From Laboratory to Building Scale: A Digital-Twin Methodology for Resilience-Oriented Assessment of RC Infrastructure Using Waste Wool-Fibre Cementitious Materials

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper proposes a method based on OpenBIM and digital twins to scale up the use of waste wool fiber cementitious materials from the laboratory scale to the building scale, comparing two structural schemes: RC CONV and RC WOOL. The topic selection of this paper is novel, the thinking logic is clear, the experimental sentence is relatively sufficient, the data volume is large, and the quantitative results are clear. The research results can be applied to engineering scenarios such as structural design, green building material selection, BIM low-carbon assessment, and resilient buildings. It is recommended to make modifications to the following issues before accepting.

(1) Line 79, regarding the current research status, the relevant descriptions of RC-WOOL are still relatively scarce. It is suggested to highlight the research achievements of RC-WOOL in digital modeling

(2) Line 151, this article adopts stages A1-A3 to conduct LCA evaluation. Has consideration been given to later stages such as construction, use, maintenance, and demolition

(3) On line 379, it seems insufficient to only use Compressive strength and Flexural strength to describe the properties of wool fibers

(4) Line 418, has the emission of carbon dioxide been calculated in detail?

(5) Line 537, The description of the conclusion is overly lengthy. It is recommended to directly express key data using numbers.

Author Response

For responses, please see attached document.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This article addresses  integrating cement materials with recycled wool fibers into an open BIM workflow to assess the quantity and environmental impact of materials at the construction level. This research is well-structured, clearly articulated, and represents a coherent methodological process that extends from the properties of materials derived from the literature to BIM-based implementations. This topic closely aligns with the current interest in evaluating the stability of circular construction materials and digital twins.

However, the manuscript shows potential key elements that need to be extensively revised.

 1. Collaboration and research
This manuscript currently simultaneously represents aspects of experimental, computational, and resilience-based research, which causes confusion in its scientific direction. This research is methodological and based on simulations, particularly because it relies on secondary data rather than primary experimental results.

The author is encouraged to clearly define the research as a comprehensive BIM evaluation framework supported by physical properties derived from the literature. It is necessary to clearly formulate the research questions or hypotheses to guide the reader and strengthen the scientific narrative. The novelty should be expressed more clearly, especially in the context of existing research on BIM-LCA and fiber-reinforced concrete. 

2. Change the domain and use the features obtained from the literature. 
A key limitation is that the results of laboratory experiments cannot be reliably transferred to construction applications involving structural elements (such as slabs, walls, and stairs).

The reason for this change in the Rupus scale should be demonstrated more rigorously or clearly defined as an approximation based on the mediator. The variety and diversity of the cited literature, including differences in blend design, fiber treatment, and testing conditions, should be discussed. If possible, include a brief discussion on uncertainty or sensitivity to demonstrate the robustness of the assumptions used.

3. A description of stability and resilience
The debate on the relationship between fibers (for example, crack control, ductility) and the probability of repair and stiffness is conceptually interesting; however, given the evidence presented, it is currently somewhat exaggerated.

The author needs to make a clear distinction between performance indicators at the material level, as well as elasticity indicator systems (for example, vulnerability, inefficiency, recovery). I recommend reformulating the resolution to avoid referring to the direct magnitude of the resistance. 

4. Discussion on depth and critical comparison. 
It is recommended to compare the proposed materials/systems with other types of fibers or sustainable solutions for cement. Highlight the advantages and disadvantages of wool fibers compared to synthetic fibers or other natural fibers. Extend the interpretation of the results to analytical perspectives rather than a simple detailed report.

5. Engage with the most recent influential literature. 
Although the manuscript contains adequate references, it does not include enough recent high-impact research (from the last 3-5 years).

6. Conclusion
The conclusion is generally consistent with the presented results, but further improvements are needed to avoid excessive generalizations.

I Recommend Major Revision.

 

Comments on the Quality of English Language

The manuscript is generally well written and understandable, and the overall quality of English is acceptable for peer review. However, minor language editing would still be beneficial to improve precision, concision, and consistency of scientific expression.

Author Response

For responses, please see attached document.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The core contribution of this manuscript lies in translating laboratory-scale evidence on sheep-wool fiber cementitious materials into building-scale assessments of quantities, environmental impacts, and “repairability-oriented” proxy indicators through an OpenBIM/IFC workflow. The topic is interdisciplinary and innovative; however, several major issues need to be addressed:

（1）The manuscript frequently elevates the findings to claims of “resilient infrastructure” or “repairability-oriented resilience” in the abstract, introduction, and conclusion. In reality, the conclusions are inferred solely from relative changes in crack control and toughness-related metrics reported in the literature, without performing actual resilience analyses. It is recommended to temper these statements.

（2）The performance of mortar specimens cannot be directly extrapolated to structural concrete members. In Section 2.2 and Table 3, mortar test results are used as references for RC slabs, stairs, and walls. However, mortar and concrete differ significantly in terms of strength, cracking mechanisms, and the effect of reinforcement, so such direct substitution is not appropriate.

（3）Figures 2–3 and Table 6 indicate that sheep-wool fibers were added as an incremental input on top of the existing BIM element quantities to calculate environmental impacts, without adjusting the original concrete mix proportions, aggregates, or cement content. As a result, the building-scale analysis reflects incremental additions rather than actual mix replacement. It is suggested to provide a replacement mix scenario or sensitivity analysis to clarify how different fiber dosages would affect environmental and performance outcomes.

（4）The results are presented mainly in tabular form (Tables 3–7). It is recommended to include plots or other visualizations of key experimental indicators to more intuitively show material performance differences and trends.

Author Response

For responses, please see attached document.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents a new and timely methodological framework by integrating digital twin workflows based on OpenBIM and the assessment of sustainability as well as the recycling of materials based on fiber-reinforced cement. The effort to connect material evidence within the laboratory framework and evaluation within the construction framework is commendable and fills a gap in the research. This study is well-structured, clearly expressed, and supported by a coherent work process as well as a clear hypothesis.

However, some minor aspects need to be clarified and strengthened.

Some sections in the methodology (especially 2.3 to 2.5) are quite dense in content and could be improved by appropriate simplification or increased readability.
To improve clarity, consider adding a concise table highlighting the main conditions and limitations.
Throughout the manuscript, improve the clear separation between the presentation of the methodology and the application of the forecasts.

Comments on the Quality of English Language

The manuscript is generally well written and understandable, and the overall quality of English is acceptable for peer review. However, minor language editing would still be beneficial to improve precision, concision, and consistency of scientific expression.

Author Response

Response from authors to reviewer 2

This manuscript presents a new and timely methodological framework by integrating digital twin workflows based on OpenBIM and the assessment of sustainability as well as the recycling of materials based on fiber-reinforced cement. The effort to connect material evidence within the laboratory framework and evaluation within the construction framework is commendable and fills a gap in the research. This study is well-structured, clearly expressed, and supported by a coherent work process as well as a clear hypothesis.

However, some minor aspects need to be clarified and strengthened.
Some sections in the methodology (especially 2.3 to 2.5) are quite dense in content and could be improved by appropriate simplification or increased readability.

Response: We would like to thank the reviewer for this helpful comment. Sections 2.3–2.5 have been revised to improve readability. In particular, redundant explanations were removed, several overly detailed sentences were simplified, and the methodological description was streamlined while preserving the original content and logic. These revisions were intended to make the workflow easier to follow and to improve the overall clarity of the methodology. The corresponding modifications are distributed throughout Sections 2.3–2.5 and are shown with Track Changes activated.

To improve clarity, consider adding a concise table highlighting the main conditions and limitations.

Response: We would like to thank the reviewer for this helpful suggestion. To improve clarity, we have included a concise bullet-point summary of the main methodological conditions and limitations at the end of Section 2. Given that the manuscript already contains seven tables, this format was adopted to synthesise the key workflow assumptions and boundaries without adding another table. We hope that the reviewer finds this amendment appropriate and that it satisfactorily addresses the comment.

Throughout the manuscript, improve the clear separation between the presentation of the methodology and the application of the forecasts.

Response: We would like to thank the reviewer for this valuable comment. To improve the separation between the presentation of the methodology and the application/interpretation of the results, Section 2.6 has been revised and streamlined. In particular, interpretive and explanatory passages were reduced, and the text was reformulated in a more neutral methodological manner. Specifically, the original extended paragraph describing hazard-based interpretation and the justification of the additive scenario was replaced by the shorter and more focused wording: “Finally, the same categorised outputs enable a repairability-oriented comparison based on literature-derived changes in cracking and post-cracking response for wool-fibre mixes relative to RC-CONV. In this study, the RC-WOOL scenario is represented as an additive input rather than as a full mix redesign, in order to preserve consistency with the BIM-based quantity take-off.” In addition, to make the scope of the methodology clearer before the Results section, we now conclude Section 2 with a concise summary of the main methodological conditions and limitations of the proposed workflow. This addition was intended to clarify the boundaries, assumptions, and interpretive scope of the methodology.

We would like to sincerely thank the reviewer for the careful evaluation of the manuscript and for the constructive comments provided. The suggestions have been very helpful in improving the paper. We greatly appreciate the reviewer’s input and hope that the revisions made satisfactorily address the comments raised.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The revised manuscript has addressed the reviewer comments satisfactorily. The authors have clarified the scope and positioning of the study, and have provided a clearer explanation of the methodological assumptions and limitations, particularly regarding the extrapolation from material-scale evidence to structural applications, the use of mortar specimens as proxy evidence, and the treatment of wool fibres as an incremental input rather than a full redesign of the concrete mix in the environmental assessment. In addition, the revised version improves the presentation of the results by including more effective visual support, which makes the main findings easier to follow. Overall, the manuscript is now more coherent, transparent, and carefully presented than the previous version. My recommendation is to accept the article.

Author Response

Response from authors to reviewer 3

The revised manuscript has addressed the reviewer comments satisfactorily. The authors have clarified the scope and positioning of the study, and have provided a clearer explanation of the methodological assumptions and limitations, particularly regarding the extrapolation from material-scale evidence to structural applications, the use of mortar specimens as proxy evidence, and the treatment of wool fibres as an incremental input rather than a full redesign of the concrete mix in the environmental assessment. In addition, the revised version improves the presentation of the results by including more effective visual support, which makes the main findings easier to follow. Overall, the manuscript is now more coherent, transparent, and carefully presented than the previous version. My recommendation is to accept the article.

Response: We would like to sincerely thank the reviewer for the careful evaluation of the revised manuscript and for this very positive assessment. We greatly appreciate the recognition of the improvements made in response to the previous comments and are grateful for the reviewer’s constructive feedback throughout the entire process and for the final recommendation of accepting the article.