A Study on the Performance of Asphalt Modified by Desulfurized Waste Rubber/Ethylene Vinyl Acetate Composite with Additives
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript investigated the effects of DR/EVA composite chemical and physical properties of asphalt. According to the current manuscript, there are some points the authors need to consider for improving the paper, some detailed comments are shown as below:
1. Line 94, what is Frequency Modulation Spectroscopy (FM)? I cannot find the corresponding description.
2. In Section 2.1, they are not Figures 1, 2, 3 and 4, they should be Tables 1, 2, 3 and 4.
3. Don't use Gun Powder, it should be desulfurized rubber powder, which remains consistent with the previous.
4. In Table 4, please standardize the units of indexes, for examples, it should be Pa·s for viscosity, or cm for ductility at 5°C.
5. Line 125, "desulfurized rubber powder was controlled at 4% and 20%", how do you determine the addition amounts? Any references?
6. Line 199, "fluorescence microscope at 400,000 times magnification", nonsense!
7. Line 327, where is the Figure 5(a)?
8. Line 399, maybe a punctuation is missing.
9. Figure 10, please supplement the DR/EVA modified asphalt without additives for comparison to better understand the functions of four additives.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Comments 1: Line 94, what is Frequency Modulation Spectroscopy (FM)? I cannot find the corresponding description.
Response 1:Thank you for pointing this out. I agree with this comment. I have therefore made a modification to change Frequency Modulation Spectroscopy to Fluorescence Microscopy (FM) in line 98.
Comments 2: In Section 2.1, they are not Figures 1, 2, 3 and 4, they should be Tables 1, 2, 3 and 4.
Response 2:Thank you for pointing this out. I agree with this comment. I have therefore made a change, in section 2-1, to change Figures 1,2,3,4 to Tables 1,2,3,4.
Comments 3:. Don't use Gun Powder, it should be desulfurized rubber powder, which remains consistent with the previous.
Response 3:Thank you for pointing this out. I agree with this comment. I have therefore made changes and have now amended Gun Powder to desulfurized rubber powder in the text.
Comments 4:In Table 4, please standardize the units of indexes, for examples, it should be Pa·s for viscosity, or cm for ductility at 5°C.
Response 4:Thank you for pointing this out. I agree with this comment. I have therefore made the changes you requested. The indicator units in table 4 have been normalized.
Comments 5: Line 125, "desulfurized rubber powder was controlled at 4% and 20%", how do you determine the addition amounts? Any references?
Response 5:Thank you for pointing this out. I agree with this comment. Therefore, I would like to explain your comment. Considering that the dosages of high dosage rubber powder modified asphalt used so far are from 20%-30%, the preparation of high dosage rubber powder modified asphalt can effectively improve the recycling rate of waste rubber tires. In this paper, 4% EVA is used, the reason is that three different ratios of EVA (2%, 4%, 6%) and 20% DRP have been done before for the preparation of composite modified asphalt, 2% EVA for asphalt performance enhancement is not obvious, 6% EVA because of the increase in the content of the asphalt, the asphalt in the lightweight component of the insufficient, but reduce the asphalt's low-temperature performance, and at the same time, the storage stability is greatly reduced, and is not applicable to the subsequent Performance improvement. In the same situation mentioned above, the dosage of desulfurization powder is selected as 20%, and the dosage of EVA is 4%. The references are roughly as follows:
- Gong Y, Pang Y, Li F, et al. Analysis of the influence of sbs content and structure on the performance of sbs/cr composite modified asphalt[J]. Advances in Materials Science and Engineering, 2021, 2021: 1-12.
- Qian C, Fan W. Evaluation and characterization of properties of crumb rubber/SBS modified asphalt[J]. Materials Chemistry and Physics, 2020, 253: 123319.
- Xue Y, Ge D, Lv S, et al. Evaluation of asphalt modified with bio-oil and high rubber content: Low temperature and short mixing time production condition[J]. Construction and Building Materials, 2023, 408: 133656.
- Guo P, Ma Q, Li Y, et al. Research on Rheological Properties by Desulfurized Rubber Powder/SBS Composite-Modified Asphalt and Road Performance of Its Mixture[J]. Advances in Materials Science and Engineering, 2022, 2022.
Comments 6: Line 199, "fluorescence microscope at 400,000 times magnification", nonsense!
Response 6:Thank you for pointing this out. I agree with this comment. Therefore a modification was made for the fluorescence microscope magnification to 400,000 and is illustrated in Figure 10.
Comments 7: Line 327, where is the Figure 5(a)?
Response 7:Thank you for pointing this out. I agree with this comment. I have therefore made the changes you requested to add Figure 5(a), and I am very grateful for your suggestion. In lines 336-341.
Comments 8: Line 399, maybe a punctuation is missing.
Response 8:Thank you for pointing this out. I agree with the comment. So I have made the changes, adding and revising after getting the punctuation checked..
Comments 9:Figure 10, please supplement the DR/EVA modified asphalt without additives for comparison to better understand the functions of four additives.
Response 9:Thank you for pointing this out. I agree with this comment. Therefore I have made the modification that the two plots in Figure 10 are for plain modified asphalt without additives and DR/EVACMA with four more additives, and for this reason I have changed the annotation of Figure 10 to Figure 10. Fluorescence charts of asphalt at 400×. (a) additive free asphalt; (b) DR/EVACMA. considering that the matrix asphalt is the background color in the fluorescence microscope and nothing can be seen, and there is no contrast, and the difference between the fluorescence charts of nine groups of different ratios of DR/EVACMA in the orthogonal experiments is not very obvious, for this reason, only the group with the best storage stability was chosen in the present study. modified asphalt and ordinary modified asphalt without additives (20% DRP+4% EVA) for comparison, which can clearly analyze the phase distribution of modifier and asphalt in the two composite modified asphalt.
Reviewer 2 Report
Comments and Suggestions for Authors1-at figure 2 put under every picture letter such as a,b and so on to be clear.
2 -the discussion at figure 3 not clear need to rewrite again and what is meaning of "test group" on x-axis ? at figure 3.
3-from table 7-11 contain A,B,C & D please clear what is this under every table.
4-at page 11 line 304 and 312 you ,mentioned figure 5a and 5b but you put only one figure and you write under it figure 5a,b please correct this.
5-write chemical structural of asphalt.
6-write a chemical equation to clear the reaction happen with additives and asphalt.
7-what is the aim of this study?
Author Response
Comments 1:at figure 2 put under every picture letter such as a,b and so on to be clear.
Response 1:Thank you for pointing this out. I agree with this comment. I have therefore labeled the bottom of Figure 2 to read "Figure 2. Processing of asphalt. (a) Matrix asphalt; (b) After shear completion; (c) After mixing completion ".
Comments 2: the discussion at figure 3 not clear need to rewrite again and what is meaning of "test group" on x-axis ? at figure 3.
Response 2:Thank you for pointing this out. I agree with this comment. I have therefore modified the discussion in Figure 3. At the same time, the "test group" on the X-axis of the figure is the meaning of the orthogonal test of nine asphalt samples and modified asphalt without additives, totaling 10 groups of asphalt samples, and has been modified in the figure to change the "test group" to " Asphalt test group".
Comments 3:from table 7-11 contain A,B,C & D please clear what is this under every table.
Response 3:Thank you for pointing this out. I agree with this comment. Therefore I have labeled all A, B, C, and D in Table 7-11. A (FEO), B (DCP), C (Sulfuric), and D (KH-550) respectively.
Comments 4:at page 11 line 304 and 312 you ,mentioned figure 5a and 5b but you put only one figure and you write under it figure 5a,b please correct this.
Response 4:Thank you for pointing this out. I agree with this comment. Therefore I have added Figures 5a and 5b, as well as written Figures 5a and b under the figure.
Comments 5:write chemical structural of asphalt.
Response 5:Thank you for pointing this out. I agree with this comment. So I need to explain that bitumen is a mixture of hydrocarbons of different molecular weights and their non-metallic derivatives. So there is not a very definite chemical structure formula, for which I apologize.
Comments 6:write a chemical equation to clear the reaction happen with additives and asphalt.
Response 6: Thank you for pointing this out. I agree with this comment.First of all, I am very sorry for your suggestion, I am not well versed in chemical equations, and secondly, most of the literature on asphalt is only analyzed by infrared spectroscopy to analyze the functional groups in it, and there is very little description of the chemical equations. But I can explain for you the reaction mechanism of peroxide DCP crosslinking EVA, peroxide decomposition at high temperatures to produce free radicals, as an initiator to trigger a number of free radical reactions, so that the polyolefin material to form a crosslinked network structure:
ROOR→2RO·
PH+RO·→P·+ROH
P·+P·→P-P
Silane coupling agents are usually compounds that contain silicon-carbon bonds and can be used to improve adhesion and durability at the interface between organic and inorganic materials. Ethylene vinyl acetate is a commonly used monomer with a double bond and carboxyl structure. The chemical reaction of the silane coupling agent with ethylene vinyl acetate can occur as an addition reaction.
Comments 7:what is the aim of this study?
Response 7:Thank you for pointing this out. I agree with this comment. Simple desulfurization rubber powder modified asphalt there is a lack of high temperature performance, generally used with other modifiers composite modification, but the commonly used SBS modifier is expensive, so the relatively inexpensive EVA composite modification, but high dosage of desulfurization rubber powder and EVA prepared composite modified asphalt will also exist in the problem of poor storage stability. Considering, this study is to improve the performance and storage stability of desulfurization powder/EVA composite modified asphalt as a starting point, to explore the effect of different additives on the conventional physical properties and rheological properties of modified asphalt, through orthogonal tests to get the optimal ratio, in order to improve the service life of the asphalt and the performance of the use of asphalt, so as to achieve the sustainable use of resources. Because, if only simply add a high dosage of rubber powder, without considering the performance and storage stability of modified asphalt, then in the subsequent use, the road performance will be greatly reduced, can not be effectively used as highway asphalt.
Reviewer 3 Report
Comments and Suggestions for AuthorsThis research aims to study the modification effect of different additives on asphalt. By conducting rheological tests, fatigue and high-temperature resistance of composite modified asphalts were explored, while the reaction mechanism and microscopic properties corresponding binders were investigated by infrared spectroscopy experiments (FTIR) and fluorescence microscopy (FM). However, the study is not very novel, as there is a wealth of literature about the desulfurized crumb rubber, and there are still some issues with the manuscript. Please see my comments on the paper:
1- Authors must clearly explain the basis for the selection of four specific additives??? how to measure the interaction between each of these modifiers with matrix asphalt??
2- According to Tables 5, on what basis authors chose these specific values for each additive? And in Table 6, why the combinations of additives were considered only for specific values??
3- According to section 2.2.2, the procedure for sample preparation is very complicated and lengthy, which may cause aging during mixing, how can authors justify that???
4- In line 155-157, how could authors assess viscoelastic properties without performing frequency sweep test and master curve construction???? Please modify the sentence or justify how viscoelastic properties were influenced???
5- Description of LAS test in line 164-165 and 166-167 are the same. Please delete the repetitive sentence.
6- What aging condition was exactly considered in LAS test in this study??
7- In Section 3, the title should be modified. Change it to “results and discussions”.
8- In Figure 3, an appropriate color and pattern must be chosen instead of colorful columns for presenting your results in a scientific journal. In addition, comparisons of these physical properties bring a question in reviewers’ mind what is the importance of all these additives combinations??
9- In line 364, how did author measure the addition of FEO changing the 363
four-component ratio? And how that help rubber powder and EVA to effectively dissolved in the asphalt??
10- The collected data was not well-organized due to lack of in-depth analysis for each part of data sets and no scientific and statistical analysis was observed.
Comments for author File: 
Comments.pdf
Moderate editing of English language required
Author Response
Comments 1:Authors must clearly explain the basis for the selection of four specific additives??? how to measure the interaction between each of these modifiers with matrix asphalt??
Response 1:Thank you for pointing this out. I agree with this comment. That's why I have explained in the material description section of the text, lines 84-106, as to why I chose the four additives. As for your reference to how the interaction between each modifier and the matrix asphalt was measured. I am sorry that it is not described in the text, probably because both about the desulfurization rubber powder and EVA, most of them are compound modification of asphalt with other modifiers, and the performance of single-doped asphalt is not not very good, so in the text, only the conventional performance of the base composite modified asphalt prepared in the Institute is described. At the same time, high dosage of desulfurization rubber powder and EVA composite modified asphalt research is less, so the study is based on this, in order to improve the physical properties of composite modified asphalt and storage stability for the purpose of adding additives. For the mutual reaction between each additive and asphalt, firstly through the reaction mechanism of each additive, which needs to be supported by research and knowledge, and secondly, the polar analysis was used in this study to determine the degree of influence of each additive, and based on the physical property data to synthesize the analysis.
Comments 2:According to Tables 5, on what basis authors chose these specific values for each additive? And in Table 6, why the combinations of additives were considered only for specific values??
Response 2:Thank you for pointing this out. I agree with this comment. Therefore, I would like to make the following explanation for your question: the ratio of each additive is a similar value obtained through a large number of preliminary experiments and related research, and then the experiment is conducted through the controlled variable method to roughly determine the corresponding dosage range. Through the orthogonal test method, four kinds of additives, each kind of additive three levels, that is, three different dosages, so as to arrive at the different ratios of different experimental groups.
Comments 3: According to section 2.2.2, the procedure for sample preparation is very complicated and lengthy, which may cause aging during mixing, how can authors justify that???
Response 3:Thank you for pointing this out. I agree with this comment. Therefore, for your mention of whether the preparation process is too cumbersome, resulting in asphalt aging to explain the explanation: this study exactly considering the asphalt in the preparation process will exist in the aging of the situation, there are studies have shown that in the asphalt aging, the original colloidal structure is destroyed. The main manifestation is a decrease in the light component content and an increase in the asphaltene content. The decrease in saturated fraction is due to a combination of thermal volatilization and oxidized poly-synthetic resins or asphaltenes. Therefore, considering this situation, FEO was added at the beginning of the preparation, and the added FEO can provide these missing lightweight components and reduce the performance effects caused by aging during the preparation process, while this study concluded that the preparation process is about 1.5h, and most of the current modified asphalt preparation process is mostly 1h or more than 1h. The aging present in the preparation process may be less.
Comments 4:In line 155-157, how could authors assess viscoelastic properties without performing frequency sweep test and master curve construction???? Please modify the sentence or justify how viscoelastic properties were influenced???
Response 4:Thank you for pointing this out. I agree with this comment. Frequency scanning experiments are primarily the primary test method for measuring the viscoelastic mechanical response of asphalt lines, and the focus of this study was to address the storage stability of DR/EVACMA. This is indicated in Fig. 3f, and I am deeply sorry for your suggestion that only TS, LAS, and MSCR were done in this study.The TS experiment was done mainly to judge the rutting resistance of prepared modified asphalt at medium and high temperatures, and for the analysis of the complex modulus and the phase angle, it was also to study the relationship between them and the temperature, and to judge the temperature sensitivity and rheological properties of asphalt with different additives.
Comments 5:Description of LAS test in line 164-165 and 166-167 are the same. Please delete the repetitive sentence.
Response 5:Thank you for pointing this out. I agree with this comment. Therefore, the sentence in lines 168-177 about the same description of the LAS test has been deleted.
Comments 6:What aging condition was exactly considered in LAS test in this study??
Response 6:Thank you for pointing this out. I agree with this comment. Therefore, for asphalt in LAS experiments there may be high temperature aging, oxidative aging, hot air aging, and UV aging. For oxidative aging and UV aging, this study took the asphalt samples after RTOFT to be completely wrapped with smooth surface paper and stored in a cool box at room temperature.
Comments 7: In Section 3, the title should be modified. Change it to “results and discussions”.
Response 7:Thank you for pointing this out. I agree with this comment. I would therefore change the title of section III to "Results and discussion".
Comments 8:In Figure 3, an appropriate color and pattern must be chosen instead of colorful columns for presenting your results in a scientific journal. In addition, comparisons of these physical properties bring a question in reviewers’ mind what is the importance of all these additives combinations??
Response 8:Thank you for pointing this out. I agree with this comment. Therefore, I have redrawn and modified the image in Figure 3, revising the pattern and color palette in order to present the results in a scientific journal. Also, in response to your comment about the importance of these additive combinations, I have added a note in the main text that corresponds to your comment on the first note. It is on lines 84-106 of the main text.
Comments 9:In line 364, how did author measure the addition of FEO changing the 363
four-component ratio? And how that help rubber powder and EVA to effectively dissolved in the asphalt??
Response 9:Thank you for pointing this out. I agree with this comment. Therefore, for the FEO addition how to measure measure the proportion of the four components in the asphalt to explain: first of all, FEO as a kind of high aromatic substance, the composition structure is similar to asphalt, so the two do not have a chemical reaction. This study through a large number of experiments to determine the modified asphalt prepared in this study in the proportion of FEO between 2.8%-3.4%, in this proportion of asphalt will not exist in the light component of too much or not enough. At the same time, FEO can adjust the ratio of saturates (S), aromatics (A), resins (R) and asphaltenes (As) in asphalt, thus improving the low temperature plasticity of asphalt. If you add a small amount of modifier, then the asphalt itself, the light component is enough to make the modifier in the asphalt soluble, too much modifier will lead to asphalt light component missing, colloidal equilibrium state is broken, this time to join the FEO can make up for the missing light component, restored to the colloidal equilibrium state, to avoid insufficient solubilization of modifier, agglomeration of the situation.
Comments 10:The collected data was not well-organized due to lack of in-depth analysis for each part of data sets and no scientific and statistical analysis was observed.
Response 10:Thank you for pointing this out. I agree with this comment. Once again, thank you very much for being able to make such valuable suggestions about the article. In this paper, firstly, additive free asphalt (20% DRP + 4% EVA) was prepared and used as a control group along with matrix asphalt. In fact, orthogonal tests were conducted for the four additives to prepare the composite modified asphalt DR/EVACMA, and the optimum ratio was obtained by combining the results of the conventional physical properties with the analysis of extreme variance for a summary analysis. (Note: the most important thing for the selection of the optimal ratio is the excellent storage stability) After that, rheological experiments (temperature scanning, LAS, MSCR) and microscopic experiments (FTIR and FM) were carried out for further analysis. Thank you for your comments, for this reason I have fully absorbed your suggestions to analyze the data more scientifically and to make the collected data better organized, the specific modifications are marked in the text. Finally, thank you once again a million times for your valuable comments.Meanwhile, I apologize for the problem of statistics, because the orthogonal test used, with four factors and three levels, does not have error columns, which does not result in an ANOVA, and by repeating the experiment I have verified that all four factors present significance, which ensures the credibility of the experiment.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe 5th comment: but I cannot find any modifications in the corresponding text.
The 6th comment: you must be kidding me, you agree with me, but you keep the 400000. Be serious, please.
Author Response
Comment 1: Comment 5: But I can't find any changes in the corresponding text.
Response 1: Thank you for pointing this out. I agree with this comment. I have therefore changed lines 88-90 of the text.
Comment 2: Comment 6: You must be kidding, you agree with me, but you kept the 400000!
Response 2: Thank you for pointing this out. I have therefore labeled Figure 10, changed the microscope magnification to 400, and revised lines 224-225.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors revised the manuscripts precisely. Thus, the current version of this paper can be accepted for publication.
Author Response
非常感谢您对本文的宝贵意见，非常感谢！
