Sulfate and Freeze-Thaw Resistance of Porous Geopolymer Based on Waste Clay and Aluminum Salt Slag

Round 1

Reviewer 1 Report

This review comprehensively compared three industrial origin secondary raw material which are used as precursors to produced porous geopolymers, and the durability is characterized by freeze-thaw resistance and sulfate attack. Totally, this paper is interesting. But the content of the article is not fully expressed, and technical routes are not clearly. In addition, the reason for the difference in performance is not clearly explained. So, It is very necessary to supplement and perfect these contents.

Author Response

We would like to thank the valuable comments and recommendations of the reviewer, mostly accomplished and discussed in the revision and answers.

1. The content of the article is not fully expressed, and technical routes are not clearly. In addition, the reason for the difference in performance is not clearly explained. So, It is very necessary to supplement and perfect these contents.

The manuscript sections have been revised according to the remarks of three reviewers. Abstract, materials, discussion and conclusion sections have been improved with additional details and discussion.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript with the title “Sulfate and freeze-thaw resistance of porous geopolymer based on waste clay and aluminum salt slag” is an interesting paper and it should be attractive to the readers of the Materials journal.

The manuscript provides interesting results on porous geopolymer, with good mechanical and chemical properties as a sustainable material obtained from entirely waste source precursors. The paper is well composed, the methods are adequate, explanations are detailed, figures are well presented. Maybe further characteristics of the newly produced materials could have been investigated, for example, its porosity i.e. Controlling the Activator modulus Ms could further control the pore structure and density of the porous In addition, the reference list is adequate.

It can be accepted after incorporating the following comments.

Abstract

Authors should highlight the results after the sulfate attack test to be consistent with the title of the research.

Materials and Methods

Which was the molarity of the alkali activator NaOH?

Also, could the authors give recommendations on how to improve the durability against corrosive conditions of future geopolymers, which use waste materials as the main component, providing safer disposal with a lower environmental impact?

In addition, in order to gain a better insight into the significance of the results obtained in this paper, I suggest to the authors that they write the purpose with which they synthesized this material, i.e. to make it clear what is the potential application of the synthesized materials, and to rewrite the conclusion and abstract accordingly.

I can recommend the publication of the following manuscript with minor revision.

 

 

 

 

Author Response

We would like to thank the valuable comments and recommendations of the reviewer, mostly accomplished and discussed in the revision and answers.

 

1. Authors should highlight the results after the sulfate attack testto be consistent with the title of the research.

 

Thank you for recommendation. The abstract was revised and repetitious sentence was replaced by conclusions from durability results.

2. Which was the molarity of the alkali activator NaOH?

Material section was revised. Alkali activators were prepared by using commercially available sodium silicate solution characterized by the silica modulus Ms 3.22. To obtain modified alkali activation solution with the required chemical composition, the addition of sodium hydroxide flakes was done to achieve sodium silicate solution with silica modulus of Ms 1.67. Commercially available sodium hydroxide flakes with 97% purity were used.

3. Also, could the authors give recommendations on how to improve the durability against corrosive conditionsof future geopolymers, which use waste materials as the main component, providing safer disposal with a lower environmental impact?

Sections discussion and conclusions was revised and additional correlation between geopolymer macrostructure, physical properties and material performance introduced. The role in mixture composition (aluminium slag content) on geopolymer matrix strength was analysed.

4. In addition, in order to gain a better insight into the significance of the results obtained in this paper, I suggest to the authors that they write the purpose with which they synthesized this material, i.e. to make it clear what is the potential application of the synthesized materials,and to rewrite the conclusion and abstract accordingly.

Sections abstract and conclusions were revised. The environmental issue and application of such materials were proposed.

Author Response File: Author Response.docx

Reviewer 3 Report

In the modern word, a great deal of attention is being paid to the problem of recycling, greenhouse gas emissions and ecology in the broadest sense.  On the one hand, materials used in construction should be ecological, on the other hand, they should meet the requirements set by standards. 

The authors have given due consideration to the possibility of using recycled materials as a precursor for the production of geopolymers. The use of recycled aluminium as a foaming agent is also well-regarded. However, I would suggest the authors to read the publication: 

Ercoli, R.; Laskowska, D.; Nguyen, V.V.; Le, V.S.; Louda, P.; Łoś, P.; Ciemnicka, J.; Prałat, K.; Renzulli, A.; Paris, E.; Basilici, M.; Rapiejko, C.; Buczkowska, K.E. Mechanical and Thermal Properties of Geopolymer Foams (GFs) Doped with By-Products of the Secondary Aluminum Industry. Polymers 2022, 14, 703. doi: 10.3390/polymers14040703

The topic of the publication corresponds to the content contained therein. The scope of the research and the analysis of the results is sufficient for this to be a scientific publication. 

The references contained in the paper are correctly cited.

The language used in the publication is correct, I would recommend the authors to pay attention to editorial details - there should be no single letters at the end of the line, the % sign should be directly after the value, in Table 3, the bulk density and mechanical properties are missing a comma, remove the dot in the name of Tables 3, 4 and 5.

Having made the above corrections, I recommend the paper for publication.

Author Response

Reviewer 3.

We would like to thank the valuable comments and recommendations of the reviewer, mostly accomplished and discussed in the revision and answers.

 

I would suggest the authors to read the publication.

 

The authors acknowledge the reviewer for pointing out the latest research about geopolymer foams from the year 2022. The authors got familiar with the results and compared the findings in this research to those published. A proper quotation was also inserted in the manuscript. 

 

I would recommend the authors to pay attention to editorial details - there should be no single letters at the end of the line, the % sign should be directly after the value, in Table 3, the bulk density and mechanical properties are missing a comma, remove the dot in the name of Tables 3, 4 and 5.

 

Thank you for your remark. Editorial details were checked and further improvements will be done in accordance with editor.

Author Response File: Author Response.docx