Natural Fibers: An Alternative for the Reinforcement of Expansive Soils
, Luis Carlos Sandoval-Herazo 2, Sergio A. Zamora-Castro 3, Rodrigo Vivar-Ocampo 4 and David Reyes-Gonzalez 2,*
Round 1
Reviewer 1 Report
the manuscript requires more work on scientific processing and discussions.
the manuscript seems a report to me not a scientific work.
Author Response
Point 1: The manuscript requires more work on scientific processing and discussions..
Response 1: In response to this point, work is done on the structure of the document to present in more detail the contributions of the revised works, including the information in Figure 1 that provides a classification of the revised fibers, Figures 2, 3 and 4 that refer to the analysis of the regions with the greatest contribution in the development of research on the use of natural fibers in soil stabilization, Figure 5 showing a location diagram of articles of soil reinforcement with fibers, and Figure 6 showing SEM images with the effect of NaOH as an alkaline agent on the mercerization of natural fibers. Additionally, Table 1 shows the selection criteria of the scientific articles considered for this review, while Tables 2 – 9 shows the analysis of soil stabilization studies with the use of natural fibers considering chemical treatments, the analysis of the characteristics of the fibers applied (length, diameter and dosage), and the analysis of mechanical tests to evaluate engineering properties of modified soils. The content of section 2 is replaced to show the research methodology and selection of works for the development of this review. The content of section 6 is modified to show the effect of alkaline treatments to improve the performance of natural fibers in soil reforcement. The content of section 7, results and discussions is modified, presenting an analysis for each of the 7 fibers addressed in this review, in addition to including the description of the main trends that should be addressed by current and future work in relation to the use of natural fibers for soil reinforcement. In addition, the content of section 8 is enriched, addressing the conclusions reached by the authors of this review.
Point 2: The manuscript seems a report to me not a scientific work.
Response 2: After the modifications made, the review shows a further analysis of current trends in the use of natural fibers from a better structured scientific approach.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The topic is very meaningful， but the whole paper is similar to a popular science articles. At the same time, the content is not well organized.For each studies mentioned in the paper, the following contents should be introduced, what the problems were concerned, which kind of methods were used and how about results. During introduction, the specific index should be give.
Author Response
Response to Reviewer 2 Comments
Point 1: The topic is very meaningful, but the whole paper is similar to a popular science articles.
Response 1: In relation to this point, the topic raises a rather novel technique regarding the reinforcement of soils with a more sustainable approach, which contributes significantly to the reduction of greenhouse gas emissions produced by many of the techniques currently used for this purpose. The new version of the document shows several modifications, made with the aim of making it more detailed and better structured to serve as a reference study for new research on the subject.
Point 2: At the same time, the content is not well organized.
Response 2: With respect to this point, modifications made to the text incorporate in the introduction a paragraph describing the sequence of information presented in the article, new sections are added, to present a better description of the research methodology, followed by a description and classification of the soils, showing specifically the characteristics of the expansive soils, the concept of soil stabilization, contributions from work applying natural fibers for soil reinforcement and a chemical technique for natural fiber treatment; In addition, the results and discussions section shows the most detailed analysis of the information acquired from the scientific articles reviewed, as well as the conclusions of the same.
Point 3: For each studies mentioned in the paper, the following contents should be introduced, what the problems were concerned, which kind of methods were used and how about results.
Response 3: In relation to this point, for the research carried out for each fiber, it was carried out a small analysis of the problems observed by the researchers in their different regions and that motivated them to advance their explorations on the topic addressed.
Point 4: During introduction, the specific index should be give.
Response 4: With respect to this point, in the introduction a paragraph is incorporated that lists and describes the different sections that make up the document, in order to place the reader in the content of the review.
Author Response File: Author Response.docx
Reviewer 3 Report
In the present work, Reyes-Gonzalez and coworkers bring into perspective geotechnical engineering, in particular the use of natural fibres to reinforce expansive soils.
The overall review reads relatively well, however considering that the subject is gaining momentum only recently, the volume of available literature currently is scarce. Therefore, I acknowledge that writing a comprehensive review at this stage may be too early or challenging, but with some creativity, the authors may be able to reformulate a minireview or a perspective-style article.
In the present review article, I did not see the authors going into the depths of the matter. Reinforcement of soils with natural fibres can be discussed from a construction chemistry and mechanics point, but the article carried virtually nothing on this.
Further on, I also feel that the authors use a “salami” approach with their figures showing geographical points where particular soil reinforcement has been tested. This is not meaningful. The authors can simply use one world map and use different coloured dots to distinguish between bamboo, jute, oil palm etc. stabilised soils and if needed can add a table for the additional information.
The conclusion and the discussion article only repeat what has been written in the abstract. What is the new wisdom that the authors gained through the review of the available works? Of course, soil containing added natural fibres will be mechanically stronger than not reinforced ones.
Author Response
Response to Reviewer 3 Comments
Point 1: In the present work, Reyes-Gonzalez and coworkers bring into perspective geotechnical engineering, in particular the use of natural fibres to reinforce expansive soils.
Response 1: Indeed, it is the focus of this review article, to make a review of the work done in recent years in this novel technique, for the reinforcement of soft soils with the use of waste materials, as a more environmentally friendly technique compared to current conventional techniques, of low cost and that contributes to mitigate the problems due to the poor disposal of residues of agro-industrial processes.
Point 2: The overall review reads relatively well, however considering that the subject is gaining momentum only recently, the volume of available literature currently is scarce. Therefore, I acknowledge that writing a comprehensive review at this stage may be too early or challenging, but with some creativity, the authors may be able to reformulate a minireview or a perspective-style article.
Response 2: In fact, the availability of articles related to the subject is not very abundant in the different databases, modifications were made to the manuscript incorporating new contributions, tables, graphs and analysis as well as more detailed conclusions regarding the information collected in the reviewed articles, indicating recent trends and future approaches to address in the development of research on this topic.
Point 3: In the present review article, I did not see the authors going into the depths of the matter. Reinforcement of soils with natural fibres can be discussed from a construction chemistry and mechanics point, but the article carried virtually nothing on this.
Response 3: From the modifications made to the review article, a greater description of the results carried out by the work addressed is given, considering the mechanical properties studied and the characteristics of the fibers that are worked, through the incorporation of tables for each type of fibers reviewed, and a subsequent analysis of the input variables in the research and that correspond to some physical properties of the fibers, as well as the response variables that correspond to mechanical properties of soils. As for the chemical construction, similar to the revised works is not addressed in depth however, derived from this review, in the discussions the need to focus a greater effort on works that address the chemical and mechanical relationships of fiber-soil interactions is pointed out, given the scarcity of published works on this subject. Additionally, it incorporates the theme of a chemical treatment (mercerization) carried out on natural fibers, prior to their use in the reinforcement of clay soils.
Point 4: Further on, I also feel that the authors use a “salami” approach with their figures showing geographical points where particular soil reinforcement has been tested. This is not meaningful. The authors can simply use one world map and use different coloured dots to distinguish between bamboo, jute, oil palm etc. stabilised soils and if needed can add a table for the additional information.
Response 4: In response to your comment, it´s replaced the figures presented previously and these are summarized in two new figures in which the countries of origin of the revised articles are more clearly indicated. Additionally, tables are included with the information of the variables considered with respect to the fibers used and the results obtained in the reviewed investigations.
Point 5: The conclusion and the discussion article only repeat what has been written in the abstract. What is the new wisdom that the authors gained through the review of the available works? Of course, soil containing added natural fibres will be mechanically stronger than not reinforced ones.
Response 5: In response to your comment, an extension of the discussions and conclusions of the document is made, making a greater analysis of the information collected in the reviewed articles, incorporating information from the results of mechanical tests, as well as the research trends aimed at a greater understanding of this technique, as well as the opportunities to replicate its application in other territories.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
manuscript improved
Author Response
Response to Reviewer 1 Comments
Point 1: Manuscript improved
Response 1: We appreciate your consideration and contribution for improving of this manuscript.
Author Response File: Author Response.docx
Reviewer 2 Report
It is Ok this time.
Author Response
Response to Reviewer 2 Comments
Point 1: It is Ok this time.
Response 1: We appreciate your consideration and contribution for improving of this manuscript.
Author Response File: Author Response.docx
Reviewer 3 Report
The authors have positively responded to my comments from the previous peer-review stage.
I would finally recommend that the authors remove the frames from Figure 3 and Figure 4.
Also if they reuse figure 6 as published in another article, they need to provide permissions for reuse.
Similarly, figure 1 also seems to use some photographs - permissions originality should be clarified with the editorial office.
Author Response
Response to Reviewer 3 Comments
Point 1: The authors have positively responded to my comments from the previous peer-review stage.
Response 1: We appreciate your consideration and contribution for improving of this manuscript.
Point 2: I would finally recommend that the authors remove the frames from Figure 3 and Figure 4.
Response 2: attending your suggestion, frames from figure 3 and figure 4 have been removed.
Point 3: Also if they reuse figure 6 as published in another article, they need to provide permissions for reuse.
Response 3: the figure 6 has the main purpose to visualize the effect of mercerization on fibers. Then, the ilustrative content of reference 67 (figure 6 of manuscript) is subtituted by a descriptive content, in third paragrhap of the section 6 “Mercerization of fibers”, followed by a paragrhap describing the content of new figure 6, which shows now images of alkaline treated wood fiber from optical microscope taken by our research group. Whit this modification, we avoid the possible problem related to the use of images with no permissions for reuse.
Point 4: Similarly, figure 1 also seems to use some photographs - permissions originality should be clarified with the editorial office.
Response 4: attending your observation, images used in figure 1 have been modified with similar images with no copyrigth taken from https://unsplash.com.
Author Response File: Author Response.docx
