Use of E-Waste in Metakaolin Blended Cement Concrete for Sustainable Construction
and Ravi Chandra Malladi 1Round 1
Reviewer 1 Report
1. Some reference errors can be found, like line 95, line 109, etc. Besides, some gramma and spelling mistakes need to be corrected, like line 133, 136, 269, etc.
2. Analyze about Fig. 8 should be added, some abbreviations should be defined at first time.
3. Error bar should be given for the data in Figs. 8, 9 and 10, etc.
4. Standard pdf card No. should be given for XRD test.
5. Elemental proportion for EDS result should be given.
6. The conclusion part should be re-constructed, the paragraphs are too scattered.
7. Some latest relevant work about the corrosion phenomena can be helpful:
(1) Zeng, Y., Kang, L., Wu, Y., Wan, S., Liao, B., Li, N., & Guo, X. (2022). Melamine modified carbon dots as high effective corrosion inhibitor for Q235 carbon steel in neutral 3.5 wt% NaCl solution. Journal of Molecular Liquids, 349, 118108.
(2) Wan, S., Zhang, T., Chen, H., Liao, B., & Guo, X. (2022). Kapok leaves extract and synergistic iodide as novel effective corrosion inhibitors for Q235 carbon steel in H2SO4 medium. Industrial Crops and Products, 178, 114649.
Author Response
The authors have addressed the reviewer's comments and made corrections in the revised manuscript. point-by-point responses to the comments are given in the attached file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The results presented in this article is ecologically important, because of circle economy and better properties of presented cement products. It was determined, that replacing 10% of cement by metakaolin and 10% by non-metallic e-waste increases strength and durability of concrete and the best results were got, then it was used complex additive. Then structure is denser and higher quantities of CSH and CASH were formed.
Remarks:
In the text are many errors: "Error! Reference source not found.. Error! Reference source not found" (2p. 95line; 3p. 109, 118, 120 lines; 4p. 132,138 lines and etc.)
They aren't noted and analysed data presented in Tables 1-3 and Figure 2.
Strength of the concrete should be presented in MPa (Figures 5-6), like in Figure 9.
It is missed dimension of water absorption in Figure 8.
It should be presented identification cards numbers of CSH, portlandite and etc.
It is difficult to say, or more CSH was formed from XRD, because it wasn't used inner standard. How it was prepared samples? How it was ensured that the amount of sand was the same in all samples? It is seen, that the amount of quartz wasn't the same. Maybe, it is possible to calculate, how it will be looked diffractograms, if the amount of quartz in all samples will be the same.
It isn't clear, what You wanted to show with numbers in SEM images. (Figure 13)
What is chemical composition of NMP?
Author Response
The authors have addressed the reviewer's comments and made corrections in the revised manuscript. point-by-point responses to the comments are given in the attached file.
Author Response File: Author Response.pdf
Reviewer 3 Report
Use of E-Waste in cement concrete fits in with issues of sustainability. The paper is interesting and carefully drafted. In my opinion, the paper after minor corrections should be accepted for publication.
Specific suggestions and comments:
- line 129 - please briefly characterize the M30 grade concrete.
- Section 2.5.1 - the test was not carried out accurately with ASTM C642. According to this standard, samples are dried and then soaked in water until they reach a constant mass (successive mass measurements taken every 24 hours do not vary by more than 0.5%). In my experience, 24 h of sample drying is not enough time to achieve constant mass. In my opinion, an estimate of water absorption was determined.
- lines 164-165 - It seems to me that according to ASTM C1585 there are different sample conditioning,
- Why does the addition of NMP at 15% cause worsening in the strength characteristics of concretes?
- Line 317- "On the addition of MK, the samples outperformed the controlled mix indicating an improvement in the chloride permeability." I guess there should be a reduction (not improvement) in chloride permeability (which is beneficial for reinforced concrete structures).
- In Figures 8-10 there is a different order of bars (specimen code) than in the earlier figures. The order of the bars should be unified. In the earlier figures, the impact of the NMP was better seen.
Author Response
The authors have addressed the reviewer's comments and made corrections in the revised manuscript. point-by-point responses to the comments are given in the attached file.
Author Response File: Author Response.pdf
Reviewer 4 Report
It requires major revision. The authors need to pay attention to the arrangement of the article.
1. The author should pay attention to some words and grammar problems in the article. This is very important to improve the readability of the article.
2. The last paragraph of the Literature review does not reflect the innovation of the article. Please comprehensively compare relevant articles and point out the innovation of this paper.
3. The references in the text are not shown, and it is recommended to modify.
4. “Table 4.” How to determine the content of MK and NMP?
5. “3.1. Characterization of raw materials” Put in Section 2.
6. “Figure 5.” There is a problem with the legend.
7. It is suggested to increase the relationship between compressive strength, tensile strength and bending strength.
8. “3.4. Analytical studies” It is suggested to increase the correspondence analysis between macro and micro parameter
9. The conclusion and abstract were lack of summary, please simplify.
10. The relevant experimental data in this paper need to be compared with relevant literature for verification and analysis to ensure the rationality of the data and laws in this paper. Analysis after discussion in each section.
11. A general discussion should be added to introduction. The importance of mineral admixtures should be indicated in the first paragraph of introduction. The following studies should be used for this purpose. Please check studies “10.1016/j.conbuildmat.2021.123209; 10.1016/j.cemconcomp.2022.104745; 10.1016/j.jhazmat.2020.123329.
Author Response
The authors have addressed the reviewer's comments and made corrections in the revised manuscript. point-by-point responses to the comments are given in the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 4 Report
1. The conclusion lacks induction and summary.
2. “Analytical techniques” Adding the sample quantity and sampling process.
Author Response
Dear Reviewer
Point-by-point responses were addressed and attached in the following word document, whereas the same corrections were made in the revised manuscript.
Thank you
Author Response File: Author Response.pdf
