Comparison of the Properties of Coal Gasification Fly Ash and Pulverized Coal Fly Ash as Supplementary Cementitious Materials
Round 1
Reviewer 1 Report
please revise the manuscript according to review's comments
Comments for author File: 
Comments.pdf
please revise the manuscript according to review's comments
Author Response
Dear reviewer,
First, we would like to thank you for the positive and constructive comments and suggestions. We have studied the valuable comments carefully, and tried our best to revise the manuscript. The point to point responds are listed as following:
Comment 1: In the results and discussion section, more references should be cited.
Response 1: According to the reviewer’s comment, we have added the references in the revised manuscript, such as [25], [26].
Comment 2: In the section of Materials and Methods, the description of some measuring methods is too simple. Please provide the detailed description.
Response 2: According to the reviewer’s comment, we have provide the detailed description in the revised manuscript. The modification section is shown in red.
Comment 3: As a supplementary cementitious materials, the specific surface area is an important performance, as it affects the adsorption of mixed water, thereby affecting the fluidity of mortar. The author should provide the specific surface area of coal gasification fly ash and pulverized coal fly ash, and combine the specific surface area analysis of the fluidity experimental results in the section of results and discussion.
Response 3: Thank you for your instructive suggestions. We have added the specific surface areas of PCFA, CGFA and UFCGFA in the table 2. Discussion of the possible effects of differences in specific surface area on fluidity has been added in the revised manuscript. The modification section is shown in red.
Comment 4: In the section of Conclusion, the author should point out the novelties and the significance of this study.
Response 4: Thank you for your instructive suggestions. According to your helpful advice, we have rewritten this part. Modify as follows: The properties of PCFA and CGFA as SCMs are compared in this paper. The main conclusions are as follows: PCFA has a positive effect on the fluidity of cement mortar, while CGFA has a negative effect on cement mortar.(1) In the scope of this study, PCFA can improve the fluidity of cement mortar after replacing cement. It has a positive effect on the cement mortar when the replacement cement content of CGFA is less than 10%. However, when the amount of cement replaced by CGFA exceeds 10%, the fluidity of cement mortar is negatively affected. (2)The compressive strength of CGFA-cement mortar is higher than that of PCFA-cement mortar when they have the same replacement amount. The XRD pattern of the hydration product shows that the consumption of CH in the CGFA-cement mortar is faster. Compressive strength and XRD results show that CGFA has higher pozzolanic activity than PCFA. (3)Ultra-fine treatment of CGFA can not only greatly improve the pozzolanic activity, but also eliminate the negative impact on the fluidity of cement mortar. (4)This study is beneficial to the application of CGFA as a SCM in cementitious materials, especially for the application of coal gasification slag instead of fly ash.
Comment 5: The horizontal coordinate fonts of the two figures in Figure 8 are inconsistent, and the author needs to modify them to be consistent.
Response 5: We are sorry for this mistake. We redrew Figure 8 in the revised manuscript.
Comment 6: The format of references is very messy, some page no is missing. Some references are out-of-dated. It should be updated according to reviewer’s comments.
Response 6: Thank you for your valuable and thoughtful comments. We are very sorry for our clerical error. We have corrected this error in the revised manuscript.
Reviewer 2 Report
Reviewer #1:
In the article titled “Comparison of the Properties of Coal Gasification Fly Ash (CGFA) and Pulverized Coal Fly Ash (PCFA) as Supplementary Cementitious Materials”, the author conducted research on the incorporation of CGFA and PCFA as replacement of cement in cement mortar. After a careful review of the article, I have found that the article covers the effect of the addition of CGFA and PCFA on the physical properties i.e., fluidity and compressive strength of cement mortar. The author also includes the research on comparison of CGFA and ultrafine CGFA on the strength of mortar. Apart from this, authors studied the effect of additives on the microstructure of cement mortar by conducting XRD and SEM analysis after 3 days, 28 days, and 90 days of hydration. Overall, the quality of the article was found to be moderate for any scientific journal. Therefore, this article should go for major changes.
Considering these major issues and the specific comments outlined below:
1. The title of the article presents a significant outline of the paper in which the author covers the influence of CGFA and PCFA on properties like fluidity and compressive strength of cement mortar.
2. The abstract is technically written and covers the introduction and novelty of the study along with a conclusion of the research. But there is no need to write hereafter in lines 10 and 11 in brackets just write (CGFA) and (PCFA). Similar in line 16 and line 19.
3. Kindly write a full form of XRD and SEM initially in the abstract then use the short form.
4. Keywords should be changed. Keywords should not include words directly from the title.
5. In line 31 kindly remove space in word grinding.
6. Table 1 and Table are not mentioned in the text.
7. Kindly check LoII? Table 1
8. Figure 2. PCFA….is not clear in the image. Please use white font
9. In the introduction kindly incorporate literature on the usage of fly ash as a full replacement of cement in cement mortar or cement concrete. For this kindly go through the papers on GPC i.e.
10. XRD and SEM images are not clear, kindly add images with good-quality pixels.
11. Line 129 size of the mold should be written as 40mm * 40mm * 160mm. Kindly check the units in Table 3.
12. Results and Discussion: Fluidity- Kindly draw the line graph or bar graph to present the change in trend due to the incorporation of PCFA and CGFA.
13. Fig. 4 Graph is not clear. Kindly draw one graph providing a change in strength for all curing days.
14. XRD Analysis- Clarity of Figure 5 is also required. Kindly explain the cause of the formation of Ca(OH)2, Elite, Belite, Quartz, and Mullite Peaks in the XRD results.
15. Error bars should be drawn in Figure 7 and Figure 8 to support the results of this research study.
16. Figure 9 is not clear and the explanation of section 3.2.3 must be improved.
17. The Conclusion section needs to be modified. The main findings must be explained in this section. General observation points are not to be included in this section.
Author Response
Dear reviewer,
First, we would like to thank you for the positive and constructive comments and suggestions. We have studied the valuable comments carefully, and tried our best to revise the manuscript. The point to point responds are listed as following:
Comment 1: The title of the article presents a significant outline of the paper in which the author covers the influence of CGFA and PCFA on properties like fluidity and compressive strength of cement mortar.
Response 1: Thank you for your careful reading of our manuscript.
Comment 2: The abstract is technically written and covers the introduction and novelty of the study along with a conclusion of the research. But there is no need to write hereafter in lines 10 and 11 in brackets just write (CGFA) and (PCFA). Similar in line 16 and line 19.
Response 2: Thank you for your instructive comments. We have deleted the hereafter word in the revised manuscript.
Comment 3: Kindly write a full form of XRD and SEM initially in the abstract then use the short form.
Response 3: Thank you for your careful reading of our manuscript. We have provided a full form of XRD and SEM initially in the abstract.
Comment 4: Keywords should be changed. Keywords should not include words directly from the title.
Response 4: Thank you for your instructive comments. We have change the Key words in the revised manuscript.
Comment 5: In line 31 kindly remove space in word grinding.
Response 5: Thank you for your valuable and thoughtful comments. We are very sorry for our clerical error. We have corrected this error in the revised manuscript.
Comment 6: Table 1 and Table are not mentioned in the text.
Response 6: We are sorry for this mistake. Table 1 provide the compositions of original materials, and we have added the description of compositions in the revised manuscript. According to the results, SiO2, Al2O3, CaO, Fe2O3 are the main components of both two fly ash. The content of CaO in CGFA is higher than that in PCFA.
Comment 7: Kindly check LoII? Table 1
Response 7: We are sorry for this mistake. We have corrected this mistake according to your comment.
Comment 8: Figure 2. PCFA….is not clear in the image. Please use white font
Response 8: Thank you for your valuable and thoughtful comments. According to your helpful advice, we have changed the color of the font.
Comment 9: In the introduction kindly incorporate literature on the usage of fly ash as a full replacement of cement in cement mortar or cement concrete. For this kindly go through the papers on GPC i.e.
Response 9: Thank you for your instructive suggestions. We have added the literature in the revised manuscript.
Comment 10: XRD and SEM images are not clear, kindly add images with good-quality pixels.
Response 10: Thank you for your valuable and thoughtful comments. We increased the resolution of the picture from 300 dpi to 600 dpi, thus improving the quality of the picture.
Comment 11: Line 129 size of the mold should be written as 40mm * 40mm * 160mm. Kindly check the units in Table 3.
Response 11: We are sorry for this mistake. We have corrected this mistake according to your comment.
Comment 12: Results and Discussion: Fluidity- Kindly draw the line graph or bar graph to present the change in trend due to the incorporation of PCFA and CGFA.
Response 12: Thank you for your valuable and thoughtful comments. According to your helpful advice, we have redrew the bar graph in the revised manuscript.
Comment 13: Fig. 4 Graph is not clear. Kindly draw one graph providing a change in strength for all curing days
Response 13: Thank you for your valuable and thoughtful comments. According to your helpful advice, we have redrew the graph in the revised manuscript.
Comment 14: XRD Analysis- Clarity of Figure 5 is also required. Kindly explain the cause of the formation of Ca(OH)2, Elite, Belite, Quartz, and Mullite Peaks in the XRD results.
Response 14: Thank you for your instructive suggestions. We have added this part in the revised manuscript. Alite and belite are due to the presence of un-hydrated cement particles, and CH is the main hydration product of cement. Quartz is from the cement clinker.
Comment 15: Error bars should be drawn in Figure 7 and Figure 8 to support the results of this research study.
Response 15: Thank you for your instructive suggestions. The data listed in the paper are averages of multiple experiments. The fluidity experiment data were carried out five times, and the experimental results were averaged. If there is a value that is more or less than 10% from the average, this value is removed and the remaining 4 numbers are averaged. The compressive strength experimental data were tested for 6 times, and the experimental results were averaged. The compressive strength experimental data were tested for 6 times, and the experimental results were averaged. If there is a value that is more or less than 10% from the average, this value is removed and the remaining 5 numbers are averaged. Therefore, we use this method to ensure the accuracy of the data.
Comment 16: Figure 9 is not clear and the explanation of section 3.2.3 must be improved.
Response 16: Thank you for your valuable and thoughtful comments. According to your helpful advice, we have redrawn Figure 9 and section 3.2.3 was rewrite in the revised manuscript.
Comment 17: The Conclusion section needs to be modified. The main findings must be explained in this section. General observation points are not to be included in this section.
Response 17: Thank you for your instructive suggestions. We have rewrite the Conclusion section in the revised manuscript.
Reviewer 3 Report
The manuscript reports on the use of pulverized coal fly ash, coal gasification fly ash and ultra-fine CGFA as a SCM replace the cement and increased the mechanical strength with high pozzolanic activity by decreasing the CH content. The authors compared this three SCMs and suggest the ultra-fine CGFA may be feasible to produce cost-effective cement mortar and reduce the negative effect to fluidity. However, there are some issues in the manuscript which require re-modification and clarification, etc.
1. Table 2. Physical properties of decarbonized CGA and CGS. What is CGA and CGS ? Please explain.
2. Line 147 “212 mm” and line 151 “180mm” , Please leave a space before the unit. Many small English errors, and some parts are difficult to follow. Recheck of whole manuscript in detail is a must. Author NEED a RECHECK from an English professional, especially for the introduction part.
3. The fluidity of cement mortar was increased with the replacement of PCFA but decreased significantly with 30% and 50% CGFA , the author give the reason to the particle shape, particle size and specific surface. At least, the author should provide a particles distribution about the raw cement in Table 2. Otherwise, it's hard to believe that the difference result in fluidity.
4. The pozzolanic activity of CGFA and UFCGFA should be the innovation in this study, but the author does not describe the inner mechanism of pozzolanic activity, including the particles distribution of the hardened mortar and the hydrates based on TG/DSC analysis.
5. The error bars of fluidity and compressive strength should be list in Figures. Please add accordingly.
6. Line 214, “For PCFA samples, there is no CH diffraction peak in the samples with only 50% replacement rate” may be a mistake. CH diffraction peak can be observed in Fig.5 (90d). Please check.
7. Fig.4 and Fig.8 may be the screenshot and the authors should ensure the resolution of the figures in the article. Furthermore, the layout of chart and Figures need to be adjusted in the center.
8. The conclusions are too short and many of them are only a description for the result.
Author NEED a RECHECK from an English professional, especially for the introduction part.
Author Response
Dear reviewer,
First, we would like to thank you for the positive and constructive comments and suggestions. We have studied the valuable comments carefully, and tried our best to revise the manuscript. The point to point responds are listed as following:
Comment 1: Table 2. Physical properties of decarbonized CGA and CGS. What is CGA and CGS ? Please explain.
Response 1: Thank you for your careful reading of our manuscript. We are very sorry for our clerical error. We have modified decarbonized CGA and CGS to CGFA and PCFA.
Comment 2: Line 147 “212 mm” and line 151 “180mm” , Please leave a space before the unit. Many small English errors, and some parts are difficult to follow. Recheck of whole manuscript in detail is a must. Author NEED a RECHECK from an English professional, especially for the introduction part.
Response 2: Thank you for your instructive comments. We have checked the English in the revised manuscript.
Comment 3: The fluidity of cement mortar was increased with the replacement of PCFA but decreased significantly with 30% and 50% CGFA , the author give the reason to the particle shape, particle size and specific surface. At least, the author should provide a particles distribution about the raw cement in Table 2. Otherwise, it's hard to believe that the difference result in fluidity.
Response 3: Thank you for your careful reading of our manuscript. We have provided a particle distribution about the raw cement in Table 2.
Comment 4: The pozzolanic activity of CGFA and UFCGFA should be the innovation in this study, but the author does not describe the inner mechanism of pozzolanic activity, including the particles distribution of the hardened mortar and the hydrates based on TG/DSC analysis.
Response 4: Thank you for your instructive comments. We have added the thermogravimetric analysis of the hydration products at 3 and 28 days of curing time in the revised manuscript.
Comment 5: The error bars of fluidity and compressive strength should be list in Figures. Please add accordingly.
Response 5: The data listed in the paper are averages of multiple experiments. The fluidity experiment data were carried out five times, and the experimental results were averaged. If there is a value that is more or less than 10% from the average, this value is removed and the remaining 4 numbers are averaged. The compressive strength experimental data were tested for 6 times, and the experimental results were averaged. The compressive strength experimental data were tested for 6 times, and the experimental results were averaged. If there is a value that is more or less than 10% from the average, this value is removed and the remaining 5 numbers are averaged. Therefore, we use this method to ensure the accuracy of the data.
Comment 6: Line 214, “For PCFA samples, there is no CH diffraction peak in the samples with only 50% replacement rate” may be a mistake. CH diffraction peak can be observed in Fig.5 (90d). Please check.
Response 6: We are sorry for this mistake. After careful observation, for samples, CH diffraction peaks exist in all three PCFA samples. For PCFA samples, CH diffraction peak existed in all the samples. We have corrected this mistake according to your comment.
Comment 7: Fig.4 and Fig.8 may be the screenshot and the authors should ensure the resolution of the figures in the article. Furthermore, the layout of chart and Figures need to be adjusted in the center.
Response 7: Thank you for your instructive comments. We redrew Fig.4 and Fig.8 in the revised manuscript.
Comment 8: The conclusions are too short and many of them are only a description for the result.
Response 8: Thank you for your valuable and thoughtful comments. According to your helpful advice, we have rewritten the part of conclusion in the revised manuscript.
Round 2
Reviewer 2 Report
Accepted in present form.
Author Response
Thank you again.
Reviewer 3 Report
the previous comments and suggestions have been well revised. And I am Ok with this version. However, the error bars of fluidity and compressive strength have not been listed in the Figures. It's suggested that the authors can learn how to make it. Many tools can make error bar, since it's a basic function.
Author Response
Dear reviewer,
First, we would like to thank you for the positive and constructive comments and suggestions. We have studied the valuable comments carefully, and tried our best to revise the manuscript. We have provided error sticks for Fig.3,Fig.4,Fig.7 and Fig.8.Thank you again.
