Geomechanical Behaviour of Recycled Construction and Demolition Waste Submitted to Accelerated Wear
Round 1
Reviewer 1 Report
- The article reflects an important issue, and a worldwide concern, which is construction and demolition wastes and what to do with them;
- It is not clear the connection between the gap observed in the literature, and the objective and the experimental plan carried out;
- It was interesting to have an analysis of the properties presented in Tables 1 and 2 compared to conventional materials;
- Reference is missing line 221;
- It would be interesting to compare these results with material materials, used for the fins presented as potential uses of these CDWs, to see the real potential of the application of these materials;
- There is a lack of clear discussion of why there are no major differences between the original samples and those that underwent accelerated wear;
- The conclusion should really reflect the conclusions of this study and the way forward, and not just list the findings of the discussion.
Author Response
Point 1: It is not clear the connection between the gap observed in the literature, and the objective and the experimental plan carried out;
Response 1: Some studies in the literature were better described (lines 54 to 87) and the connection between the objectives and the experimental plan was better, so the research gap was better clarified (lines 89 to 105).
Point 2: It was interesting to have an analysis of the properties presented in Tables 1 and 2 compared to conventional materials;
Response 2: Some properties of the CDW materials ware compared to conventional materials used for earth structures (lines 136 to 144).
Point 3: Reference is missing line 221;
Response 3: In line 221, no references are not necessary considering that the text is only reporting the results, the text is not supported by the literature.
Point 4: It would be interesting to compare these results with materials, used for the fins presented as potential uses of these CDWs, to see the real potential of the application of these materials;
Response 4: A comparison of the results with conventional materials and also with results found by other authors for CDWs was included (lines 285 to 296).
Point 5: There is a lack of clear discussion of why there are no major differences between the original samples and those that underwent accelerated wear;
Response 5: Only some of the parameters studied showed negligible differences between the original and worn materials. The strength parameters, for instance, were significantly affected by the accelerated wear. Regarding the small differences between the respective PSD, additional comments were included, in Section 3.2.
Point 6: The conclusion should really reflect the conclusions of this study and the way forward, and not just list the findings of the discussion.
Response 6: The conclusions have been modified and new comments have been added to better present the conclusions of this work (lines 348 to 353).
Reviewer 2 Report
The manuscript is interesting and I could merits in it. But I still some suggestions for the authors as follows:
- Cluster citations like [8-16] should be avoided. Each citation should be briefly introduced.
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Too many tables were used in the section 2.1, which are a little but confusing and not reader-friendly. In my mind, table 1 & 2 could be merged into one.
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Figure 1 & 2 could be could be listed as fig.1a & 1b. It would be more logical clear.
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Figure 7-10 have not been well introduced. It is recommended to introduced these figures one by one in the main text.
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A discussion section is needed between the current section 3 and 4. Thought-provoking discussion based on the research findings should be added in this new section.
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It is not usual to acknowledge to research materials like recycled waste. It should be thought twice.
Author Response
Point 1: Cluster citations like [8-16] should be avoided. Each citation should be briefly introduced.
Response 1: Each citation was briefly introduced into the text (lines 54 to 88).
Point 2: Too many tables were used in the section 2.1, which are a little but confusing and not reader-friendly. In my mind, table 1 & 2 could be merged into one.
Response 2: Table 1 and Table 2 were merged into one (Table 1)
Point 3: Figure 1 & 2 could be could be listed as fig.1a & 1b. It would be more logical clear.
Response 3: Figure 1 and Figure 2 were listed as Figure 1a and Figure 1b.
Point 4: Figure 7-10 have not been well introduced. It is recommended to introduced these figures one by one in the main text.
Response 4: Figure 7-10 were introduced into the text (lines 243 to 247).
Point 5: A discussion section is needed between the current section 3 and 4. Thought-provoking discussion based on the research findings should be added in this new section.
Response 5: Due to the space available for the manuscript, there is no space for a new section, however new comments improving the discussion of the results were included in the results section (Section 3. Results and discussion).
Point 6: It is not usual to acknowledge to research materials like recycled waste. It should be thought twice.
Response 6: The acknowledge was withdrawn.
Reviewer 3 Report
Dear Authors
Your article reveals an important topic of reuse of crushed concrete (or general Construction Demolition Waste) in geotechnical engineering. I know many former works of C. Silva Vieira concerning this subject and I appreciate current contribution. The relevance of the chosen topic is well and voluminously substantiated. A brief review of previous studies has been made. However, from my point of view, the current "State of the Art" could be significantly improved. Some correction of minor faults may still improve the quality of the manuscript and also improve the perception of these studies by the reader.
I made a list of my general and detailed comments below.
- Please try to avoid "group references" in your introductory part. I could accept [3-5] but [8-16] is really too much. Every cited paper deserves a proper and cautious introduction to the Reader to manifest (and prove) its importance for the current study. I have an impression that you planned your paper as a short report without a wider "State of the Art" description. For a full-length article, an in-depth presentation of recent developments is rather mandatory. I'm personally a mining engineer but I know many contributions related to reuse of spoil materials for the civil engineering industry (including CDW). You may check in Scopus:
https://0-doi-org.brum.beds.ac.uk/10.1088/1755-1315/95/2/022057
https://0-doi-org.brum.beds.ac.uk/10.1088/1757-899X/867/1/012018
https://0-doi-org.brum.beds.ac.uk/10.1088/1755-1315/362/1/012132
https://0-doi-org.brum.beds.ac.uk/10.5593/sgem2017/12/S02.006
I have no personal gain from my suggestions and they are certainly not mandatory for your choice of references.
It is also important to express clearly your motivation and the goals of your study. For example, I know of a project of the earth-dam build of crushed rock fines where additional crushing in the course of embankment formation became an important issue in terms of future permeability. Several parameters were tested in your study, It would be nice to know something about the practical importance of your findings.
- Figure 6 does not tell us much on "CDW particle size distribution after degradation cycles" as all charts look pretty similar. Is there any measure to define the level of this "degradation"? Please comment.
- Referring once again to the practical issues. Could you please define the risk that the entire earth structure would be subject to cycles of wetting and drying and other impacts under study. I have an impression that except "crushing in the course of compaction" that may significantly change the permeability, all issues under study may appear only in the surface layer. Please comment.
- Concerning your conclusions. It is important to notice that you draw very general conclusions from limited testing data (just one CDW material). Please make some reservations on generalisations of your findings.
- Your reference list is not formatted to the MDPI template. I noticed that almost a half of your reference list is composed of codes and recommendations (11 documents) and canonical works (3 works, [27, 28, 31]). Please develop and/or refer directly to C.S. Vieira recent studies.
Sincerely,
Author Response
Point 1: Please try to avoid "group references" in your introductory part. I could accept [3-5] but [8-16] is really too much. Every cited paper deserves a proper and cautious introduction to the Reader to manifest (and prove) its importance for the current study. I have an impression that you planned your paper as a short report without a wider "State of the Art" description. For a full-length article, an in-depth presentation of recent developments is rather mandatory. I'm personally a mining engineer but I know many contributions related to reuse of spoil materials for the civil engineering industry (including CDW). You may check in Scopus:
https://0-doi-org.brum.beds.ac.uk/10.1088/1755-1315/95/2/022057
https://0-doi-org.brum.beds.ac.uk/10.1088/1757-899X/867/1/012018
https://0-doi-org.brum.beds.ac.uk/10.1088/1755-1315/362/1/012132
https://0-doi-org.brum.beds.ac.uk/10.5593/sgem2017/12/S02.006
I have no personal gain from my suggestions and they are certainly not mandatory for your choice of references.
It is also important to express clearly your motivation and the goals of your study. For example, I know of a project of the earth-dam build of crushed rock fines where additional crushing in the course of embankment formation became an important issue in terms of future permeability. Several parameters were tested in your study, It would be nice to know something about the practical importance of your findings.
Response 1: Some important studies in the literature about recycled CDW were included and better described so that the motivation and goals is clearer, also the “State of the Art” was improved (lines 54 to 94).
Point 2: Figure 6 does not tell us much on "CDW particle size distribution after degradation cycles" as all charts look pretty similar. Is there any measure to define the level of this "degradation"? Please comment.
Response 2: In addition to Figure 6, the exact percentage of material that passes through the specific sizes of the granulometry sieves is shown in Table 3, where, even without changing the material classification (classified as SM), it can be seen that the percentage of material passing through each sieve is different.
Point 3: Referring once again to the practical issues. Could you please define the risk that the entire earth structure would be subject to cycles of wetting and drying and other impacts under study. I have an impression that except "crushing in the course of compaction" that may significantly change the permeability, all issues under study may appear only in the surface layer. Please comment.
Response 3: Wetting-drying cycles were used as an attempt to simulate weather damaging effects. Indeed, depending on the type of earth structure being considered (e.g. retaining walls), only the superficial surface layer would be subjected to such conditions. For other types of earth structures, such as pavements, shallow foundations and slopes, authors understand the adopted procedures could simulate practical conditions. Text has been enhanced to address this comment (lines 89 to 94).
Point 4: Concerning your conclusions. It is important to notice that you draw very general conclusions from limited testing data (just one CDW material). Please make some reservations on generalisations of your findings.
Response 4: The conclusions were changed, reinforcing the specificity for the particular type of CDW studied (lines 322 to 323 and lines 348 to 353).
Point 5: Your reference list is not formatted to the MDPI template. I noticed that almost a half of your reference list is composed of codes and recommendations (11 documents) and canonical works (3 works, [27, 28, 31]). Please develop and/or refer directly to C.S. Vieira recent studies.
Response 5: The formatting of references has been changed to the MDPI template. Also, new references to better support the literature review were added (lines 54 to 94).
Round 2
Reviewer 1 Report
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Reviewer 2 Report
All my suggestions have been well tackled, and I recommend to accept the paper in the current version.
Reviewer 3 Report
Dear Authors,
After revision the article "Geomechanical Behaviour of Recycled Construction and Demolition Waste Submitted to Accelerated Wear" by Marina Paula Secco, Giovani Jordi Bruschi, Castorina S. Vieira and Nuno Cristelo is submitted for re-review.
The revised version of the manuscript is significantly improved compared to the previously presented one, which allows the authors to present their research more clearly and readers to understand it.
The authors took into account my remark 1 and made adjustments accordingly. However, the implementation leaves a lot to be desired. As I noted earlier: "For a full-length article, an in-depth presentation of recent developments is rather mandatory" and I can not get away from this postulate. You have added a number of references and removed some references. However, from my point of view, this is not enough. You are claiming to publish your research in an international edition, therefore, the relevance of the disclosed issue should be of international importance. But the geography of the early research you have presented is quite narrow.
Moreover, if documents and regulations are excluded from the list of references, then no more than 20 previously published studies are left, which in my view is very few. In addition, 4 papers are related to your research, and the percentage of self-citations exceeds 20%, which is a lot. At the same time, about 40% of the cited papers are from the studies of Portuguese scientists. Such proportions underestimate the relevance and significance of your work.
From my point of view, there is a need to provide a geographically broader 'Status Report' based on a wider range of diverse Eastern European, Russian, American and African references.
In my opinion: the authors need to supplement the review with research of scientists from other countries, which would expand the geography of citations, confirm the relevance and increase interest in this work of scientists from all over the world. And last but not least, a wider reference list increases the future citation potential of the study, which is a benefit for both authors and editors.
Sincerely,
