 2 and No3 mentioned below.

1. This test is dedicated to investigate dense asphalt mixtures where the introduced water cannot easily drain away. In the case of porous mixtures (more than 24% air voids - easy outflow of water accumulated inside the pores), it is difficult to recognize the effectiveness of this test.

• That is why 5 freeze-thaw cycles were conducted, keeping the samples submerged in the water to simulate the saturated condition.

1. SD value is 60% of average! This result cannot be regarded as reliable. The test should be repeated.

• Since those laboratory samples were prepared from field mixes during trial section construction, later on, new samples preparation to repeat the test in the laboratory was not justified

1. I consider the main weakness of the work is the lack of a clearly defined objectives as well as the lack of generalized conclusions resulting from the analyzes carried out in the research.

• Conclusion is re-written

Reviewer 2 Report

The paper " Construction of polyurethane-bound Porous Rubber Pavement (PRP) trial section in Canadian climate and understanding its behaviour based on field performance evaluation" presents a relevant theme and within the scope of this journal, and can be considered after some corrections suggested below:

(a)    The title presented, despite reflecting what is expected of the paper, is very extensive, and may be confusing to potential readers;

(b)   The abstract is very extensive, such a long abstract cannot be allowed, which makes it unattractive to potential readers, and reduces the impact of the research;

(c)    Scientific innovation is limited in the introduction of the paper, the authors must go deeper and detail what this research differs from countless others that exist on this topic, this must be evidenced together with the objectives at the end of the introduction;

(d)   The state of the art of the evaluated topic needs to be improved by the authors, note that some topics are absent and need to be known with current research, such as: 10.3390/ma15072598; 10.1016/j.cscm.2022.e01697; 10.1016/j.cscm.2022.e01708.

(e)    The presentation of all Figures is confusing, note that they must be carefully reviewed and renumbered, consecutive figures can be composed, and others that are already composed must be renamed, such as (a) and (b), in their legend and in the body of the figure;

(f)    Graphs must be standardized, in addition some standard deviations and statistical analyzes can be added;

(g)   “Besides the test timing, the mixes with a higher percentage of rubber aggregates and 426 binders compacted more than other mixes after opening for traffic. The Control Mix con- 427 tained a higher percentage of rubber (45.25%) and binder (9.5%); thus, it compacted more 428 after opening for traffic. Although initially, the average elastic modulus of the Control Mix 429 was 36 MPa, during the 2nd test, it reached 45 MPa. New Mix 1 also contained a higher 430 percentage of rubber aggregates (37.5%) and compacted more than other mixes (from 1st 431 to 2nd test).” This part of the text should be revised.

(h)   Conclusion is too long, authors should make this topic more objective to potential readers;

(i)     The English language must be revised carefully by a specialized native professional.

Author Response

1. The title presented, despite reflecting what is expected of the paper, is very extensive, and may be confusing to potential readers;

• Title changed

1. The abstract is very extensive, such a long abstract cannot be allowed, which makes it unattractive to potential readers, and reduces the impact of the research;

• Abstract changed

1. Scientific innovation is limited in the introduction of the paper, the authors must go deeper and detail what this research differs from countless others that exist on this topic, this must be evidenced together with the objectives at the end of the introduction;

• Only a few research have been conducted on this topic. However, more information was added in the introduction.

1. The state of the art of the evaluated topic needs to be improved by the authors, note that some topics are absent and need to be known with current research, such as: 10.3390/ma15072598; 10.1016/j.cscm.2022.e01697; 10.1016/j.cscm.2022.e01708.

• The comment was not clearly understood

1. The presentation of all Figures is confusing, note that they must be carefully reviewed and renumbered, consecutive figures can be composed, and others that are already composed must be renamed, such as (a) and (b), in their legend and in the body of the figure;

• Corrected as per suggestions

1. Graphs must be standardized, in addition some standard deviations and statistical analyzes can be added;

• Corrected as per suggestions

1. “Besides the test timing, the mixes with a higher percentage of rubber aggregates and 426 binders compacted more than other mixes after opening for traffic. The Control Mix con- 427 tained a higher percentage of rubber (45.25%) and binder (9.5%); thus, it compacted more 428 after opening for traffic. Although initially, the average elastic modulus of the Control Mix 429 was 36 MPa, during the 2nd test, it reached 45 MPa. New Mix 1 also contained a higher 430 percentage of rubber aggregates (37.5%) and compacted more than other mixes (from 1st 431 to 2nd test).” This part of the text should be revised.

• This part of the text was reviewed and re-written

1. Conclusion is too long, authors should make this topic more objective to potential readers;

• Conclusion is re-written

1. The English language must be revised carefully by a specialized native professional.

• Checked

Reviewer 3 Report

The use of porous pavement in Canada is an important topic. The paper presents interesting data. Some  refinement comments are shown as follows:(1) The abstract is too long. The abstract should state briefly the purpose of the research, the principal results and major conclusions. An abstract is often presented separately from the article, so it must be able to stand alone.

(2) The paper should address the important features of PRP to survive from the Canadian climate. For example, the freeze-thaw performance. Otherwise, the PRP may not last for few winters.

(3) “2.5 Mixes used for placement”, what are the properties of stone aggregate, rubber aggregate, and stockmeier polyurethane binder. The basic properties should be provided.

(4) Table 3, the ITS for the new mix 2 has higher standard deviations compared with other mixes, why?

(5) Table 4, the new mix show poorer moisture-induced damage resistance, how to improve?

(6)  Figure 19, what are the title and the unit for y-axis, and what is the title for x-axis. In addition, what are the testing temperature?

(7) “4.5.2 British Pendulum Test”, what are the testing temperature. Does the BPN value convert to BPN20 (BPN at 20 C)?

(8)  Please note the citation format. For example, line #284 “Error! References source not found”.

(9)  For the bar charts, please add error bars.

(10)  The conclusion needs to be refined, please leave only the important findings.

(11)  References, please revise the reference format according to the journal guide.

Author Response

1. The abstract is too long. The abstract should state briefly the purpose of the research, the principal results and major conclusions. An abstract is often presented separately from the article, so it must be able to stand alone.

• Abstract changed

1. The paper should address the important features of PRP to survive from the Canadian climate. For example, the freeze-thaw performance. Otherwise, the PRP may not last for few winters.

• Actually, it addressed freeze-thaw performance under moisture-induced damage test

1. “2.5 Mixes used for placement”, what are the properties of stone aggregate, rubber aggregate, and stockmeier polyurethane binder. The basic properties should be provided.

• A new table was added as per the suggestion

1. Table 3, the ITS for the new mix 2 has higher standard deviations compared with other mixes, why?

• Since those laboratory samples were prepared from field mixes during trial section construction, later on, new sample preparation in the laboratory to repeat the test was not justified. In the laboratory, a strict environment can be maintained. However, in the field, it was not possible.

1. Table 4, the new mix show poorer moisture-induced damage resistance, how to improve?

• Not all the new mixes showed poorer moisture-induced damage. Mixes with a higher percentage of rubber aggregates showed lower moisture-induced damage.

1. Figure 19, what are the title and the unit for y-axis, and what is the title for x-axis. In addition, what are the testing temperature?

• - Corrected

1. “4.5.2 British Pendulum Test”, what are the testing temperature. Does the BPN value convert to BPN20 (BPN at 20 C)?

• – No, it was not converted to BPN20. The test temperature was the ambient temperature during the field testing.

1. Please note the citation format. For example, line #284 “Error! References source not found”.

• - Corrected

1. For the bar charts, please add error bars.

• - Added

1. The conclusion needs to be refined, please leave only the important findings.

• – The conclusion is re-written

1. References, please revise the reference format according to the journal guide.

• References were prepared using Refwork software. Journal’s exact format is not available in RefWorks. I need some guidelines here.

Round 2

Reviewer 2 Report

ok.

Reviewer 3 Report

Reviewer's comments have been addressed. No further comments were made.