A Study on the Applicability of Bio-Sulfur as a Cement Admixture
Round 1
Reviewer 1 Report
The study is interesting to recycle bio-sulfur powder by mixing with cement and partially replace cement. The section of Introduction must improved with more literature review on sustainable concrete with improved binder. The English writing and expression must be further improved. The detailed comments are listed:
1. The introduction should be improved with more literatures on sustainable cement materials with recycled products. E.g. Resources, Conservation and Recycling, 2021, 172: 105664. Materials & Design, 2012, 35: 434-439.
2. The particle size distribution of cement used should be placed with bio-sulfur for easier comparison.
3. The composition of cement used in this study is recommended to display.
4. In the section of 2.2.1, what does the 'aggregate' mean here? You only tested the strengths of cement paste, right?
5. Re-write the sentence of line 156-159.
6. In the section of 2.2.2, you only mentioned the weight loss to evaluate the sulfuric acid resistance, you may cite this article and consider more factors: Piezoresistivity deterioration of smart graphene nanoplate/cement-based sensors subjected to sulphuric acid attack
Author Response
1. Added 3 documents for recycling waste into cement.
2. I agree with the reviewers, but I did not analyze the cement particles. Therefore, the opinion could not be reflected.
3. As in No. 2, using standard cement, the properties of conventional cement could not be analyzed.
4. aggregate means aggregate. In 2.2.1, only the strength of cement was analyzed.
5. Edited again.
6. We considered more factors using the references you provided.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The authors have attempted to develop the concrete mix with bio-sulfur as a cement admixture, a good attempt, but the following comments are to be addressed before the acceptance.
It is unclear whether the bio sulfur was added as cementitious material or replaced with cement; explain figure 5 for a more appropriate discussion.
The aim of the study is not well connected to the application or strong background for choosing this research, discuss
The quality of figure 5 is to be improved. It is difficult to read
The utilization of bio sulfur exhibited a reduction in strength, to be explained better
It is reported that the addition of bio sulfur showed better resistance to sulfate attack, but the mechanism is not explained
A hydration reaction equation can be given for understanding the microstructure formation
The order of presentation is confusing and affects the readability, first the materials and methods to be given, following results and discussions. I did not see any title showing Conclusions.
Check all the tables and figures, improve the quality
Adequate experiment pictures do not support the presentation of the manuscript.
It was mentioned in the Abstract section, stating that the replacement of cement-based admixture can reduce carbon emission, but the impact is not explained in the manuscript.
It is important to add the limitations of the proposed work and the scope for future studies.
Some microstructure analysis is to be added to understand the strength and weaknesses of mixing with bio-sulfur.
Refer to the following literature for discussion
Oh, M. H., Park, W. P., & Hyun, H. N. (2020). Effects of Using Bio-Sulfur on Open Field Citrus Melanose (Diaporthe citri) and Panonychus citri. Journal of Environmental Science International, 29(10), 997-1002.
Olutoge, F. A., Buari, T. A., & Adeleke, J. S. (2013). Characteristics strength and durability of groundnut shell ash (GSA) blended cement concrete in sulphate environment. International Journal of Scientific and Engineering, 4(7), 2122-2134.
Kanagaraj, B., Kiran, T., Anand, N., Al Jabri, K., & Justin, S. (2022). Development and strength assessment of eco-friendly geopolymer concrete made with natural and recycled aggregates. Construction Innovation.
Author Response
In general, English has been corrected. 1. In Figure 5, bio-sulfur was added instead of cement, and the substitutes were presented separately. 2. By adding that it is helpful to use waste in cement in the introduction, we suggested the justification for using biosulfur in cement. 3. Figure 5 has been rewritten. 4. It was described as having strong sulfur resistance as lower hydrates were produced in cement containing biosulfur. 5. As this study looks at the possibility of substitutes, carbon reduction effects are not presented. 6. As an advantage of biosulfur, it is suggested that sulfuric acid resistance increases, and as a weakness, compressive strength decreases. 7. For the conclusion, please refer to the discussion section.Round 2
Reviewer 1 Report
The manuscript has been improved and can beq accepted.
Reviewer 2 Report
The manuscript can be accepted
