Review Reports - Hydrothermally Treated Biomass Fly Ash as an Additive for Portland Cement

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

The work is interesting and specific. The topic is current. However, I would like to point out some suggestions and remarks in your work.

The introduction is too long, it must be shortened and written as concisely as possible.

Pay attention to the terms you use in English, the order of words in a sentence.

Why is it important to us, Three samples (abbreviation S, A and R) with 115 the lowest, highest and average C/S ratio were selected for the investigation?

Did you use a portable XRF or a static one?

I think that testing methods should go after the preparation of the materials and only after the results.

Analyze XRF and XRD in more detail and also explain where these two methods complement each other and in what way.

In Figure 2. Mark the important peaks and explain.

Why exactly 950rpm and 0.08 mm seed?

Explain better the experimental part of sample preparation.

Figure 4. Highlight important peaks.

Table 3. What would happen after 24 hours? or say 48h?

Why did you take a hydrothermal treatment of 2 hours and not more or less?

Your XRD and DSC analyzes are scattered, I think you should have combined them in one place.

Why didn't you do morphology using SEM and surface chemistry using FTIR?

Also better explain the application of your research, compare it with other authors and literature data.

Author Response

Please see the attachment

Author Response File: Author Response.doc

Reviewer 2 Report

Comments and Suggestions for Authors

This paper focused on the possibility of using biomass fly ash as a cement additive after hydrothermal modification. The results show that the synthesised additive accelerated the initial hydration of Portland cement. It is useful to replace some cement without reducing the compressive strength of cement. The study is meaningful and important. But some issues should be addressed at first.

1.The reference entries for Reference 4 and Reference 11 are duplicated. It is recommended that the authors remove one of them to avoid redundancy in the reference list.

2. The citation page numbers for Reference 2 and Reference 4 are incorrect. Please ensure that the page numbers are accurately cited for these references.

3.The introductory paragraph is too lengthy and lacks conciseness. Please consider revising this section to make it more concise and focused.

4.There is a clustering of reference citations on the second page. It is recommended to distribute the citation of references more evenly throughout the manuscript.

5. Table 1:The formatting of Table 1 is not sufficiently standardized, with misaligned header text. Please ensure that the table headers are properly aligned for improved presentation.

6. Table 2:The number of decimal places retained after the decimal point is inconsistent in Table 2. It is recommended to standardize the number of decimal places to ensure the consistency of the data.

7.In the discussion on page nine, it is mentioned that all samples with additives exhibited slightly prolonged setting times compared to pure Portland cement paste. However, Table 5 indicates that the initial setting time of sample "10s1" is slightly reduced compared to the blank group.

8.Table 6 is poorly drawn and not easy to understand. It is recommended to redesign and edit the table for improved readability and clarity.

9. Table 6:Should the time in the table be 2 days instead of 7 days? Please verify.

10. Figure 6:The abbreviation in Figure 6 is listed as "Et" while the corresponding explanation mentions "E," which is inconsistent. Please ensure consistency between the abbreviation and its explanation.

11. Figure 8:The compressive strength data provided is only for 2 days and 28 days, which is not sufficient.

12. The statement “It is possible that C/S = 1.5 is too high for the formation of tobermorite, and the amount of amorphous CSH does not compensate the lower amount of tobermorite.” is suspectable. Author should compare the previous findings to verify the statement, such as Stress relaxation properties of calcium silicate hydrate: a molecular dynamics study Structure, fractality, mechanics and durability of calcium silicate hydrates Comparison between the effects of phosphorous slag and fly ash on the C-S-H structure, long-term hydration heat and volume deformation of cement-based materials Investigation of microstructure of C-S-H and micro-mechanics of cement pastes under NH4NO3 dissolution by 29Si MAS NMR and microhardness

13.Some notations “CSH” in the manuscript are wrong. They should be “C-S-H”.

14.In the discussion on page six, it is mentioned "(Figure 3, curves 2-4)", however, curves 2-4 are not clearly specified. Please provide clarification on which specific curves are being referred to.

15.In figure 3(c), only the peak value of quartz at 2 hours is marked, while the peak values at 4 hours, 8 hours, and 24 hours are not indicated, which is inconsistent with figures 3(a) and 3(b).

16. Regarding conclusion 1, it is recommended to provide a more detailed description of the specific steps for data collection in the paper. Furthermore, a detailed explanation of the data processing and analysis methods should also be included to ensure that readers can understand the reliability and accuracy of the resulting data.

Comments on the Quality of English Language

none

Author Response

Manuscript Number: sustainability-2915576

Title: HYDROTHERMALLY TREATED BIOMASS FLY ASH AS AN ADDITIVE FOR PORTLAND CEMENT

Answers of Authors Answers of Authors

Thank You for your remarks and suggestions.

We have made the required corrections and answered to your remarks (listed below).

Reviewer #2

Remark	Answer
The reference entries for Reference 4 and Reference 11 are duplicated. It is recommended that the authors remove one of them to avoid redundancy in the reference list.	Thank you for your remark, the citation was corrected
The citation page numbers for Reference 2 and Reference 4 are incorrect. Please ensure that the page numbers are accurately cited for these references.	Thank you for your remark, the References was corrected
The introductory paragraph is too lengthy and lacks conciseness. Please consider revising this section to make it more concise and focused.	Thank You for your remark, Introduction was corrected according Yours suggestion.
There is a clustering of reference citations on the second page. It is recommended to distribute the citation of references more evenly throughout the manuscript.	Thank You for your remark, citations was corrected
Table 1:The formatting of Table 1 is not sufficiently standardized, with misaligned header text. Please ensure that the table headers are properly aligned for improved presentation.	Thank you for your observation, the Table 1 was corrected
Table 2: The number of decimal places retained after the decimal point is inconsistent in Table 2. It is recommended to standardize the number of decimal places to ensure the consistency of the data.	Thank You for your remark, the Table 2 was corrected
In the discussion on page nine, it is mentioned that all samples with additives exhibited slightly prolonged setting times compared to pure Portland cement paste. However, Table 5 indicates that the initial setting time of sample "10s1" is slightly reduced compared to the blank group.	Thank You for your remark, the text was corrected
Table 6 is poorly drawn and not easy to understand. It is recommended to redesign and edit the table for improved readability and clarity.	Thank you for your remark, the Table 6 was redesigned
Table 6: Should the time in the table be 2 days instead of 7 days? Please verify.	Thank you for your remark, the time in the Table 6 must be 2 days.
Figure 6: The abbreviation in Figure 6 is listed as "Et" while the corresponding explanation mentions "E," which is inconsistent. Please ensure consistency between the abbreviation and its explanation.	Thank you for your remark, the explanation was corrected
Figure 8:The compressive strength data provided is only for 2 days and 28 days, which is not sufficient.	These terms of estimating the compressive strength of samples are defined in “EN 196-1:2016: Methods of testing cement. Determination of strength” standard
The statement “It is possible that C/S = 1.5 is too high for the formation of tobermorite, and the amount of amorphous CSH does not compensate the lower amount of tobermorite.” is suspectable. Author should compare the previous findings to verify the statement, such as Stress relaxation properties of calcium silicate hydrate: a molecular dynamics study Structure, fractality, mechanics and durability of calcium silicate hydrates Comparison between the effects of phosphorous slag and fly ash on the C-S-H structure, long-term hydration heat and volume deformation of cement-based materials Investigation of microstructure of C-S-H and micro-mechanics of cement pastes under NH4NO3 dissolution by 29Si MAS NMR and microhardness	Thank you very much for your comment. We agree with your opinion: There are many methods for determining the microstructure of C-S-H. However, in our case, we do not focus on the microstructure of C-S-H. We have determined the possibility of using biomass fly ash as a raw material to make the potential additive for cement. The results presented showed that this additive has a positive effect on the hydration of cement. For this reason, we plan to use the mentioned methods in further studies. We apologise for the confusion of reviewer and this sentence was deleted from the text.
Some notations “CSH” in the manuscript are wrong. They should be “C-S-H”.	Thank You for your remark, the text was corrected
In the discussion on page six, it is mentioned "(Figure 3, curves 2-4)", however, curves 2-4 are not clearly specified. Please provide clarification on which specific curves are being referred to.	Thank you for your remark; clarification on these curves was provided
In figure 3(c), only the peak value of quartz at 2 hours is marked, while the peak values at 4 hours, 8 hours, and 24 hours are not indicated, which is inconsistent with figures 3(a) and 3(b).	Thank you for your remark; the peak value of quartz was added
Regarding conclusion 1, it is recommended to provide a more detailed description of the specific steps for data collection in the paper. Furthermore, a detailed explanation of the data processing and analysis methods should also be included to ensure that readers can understand the reliability and accuracy of the resulting data.	Thank you for your remark; a more detailed description of sample selection, data collection, and analysis methods was provided in the text (lines 78-81;140-144;147-148; 150, 156, 163)