Relationship between Alternated Current Impedance Spectrum and Microstructure of Graphene Enhanced Concrete
Round 1
Reviewer 1 Report
The authors reported the relationship between alternated current impedance spectra and microstructure of graphene enhanced concrete. The following issues need to be addressed before further consideration.
The use of graphene for the enhancement of concrete has been well reported in literature. The authors will need to cite the previous work objectively and highlight the novelty of the present work.
The authors indicated that the thickness of the graphene samples is around 2-3 nm. However, from the resolution of the SEM image in Figure 1, it is unlikely to determine the thickness accurately. Other techniques like HRTEM will need to be performed to measure the thickness accurately.
Raman, TGA and XPS measurement will need to be conducted to characterize the graphene sample and graphene/cement nanocomposites.
The statement in lines 173-174 needs to be proved by be confirmed by other literature, not only by reference 13.
The fittings in Figure 12 and Figure 13a need to be improved (to get better fittings).
The english writing can be improved further to facilitate reading
Author Response
The authors reported the relationship between alternated current impedance spectra and microstructure of graphene enhanced concrete. The following issues need to be addressed before further consideration.
The use of graphene for the enhancement of concrete has been well reported in literature. The authors will need to cite the previous work objectively and highlight the novelty of the present work.
Answer: Thank you for your valuable suggestions. We have revised the manuscript according to the reviewer’s advice.
The authors indicated that the thickness of the graphene samples is around 2-3 nm. However, from the resolution of the SEM image in Figure 1, it is unlikely to determine the thickness accurately. Other techniques like HRTEM will need to be performed to measure the thickness accurately.
Answer: Thank you for your advice. It is true that it is impossible to tell the thickness of graphene particles from Figure 1. We know the thickness from the merchant (Jicang Nano Ltd.). We have revised the sentence related. As far as I know, the merchant did the TEM test for their products and provide the product certificate showing the TEM pictures and the thickness of the graphene particles.
Raman, TGA and XPS measurement will need to be conducted to characterize the graphene sample and graphene/cement nanocomposites.
Answer: Thank you for your advice. At present we use the BSE-SEM to find the graphene particles during SEM test. We use BSE to find out the graphene by calculating the relative molecular mass.
The statement in lines 173-174 needs to be proved by be confirmed by other literature, not only by reference 13.
Answer: Thank you for your advice. We have revised the manuscript according to the reviewer’s advice, more references have been added.
The fittings in Figure 12 and Figure 13a need to be improved (to get better fittings).
Answer: Thank you for your advice. We have revised the figures according to the reviewer’s advice. Figure 12 and Figure 13a have been redrawn.
Reviewer 2 Report
In this manuscript, the authors present the possibility to use current (AC) impedance spectrum test to evaluate the porosity of concrete containing graphene. Herein, a few comments need to be addressed before the acceptance of publication.
Abstract:
The author needs to enhance the results section by including microstructure results and concrete porosity to ensure alignment with the title.
Introduction:
Line 27. The word “ a good strength” should be changed to ‘ a good compressive strength”. This is because concrete is a weak in tension and a good in compression.
The literature in the introduction is not enough and did noy well show the gap. So that a few references must be added.
Materials and testing methods:
Line 81 “0.3 mm” . Please double check.
Table 1. what is the specific name of graphene? how do you find specific area of graphene. Please mention.
Please mention the standard that u follow in section 2.2
Line 91. The word “doped” Is it forml? Please check.
Line 105-107 add references.
Line 107- 108 you mentioned that the size of (40mm×40mm×160mm) was sued for compressive strength. Normally, this size was used for flexural strength. Please check and prove it with reference.
Section 2.3 . Can u give more information about this test in order to be easily for the reader
Section 2.4 write the full name of “MIP”. Also highlight the References that you follow.
Results:
Section 3.2 :
line 207-210 any test to validate this sentence?
Line210-212. This is not correct because u have already mentioned that the G8 possess the highest strength. Please check
Section 3.3
Line 217. why only these samples (N, G1, G2 and G4 ) were chosen.
Line 223 in MIP test, G4 is the best, while G8 is the best in term of strength. Is there any interpret or explanation?
Figure 7. it is not clear. Why G2 decreased strength.
Line 231-233. Please rewrite these sentences.
Why u have used only G32 for SEM test?
Figure 9 is it enough to adopt 1 micro scale to see the nano graphene particles?
Line 274. Please check the superscript
Line 311 please check this sentence
it is ok.
Author Response
In this manuscript, the authors present the possibility to use current (AC) impedance spectrum test to evaluate the porosity of concrete containing graphene. Herein, a few comments need to be addressed before the acceptance of publication.
Abstract:
The author needs to enhance the results section by including microstructure results and concrete porosity to ensure alignment with the title.
Answer: Thank you for your valuable suggestions. We have revised the conclusion part by adding microstructure results.
Introduction:
Line 27. The word “ a good strength” should be changed to ‘ a good compressive strength”. This is because concrete is a weak in tension and a good in compression.
Answer: Thank you for your valuable suggestions. We have revised it in the paper.
The literature in the introduction is not enough and did noy well show the gap. So that a few references must be added.
Answer: Thank you for your advice. We have added more references.
Materials and testing methods:
Line 81 “0.3 mm” . Please double check.
Answer: Thank you for your valuable suggestions. The meaning expressed in the manuscript is that a 0.3 mm screen removes the natural sand greater than 0.3 mm.
Table 1. what is the specific name of graphene? how do you find specific area of graphene. Please mention.
Answer: Thank you for your valuable suggestions. We know the thickness from the merchant (Jicang Nano Ltd.) that provided the product certificate. We have revised the sentence related.
Please mention the standard that u follow in section 2.2
Answer: Thank you for your valuable suggestion, the standard has been cited in the reference.
Line 91. The word “doped” Is it forml? Please check.
Answer: Thank you for your valuable suggestion, I have amended the paper to read 'Graphene was incorporated into the mortar in 6 different dosage groups '
Line 105-107 add references.
Answer: Thank you for your valuable suggestions, we have added two papers in the manuscript.
Line 107- 108 you mentioned that the size of (40mm×40mm×160mm) was sued for compressive strength. Normally, this size was used for flexural strength. Please check and prove it with reference.
Answer: Thank you for your valuable suggestion, it was an error in the paper, we intended 40mm x 40mm x 160mm for flexural test and 40mm x 40mm x 40mm for compressive test. I have changed it to 40mm x 40mm x 40mm both in the diagram and in the paper.
Section 2.3. Can u give more information about this test in order to be easily for the reader
Answer: Thanks to your valuable suggestions, we have reorganized the wording of Section 2.3 and added several documents.
Section 2.4 Write the full name of “MIP”. Also highlight the References that you follow.
Answer: Thank you for your valuable suggestion, we have provided the full name of the MIP.
Results:
Section 3.2 :
line 207-210 any test to validate this sentence?
Answer: Thank you for your valuable suggestion. There is no test to validate, therefore, we add one reference to support this and the sentence use a word “may” to show this is a possibility when nano-particles were used in cementitious composites.
Line210-212. This is not correct because u have already mentioned that the G8 possess the highest strength. Please check
Answer: Thank you for your valuable suggestion. It is because the graphene particles occupying too much water with the assistant of surfactant, which reduces the effective water–cement ratio, resulting in strength improvement. This probably explains that G8 has the highest compressive strength. However, G16 and G32 have lower strengths. It was found during casting the samples that G16 and G32 were hard to mix evenly.
Section 3.3
Line 217. why only these samples (N, G1, G2 and G4 ) were chosen.
Answer: According to the testing phenomenon, when the content of Graphene exceeds 0.8%, the workability of the cement-based composite is seriously affected, and even it is difficult to mix evenly. Although the strength of concrete with the content of Graphene of 0.8% is the highest, this improvement does not due to the strengthening effect of nano particles on cement hydration products. It is because the graphene particles occupying too much water with the assistant of surfactant, which reduces the effective water–cement ratio, resulting in strength improvement. In addition, the dosage higher than 0.8% means the concrete have a price much higher than normal, so as to make the concrete lost the practical or research value. Therefore, in this study, we pay more attention on the samples with a lower dosage of graphene.
Line 223 in MIP test, G4 is the best, while G8 is the best in term of strength. Is there any interpret or explanation?
Answer: Thank you for your valuable suggestion. the dosage higher than 0.8% means the concrete have a price much higher than normal, so as to make the concrete lost the practical or research value. Therefore, in this study, we pay more attention on the samples with a lower dosage of graphene.
Figure 7. it is not clear. Why G2 decreased strength.
Answer: The incorporation of graphene is conducive to improving the cementitious material's microstructure and thereby improving its strength. However, when the amount of graphene is as high as 0.2%, there may be nanoparticle agglomeration, resulting in an increase in the microporous size of cementitious materials, which leads to a deterioration of its mechanical properties (Chintalapudi & Pannem, 2020).
Line 231-233. Please rewrite these sentences.
Answer: Thank you for your valuable suggestion. The sentences were rewritten.
Why u have used only G32 for SEM test?
Answer: It is because G32 has more graphene nano particles and it is easy to find out.
Figure 9 is it enough to adopt 1 micro scale to see the nano graphene particles?
Answer: the graphene nano particle has a size around 5-15 um according to the products certification. From Figure 9, the size of the graphene nano particles are coincide with the certification. Therefore, it is
Line 274. Please check the superscript
Answer: Thank you for your valuable suggestion. The superscript has been checked.
Line 311 please check this sentence
Answer: Thank you for your valuable suggestion. The sentences were rewritten.
Reviewer 3 Report
In general the paper highlights on collecting the AC impedance spectroscopy of cement matrix composites with different graphene dosages and comparing the Nyquist plots, Bode plots, and Phase angle diagrams. And then, the influence of different graphene dosages on the impedance spectrum of cementitious matrix composites is summarized and analyzed. Based on an appropriate equivalent circuit, parameters can be obtained by fitting the Nyquist diagram. Combined with the pore structure distribution obtained with mercury intrusion porosimetry (MIP) experiments, the relationships between the content of pores of specific sizes and the parameters of the fitted electrical parameters are established. Furthermore, the effects of different dosages of graphene on the pore structure and electrical properties of cement matrix composites are analyzed, laying a foundation for predicting the properties of graphene-enhanced cementitious composites. The paper could be considered to be accepted with some suggestions for improvement as follows:
Abstract:
The novelty of study on the prediction of the properties of graphene-enhanced cementitious composites should be highlighted
Introduction:
Detail literature review supported with current references should be provided in relation to support the background of the study as follows:
(a) Properties of different carbon-based filler on the cementitious composites
(b) Effect on pore structure distribution obtained from different nondestructive characterization techniques on the cementitious composites
(c) Effect of hydration and reaction rate on pore size and its homogeneity in cementitious composites
Results and discussion
Details of technical discussion supported with current and related references should be provided for the following points:
(a) Effect of In-plane diameter, thickness, density, and specific surface area of graphene on the distribution and interface in cementitious composites
(b) Effect on the composition of graphene on the hydration of cementitious composites
(c) Effect of hydration rate on the conductivity and polarization effect of the cementitious composites
Conclusion
The conclusion part should be re-written in line with the objective of the study
Author Response
In general the paper highlights on collecting the AC impedance spectroscopy of cement matrix composites with different graphene dosages and comparing the Nyquist plots, Bode plots, and Phase angle diagrams. And then, the influence of different graphene dosages on the impedance spectrum of cementitious matrix composites is summarized and analyzed. Based on an appropriate equivalent circuit, parameters can be obtained by fitting the Nyquist diagram. Combined with the pore structure distribution obtained with mercury intrusion porosimetry (MIP) experiments, the relationships between the content of pores of specific sizes and the parameters of the fitted electrical parameters are established. Furthermore, the effects of different dosages of graphene on the pore structure and electrical properties of cement matrix composites are analyzed, laying a foundation for predicting the properties of graphene-enhanced cementitious composites. The paper could be considered to be accepted with some suggestions for improvement as follows:
Abstract:
The novelty of study on the prediction of the properties of graphene-enhanced cementitious composites should be highlighted
Answer: Thank you for your valuable suggestions. We have revised it in the introduction.
Introduction:
Detail literature review supported with current references should be provided in relation to support the background of the study as follows:
(a) Properties of different carbon-based filler on the cementitious composites
(b) Effect on pore structure distribution obtained from different nondestructive characterization techniques on the cementitious composites
(c) Effect of hydration and reaction rate on pore size and its homogeneity in cementitious composites
Answer: Thank you for your valuable suggestions. We have revised it in the introduction and add some references. The related part has been revised according to the reviewer’s suggestion.
Results and discussion
Details of technical discussion supported with current and related references should be provided for the following points:
(a) Effect of In-plane diameter, thickness, density, and specific surface area of graphene on the distribution and interface in cementitious composites
Answer: Thank you for your valuable suggestions. The related part has been revised according to the reviewer’s suggestion and some references has been added.
(b) Effect on the composition of graphene on the hydration of cementitious composites
Answer: Thank you for your valuable suggestions. The related part has been revised according to the reviewer’s suggestion.
(c) Effect of hydration rate on the conductivity and polarization effect of the cementitious composites
Answer: Thank you for your valuable suggestions. The related part has been revised according to the reviewer’s suggestion.
Conclusion
The conclusion part should be re-written in line with the objective of the study
Answer: Thank you for your valuable suggestions. The conclusion has been revised according to the reviewer’s suggestion.
Reviewer 4 Report
Summary
This paper has studied alternating current (AC) impedance spectrum of graphene doped cement matrix composites with different dosage amounts. Mechanical study, stress, pore structures were also studied along with the electrical properties. Although author provide some interesting correlation between the graphene dosage and electric properties and mechanical properties, some points need to be addressed before publishing.
1) Explain what C-S-H represents and how formation of that will lead to increase cement strength.
2) Previously many Graphene doped cement composite been studied. Explain in detail how this study is different than previous study.
3) Author mentioned to facilitate the dispersion of graphene a polycarboxylate superplasticizer is used. Explain how superplasticizer help disperse chemically?
4) Provide some experimental details about the MIP tests.
5) AC independence were done for 3 specimens for each sample. Why does the three plots are very different. For example, figure 3 Nyquist plot sample G32-1 and G32-3 are very different. Same with the other samples. Provide standard deviation of these results?
6) Need better explanation of the trend of Nyquist and Bode plot. Why does these show this kind of behavior?
7) The explanation for the compressive strength between G1- G4 is not very clear. Author mentioned in G2 the lowest strength is due to close distance between the small holes. Why this happens for particularly this sample?
8) Why does the pore size change with different graphene dope concentration? What are the factors that contribute to the pore size. For example, Does chemical bond at different concentration play any role.
9) Need a better description of why this study is so important, what is new about these studies and a better conclusion? Also, how this study is useful for making better future concrete composite.
Its alright
Author Response
This paper has studied alternating current (AC) impedance spectrum of graphene doped cement matrix composites with different dosage amounts. Mechanical study, stress, pore structures were also studied along with the electrical properties. Although author provide some interesting correlation between the graphene dosage and electric properties and mechanical properties, some points need to be addressed before publishing.
- Explain what C-S-H represents and how formation of that will lead to increase cement strength.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- Previously many Graphene doped cement composite been studied. Explain in detail how this study is different than previous study.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript
- Author mentioned to facilitate the dispersion of graphene a polycarboxylate superplasticizer is used. Explain how superplasticizer help disperse chemically?
Answer: Thanks for your suggestions, we have revised the related part of the manuscript
4) Provide some experimental details about the MIP tests.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- AC independence were done for 3 specimens for each sample. Why does the three plots are very different. For example, figure 3 Nyquist plot sample G32-1 and G32-3 are very different. Same with the other samples. Provide standard deviation of these results?
Answer: Thanks for your suggestions. For Nyquist plot, we pay more attention to the low frequency part, that is the part close to 0. The curve of the high frequency part has only a few points, this is also a reason that the high frequency part is quite different.
- Need better explanation of the trend of Nyquist and Bode plot. Why does these show this kind of behavior?
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- The explanation for the compressive strength between G1- G4 is not very clear. Author mentioned in G2 the lowest strength is due to close distance between the small holes. Why this happens for particularly this sample?
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- Why does the pore size change with different graphene dope concentration? What are the factors that contribute to the pore size. For example, Does chemical bond at different concentration play any role.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
9) Need a better description of why this study is so important, what is new about these studies and a better conclusion? Also, how this study is useful for making better future concrete composite.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
Reviewer 5 Report
Manuscript sustainability-2444053
The manuscript explores the dependency of electric properties of cement matrix composites depending on their composition. The manuscript features an original research and, in general, fits within the scope of the Sustainability journal. Before publishing of the manuscript, it should be improved. Please refer to the comments below.
GENERAL COMMENTS:
-the manuscript needs extensive language editing; there is a lot of phrases repetitions especially in the results part
-the introduction does not cite relevant references for the statements there
ABSTRACT
-‘MIP’ abbreviation should be introduced also in the abstract
INTRODUCTION
-line 27: reference need (the first sentence
-line 28: reference needed
-how does the addition of graphene reduce the carbon footprint of the cement composite?
-line 33: reference needed
-line 42: reference needed
-line 50: reference needed to support the statement
-line 76: what do the Authors mean by “predicting the properties”? please specify
MATERIALS AND METHODS
-from was the polycarboxylate superplasticizer acquired?
-what water was used to prepare the cement composites and aqueous suspensions?
-‘by ultrasonic dispersing equipment’, do the Authors mean an ultrasound bath? seems so from Figure 2.
-caption of figure 2 should be improved
RESULTS
-lines 131-133 should be removed or edited
-caption of Fig. 3 should be improved; the same for all the other figures, they are not informative or specific
CONCLUSIONS
-conclusion no. 3 is not clear; please rephrase
-what is the relevance of your study for the current research and impact for the environment?
included in the review
Author Response
This paper has studied alternating current (AC) impedance spectrum of graphene doped cement matrix composites with different dosage amounts. Mechanical study, stress, pore structures were also studied along with the electrical properties. Although author provide some interesting correlation between the graphene dosage and electric properties and mechanical properties, some points need to be addressed before publishing.
- Explain what C-S-H represents and how formation of that will lead to increase cement strength.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- Previously many Graphene doped cement composite been studied. Explain in detail how this study is different than previous study.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript
- Author mentioned to facilitate the dispersion of graphene a polycarboxylate superplasticizer is used. Explain how superplasticizer help disperse chemically?
Answer: Thanks for your suggestions, we have revised the related part of the manuscript
4) Provide some experimental details about the MIP tests.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- AC independence were done for 3 specimens for each sample. Why does the three plots are very different. For example, figure 3 Nyquist plot sample G32-1 and G32-3 are very different. Same with the other samples. Provide standard deviation of these results?
Answer: Thanks for your suggestions. For Nyquist plot, we pay more attention to the low frequency part, that is the part close to 0. The curve of the high frequency part has only a few points, this is also a reason that the high frequency part is quite different.
- Need better explanation of the trend of Nyquist and Bode plot. Why does these show this kind of behavior?
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- The explanation for the compressive strength between G1- G4 is not very clear. Author mentioned in G2 the lowest strength is due to close distance between the small holes. Why this happens for particularly this sample?
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
- Why does the pore size change with different graphene dope concentration? What are the factors that contribute to the pore size. For example, Does chemical bond at different concentration play any role.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
9) Need a better description of why this study is so important, what is new about these studies and a better conclusion? Also, how this study is useful for making better future concrete composite.
Answer: Thanks for your suggestions, we have revised the related part of the manuscript.
Round 2
Reviewer 2 Report
the author responce is acceptable.
