Influence of Complex Service Factors on Ravelling Resistance Performance for Porous Asphalt Pavements
Round 1
Reviewer 1 Report
Manuscript ID: buildings-2120052
Title: Influence of Complex Service Factors on Raveling Resistance Performance for Large-void drainage asphalt pavements
Authors analyzed the influence of complex service factors on ravelling resistance performance for large-void asphalt pavements. This is an interesting paper. The findings are specific and could be a reference for the community. Some concerns are shown below.
(1) The highlights should be rewritten.
(2) Some English grammar errors should be revised.
(3) Conclusions should be concise.
Author Response
Title: Influence of Complex Service Factors on Raveling Resistance Performance for Large-void drainage asphalt pavements
Authors analyzed the influence of complex service factors on ravelling resistance performance for large-void asphalt pavements. This is an interesting paper. The findings are specific and could be a reference for the community. Some concerns are shown below.
- The highlights should be rewritten.
Response: Thanks for your comment. The highlights has been rewritten.
- Some English grammar errors should be revised.
Response: Thanks for your comment. The manuscript has been polished in terms of English writing.
(3) Conclusions should be concise.
Response: Thanks for your comment. The conclusions have been concise.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The ABSTRACT section is well–structured, is informative, can stand alone and covers the content. The aims and objectives of the research are well defined. The study aims at analyzing the influence of complex service factors on ravelling resistance performance for large-void asphalt pavements
The INTRODUCTION section provide the necessary background information needed to understand the paper.
The METHODOLOGY / MATERIALS & METHODS section is relatively well described and include detailed informations.
The body of paper describe the important RESULTS of the research, followed by several DISCUSSIONS. The result shows that environmental factors significantly affect the ravelling resistance performance of drainage asphalt pavements. In the study, numerous tests are conducted to find out the impact of environmental and vehicle factors on the ravelling resistance performance of drainage asphalt pavements. Finally, the two test results of the Cantabro Abrasion test and Rotating Surface Abrasion test are consistent in their changes during single/composite factor analysis, confirming the feasibility.
The authors proceed directly to CONCLUSIONS, which succinctly summarize the major points of the paper, derived from the results. Based on this, the research on the ravelling resistance performance of large-void asphalt pavements is carry out under complex factors by simulating natural aging effect and temperature-water damage through UV aging, freeze-thaw cycles, coupled with vehicle loading factors.
The list of REFERENCES is long and relatively well chosen. The entire bibliography is current (the oldest being from 2001), but modern works (over the last 5 years) are mainly used. Literature review provides comprehensive information about the current state of research.
Figures are particularly important because they show the most objective support of the research. The graphic addenda is remarkable.
I have not detected any mistakes (neither grammatical, nor in experimental method or data processing).
Author Response
The ABSTRACT section is well–structured, is informative, can stand alone and covers the content. The aims and objectives of the research are well defined. The study aims at analyzing the influence of complex service factors on ravelling resistance performance for large-void asphalt pavements
The INTRODUCTION section provide the necessary background information needed to understand the paper.
The METHODOLOGY / MATERIALS & METHODS section is relatively well described and include detailed informations.
The body of paper describe the important RESULTS of the research, followed by several DISCUSSIONS. The result shows that environmental factors significantly affect the ravelling resistance performance of drainage asphalt pavements. In the study, numerous tests are conducted to find out the impact of environmental and vehicle factors on the ravelling resistance performance of drainage asphalt pavements. Finally, the two test results of the Cantabro Abrasion test and Rotating Surface Abrasion test are consistent in their changes during single/composite factor analysis, confirming the feasibility.
The authors proceed directly to CONCLUSIONS, which succinctly summarize the major points of the paper, derived from the results. Based on this, the research on the ravelling resistance performance of large-void asphalt pavements is carry out under complex factors by simulating natural aging effect and temperature-water damage through UV aging, freeze-thaw cycles, coupled with vehicle loading factors.
The list of REFERENCES is long and relatively well chosen. The entire bibliography is current (the oldest being from 2001), but modern works (over the last 5 years) are mainly used. Literature review provides comprehensive information about the current state of research.
Figures are particularly important because they show the most objective support of the research. The graphic addenda is remarkable.
I have not detected any mistakes (neither grammatical, nor in experimental method or data processing).
Response: Thanks for your comment.
Author Response File: 
Author Response.docx
Reviewer 3 Report
The paper presents a laboratory characterization of a porous asphalt (PA) mixtures surface, analysing the influencing factors on the ravelling resistance. A lot of environmental and traffic variables are taken into account, such as the UV radiation, the temperature, the freeze-thaw cycles, and the speed, weight and traffic volume.
The objective is interesting, and the study is well structured, since also a new self-developed equipment is employed. However, the paper should be generally revised, and the results are not clearly presented.
Here the comments:
-The email of the corresponding author should be an institutional email.
-In Line 37, it is stated that PA is used in urban areas. However, it is not recommended since the major advantage of PA is to remove the water to avoid aquaplaning and increase the friction wheel-pavement. Moreover, in the urban areas, the PA would be quickly clogged. For this reason, it should be used mostly in the motorways and expressway.
In addition, PA cannot be used in highland mountainous areas, as stated in Line 192, since the water freezing and its increasing volume would destroy the PA layer.
-In the paper, the acronym PA should be always used, once defined, and the same terminology should be used.
-Line 63, “ultra-thin” wearing course should be briefly defined.
-In Line 106, the Rotating Surface Abrasion test should be briefly explained. In fact, it is then written that is self-developed only in the Methodology part and it is known generally known.
-Regarding the methodology, the compaction method and production of the trapezoidal specimens should be written and explained.
-Section 2.2.1. Does the UV ageing test is standardised? If yes, it should be written.
-Section 2.2.3. The Cantabro drum should have also the bar inside. Since the dimensions and geometry are specified, also this information is may needed.
-Section 2.2.4. Since the temperature is an influencing factor, did you consider to put the RSTA in a climatic chamber?
-Section 3.1. should not be written before the explanation of the following results.
-In the Results section 3.1.1-3.1.3-3.2.1-3.2.2-3.2.3, the first lines should be placed in the methodology section.
-Lines 230-231-232 should be referenced.
-The comparisons made in the parts from Line 255, and then 290 are not clear.
-The presentation of the results is not clear. I suggest to make figures (histograms maybe) to better compare the results.
-Lines 357-358. Why did you decide these loading force? It should simulate the actual vehicle mass.
Author Response
The paper presents a laboratory characterization of a porous asphalt (PA) mixtures surface, analysing the influencing factors on the ravelling resistance. A lot of environmental and traffic variables are taken into account, such as the UV radiation, the temperature, the freeze-thaw cycles, and the speed, weight and traffic volume.
The objective is interesting, and the study is well structured, since also a new self-developed equipment is employed. However, the paper should be generally revised, and the results are not clearly presented.
Here the comments:
-The email of the corresponding author should be an institutional email.
Response: Thanks for your comment. The email of the corresponding author has been provided an institutional email.
-In Line 37, it is stated that PA is used in urban areas. However, it is not recommended since the major advantage of PA is to remove the water to avoid aquaplaning and increase the friction wheel-pavement. Moreover, in the urban areas, the PA would be quickly clogged. For this reason, it should be used mostly in the motorways and expressway.
Response: Thanks for your comment. The error has been modified.
In addition, PA cannot be used in highland mountainous areas, as stated in Line 192, since the water freezing and its increasing volume would destroy the PA layer.
Response: Thanks for your comment. Due to the strong stimulation of ultraviolet aging, the porous asphalt material has a serious aging attenuation and cannot adapt to areas with strong ultraviolet radiation.
-In the paper, the acronym PA should be always used, once defined, and the same terminology should be used.
Response: Thanks for your comment. Relevant contents have been reorganized and unified.
-Line 63, “ultra-thin” wearing course should be briefly defined.
Response: Thanks for your comment. Ultra-thin wearing course can repair slight cracks, loose and aging pavement during pavement maintenance. Meanwhile, it can also improve the smoothness and anti-rutting performance of the pavement, and has obvious effect on restraining or delaying the reflective cracks of the pavement. In addition, the super thin wearing course has relatively good water tightness, which can effectively avoid water damage to asphalt pavement and increase the service life of pavement. Its thickness is generally less than 30mm.
-In Line 106, the Rotating Surface Abrasion test should be briefly explained. In fact, it is then written that is self-developed only in the Methodology part and it is known generally known.
Response: Thanks for your comment. Rotating Surface Abrasion Test-a new test method for porous asphalt in general, investigating the mechanical stability.
-Regarding the methodology, the compaction method and production of the trapezoidal specimens should be written and explained.
Response: Thanks for your comment. The trapezoidal test piece mold (top edge width 8.4cm - bottom edge width 30cm - height 30cm - thickness 5cm) directly modified from the vehicle's track plate mold (30cm*30cm*5cm), see the following figure. The compaction method is the same as that of the asphalt mixture sample formed by the traditional rut board. The proper compaction times can be determined through pressure test, which can finally make the specimen reach the target void rate. After demoulding, when installing the specimen, the upper and lower edges will be slightly cut as required to facilitate installation.
84mm
300mm
-Section 2.2.1. Does the UV ageing test is standardised? If yes, it should be written.
Response: Thanks for your comment. The UV aging experiment is based on the local climate conditions in Yunnan, and the specific experimental parameters are determined after consulting the relevant literature. It is not a standard test. In order to carry out the UV aging test, test conditions of 8-hour exposure (black plate temperature of 60 ℃) plus 4-hour condensation (black plate temperature of 50 ℃) were determined, and UVA340 lamp UV irradiance was set at 1W/m2 * nm, with control wavelength of 340 nm. Moreover, 8h light + 4h condensation for one cycle was determined in this UV aging test.
-Section 2.2.3. The Cantabro drum should have also the bar inside. Since the dimensions and geometry are specified, also this information is may needed.
Response: Thanks for your comment. The Cantabro drum has the bar inside,as showed in following figure.
-Section 2.2.4. Since the temperature is an influencing factor, did you consider to put the RSTA in a climatic chamber?
Response: Thanks for your comment. Your suggestion is very good. At first, the equipment we developed and designed was installed with an air-heat heating device above the test piece, but the impact of the low temperature state should be more obvious than that of the high temperature state for the dispersion loss and damage of surface particles. At present, the test is completed at the same room temperature. In the follow-up study, we will focus on this factor and improve the test plan to make it more suitable to carry out the test at a constant temperature (such as 15 ℃).
-Section 3.1. should not be written before the explanation of the following results.
Response: Thanks for your comment. Section 3.1 has been deleted.
-In the Results section 3.1.1-3.1.3-3.2.1-3.2.2-3.2.3, the first lines should be placed in the methodology section.
Response: Thanks for your comment. Relevant contents have been modified, and the introduction of the test method has been placed in the methodology section.
-Lines 230-231-232 should be referenced.
Response: Thanks for your comment. Done.
-The comparisons made in the parts from Line 255, and then 290 are not clear.
Response: Thanks for your comment. Relevant contents have been modified.
-The presentation of the results is not clear. I suggest to make figures (histograms maybe) to better compare the results.
Response: Thanks for your comment. Some pictures are added to make the result comparison more readable.
-Lines 357-358. Why did you decide these loading force? It should simulate the actual vehicle mass.
Response: Thanks for your comment. The equipment can not operate for a long time under large load conditions, which may lead to the risk of mechanical failure. We are adjusting and solving this problem. At present, the load forces listed in the article are selected after the test, which can ensure a certain degree of discrimination for the loading of the test piece, and also ensure the long-term normal operation of the equipment.
Author Response File: Author Response.docx
Reviewer 4 Report
The article describes the studies carried out in order to evaluate the factors that cause raveling on asphalt mixtures with high void contents and the analysis of the correlation between the Cantabro Abrasion test and 513 the Rotating Surface Abrasion.
The name used for these mixtures: they are more often called “porous asphalt” instead of “large-void drainage asphalt”. So, I would like to know if the authors are speaking about porous asphalt exclusively of if they are including different types of asphalt mixtures with high void contents.
The most important comment I have for the authors is that I understand the study of the UV cycles effect but not so much the freeze-thaw cycles: specifications in some countries do not allow the use of porous mixtures in mountain areas above 1200 meters. Is there a similar limitation in your country?
Section 2.2.4: when authors describe RSAT, I don’t understand some of the dimensions of the trapezoidal plates: “ with their top and bottom measured at 80 mm and 300 mm respectively, and the height and thickness of 300 mm and 50 mm respectively”. The 300 mm height, I think it is the length, is it right?
Figure 4(a): is this sample composed by different types of specimens? Why are many colors seen in the sample?
Regarding section 3, authors should indicate the dispersion of results, especially in figure 8, where the trend of the Raveling loss rate does nor seem to be always the same.
Page 6, lines 195-198: as I have said, porous asphalt is not allowed under very cold weather with a risk of freezing-thawing cycles.
Typing errors and/or missing information:
Page 3, line 113: it is “carried” instead of “carry”
Page 3, lines 121-122: the two words in brackets are already written before the brackets.
Page 3, line 131: please explain “oil-to-stone ratio”.
Page 3, table 2: what are the gradation maximum and minimum percentages?
Figure 1(b): I think it is “radiation” instead of “radiation”.
Page 6, lines 195-198: is there a verb missing here? In “though mostly paved in hot areas with heavy rainfall …”
Page 6, line 200: I think it is “raveling”.
Author Response
The article describes the studies carried out in order to evaluate the factors that cause raveling on asphalt mixtures with high void contents and the analysis of the correlation between the Cantabro Abrasion test and 513 the Rotating Surface Abrasion.
The name used for these mixtures: they are more often called “porous asphalt” instead of “large-void drainage asphalt”. So, I would like to know if the authors are speaking about porous asphalt exclusively of if they are including different types of asphalt mixtures with high void contents.
Response: Thanks for your comment. It is suggested that the full paper be unified as "porus aspert".
The most important comment I have for the authors is that I understand the study of the UV cycles effect but not so much the freeze-thaw cycles: specifications in some countries do not allow the use of porous mixtures in mountain areas above 1200 meters. Is there a similar limitation in your country?
Response: Thanks for your comment. No limit. The requirements of Chinese industry standards for the performance design of PA materials include the residual stability index. The realization of this index is to evaluate the water damage resistance of materials through the Marshall stability ratio before and after the freeze-thaw cycle. At present, there is no provision in China's industry standards to limit the altitude of the area where the PA drainage pavement is used. We think its application area should be related to latitude.
Section 2.2.4: when authors describe RSAT, I don’t understand some of the dimensions of the trapezoidal plates: “ with their top and bottom measured at 80 mm and 300 mm respectively, and the height and thickness of 300 mm and 50 mm respectively”. The 300 mm height, I think it is the length, is it right?
Response: Thanks for your comment. The trapezoidal test piece mold (top edge width 8.4cm - bottom edge width 30cm - height 30cm - thickness 5cm) directly modified from the vehicle's track plate mold (30cm*30cm*5cm), see the following figure. The compaction method is the same as that of the asphalt mixture sample formed by the traditional rut board. The proper compaction times can be determined through pressure test, which can finally make the specimen reach the target void rate. After demoulding, when installing the specimen, the upper and lower edges will be slightly cut as required to facilitate installation.
84mm
300mm
Figure 4(a): is this sample composed by different types of specimens? Why are many colors seen in the sample?
Response: Thanks for your comment. The drainage asphalt mixture with the same gradation is used. In the test, it is found that the surface of the test piece will change color after three or more ultraviolet aging cycles; We preliminarily speculate that it may be due to the severe aging of the asphalt film on the surface due to the condensation at 50 ℃ during the UV aging.
Regarding section 3, authors should indicate the dispersion of results, especially in figure 8, where the trend of the Raveling loss rate does nor seem to be always the same.
Response: Thanks for your comment. The relevant results were redrawn and the standard deviation was added to represent the difference of the results.
Page 6, lines 195-198: as I have said, porous asphalt is not allowed under very cold weather with a risk of freezing-thawing cycles.
Response: Thanks for your comment. Agree with this statement. Freeze-thaw does cause great damage to the large void structure. It cannot be popularized on a large scale under cold weather areas.
Typing errors and/or missing information:
Page 3, line 113: it is “carried” instead of “carry”
Response: Thanks for your comment. Done.
Page 3, lines 121-122: the two words in brackets are already written before the brackets.
Response: Thanks for your comment. Done.
Page 3, line 131: please explain “oil-to-stone ratio”.
Response: Thanks for your comment.The “oil-to-stone ratio”should be the asphalt-aggregate ratio.
Page 3, table 2: what are the gradation maximum and minimum percentages?
Response: Thanks for your comment. In the grading design, there is a specific scope according to the specification. In the mixture design, the mixture shall meet the requirements of the specification within this range.
Figure 1(b): I think it is “radiation” instead of “radiation”.
Response: Thanks for your comment. Done.
Page 6, lines 195-198: is there a verb missing here? In “though mostly paved in hot areas with heavy rainfall …”
Response: Thanks for your comment. Done.
Page 6, line 200: I think it is “raveling”.
Response: Thanks for your comment. Done.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
The Authors provided a properly modified version of the paper according the comments, and the manuscript can be considered for the publication in the present form.
Reviewer 4 Report
The authors took my indications into account and made the pertinent corrections.
