Experimental Study of the Factors Influencing the Performance of the Bonding Interface between Epoxy Asphalt Concrete Pavement and a Steel Bridge Deck
, Wei Xu 1,*, Jian Zhao 2,*, Luming An 2, Feng Wang 1, Zizhan Du 1 and Qiang Chen 1Round 1
Reviewer 1 Report
Line 61-90. The sentences are too long and therefore difficult to understand. Please use shorter sentences that are easier to understand.
Tables 2-6. A bibliographic description of the standards and procedures for the test methods listed in Tables 2-6 should be added to the reference list.
Tables 2-6. What was the number of samples tested to determine the parameters listed in the tables? Are these average values? In addition to these values, the coefficient of variation of the results should be given. The variability of the input data can significantly affect the formulated conclusions!
Table 7. How was the gradation curve determined? Does it result from any optimal curves recommended for asphalt layers for bridge pavements? What were the boundary curves? It needs to be cleared.
Line 147. How has the asphalt content (6.5%) been optimized?
Table 8. Unit (d) is unclear.
Table 8. The number of samples tested in each series should be added to the table.
Line 181. The sentences on line 184 and 192 should be removed and merged with the sentence on line 181.
Line 218. Why test with saltwater were conducted at a temperature of plus 25°C? Salt water is used in winter maintenance when temperatures are about or below freezing. The applied procedure is different from the real conditions. Please explain.
Line 275. Please provide the source of literature from which formula no.1 was taken.
Line 322. What do the whiskers in Figure 9 show? It should be described.
Figure 10. The description of the drawing is not clear. What does sample e.g. 1 or 6 mean? Are these samples of the same series? What is the reason for the large dispersion of the results between the samples?
Figure 11. The drawing is unclear. Are the averaged results shown here or have one sample been compared before and after primer application? Why after applying the primer in some places where was a peak (eg. 0.85 mm) the valley was created?
Table 11 is not clear. How is it possible that, for example, sample No. 12 has four different strength results?
Line 525. Only relatively short-term laboratory studies have been performed. It is worth adding in the conclusions that in order to confirm the results and for a more comprehensive assessment of the analyzed variants, field tests should be carried out under real conditions over a longer period of time.
References. There are no doi numbers in the bibliography. Moreover, in accordance with the current journal format, the abbreviations of the journal names should be used.
Author Response
Thank you for your comments and suggestions.
Point 1: Line 61-90. The sentences are too long and therefore difficult to understand. Please use shorter sentences that are easier to understand.
Response 1: These sentences were revised to shorter sentences.
Point 2: Tables 2-6. A bibliographic description of the standards and procedures for the test methods listed in Tables 2-6 should be added to the reference list.
Response 2: The test methods listed in Tables 2-6 was added to the reference list.
Point 3: Tables 2-6. What was the number of samples tested to determine the parameters listed in the tables? Are these average values? In addition to these values, the coefficient of variation of the results should be given. The variability of the input data can significantly affect the formulated conclusions!
Response 3: The test is carried out according to the corresponding standard, which is generally the average value of five samples. If the standard deviation exceeds the allowable range specified by the standard, a supplementary test is required.
Point 4: Table 7. How was the gradation curve determined? Does it result from any optimal curves recommended for asphalt layers for bridge pavements? What were the boundary curves? It needs to be cleared.
Response 4: The boundary limits of the gradation were added. The gradation resulted from optimal curves recommended for asphalt mixture from engineering applications.
Point 5: Line 147. How has the asphalt content (6.5%) been optimized?
Response 5: The optimal asphalt–aggregate ratio was 6.5% according air void and Marshall stability and explanation added in the paper.
Point 6: Table 8. Unit (d) is unclear.
Response 6: Unit (d) was modified as day.
Point 7: Table 8. The number of samples tested in each series should be added to the table.
Response 7: Three samples are collected for each test of each pavement composite structure and explanation added in the paper.
Point 8: Line 181. The sentences on line 184 and 192 should be removed and merged with the sentence on line 181.
Response 8: These sentences are revised as suggested.
Point 9: Line 218. Why test with saltwater were conducted at a temperature of plus 25°C? Salt water is used in winter maintenance when temperatures are about or below freezing. The applied procedure is different from the real conditions. Please explain.
Response 9: Erosion test with saltwater is a simulation of the effects of coastal rainwater on steel deck pavement. Supplementary explanations are given in the paper.
Point 10: Line 275. Please provide the source of literature from which formula no.1 was taken.
Response 10: The image processing function of ImageJ is used to quickly and accurately identify and quantify the number of cells and wound area from the images captured by the microscope. The migration can be evaluated by measuring the surface area occupied by cells over time [37]. This method (formula) was used to represent the proportion of corrosion area of steel plate in this paper. The references was added.
Point 11: Line 322. What do the whiskers in Figure 9 show? It should be described.
Response 11: This is the error bar and is used to illustrate the magnitude of the uncertainty in the measured data. According to Figure 9, it can be known that the test data is relatively uniform and the error is small.
Point 12: Figure 10. The description of the drawing is not clear. What does sample e.g. 1 or 6 mean? Are these samples of the same series? What is the reason for the large dispersion of the results between the samples?
Response 12: Figure 10 is to illustrate that spraying a zinc-rich epoxy primer reduces the surface roughness of the samples. Samples 1-6 are a series of samples with a roughness range of 80-150 μm. Through the test of a series of samples, it is more fully proved that spraying zinc-rich epoxy primer reduces the surface roughness of the samples. (Explanation has been added to the paper)
Point 13: Figure 11. The drawing is unclear. Are the averaged results shown here or have one sample been compared before and after primer application? Why after applying the primer in some places where was a peak (eg. 0.85 mm) the valley was created?
Response 13: The curves are the averaged results from the surface profile measurements. Due to the viscosity and spray unevenness of epoxy zinc-rich, it will locally accumulate into peaks and valleys.
Point 14: Table 11 is not clear. How is it possible that, for example, sample No. 12 has four different strength results?
Response 14: Table 11 shows the results obtained by repeating the pull test several times. The value of No-WBM sample 12 is quite different, because the combination of "A3+B2" is prone to test errors without the waterproof adhesive layer.
Point 15: Line 525. Only relatively short-term laboratory studies have been performed. It is worth adding in the conclusions that in order to confirm the results and for a more comprehensive assessment of the analyzed variants, field tests should be carried out under real conditions over a longer period of time.
Response 15: This sentence was added as suggested.
Point 16: References. There are no doi numbers in the bibliography. Moreover, in accordance with the current journal format, the abbreviations of the journal names should be used.
Response 16: the references form was check and modified accordingly.
Reviewer 2 Report
The paper presents an experimental laboratory study aimed at evaluating the influence of several factors in the bonding behaviour at the interface of epoxy asphalt layer–steel bridge deck composite structures. Parameters such as the asphalt voids content, the deck surface roughness, the thickness of a zinc-rich primer and the waterproofing attitude of a bonding membrane were included in the investigation. Based on the experimental findings, some recommendations are also stated.
The following list summarizes the main aspects that, according to Reviewer opinion, should be improved priorly to the manuscript for publication:
- Minor typing errors have been identified (Examples: Line 126: missing verb; Line 178: repeated parenthesis; Line 229: missing 2 superscript for the square meter; In the reference list: n. 1, 17, 18, 26, 28, 30, 31, 32: Missing space between Authors and title). Please, correct them and perform a final form check, also to comply with Journal format.
- Line 118: At the conclusion of “1. Introduction” paragraph, after the description of the research target, a flow chart schematizing the experimental workflow should be included, above all considering the various aspects involved in the plan (various material-components combinations, conditions, setting up parameters, test methods, etc.). This should surely boost the paper comprehension.
- Line 278: For experience, the application of digital image processing (also with ImageJ) is quite affected by the quality and the specs of the collected pictures of the samples (above all lighting). If available, authors could specify the equipment used for the photo capturing and its setting (at least resolution – chromatic profile). For the same reasons, the setting of ImageJ processing should be indicated (chromatic/light tolerances can deeply affect numerical results). This, to promote the experiment reproducibility.
- Many analyses of results were carried out through ANOVA. Where missing, please report the numerical outcomes of the analysis of variance (some Tables would be appreciated).
- Line 491, at the end of “4.4.Optimal design of a steel deck pavement structure” paragraph: Given the significant amount of collected information, that were finally traduced in a sort of recommendation’s frame, a schematic representation of these final outcomes (matrix? graph? nomograph?) would be great and should enhance the quality (it is only a suggestion)
Author Response
Thank you for your comments and suggestions.
Point 1: Minor typing errors have been identified (Examples: Line 126: missing verb; Line 178: repeated parenthesis; Line 229: missing 2 superscript for the square meter; In the reference list: n. 1, 17, 18, 26, 28, 30, 31, 32: Missing space between Authors and title). Please, correct them and perform a final form check, also to comply with Journal format.
Response 1: These Typing errors were corrected and the form of the paper was checked.
Point 2: Line 118: At the conclusion of “1. Introduction” paragraph, after the description of the research target, a flow chart schematizing the experimental workflow should be included, above all considering the various aspects involved in the plan (various material-components combinations, conditions, setting up parameters, test methods, etc.). This should surely boost the paper comprehension.
Response 2: Thanks you for this suggestion. Figure 4 of flow chart schematizing the experimental workflow was added.
Point 3: Line 278: For experience, the application of digital image processing (also with ImageJ) is quite affected by the quality and the specs of the collected pictures of the samples (above all lighting). If available, authors could specify the equipment used for the photo capturing and its setting (at least resolution – chromatic profile). For the same reasons, the setting of ImageJ processing should be indicated (chromatic/light tolerances can deeply affect numerical results). This, to promote the experiment reproducibility.
Response 3: Thanks you for this suggestion. The information of the equipment and the setting of ImageJ processing will be noted and described in subsequent studies.
Point 4: Many analyses of results were carried out through ANOVA. Where missing, please report the numerical outcomes of the analysis of variance (some Tables would be appreciated).
Response 4: The numerical outcomes of the analysis of variance and Table 12, Table 15 were added.
Point 5: Line 491, at the end of “4.4. Optimal design of a steel deck pavement structure” paragraph: Given the significant amount of collected information, that were finally traduced in a sort of recommendation’s frame, a schematic representation of these final outcomes (matrix? graph? nomograph?) would be great and should enhance the quality (it is only a suggestion)
Response 5: Thanks you for this suggestion. A pavement structure diagram with suggested parameters was added
Reviewer 3 Report
The authors presented an interesting study and well prepared. I have a few minor suggestions:
- In the abstract, information on methodology is missing. Please revise
- Authors should check the symbols and units used throughout the paper.
Author Response
Thank you for your comments and suggestions.
Point 1: In the abstract, information on methodology is missing. Please revise
Response 1: Information on methodology was added in the abstract.
Point 2: Authors should check the symbols and units used throughout the paper.
Response 2: The symbols and units used throughout the paper were checked and modified accordingly.
Round 2
Reviewer 1 Report
Line 151. The reference number of the literature recommending such asphalt mixture and gradation curve for bridge pavements should be added.
Table 7. It would be useful to add a gradation curve chart.
Response 11. This information should be added in the article.
Response 13. This information should be added in the article.
Response 14. This information should be added in the article.
Author Response
Point 1: Line 151. The reference number of the literature recommending such asphalt mixture and gradation curve for bridge pavements should be added.
Response 1: The reference number of the literature recommending such asphalt mixture and gradation curve for bridge pavements was added.
[29] Xu, W.; Wei, J.; Chen, Z.; Wang, F.; Zhao, J. Evaluation of the Effects of Filler Fineness on the Properties of an Epoxy Asphalt Mixture. Materials 2021, 14, 2003.
Point 2: Table 7. It would be useful to add a gradation curve chart.
Response 2: A gradation curve chart was added.
Point 3: Response 11. This information should be added in the article.
Response 3: This information was added in the article.
Point 4: Response 13. This information should be added in the article.
Response 4: This information was added in the article.
Point 5: Response 14. This information should be added in the article.
Response 5: This information should be added in the article.
Author Response File: 
Author Response.pdf
