Component-Based Model for Building Material Stock and Waste-Flow Characterization: A Case in the Île-de-France Region

Round 1

Reviewer 1 Report

In this study, the component-based BTP-Flux model was proposed to describe in detail the building stock and building waste flow in Ile-de-France region for a long time series. The method was novel and the content was rich, but there were still some problems to be solved. Specific problems are as follows:

1. From the perspective of content, building stock and building waste flow are the focus of the study, while from the perspective of title, the study focuses more on building waste flow. Would it be better if "stock" was added in the title?
2. Abstract lacks a summary of the results, and it is suggested to be supplemented.
3. It would be better for other researchers to use your model to extend relevant researches if you could write down software and drawing tools.
4. What are the scientific problems and objectives of this study? It is suggested to make intuitive explanations in the introduction to enhance the logic of the research.
5. What is the four main elements of the BTP-Flux model in lines 142-143?
6. In lines 502-503, the paper shows that the retained sample comprises 88,749 residential buildings and 12,603 non-residential buildings, but figure 5 shows 88688 residential buildings and 12632 non-residential buildings, which needs to be confirmed.
7. In lines 510-511, for residential houses, only period P2 was analyzed, but for non-residential houses, all periods were considered. Why is P2 (1945-1970) only considered for residential buildings? Please explain the rationality.
8. In Table 4, the column name of “proportion” or “ratio” seems to be more appropriate than “%”.
9. Both discussion and conclusion include limitations and future prospects, which are suggested to be explained in one chapter.
10. Conclusion is a summary of the research work, including the main results, validity, novelty, and research significance. Conclusion in this paper fails to cover the important research results, which is suggested to be supplemented.

Author Response

Attached file

Author Response File: Author Response.docx

Reviewer 2 Report

To deal with the increasing demolition waste problem, this paper presents the BTP-flux model, based on a bottom-up macro-component approach which allows the multiscale characterization of construction materials and the estimation of demolition waste flows. The paper mainly used data mining, analytical techniques, and GIS tools for data collection and analysis. The proposed model was empirically analyzed by using samples from French buildings. Overall the paper is interesting and would merit the community of construction and demolition waste management. I list my key comments as follows:

1. I would suggest the paper to provide full name of some abbreviations when they first appear, such as GIS, BTP-flux, etc. Otherwise the readers would not well understand the terms.
2. The introduction is too lengthy. I would strongly suggest the paper to focus more on the proposition of the core research question(RQs). That is to say, to enhance the contents regarding what is the RQ and why it is important particularly to the BoK in waste mgt.
3. Before defining the research objectives, the paper should state clearly the overall aim of the research and relate the aim to existing related research outcomes.
4. Does the methods for measurement and estimation developed by the research team or from some sophisticated research? I think the rational is critical for enhancing the quality of the paper.
5. I searched through Google Scholar and found that there are some leading research teams worldwide in studying construction and demolition waste management issues, including Yuan H.P. (you cited the reference 10 from the team) and Vivian Tam. I would strongly suggest the paper to get more statements and arguments supported by the research findings from the two research teams.

Author Response

Attached file

Author Response File: Author Response.docx

Reviewer 3 Report

This study has done a detailed and comprehensive building and material stock and flow estimation in the Ile-de-France region. It is a very interesting case to shown how to use MFA to guide urban metabolism and waste management. I suggest a further revision needs to be done which could help improve this manuscript.

 

For method, it seems too many details have been shown for the model but lacks a clear logic flow, especially for those audiences do not familiar with BTP-Flux model and related database. Another question is that could this case be reproduced in other cities without this detailed database? If not, how could they do?

For material flow assessment, how could a demolition rate be assessed based on the individual-building level rather than an urban-level? It seems that there are not many spatially explicit results have been shown in the result section but authors highlighted the significance of these previous studies.

For results, I further suggest authors could highlight the cross-validation of predicted CDW with in-situ values.

 

For discussion, it could enrich the practical implication of this study for the study area and how to use these results to guide related planning.

Author Response

"Please see the attachment." 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I read the revisions and respondes carefully. The major concerns raised were all addressed by the authors and I suggest acceptance. Thanks.