Influence of the Steel Slag Particle Size on the Mechanical Properties and Microstructure of Concrete

Round 1

Reviewer 1 Report

Review comments

This paper aims to improving the hydration activity of steel slag in the application of concrete, which has good research significance for improving the comprehensive utilization rate of steel slag. It can be accepted after minor revision. My review comments are listed below.

1.     What is ‘c alkalinity’ in line 87? Please check.

2.     Table 3 mixing proportion, please incorporate the adding amount of cement.

3.     Section 3.1, please give explanation of D10, D50, and D90.

4.     Figure 4, it is the surface area varies when grinding steel slag grinds in multiple times. I recommend change the x-axis to ‘surface area’ in Figure 4.

5.      In the second paragraph of the introduction, the author said ‘particle size of steel slag can significantly alter the microstructure of concrete, subsequently impacting its macroscopic mechanical properties’. Can the author give some literature reviews and explain what specific gap in the field does the paper address? Because there are many studies investigating effects of PSD on concrete mechanical properties as you can see below:

https://doi.org/10.1016/j.conbuildmat.2018.01.193

6.      Table 3 mixing proportion, please incorporate the adding amount of cement.

7.      Section 2.3, for the repeatability of the test, please add details about the testing procedures, sample preparations and process parameter of all your test. A good example of describing the methodology can be seen at https://doi.org/10.1016/j.conbuildmat.2021.126152

8.      Section 3.1, please give explanation of D10, D50, and D90.

9.      Figure 4, it is the surface area varies when grinding steel slag grinds in multiple times. I recommend change the x-axis to ‘surface area’ in Figure 4. Furthermore, error bars should be added.

10.      Lines 201-205, the authors are describing the compressive strength and flexural strength results, however, reference 24 was cited. Did the data originally obtained in your research or refer to a different paper? This is improper citation. Please correct. Furthermore, the testing results in should be compared with other research and give explanation.

11.      Section 3.4, the microstructure part can be plain. I strongly recommend the authors carry out some supplemental experiments about the porosity properties of the concrete using CT or MIP methods. 

Author Response

Dear Reviewer,
Thank you very much for your comments on the thesis. We have revised the comments, details are attached.
Best regards
Maohui Li.

Author Response File: Author Response.doc

Reviewer 2 Report

In this paper, steel slag was used as the main raw material to explore the influence of steel slag particle size on the mechanical properties and microstructure of concrete. The effects of steel slag on the compressive strength, flexural strength and microstructure of concrete were analyzed by laser particle size analyzer, specific surface area analyzer, strength tester, X-ray diffraction (XRD) and scanning electron microscope (SEM). Experimental research has certain guiding significance for the neutralization and utilization of steel slag. The quality of the results and arguments is at a good level. The content of the paper is well-structured, the conclusions and references are readable, and the paper as a whole meets the publication requirements, but there are still some minor issues that need further revision, and the comments mentioned below should be considered and the manuscript should be further improved before submitting the final version:

Figure 2-8 should explain what (a), (b) and (c) correspond to.

Author Response

Dear Reviewer,
Thank you very much for your comments on the thesis. We have revised the comments, details are attached.
Best regards
Maohui Li.

Author Response File: Author Response.doc

Reviewer 3 Report

Line 2: Please delete “The” at the beginning of the title.

Lines 14-28, Abstract: It is well-written but needs some minor modifications, for example in line 15 the authors need to use either microstructure or miscrostructural aspects. Also, please keep space between numbers and units of all kinds, e.g. time, size, ....etc.

Line 29: The keywords are ok, but better to include "Additive" among them. You can use admixture as an alternative keyword same as the authors mention in their text.

Lines 40 and 48, Introduction: You need to insert the number in the reference list. In general, introduction is ok.

Line 81, Table 1: Use “Oxides” instead of “Compound”. Also, "Others" should be used instead of "Other". Also, the amount is appreciable so that you need to provide what are these other oxides because they are more than 6 wt%.

Line 88, Table 2: Punctuation issue should be considered so write the first letter as "Capital Letter".

Line 89, Figure 1: Use a bar scale instead of the ruler in Figure 1a and Figure 1b.

Line 99: Use one of the following words: presented/given instead of shown.

Line 132: It is highly recommended to separate results from discussion. They should be in two independent sections and in the discussion do your best to comment on the results and focus on the interpretation.

Line 144: Please modify the caption of Figure 2. Do not use capital letters for every word.

Lines 144 and 163: Do not use the word “Graph” at all. In addition, consider the punctuation issue in Figure 3 and rest of figures.

Line 163: In the caption of Figure 3, you must indicate in the caption what do the red arrows mean?. Also, scale is not readable, so please make it distinct for readers. Delete the lower part and insert readable scale into the SEM images.

Line 213, Figure 5: The presented graph are not phase diagrams but classical XRD charts of substances. Also, the XRD runs produce peaks of minerals and not oxides, so please correct this fatal mistake.

Line 252: For Fig. 6, please modify scale and include in the caption the meaning and abbreviations of components (lines in red) seen by the SEM.

For all SEM figures, please modify namely; Fig. 7 and Fig. 8.

Lines 287-304: Conclusions are good and competent with results and their interpretations. They are presented in the form of 3 numbered paragraphs. Instead, conclusions should be concise and informative so it is recommended to change them into 4-6 bullets of shorter bullets.

Line 317, References: Please check if you need to write down names of authors as capital letters or not. Other punctuation issues in the reference list should be considered.

Comments for author File: Comments.pdf

Fine polishing is needed only.

Author Response

Dear Reviewer,
Thank you very much for your comments on the thesis. We have revised the comments, details are attached.
Best regards
Maohui Li.

Author Response File: Author Response.doc

Round 2

Reviewer 3 Report

Please see the comments in the report to editor.

It is not bad English and just needs smoothing.

Author Response

Dear Reviewer，
Thank you very much for your careful reading and suggesting helpful revisions. We have revised some of the descriptions to make the paper smoother. The references have been updated and irrelevant literature has been removed.

1) Minor editing of English language required.

Reply: Thank you for your careful reading. Based on your suggestions, we have revised the text description of the manuscript.

2) Are all the cited references relevant to the research? (Can be improved).

Reply: Thank you for your careful reading. We revised references 3 and 9 in the manuscript.
Best regards to you.
Dr. Maohui Li