Impact of Pumice Substitution on Mortar Properties: A Case Study on Mechanical Performance and XRD Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. The introduction should be expanded to include a broader context of sustainable construction materials. In particular, authors should discuss recent approaches that researchers are investigating to enhance the sustainability and thermophysical properties of mortars and concretes, such as supplementary cementitious materials (SCMs) and bio-based additives.

For SCMs (e.g., clay, fly ash, steel slags), consider the recent study:

DOI: 10.3390/buildings14123906

For bio-composite materials enhancing thermal, recent relevant studies include:

DOI: 10.1016/j.enbuild.2014.05.032
DOI: 10.1061/JMCEE7/MTENG-17828


2. The introduction currently lacks a clear statement of the research gap and the novelty of this study. Authors should explicitly highlight the specific limitations or knowledge gaps addressed by their work and clarify how the use of pumice from Perote, Veracruz introduces novelty.
3. The authors mention density and specific surface area after grinding but do not specify the test methods used to determine these properties. Recommend explicitly stating standard methods or equipment used.
4. The Alkaline Activator section lacks clarity regarding the purpose of the alkaline activator. Since the title, abstract and introduction imply the use of pumice as partial cement replacement, clarify why NaOH was employed. Was pumice activated, or is it simply pozzolanic?
5. The caption of Figure 3 (line 153) mentions "Pumice sieving," but the surrounding text discusses and the image shows mixture preparation, not sieving. The figure illustrates mortar preparation, the caption must reflect this accurately.
6. Consider briefly stating the loading rate used in the compression test, as recommended by the standard (ASTM C109), for completeness and reproducibility.
7. Throughout the manuscript, several instances of repetition, redundancy, and linguistic inaccuracies were noted. In particular, descriptions of methodologies (such as drying, sieving, and mixing procedures) and discussions of the results (mechanical properties, statistical analysis) were overly repetitive, reducing clarity and conciseness. Furthermore, numerous grammatical errors and awkward phrasings negatively impact readability and overall scientific communication.

These issues must be thoroughly addressed through careful editing, proofreading, and restructuring of repetitive content. Failing to adequately resolve these points may significantly diminish the quality and clarity of the manuscript, potentially rendering it unsuitable for publication in its current form.

Comments on the Quality of English Language

7. Throughout the manuscript, several instances of repetition, redundancy, and linguistic inaccuracies were noted. In particular, descriptions of methodologies (such as drying, sieving, and mixing procedures) and discussions of the results (mechanical properties, statistical analysis) were overly repetitive, reducing clarity and conciseness. Furthermore, numerous grammatical errors and awkward phrasings negatively impact readability and overall scientific communication.

These issues must be thoroughly addressed through careful editing, proofreading, and restructuring of repetitive content. Failing to adequately resolve these points may significantly diminish the quality and clarity of the manuscript, potentially rendering it unsuitable for publication in its current form.

Author Response

Estimado revisor,

 

Agradecemos sinceramente el tiempo y el esfuerzo que dedicó a revisar nuestro manuscrito titulado "Impacto de la sustitución de piedra pómez en las propiedades del mortero: un estudio de caso sobre el rendimiento mecánico y el análisis XRD". Sus comentarios detallados y constructivos han sido fundamentales para mejorar la calidad de nuestro trabajo. A continuación, respondemos a cada una de sus observaciones:

 

No.	Comentarios y Sugerencias	Respuesta	Mensaje de texto
1	La introducción debería ampliarse para incluir un contexto más amplio de los materiales de construcción sostenibles. En particular, los autores deben discutir los enfoques recientes que los investigadores están investigando para mejorar la sostenibilidad y las propiedades termofísicas de morteros y hormigones, como los materiales cementosos suplementarios (SCM) y los aditivos de base biológica. Para SCM (por ejemplo, arcilla, cenizas volantes, escorias de acero), considere el estudio reciente: DOI: 10.3390/buildings14123906 Para materiales biocompuestos que mejoran la temperatura, los estudios relevantes recientes incluyen: DOI: 10.1016/j.enbuild.2014.05.032 DOI: 10.1061/JMCEE7/MTENG-17828	Agradecemos su atenta sugerencia. La introducción se ha revisado para presentar un contexto más amplio sobre los materiales de construcción sostenibles. Hemos incorporado literatura relevante que aborda los avances recientes en SCMs y aditivos de base biológica, destacando su papel en la mejora de la sostenibilidad y el comportamiento termofísico de morteros y hormigones. Esta adición refuerza la justificación y pertinencia de nuestro estudio.	Línea 42. Líneas 46-63. Línea 69. Líneas 72-80.
2	En la introducción, en la actualidad, no se expresa con claridad el vacío de investigación y la novedad de este estudio. Los autores deben resaltar explícitamente las limitaciones específicas o las brechas de conocimiento abordadas por su trabajo y aclarar cómo el uso de piedra pómez de Perote, Veracruz introduce novedad.	Gracias por el perspicaz comentario. Hemos aclarado la brecha de investigación y enfatizado la novedad de nuestro estudio en la introducción revisada. Específicamente, destacamos la evaluación integral de la piedra pómez Perote como una alternativa viable al cemento Portland, enfocándonos en su desempeño mecánico y microestructural bajo diversos niveles de reemplazo. Este estudio contribuye a la literatura al demostrar el potencial de este material volcánico infrautilizado como aglutinante sostenible.	Líneas 81-86
3	The authors mention density and specific surface area after grinding but do not specify the test methods used to determine these properties. Recommend explicitly stating standard methods or equipment used.	Agradecemos el comentario del revisor. El manuscrito ha sido actualizado para incluir la siguiente información: después de la molienda, el material se tamizó utilizando una malla Nº 200 (0,075 mm), siguiendo la norma ASTM C136-14. La densidad real (sólida) de 2358 kg/m³ se determinó con base en la norma ASTM C188-17. Además, se reportó una superficie específica de 600 m²/kg, haciendo referencia a Cabrera Luna et al. (2019), quienes trabajaron con materiales volcánicos similares.	Lines 109-113
4	The Alkaline Activator section lacks clarity regarding the purpose of the alkaline activator. Since the title, abstract and introduction imply the use of pumice as partial cement replacement, clarify why NaOH was employed. Was pumice activated, or is it simply pozzolanic?	Thank you for the observation. Many pozzolanic materials require chemical activation to enhance their reactivity as SCMs. In this study, sodium hydroxide (NaOH) was used as an alkaline activator due to the partially amorphous aluminosilicate structure of the pumice. NaOH was selected based on its availability, low cost compared to other activators (e.g., KOH, Mg(OH)₂), and ease of preparation at controlled molar concentrations. Its use promoted a more efficient pozzolanic reaction and improved the cementitious performance of the mixture. These clarifications have been added to the manuscript along with relevant citations.	Lines 116-128.
5	The caption of Figure 3 (line 153) mentions "Pumice sieving," but the surrounding text discusses and the image shows mixture preparation, not sieving. The figure illustrates mortar preparation, the caption must reflect this accurately.	Thank you for pointing this out. The caption of Figure 3 has been corrected to accurately describe the content shown, which corresponds to mortar preparation.	Line 153
6	Consider briefly stating the loading rate used in the compression test, as recommended by the standard (ASTM C109), for completeness and reproducibility.	We appreciate this suggestion. The loading rate has been included in accordance with ASTM C109/C109M-20. It is now specified that the compressive strength tests were performed at a loading rate of 0.9 ± 0.2 MPa/s, maintained constant until specimen failure. This ensures test integrity and reproducibility.	Lines 174-181
7	Throughout the manuscript, several instances of repetition, redundancy, and linguistic inaccuracies were noted. In particular, descriptions of methodologies (such as drying, sieving, and mixing procedures) and discussions of the results (mechanical properties, statistical analysis) were overly repetitive, reducing clarity and conciseness. Furthermore, numerous grammatical errors and awkward phrasings negatively impact readability and overall scientific communication.	We take this comment very seriously. The manuscript has undergone a thorough language and structure revision. Redundant phrases have been removed, grammatical errors corrected, and the overall flow improved to enhance clarity and scientific readability.	Lines 90-98. Lines 102-106. Lines 109-113. Lines 130-141. Lines 145-172. Lines 174-181. Lines 234-252. Lines 257-270. Lines 273-277. Lines 280-287. Lines 291-299. Lines 302-312.

 

 

We look forward to your hopefully positive response,

 

With kind regards,

 

 

Joaquin Sangabriel-Lomeli

Corresponding Author

Email: jsangabriell@itsm.edu.mx

 

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is devoted to a relevant topic: replacing traditional Portland cement and materials based on it in construction with alternative but no less effective cementless analogs, which also reduce the negative environmental impact of Portland cement on the environment.
A large volume of research has been conducted in the work.
The article clearly expresses the purpose of the study, traces scientific novelty, and formulates practical significance.
The conclusions fully correspond to the stated purpose of the study.
However, there are some of the following comments on the manuscript, aimed at improving the quality and understanding of the idea of ​​the manuscript:

Lines 32. Keyword «Activated» should be changed. Perhaps the authors meant «Activation» or «Activated ???? (what)». Keyword «substitution» is also poorly chosen. It should indicate: substitution of what??? Please review this.
Line 123. «…resulting in a density of 2358 kg/m³…». Please clarify what density is indicated here: real or bulk?
Lines 141-143. «… Subsequently, the solid materials (sand and Portland cement) are dry-mixed. The alkaline activating solution is then added to the pumice, and the mixture is combined with the solid materials… ». Please explain why this method of mixing the components was chosen? Why is the pumice first mixed with the alkaline solution and then mixed with the rest of the solid phase? Was the following mixing method considered: mixing 3 types of solid-phase components (Portland cement, sand and pumice) and then mixing them with the alkaline solution?
Line 199. Here, «low quartz» should be replaced by «low reactive quartz»;
Line 203. Here, «low-phase quartz» should be replaced by «crystalline quartz»;
Line 222. Figure 5. Here, «Volumetric Mass» should be replaced by «Average density». Also use the term "Average density" instead of "Volumetric Mass" in the manuscript;
Line 268. Figure 6. On the Y-axis: replace "Mpa" by "MPa";
Line 271. Replace the numbering of section 3.3. "Analysis of Variance" by "3.4";
Line 322. Figure 7 is missing from the manuscript, please check it;
Line 368. "…..he results from the analysis of variance in Table…". The capital letter "T" is missing from the beginning of the sentence.

Author Response

Dear Reviewer,

We greatly appreciate you taking the time to review our manuscript titled "Impact of Pumice Substitution on Mortar Properties: A Case Study on Mechanical Performance and XRD Analysis." Your detailed and constructive comments were very helpful and have allowed us to improve the quality of our work. Below, we respond to each of the comments you provided:

 

No.	Comments and Suggestions	Response	Text
1	Lines 32. Keyword «Activated» should be changed. Perhaps the authors meant «Activation» or «Activated ???? (what)». Keyword «substitution» is also poorly chosen. It should indicate: substitution of what??? Please review this.	We appreciate your observation. The term "Activated" has been corrected to "Activation" and "substitution" to "cement substitution" to improve the clarity of the study's purpose.	Line 32
2	Line 123. «…resulting in a density of 2358 kg/m³…». Please clarify what density is indicated here: real or bulk?	n response to your comment, we confirm that the indicated density corresponds to the real or solid density, obtained from pumice solid particles passing through the No. 200 sieve, according to ASTM C188-17. This information has been specified in the text..	Line 112
3	Lines 141-143. «… Subsequently, the solid materials (sand and Portland cement) are dry-mixed. The alkaline activating solution is then added to the pumice, and the mixture is combined with the solid materials… ». Please explain why this method of mixing the components was chosen? Why is the pumice first mixed with the alkaline solution and then mixed with the rest of the solid phase? Was the following mixing method considered: mixing 3 types of solid-phase components (Portland cement, sand and pumice) and then mixing them with the alkaline solution?	The mixtures were prepared following the usual method for geopolymeric mortars, which involves a two-step process: first, the alkaline solution (NaOH + H₂O) is prepared; subsequently, the pumice is activated with this solution. It is then mixed with Portland cement and finally homogenized with sand and water to achieve the desired workability. The alternative approach of mixing all solid materials first and then adding the alkaline solution was considered; however, this method could lead to non-homogeneous activation of the pumice, which could negatively affect the mechanical properties of the mortar. Therefore, the described method was chosen, ensuring more effective activation and, consequently, better properties of the final material.	Lines 145-150
4	Line 199. Here, «low quartz» should be replaced by «low reactive quartz»;	We appreciate the observation. The term has been corrected to "low reactive quartz," as recommended.	Lines 188.
5	Line 203. Here, «low-phase quartz» should be replaced by «crystalline quartz»;	The wording has been corrected, replacing "low-phase quartz" with "crystalline quartz," as suggested.	Line 192
6	Line 222. Figure 5. Here, «Volumetric Mass» should be replaced by «Average density». Also use the term "Average density" instead of "Volumetric Mass" in the manuscript;	We appreciate the suggestion. The term "Volumetric Mass" has been replaced by "Average density" both in the text and in the title and axis of Figure 5.	Figure 5. Line 207, 220, 222, 226.
7	Line 268. Figure 6. On the Y-axis: replace "Mpa" by "MPa";	The observation has been addressed, and the notation on the Y-axis of Figure 6 has been corrected, replacing "Mpa" with "MPa".	Figure 6.
8	Line 271. Replace the numbering of section 3.3. "Analysis of Variance" by "3.4";	The section numbering has been corrected, changing it from "3.3" to "3.4," in accordance with the logical structure of the manuscript.	Line 256.
9	Line 322. Figure 7 is missing from the manuscript, please check it;	We appreciate your comment. It was found that the text incorrectly referenced Figure 7. This has been corrected, indicating Figure 6 correctly.	Line 310.
10	Line 368. "…..he results from the analysis of variance in Table…". The capital letter "T" is missing from the beginning of the sentence.	The typographical error has been corrected, and the capital letter "T" has been added at the beginning of the sentence.	Line 357.

 

 

We look forward to your hopefully positive response,

 

With kind regards,

 

 

Joaquin Sangabriel-Lomeli

Corresponding Author

Email: jsangabriell@itsm.edu.mx

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Satisfactory responses to my comments.

Author Response

Dear Reviewer,

 

Thank you very much for confirming that our responses to your comments were satisfactory. We deeply appreciate the time you devoted to reviewing our manuscript and the valuable suggestions that helped strengthen the quality of our work.

 

We remain attentive to the next steps in the editorial process and once again express our sincere gratitude for your kind contribution to the improvement of our study.

 

With appreciation,

 

Joaquin Sangabriel-Lomeli

Corresponding Author

Email: jsangabriell@itsm.edu.mx

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Line 153. Figure 3. The presented Mortar preparation diagram does not correspond to its description in the text. According to the diagram, before adding the alkaline solution, which already contains pumice, cement and sand are mixed together. But the text states that the solid components are added to the alkaline solution sequentially: first pumice, then Portland cement and finally sand. Please correct the diagram;

Line 207. Figure 5. The title to the Figure still uses "Volumetric Mass" instead of "Average density". Check this.

Author Response

Dear Reviewer,

 

We sincerely thank you for your careful review and for the valuable comments that have significantly contributed to improving the clarity and accuracy of our manuscript. Below, we provide specific responses to your observations:

 

Comment (Line 153 – Figure 3):

The presented Mortar preparation diagram does not correspond to its description in the text. According to the diagram, before adding the alkaline solution, which already contains pumice, cement, and sand are mixed together. But the text states that the solid components are added to the alkaline solution sequentially: first pumice, then Portland cement, and finally sand. Please correct the diagram.

Response:

Thank you very much for this precise observation. We acknowledge that the original diagram in Figure 3 did not accurately represent the mortar preparation process described in the manuscript. Specifically, pumice is first activated with the alkaline solution, followed by the incorporation of Portland cement and then sand. To resolve this inconsistency, we have updated Figure 3 to clearly reflect the correct sequence of preparation steps:

Preparation of the alkaline solution (NaOH + water);

Activation of pumice with the alkaline solution;

Addition of cement;

Incorporation of sand;

Final mixing to obtain the mortar.

The revised figure now fully aligns with the methodology section of the manuscript.

 

Comment (Line 207 – Figure 5):

The title to the figure still uses "Volumetric Mass" instead of "Average density". Please verify this.

Response:

We appreciate your attention to this detail. The caption of Figure 5 has been corrected, and the term "Volumetric Mass" has been replaced with "Average Density" to reflect the proper terminology. The figure caption now reads:

"Figure 5. Properties of mortar mixes: (a) Fluidity (%) and (b) Average density (kg/m³). The recorded values are presented with their respective meaning."

 

We remain grateful for your constructive feedback, which has greatly contributed to the improvement of our manuscript.

 

With kind regards,

 

Joaquin Sangabriel-Lomelí

Corresponding Author

Email: jsangabriell@itsm.edu.mx

Author Response File: Author Response.docx