Laboratory Preparation and Performance Characterization of Steel Slag Ultrafine Powder Used in Cement-Based Materials
, Meizhu Chen 1,2,*, Dongyu Chen 1, Shaoyan Liu 3, Xintao Zhang 1 and Shaopeng Wu 1Round 1
Reviewer 1 Report
In this study, a new process of preparing SSUP in the laboratory is proposed. The differences in soundness and cementitious activity between SSUP and SSP were also evaluated extensively. The results obtained are positive and important to the scientific community. However, the Authors are suggested to include/address the following suggestions/modifications.
General comments:
1. The Authors should extensively correct Grammatical errors and erroneous sentence formation throughout the text.
Introduction:
1. The Authors are required to explain the term ‘cementitious activity’ for the benefit of readers.
2. The Authors are requested to provide a little more explanation on the selection of physical excitation over other alternatives.
3. The age of ‘28d, 3d, and 360d’ must be explained more clearly.
4. Why is the study of SSUP so important? The Authors must clearly explain this in the Introduction
5. The Introduction is quite difficult to understand due to poor English. The Authors are strongly advised to revise their text.
Materials and Methods
1. Are there any references for Eqn.1?
2. ‘Calculated from Eq. (1), the basicity of steel slag used in this study is 2.86, which is higher than 2.5. It means that this kind of steel slag belongs to high basicity slag, and it is known that its main mineralogical phases are C2S, C3S, C3A, and dicalcium ferrite (C2F), which are similar to that of cement. Therefore, this kind of steel slag has good cementitious activity theoretically’. This statement requires appropriate references.
3. Table 3 requires to be cited.
4. The subsection numbering seems to be off. The Authors are requested to check the same.
5. ‘The mass ratio of SSUP to cement was 15 %, 30%, 45%, and 60% in this study’. Why were these ratios selected?
6. If possible, the Authors are requested to arrange their Materials and Methods section to be a bit more reader friendly. Currently, it looks quite random and haphazard.
Results and Discussion
1. Please mention the selection criteria for grinding agents.
2. Fig. 5 is blurred. Please replace it.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
This paper aims to the feasibility of using steel slag ultrafine powder in cement replacement. The content of the article is comprehensive, but some details are not well done. There are some comments below that authors may consider revising their paper.
1. In the introduction, what does the last sentence of the penultimate paragraph mean? Detailed analysis is required.
2. Where does Eq. (1) come from? Add references. Also, what do the terms in the formula represent?
3. What standard is the classification in Table 3 based on?
4. 2.1, “0.075mm” to “75μm”
5. How long the SSUP used in this study was milled needs to be stated in the text.
6. 3.3, The morphological effect needs to be clarified and add references on this effect.
7. 3.3, It is well known that smaller particle size increases specific surface area, which leads to increased water demand. But the results of this study are the opposite, so the authors need to add more convincing explanation.
8. 3.4, Added reference to "Le chatelier soundness test".
9. 3.5, The authors need to label two hydration heat peaks in Figure 11a and two heat stages in Figure 11b.
10. 3.5, Is the second hydration exothermic peak due to C2S? In addition, the cement hydration heat is divided into five stages, and after the peak appears, it enters the deceleration stage. The authors need to make detailed revisions to the heat of hydration section.
11. Where does Eq. (2) come from? Add references.
12. Many of the crystal phase peaks in Figure 15 are not noted.
13. In the “3. Results and discussion”, the authors only mentioned the hydration reactivity of the steel slag. However, for auxiliary cementitious materials, the pozzolanic reaction may be more pronounced than the hydration reaction. So, is there a pozzolanic reaction in steel slag? In addition, the particle size of SSUP is small. So is there a physical effect when adding SSUP? The authors need to address both aspects in the Results Discussion.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
In this manuscript, a new process of preparing SSUP in the laboratory is proposed. The difference in soundness and cementitious activity between the SSUP and SSP was investigated. This manuscript must be revised after fixing the following comments.
The main comments are shown as below:
(1). The reference cited in this manuscript is FAR from enough. The literature review in this manuscript is not comprehensive.
For example, the introduction part, “Chemical excitation activates the cementitious activity by adding chemical excitant.” Please cite more references here:
Ø Yang, S., Wang, J., Cui, S., Liu, H. and Wang, X., 2017. Impact of four kinds of alkanolamines on hydration of steel slag-blended cementitious materials. Construction and Building Materials, 131, pp.655-666.
Ø Wang, J., Chang, L., Yue, D., Zhou, Y., Liu, H., Wang, Y., Yang, S. and Cui, S., 2022. Effect of chelating solubilization via different alkanolamines on the dissolution properties of steel slag. Journal of Cleaner Production, 365, p.132824.
Ø Zhang, Y.J., Liu, L.C., Xu, Y. and Wang, Y.C., 2012. A new alkali-activated steel slag-based cementitious material for photocatalytic degradation of organic pollutant from waste water. Journal of hazardous materials, 209, pp.146-150.
Ø Xu, C., Ni, W., Li, K., Zhang, S. and Xu, D., 2021. Activation mechanisms of three types of industrial by-product gypsums on steel slag–granulated blast furnace slag-based binders. Construction and Building Materials, 288, p.123111.
(2). There are a lot of grammar issues and spelling issues in the manuscript. Please fixed that.
(3). For Fig. 11, it is suggested to plot A1/A2/A3/A4 and B1/B2/B3/B4 with the same line color and different line types. Meanwhile, Fig.11(b) should also have the labels of each line
(4). According to Figure 11 (a), the position of the second peak is promoted compared to the blank sample. Any explanation for this?
(5). For Fig 15, try to mark the peak by using symbols instead of alphabets.
(6). The reductions of C3S, C2S, C3A, and C2F can be detected by quantitate x-ray diffraction analysis or the measurement of chemically bound water (TGA). The decrease of the peak height is not always representing the decrease of the phase amount.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have appropriately answered all the comments. The manuscript is recommended for publishing.
Author Response
Thank you for your kind comment. The relevant corrective language has been added to the paper.
Reviewer 2 Report
The author has made revisions, and most of the revisions are agreed upon, but there are still points for improvement. Below are some comments that authors may consider revising their paper.
1. I think the interpretation of the exothermic peak in the heat of the hydration section is still wrong, and I don't understand what the numbers marked in Figure 11a mean. Please refer to https://doi.org/10.1016/j.cemconcomp.2020.103859; https://doi.org/10.1016/j.jclepro.2020.121455; https://doi.org/10.1016/j.cemconres.2013.11. 013; https://doi.org/10.1016/j.cemconres.2017.05.013 and other references to modify the heat of the hydration section.
2. In Figure 15, what do the diffraction peaks around 10°, 15-20°, 40-42°, and 50° represent?
3. The physical effects of particles include nucleation, dilution, and other effects. not limited to morphological effects.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 3 Report
N/A
Author Response
Thank you for your kind comment. English language and style have been revised.
