Strength and Microstructure Characteristics of Metakaolin-Based Geopolymer Mortars with High Water-to-Binder Ratios

Round 1

Reviewer 1 Report

Dear Authors

I find this article start with a good aim, during its presentation, finally to conclusion, the aim has been shifted a lot.  Such the abstract starts on demanding mechanical strength  at water to binder ratio 0.75 to 0.95, aims at high water to binder ratio for god mechanical strength. Then the conclusion mention at ratio of H20/na2O and SiO2/Al2O3 without mention mechanical strength. 

 

So i found a bit mismatch in presentation. Authors need to be coherent with their approach. Such as Figure 5 , very difficult to interpret and its unnecessary.  As authors already calculated porosity in Figure 6 using reliable method. Figure 7, 8 is nice, but the presentation and drawing should improve. 

Finally although in title authors claim about microstructure, hardly i see any SEM or OM pictures regarding this.  Some related articles need to consider for this study

Thermal Characterization of Metakaolin-Based Geopolymer

JOM, 1-5, 2017.  An Application Review of Fiber-Reinforced Geopolymer Composite  

Fibers  9 (4), 23 (2021)

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In this manuscript, the authors presented a comprehensive study over the preparation and characterization of a metakaolin-based geopolymer mortar with high water to binder ratio. However, they may need to address the following concerns before publication:

• More structural information regarding the phases, boundaries, and their distributions of the metakaolin-based mortar, i.e., SEM images and photographs, may need to be provided to better understand the differences in the mechanical strength of metakaolin-based mortars prepared by different recipes.
• The mechanism for the inverse proportional correlation between mechanical strength and H₂O/Na₂O ratio may need to be discuss more detailedly either in a chemical or physical aspect.
• Specific units may need to be added in the Tables.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear Authors and  Editor

The article has been improved significantly based on reviewer comments. However there are some points missing to accept in present form. i would say authors donot care about reviewer comments much. Such as Fig. 7 is too enlarge and out of format. Fig 8, 9 , Y axis is hardly visible, there is a faint line.  One of the related article author should consider

Thermal Characterization of Metakaolin-Based Geopolymer

  JOM, 1-5, 2017.   After this modification i suggest for acceptance. 

Author Response

Dear,

I'm sorry that you feel that we do not care about the reviewer's comments, as we did follow your original remarks as much as possible. I hope that in the current revision your additional remarks are met as well:

• Figure 7 was rescaled to fit the page
• Figure 8: We have increased the line size of the axes for both (a) and (b)
• Figure 9: The reason the original y-axis was set as a low visibility, is because you define new axes in the biplot (the dashes ones in the figure). We have increased the line size for the original axes.
• References: In the original revision we did add one of your two suggested papers as we felt that it best fit the narrative we present in the manuscript. We have added your additional reference as well.

Best regards,

Dr. Lander Frederickx