Geopolymers Based on a Mixture of Steel Slag and Fly Ash, Activated with Rice Husks and Reinforced with Guadua angustifolia Fibers
Round 1
Reviewer 1 Report
Suggestion: Along the document “guadua angustifolia” could be written in italics, is a scientific or common name.
Page 2
Line 74 and 75, How the authors determined the form (shape) and composition of the ash particles did you use SEM and EDX besides XRF?
Figure 1. What FA, BFS and CCA stand for, those abbreviations are not mentioned in the text. Better figure caption.
Page 3
Line 90 and 91, “X-ray counter. guadua angustifolia was determined by scanning electron microscopy” looks like something is missing.
Line 112 – 115, It doesn´t have sense. It is well known what “mechanical test” are for. Perhaps remove.
Line 116, The tensile strength test was performed.
Line 128, are you sure the treatment given to the guadua fiber is to eliminate the biological effect in the concrete´s quality? A better explanation should be given.
Line 133, there´s no peak at 1250 cm-1, when looking in figure 2. Better interpretation is necessary.
The authors never describe the morphological, or dimensions of the fibers, how different they are. It is not the same to use fiber with micrometric scale, as fiber with millimetric dimensions.
Page 4
Figure 2. there´s no peak at 2925 cm-1, when looking in figure 2. Better interpretation is necessary. Better figure caption. The labels do not describe the explanation in the text. Did you mean raw (untreated) fiber and treated fiber? Perhaps indicate with number the bands, as you did in figure 3.
Page5
Do you expect to have a different FTIR spectrum after adding the fibers? You didn’t include a comparative image, but you should mention that what differences could be found. You did that with the SEM images.
Line 179, the supposed fragility observed in the fibers from the SEM images, could affect the concrete performance?
Page 6
The figure the author refers to Figure 4, has number “3” instead of “4”. How long were the fibers, and their diameter?
Lines 176 – 177. Are we observing a transversal or longitudinal cut of the guadua angustifolia?
Line 177, lamellar form instead of sheets
Line 181 and 188, various or different?
Line 181, Those particles to what type of material could be related due to the irregular shape, unhydrated cement particles, aggregate, ash or what?
Lines 188 – 189, The “conclusion” comment, is ambiguous. In the other figure 4c you have concrete, therefore you have hydrated product, why the author did not observe lamellar forms?
Figure 3, most be figure 4.
Line 194 – 195. The number of the figure is 5, instead of 4.
Figure 5. size label is incorrect. According to what is given on line 195. The value given for the roughness is incorrect too. What is the cause of the “glitches” one can observe? Those glitches interfere with the observation and the real roughness.
Page 7
Referring to XRD analysis, what reference cards were used along the interpretation of the diffractograms for figures 6 and 7?
Numbers are incorrect of figures, the numbers given were 5 and 6, instead of figures 6 and 7.
In figure 6, what type of concrete was analyzed, with or without fibers? Line 214 does not mention that.
Line 225, indicator?
Line 235, by adding of when adding?
Line 236 and 240, evidenced or evident?
Line 238, due to adding or, due to the incorporation of?
Page 8
Figure 6, what samples the author is talking about? With or without fibers? This figure must be number 7.
Figure 7, must be number 8. The legends in the x axe are not readable. Correct on line 248 too.
Page 9
Figure 8 must be number 9. The legends in the x axe are not readable. Correct on line 261 too.
Line 266, establishment, what do you mean?
Line 268, it is not good to have low flexural strength when having the fiber. One expects to have a high value, compared to a control specimen. One expects a higher flexural behavior with fibers.
Lines 270 to 271, contradicts what is said previously or the author didn´t explained properly.
Line 278, younger or early ages?
Line 278 to 280, the behavior the author attributes is not properly explained, is ambiguous. Moreover, is talking about mortars, are they working with mortars or concrete?
Conclusions
From line 288, The high alkaline system should affect the guadua fibers, how do you explain that.
From line 290, What other structural components were found?
Line 292-293, most be rewritten to have coherence.
Line 295, What other crystalline compounds where found and how they could affect or enhance the concrete performance.
Line 296 – 301, what was found, you play around and do not say what was understood, regarding the fiber and the alkali activated system (concrete). Perhaps explain the chemistry involved. Maybe erase and only leave the next paragraph (line 302 – 308)
Comments for author File: 
Comments.pdf
The investigation is relavant but explanation and interpretation of the results in most of the document must be improved.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
This manuscript discusses the geopolymers based on a mixture of steel slag and fly ash, activated with rice husks and reinforced with guadua angustifolia fibers. This study has certain value for concrete engineering, but there are also some issues that need to be carefully revised before it is accepted.
(1) In the abstract, only one of “In this search,” and “In this article,” in the abstract is needed.
(2) The conclusion of the abstract is too general and not specific enough, and it is best to use data to describe the performance of the material. There are many methods written in the abstract, but there are few statements about experimental results and conclusions.
(3) The introduction section is limited and does not clearly articulate the issues and innovative points studied. In addition, the introduction section lacks strong logic and simply accumulates the research results of others without analyzing them. The introduction is suggested to be reorganized.
(4) Materials and Methods: This section lacks a detailed test plan, and it is recommended to use a list format to express the material mix proportion. After the experimental plan, provide a detailed introduction to the experimental method.
(5) The font of the coordinate axis in Figure 4 is too large and does not match the text. It is recommended to keep the font of other figures consistent with the text.
(6) In Figures 7 and 8, the font size of the horizontal axis is small, and it is strongly recommended to modify them.
(7) The maintenance period is 28 days, why does the manuscript use the expression of 27 days for analysis? which is not professional enough
(8) The conclusion is not specific enough, it is only a general and regular conclusion without specific description. It is recommended to use data support to express the experimental conclusion.
Some expressions and English writing need improvement, and the language is not concise enough.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for accepting and work on the observations made on your document. Some other comments and observations can be found...
They must revise their English along with the document.
The authors mention the fiber length but not the diameter.
Figure 2. The authors must write the "acronym" for each compound in the figure caption, as in the figure legends.
Figure 3. Suggestion, the legends must be changed, i.e. raw fiber and embedded fiber in concrete.
In the conclusion. The authors are not specific enough. It can be observe a general explanation with regular discussion and description. A better-explained interpretation of the data and experiment is needed. For instance, line 342, "and other crystalline compounds. Of course, you will find CSH structures. Which compounds and what kind of crystal structure were found, and how did they affect the concrete´s performance? Besides, did the ashes play an important role in the concrete´s performance? How, besides the pozzolanic reaction? What do you expect in aged concrete (more than 28 days).
They must revise their English along with the document.
Author Response
"Please see the attachment."
Author Response File: Author Response.pdf
Reviewer 2 Report
Thank you. The modifications basically meet the requirements. It would be even better if the conclusions of the manuscript could be further improved and improved.
The language basically meets the requirements.
Author Response
"Please see the attachment."
Author Response File: Author Response.pdf
