The Utilization of Recycled Sewage Sludge Ash as a Supplementary Cementitious Material in Mortar: A Review

Round 1

Reviewer 1 Report

The review article analyses properties of sewage sludge ash (SSA) and possibilities to use it in the mortar. The impact of SSA on such mortar properties was analysed: workability, setting time, water absorption and water requirement, compressive strength, flexural strength, durability and microstructure. The article is interesting and useful, because much information from 151 literature resources were analysed and the main characteristics of SSA and mortar with SSA were presented. This is rewiev article and all information is collected from the works of other authors, but the style of presentation (created new graphs, tables from many resources) provides clarity of possibilities to use SSA. In this article is concentrated information about SSA, not one research. From one article it is clear, how changes properties of mortar by using SSA. However, it is analysed SSA properties, such as chemical composition, particle size, burning temperature, leaching etc. The paper is well written, but some Enlish and style mistakes were found. The text should be carefully checked. The conclusions are written according the main analysed results.

 

The review article is very interesting and high quality. 151 references were cited and the main properties of sewage sludge ash (SSA) were analysed. However, it was analysed the impact of different prepared SSA on mortar structure and properties.

Remark: The English language should be carefully checked. (319 line: in in ; and etc.)

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The work is well presented and attractive for scientist working on this area. But it needs further improvement before acceptance in this journal

 

1. Abstract should include future perspectives and concluding sentence
2. I prefer, if author provide main findings in the abstract in terms of numbers
3. The authors should clearly indicate the novelty of this work compared to a previously reported review articles on the same topic
4. The introduction should mention other possible utilization of sewage sludge see papers

https://doi.org/10.3390/ijerph14101094; https://doi.org/10.1016/j.chemosphere.2021.133196;

5. Introduction lacks the key benefits of using sewage sludge ash for cement replace.
6. Section 2.6, the author should elaborate more on this topic, support this with key findings from previous research
7. The mechanism of interaction of SSA with cement affecting the performance of mortar is missing. The authors comprehensively summarize this in a separate section.
8. Future recommendations should be provided
9. Any findings related to thermal performance ? see https://doi.org/10.1016/j.jobe.2021.103747

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Overall, the manuscript report an  interesting literature survey conducted by the author on “Utilization of Sewage Sludge Ash as Supplemen-2 tary Cementitious Materials in Mortar”. The following minor issues need to be addressed by the authors.

1. Line 13-15. The reported work is a literature survey rather than an “investigation” which is usually linked to experimental works. Hence, the author should correct the sentence to reflect on the actual scope which is a literature review/survey.
2. Figure 1 is prepared by the author or is a published data by Ministry of Housing and Urban-Rural Development of China? If it is referred data, it should be cited properly in the caption of the figure.
3. Figure 2. How the values of the figure is interpreted needs to be mentioned by the author in paragraph line 72-84.
4. Line 129-130. Does the author mean “potential pozzolanic activity of SSA”?
5. Figure 6 is a direct adaptation from reference 12,16,94. The author needs to obtain the relevant permission for use of the figures. In the present manuscript, the permission document is not found.
6. The presentation of data in Figure 9 is not very clear to the reader. The author is advised to condense it further to a more understandable form. Or the author can also guide the reader on how the data are interpreted in the text in line 294-313.
7. Images in Fig 11 is a direct adaptation from reference 81,94,127-128. The author needs to obtain the relevant permission for use of the figures. In the present manuscript, the permission document is not found.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The author addressed all comments and it is now can be accepted for publication