Advancements in Lightweight Artificial Aggregates: Typologies, Compositions, Applications, and Prospects for the Future

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript titled "Advancements in Lightweight Artificial Aggregates: Typologies, Compositions, Applications, and Prospects for the Future" provides a thorough review of artificial lightweight aggregates, exploring their types, production methods, and potential applications, especially in sustainable construction. The manuscript need several improvements as stated below.

 The abstract is not clear and lacks quantitative details on environmental impact assessments,

Some figures such as Figure 2 and Figure 3, captions are not clear and need improvement.

In the Introduction section author should add limitations of natural aggregates and ink it why  artificial alternatives are required.

In introduction add some unique advantages and limitations of artificial lightweight aggregates compared to natural ones.

Explain in details the environmental impacts associated with each type of aggregate, such as greenhouse gas emissions

The use of "lightweight" and "artificial lightweight" is inconsistent make all suc word consistent through the manuscript.

Author should discuss potential health risks and safety considerations associated with using industrial waste products in artificial aggregates,

Comments on the Quality of English Language

proof read is required thorugh out the manuscript, check for gramatical errors

Author Response

The authors highly appreciate the time and valuable suggestions. We have attached the responses to each and every point in the Word file. Please find the attached file. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Page
2-3	Paragraphs are not well separated, e.g. on page 2 (a gap within the sentence), ор the first line is pushed out, and the rest of the text is tucked in, e.g. on page 3.
4	Figure 2c is mentioned in the text, but no such picture exists.
4	Figure 2. Expanded clay aggregates - the red marks in pictures a and b are not visible well - either strengthen or change the colour.
5	"...guarantees the creation of outstanding aggregates that are suited for a wide range of construction projects" - specify for which projects, for example
17	You are missing the "Relationship between expanded perlite aggregate ratio and thermal conductivity (a)" in the title of Figure 11.
19	Figure 13 should appear in the text before the figure, not just in section 4.1.
25	The paper generally contains a lot of repetition. It is recommended that the paper be shortened so that the reader does not lose attention when many phrases are repeated. For example, "effective sound absorption properties, reducing noise transmission and improving acoustic comfort in buildings... valuable in residential, commercial, and industrial settings where noise control is essential for occupant well-being and productivity."
27	" In Table 1 various environmental…" switch to page 26 so the table is referenced before displaying.
30	"... the average scores of sound pollution and land use and ecology for SFAA are higher than those of CBFAA." add whether the aggregates should have a lower or higher rating.
33	A detailed retelling of someone else's work would shorten it.
36	Shorten the conclusion. Highlight only the essentials.
37	Align references 1 and 2 with the others.

Author Response

The authors highly appreciate the time and valuable suggestions. We have attached the responses to each and every point in the Word file. Please find the attached file. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The article presents an extensive literature review devoted to the issues of using lightweight artificial aggregates in sustainable construction. An exhaustive classification of existing artificial lightweight fillers is provided, issues of their manufacturing technology, as well as areas of effective application are considered. Prospects for further development of this area have been identified. Overall, the article is well organized and can be useful not only for researchers but also for practitioners.

However, the article also contains controversial provisions. In paragraph 8.3.1 and further, the authors write that lightweight aggregates enable taller and more slender structures while maintaining structural integrity and performance, therefore they can be used in high-rise construction. 

Lightweight aggregates have significantly lower load-bearing capacity than traditional crushed stone, and therefore their use in load-bearing structures of high-rise buildings is highly questionable. It should be clarified that this only applies to enclosing structures.

Author Response

The authors highly appreciate the time and valuable suggestions. We have attached the responses to each and every point in the Word file. Please find the attached file. 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

– Please add an explanation of the abbreviation LWA. It is probably the same as ALWA. In this case, please use one of the abbreviation variants;

– Introduction. This section contains sentences that are broken into paragraphs. Please correct this;

– «Lightweight aggregates are noteworthy in the field of construction materials due to their versatility, efficiency, and environmentally friendly nature». Please explain how the authors justify the environmental friendliness of Lightweight aggregates. After all, they can be of different origin and chemical composition;

– In the caption to Figure 2, it is necessary to add explanations for images a) and b);

– Since paragraph 2.1 «Expanded Clay aggregates» consists of only one point 2.1.1 «Clay Extraction», it makes sense to combine them into one section 2.1. It makes sense to do the same with sections 2.2 and 2.2.1;

– «Despite fibrous reinforcement, LWAC struggles to achieve required stiffness [29-31]». It is not clear what fibrous reinforcement has to do with it if we are talking about Sintered fly ash aggregates as lightweight aggregates;

– Section 2.5 «Recycled polyolefins» is recommended to be removed from the text of the manuscript, because it is not related to Lightweight Aggregates, as stated in the title of the manuscript;

– Sections 3.1-3.3 do not say anything about compositions of lightweight aggregates, as stated in the heading of paragraph 3. In addition, the information in these sections duplicates the information presented in sections 2.1-2.4. Thus, it is advisable to remove these sections from the text of the manuscript. In accordance with the content, it is better to rename section 3 as follows: «Properties of lightweight aggregates»;

– The following information in Section 3.4: «The impact of composition on lightweight aggregates encompasses several key properties, including density, thermal conductivity, and mechanical strength. Understanding how different compositions influence these properties is essential for selecting the most suitable aggregates for specific applications and optimizing performance in construction and engineering projects [53] » should be moved as an introduction to Section 3. Sections 3.4.1–3.4.3 should be renumbered as 3.1–3.3;

– The article entitled «Advancements in Lightweight Artificial Aggregates…» also discusses aggregates obtained from natural raw materials: expanded clay, expanded shale, which contradicts the stated title of the article, since expanded clay, expanded shale are obtained from natural raw materials;

– Sections 4.2–4.6 relate to the construction industry. Therefore, they should be renumbered as 4.1.1–4.1.5;

– Section 4.7 should be renumbered as 4.2. Sections 4.8 and 4.9 – renumber as 4.2.1 and 4.2.2 respectively as they relate to Geotechnical Engineering;

– Section 4.10, 4.10.1–4.10.3 should be renumbered as 4.3, 4.3.1–4.3.3 respectively;

– Please provide the reference source used to present the data in Figure 14;

– Paragraph 8.1.1. Add an explanation for the abbreviation LCA;

– The Title for Section 8.1.1. should be deleted as it is the only paragraph in Section 8.1;

– The information in Section 8.2 “Characteristics and Performance” completely duplicates the idea of ​​the information presented in the sections of Section 3.4. Therefore, sections 8.2, 8.2.1 – 8.2.3 should be deleted, and the information should be moved to the sections from paragraph 3.4;

– Table 2 should be moved to the beginning of section 2 “Types of lightweight aggregates”.

Author Response

The authors highly appreciate the time and valuable suggestions. We have attached the responses to each and every point in the Word file. Please find the attached file. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Article can b accepted now

Comments on the Quality of English Language

minor check are required at proofread

Reviewer 2 Report

Comments and Suggestions for Authors

You have made a great effort to extract everything about advances in lightweight artificial aggregates from the literature. They deserve to be used more in the construction industry. At the same time, regulations must follow them, especially for countries without experience with them.

Reviewer 4 Report

Comments and Suggestions for Authors

Manuscript can be accepted in present form