Balancing Environmental Impact and Practicality: A Case Study on the Cement-Stabilized Rammed Earth Construction in Southeast Rural China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

The topic of the article is interesting but the article is poorly written. The lack of rigour and the flaws of the literature review lead to some misunderstandings. The whole article must be deeply revised accordingly, in particular after reading at least Van Damme et Houben 2017 ; Pelé-Peltier et al. 2023. The discussion to back the stabilisation with cement is very weak, with no evidence, or based on inappropriate references. It is difficult to believe that in China (the second largest economy in the world), it is not possible to protect unstabilised modern rammed earth during the construction process on-site. Moreover it is possible that it is more costly to add cement compared to other materials. The understanding of European modern rammed earth is very limited. Prefabrication is actually under development in factories, but there is no consensus on this approach. The mechanization of manufacturing on-site is often preferred.

Please see the comments below for details.

P.1 line 32 : The first sentence of the introduction is not in the right place (no links with the following). Therefore the content of the sentence is not given into a context. The context is that there is not a consensus on the cement stabilisation of the earth, in particular of France and Germany, cement stabilization is very questioned. Particularly, the publication of Van Damme et Houben 2017 is not known by the authors whereas it is key to discuss the topic of the article.

Line 43-44 : the sentence is not clear.

P.2 Line 46 : « Who is profile » does not make sense

Line 57 : only rammed earth… Again out of any context, this does not make sense. Explain further what do you mean?

Line 59-60 : no academic research until the 1990s, again be more specific

Line 62 : ref [11] is not well cited, because it is about unstabilized rammed earth. ref [16] is not well cited, because it is about mortars, not rammed earth. The binder in rammed earth is clay, when cement is added it is a stabiliser, not a binder. Cement is the binder in concrete not in stabilised rammed earth. The sentence is not clear from, « or contemporary structures…

Line 63 : Martin Rauch is not an architect, he is a mason. I don’t think that he is a researcher either.

Line 67 : « Andra‘s » ???

P. 4 line 139, reinforced concrete is more used than “concrete and reinforced steel bar”

Table 1 : remove significant digits

Figure 2 is not cited in the text.

Why Figure 3 is presented ? there is no links with embodied carbon emission evidence.

P.9 Section 3.1: the section is confusing because it is said the local vernacular architecture is not rammed earth, then why using rammed earth?

Figure 8 is not clear

Line 288: the problem lies in the 2MPa requirement, (1) this can be achieved without cement, (2) why this value is so high ?

P.10, line 311-313: the argument is not correct because the comparison of stabilized rammed earth is not made with rammed earth but something unknown closer to wattle and daub. Probably unstabilised modern rammed earth (not prefabricated) would have been acceptable.

Line 317, please explain how why vandalism is a problem in the area…Again this sentence is not backed with solid reference/evidence.

Line 325-327 not clear explain why.

Line 311 to 333 again no evidence is given to back this statement.

P.11 line 340: explain how sustainability is assessed through the cost of the project. This is not usual.

Table 2: Why stabilized rammed earth is chosen instead of reinforced concrete that has less impact on the environment following Figure 4?

Paragraph lines 354-358 is repeated lines 359-352

P.12, lines 365-367: no evidence is given to the statement

Line 371: not half, twice; so the meaning is completely different

Line 371: it is said previously that modern construction materials like reinforced concrete are not available in the region, this is contradictory to the sentence.

Line 378: no it is far from holistic, for example, the end of life of the building is not taken into account, which may change the assessment, the brick can be reused whereas the stabilised rammed earth is not longer recyclable…

 

References 

Pelé-Peltier, A, R Charef, JC Morel, Factors affecting the use of earth material in mainstream construction: a critical review, Building Research & Information, 2023, https://doi.org/10.1080/09613218.2022.2070719

Van Damme, H. and Houben, H. (2017) Earth Concrete. Stabilization Revisited. Cement and Concrete Research, 114, 90-102.
https://doi.org/10.1016/j.cemconres.2017.02.035

 

 

 

 

 

 

 

 

Comments on the Quality of English Language

P1, Line 34: delete 1 after CEB

P.2, Line 80: Even (capital letter to be removed)

P. 4, Table 1 first row « title 1 » to be removed

P.5, line 150, Figure 3 not 2

Line 155 removed the sentence that is a part of the caption of Figure 4

P. 9 line 272 delete “subsubsection”; line 298 case study, not study case

Author Response

Please see the responses in detail as attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Editor,

Thank you for your invitation to review this manuscript.

1. I carefully studied the Aim and Scope of the Journal. The last sentence of the second paragraph under the title Aim and Scope of the Journal states "As a transdisciplinary journal, Sustainability encourages researchers to provide full experimental and methodological details so that results can be reproduced and assessed." The current manuscript is not in compliance with this statement and falls outside Scope of the Journal. The manuscript (1) is mainly a qualitative study with numerous questionable simulation assumptions, and (21) lacks any correlation between the simulation and the "pilot project". The manuscript does not have the technical merit and the rigor to be considered as a technical journal article.

2. May I suggest the following. In my opinion, this manuscript fits very nicely in a conference presentation.

THE END

Author Response

Please see the detail responses in attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

 

The manuscript titled “Sustainable analysis of cement-stabilized rammed earth construction in rural areas: a case study in southeast China” is an interesting study and would be a good fit for publication in Sustainability. However the article needs addressing of the following comments and updates in the manuscript before publication:

 

1.     What are the long-term durability and maintenance requirements of cement-stabilized rammed earth structures compared to brick and reinforced concrete structures? How do these factors influence the overall sustainability and economic viability of the construction methods?

2.     Can you provide more details on the lifecycle analysis of the different construction methods, including end-of-life scenarios such as demolition and potential recycling or reuse of materials?

3.     How do regional variations in soil composition, climate, and construction practices in rural China impact the performance and environmental impact of cement-stabilized rammed earth? Are there specific regions where this method is particularly advantageous or challenging?

4.     How have local communities responded to the use of cement-stabilized rammed earth? What measures have been taken to engage and educate these communities about the benefits and drawbacks of this construction method?

5.     The In figure 9. how do you measure the water resistive performance of earth walls with and without the addition of cement?

6.     The conclusion suggests exploring eco-friendly binders and updating living habits. Can you outline specific future research directions or projects that could address these areas? What methodologies would you use to test and implement these alternatives?

Author Response

Please see the details responses in attached file.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

This paper discusses the ecological sustainability of construction using locally sourced earth materials and environmentally friendly demolition methods. The study evaluates three construction scenarios: cement-stabilized rammed earth walls, fired brick walls, and localized reinforced concrete frame structures. It compares their quantitative environmental impacts and qualitative differences in adaptation, economic sustainability, and other factors within the context of rural development in China. The results indicate that cement-stabilized rammed earth walls have higher embodied carbon emissions compared to reinforced concrete frames but lower emissions than fired brick walls, while still meeting structural requirements effectively.

The subject under investigation is of interest and comprehensive but lacks well designing and writing for the scientific significance and purpose. I recommend this paper a major revision.

More detailed problems are listed as follows:

Figures 4 and 7(a) in the manuscript require improvement in clarity. It is recommended to enhance the readability;

Does the discrepancy between the building model depicted in Figure 2 and the actual building structure illustrated in Figure 5 impact the analysis results of hidden energy consumption?

There is no explanation for the tool One Click LCA database used in the manuscript. Please provide a brief explanation;

Line 400-401: Based solely on the carbon consumption shown in Figure 4, “the adverse effects of cement-based materials on the environment” cannot be directly inferred. Suggestions include quantifying adverse gas emissions and waste to confirm the potential adverse environmental impacts of cement-based materials;

There are some low-level writing errors in the paper, such as forgetting to delete the words on the template in Line 268-270, and what does the “3.1.1. Subsubsection” mean? Please carefully review the entire paper.

Comments on the Quality of English Language

English writting needs improvement. 

Author Response

Please refer to the revised version for details.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Approximately half of my comments were not properly addressed, please revise my comments and provide appropriate answers. Please do not only write "noted: the content has been revised" when you have done nothing. Explain how you have addressed the comments

Comments on the Quality of English Language

There is a lack of clarity

Author Response

Comment1: The topic of the article is interesting but the article is poorly written. The lack of rigour and the flaws of the literature review lead to some misunderstandings. The whole article must be deeply revised accordingly, in particular after reading at least Van Damme et Houben 2017 ; Pelé-Peltier et al. 2023. The discussion to back the stabilisation with cement is very weak, with no evidence, or based on inappropriate references. It is difficult to believe that in China (the second largest economy in the world), it is not possible to protect unstabilised modern rammed earth during the construction process on-site. Moreover it is possible that it is more costly to add cement compared to other materials. The understanding of European modern rammed earth is very limited. Prefabrication is actually under development in factories, but there is no consensus on this approach. The mechanization of manufacturing on-site is often preferred.

Response 1: This is research is case study in the context of low resources settlement in local, which is mainly concentrated on the rammed earth renovation for rural China. A great challenge to renovating the rammed earth building for this kind of village is the limitation of transportation and the stereotyping of house building by local residents. Therefore, this case study emphasized a specific construction organization with local community involvement and low professional management at the same time. Moreover, the transportation limitation and economic constraints are two domain factors to push the local rammed earth construction mainly relying on manpower, which might generate much more turbulence during constructions progress in comparing with the prefabrication.  And further exploration of the combined working progress with semi-prefabrication and in-situ workmanship is needed, not only to reduce the cost and the threaten of weather challenges but increase the construction efficiency and quality at the same time.

Comment 2: P.1 line 32 : The first sentence of the introduction is not in the right place (no links with the following). Therefore the content of the sentence is not given into a context. The context is that there is not a consensus on the cement stabilisation of the earth, in particular of France and Germany, cement stabilization is very questioned. Particularly, the publication of Van Damme et Houben 2017 is not known by the authors whereas it is key to discuss the topic of the article.

Response 2: 

The case study in this paper is located in an area where the level of construction is relatively low due to local economic conditions and labour shortages and where there is now widespread practice of knocking down traditional rammed-earth buildings and redeveloping brick-concrete dwellings. This is coupled with the fact that the region is mountainous and can mine its own sand and gravel supply for construction as far as the policy allows. Conventional industrialized materials such as cement, steel, and gravel are, therefore, locally affordable to the public.

Since the economic cost of delay or rework due to a lack of skilled craftsmen is higher than the cost of materials, the choice of adding cement was made based on the considerations of the villagers' craftsmen and the heads of households. On-site training for villagers on both cement-added and cement-absent construction techniques was organised.

Comment 3:Line 43-44 : the sentence is not clear.

Response 3: Noted. The content has been revised appropriately.

Comment 4: P.2 Line 46 : « Who is profile » does not make sense

Response 4: Noted. The sentence should be “Who is Profits?” cited from the books < Heringer, A., L.B. Howe, and M. Rauch, Upscaling Earth: Mateiral, Process, Catalyst. 2022.>

Comment 5: Line 57 : only rammed earth… Again out of any context, this does not make sense. Explain further what do you mean?

Response 5: This sentence has been removed and replaced with more appropriate expression.

Comment 6: Line 59-60 : no academic research until the 1990s, again be more specific

Response 6: Noted. The content has been revised appropriately.

Comment 7: Line 62 : ref [11] is not well cited, because it is about unstabilized rammed earth. ref [16] is not well cited, because it is about mortars, not rammed earth. The binder in rammed earth is clay, when cement is added it is a stabiliser, not a binder. Cement is the binder in concrete not in stabilised rammed earth. The sentence is not clear from, « or contemporary structures…

Response 7: Noted. The content has been revised appropriately.

Comment 8: Line 63 : Martin Rauch is not an architect, he is a mason. I don’t think that he is a researcher either.

Response 8: Noted. The content has been revised appropriately.

Comment 9: Line 67 : « Andra‘s » ???

Response 9: Noted. The content has been revised appropriately.

Comment 10: P. 4 line 139, reinforced concrete is more used than “concrete and reinforced steel bar”

Response 10: Noted. The sentence has been revised.

Comment 11: Table 1 : remove significant digits

Response 11: Noted. The table has been revised.

Comment 12: Figure 2 is not cited in the text.

Response 12: Noted. The content has been revised appropriately.

Comment 13: Why Figure 3 is presented ? there is no links with embodied carbon emission evidence.

Response 13: Noted. Figure 3 was removed in the revision.

Comment 14: P.9 Section 3.1: the section is confusing because it is said the local vernacular architecture is not rammed earth, then why using rammed earth?

Response 14: Noted. The main purpose of section 3.1 is to combine the actual situation of the analysed case with the construction techniques of traditional earth buildings, and in the process of transforming or rebuilding to modernisation, the converted rammed earth buildings need to greatly satisfy the needs of three generations of people living together. By observing and analysing the construction practices of local traditional rammed earth buildings and the living habits of the older generation, we will analyse what can be preserved and what needs to be improved by incorporating modern rammed earth construction techniques. Based on the technical data of the actual project and the records made during the process, it was concluded that the microclimate in the mountainous area where the case is located is subject to frequent microclimatic variations, and that irregular rainfall is the reason for hindering the construction process of the rammed-earth dwellings, and the villagers' preference for cement-stabilised practices. With limited costs and labour, it was critical to accelerate the construction schedule and reduce the frequency of rework.

Comment 15: Figure 8 is not clear

Response 15: Note. Figure 8 showed the inner details of traditional rammed earth wall filled with wooden strip to increase the tensile strength of the wall. And the right image in Figure 8 indicated a maintained pre-drilled holes for scaffolding during ramming

Comment 16: Line 288: the problem lies in the 2MPa requirement, (1) this can be achieved without cement, (2) why this value is so high ?

Response 16: The construction code in the case location requires that all housing meets a six-degree seismic protection requirement, and according to China's national seismic requirements for housing as well as vibration table experimental analyses, rammed-earth walls with a compressive strength of less than 2 Mpa can be constructed with one floor and only one floor. The average compressive strength of rammed-earth walls made of local soil without the addition of cement is only 1.5 Mpa, which is far from being able to meet the seismic requirements and the need to build two-storey houses.

Comment 17: P.10, line 311-313: the argument is not correct because the comparison of stabilized rammed earth is not made with rammed earth but something unknown closer to wattle and daub. Probably unstabilised modern rammed earth (not prefabricated) would have been acceptable.

Response 17: Noted. The content has been adjusted.

Comment 18: Line 317, please explain how why vandalism is a problem in the area…Again this sentence is not backed with solid reference/evidence.

Response 18: Noted. The content has been revised appropriately.

Comment 19: Line 325-327 not clear explain why.

Response 19: Noted. The content has been revised appropriately.

Comment 20: Line 311 to 333 again no evidence is given to back this statement.

Response 20: Noted. The content has been revised appropriately.

Comment 21: P.11 line 340: explain how sustainability is assessed through the cost of the project. This is not usual.

Response 21: Economic sustainability refers to practices that support long-term economic growth without negatively impacting social, environmental, and cultural aspects of the community.

The object of this study, on the other hand, is the construction of houses in rural areas where resources are scarce. The annual income level of the user's family members directly determines the acceptable cost of construction. Combined with the fact that the main economic income of the local population comes from labour outside the village and from farming within the village, the total annual household income and its channels are relatively stable. The total annual household income and its channels are relatively stable. This also reflects a low capacity to cope with sudden and large expenditures. In order to be economically sustainable, it is important to ensure that large one-off expenditures, such as building a house, do not result in large liabilities for household members, at least not liabilities that exceed the level of annual income.This is becauseThusAs well asAs well as being better thanAs well asAs well as due toAs well as the fact that household indebtednessAs well as the fact that household indebtedness leads to a series ofAs well as a series of social instability caused by household indebtedness.As well as a series of social instability caused by household indebtedness.As well as a series of social destabilising factors due to household indebtedness.As well as a series of social instability caused by household indebtedness.As well as a series of social instability due to household indebtedness.As well as the emergence of a series of social instability due to household indebtedness.

Therefore, from an economic point of view, it is appropriate that the cost of building a house should not exceed a maximum of twice the total annual income of the members of the family.

Comment 22: Table 2: Why stabilized rammed earth is chosen instead of reinforced concrete that has less impact on the environment following Figure 4?

Response 22: Depending on the local construction conditions and the skill level of the craftsmen, cement-stabilised rammed earth construction can be done by the head of the household with the village's surplus labour (elderly or women) or directly by the head of the household's own family members, with the head of the household contributing most of the labour costs. Reinforced concrete frame houses, on the other hand, require the hiring of skilled craftsmen from outside the village, and the salary level of local skilled craftsmen is twice as high as that of the remaining labour force in the village, which makes the labour cost high.

Comment 23: Paragraph lines 354-358 is repeated lines 359-352

Response 23: Noted. The content has been revised.

Comment 24: P.12, lines 365-367: no evidence is given to the statement

Response 24: Noted. The content has been revised.

Comment 25: Line 371: not half, twice; so the meaning is completely different

Response 25: Noted. The content has been revised.

Comment 26: Line 371: it is said previously that modern construction materials like reinforced concrete are not available in the region, this is contradictory to the sentence.

Response 26: Noted. The content has been revised.

Comment 27: Line 378: no it is far from holistic, for example, the end of life of the building is not taken into account, which may change the assessment, the brick can be reused whereas the stabilised rammed earth is not longer recyclable…

Response 27: Noted. This case study is on development progress, in this research is capable to provide a localized preliminary analysis for early design and construction stage, further ongoing monitoring and further research is needed.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

 The authors have added a few paragraph barely improving the manuscript. I believe this manuscript is more appropriate in a conference venue.

Author Response

Comment 1: I carefully studied the Aim and Scope of the Journal. The last sentence of the second paragraph under the title Aim and Scope of the Journal states "As a transdisciplinary journal, Sustainability encourages researchers to provide full experimental and methodological details so that results can be reproduced and assessed." The current manuscript is not in compliance with this statement and falls outside Scope of the Journal. The manuscript (1) is mainly a qualitative study with numerous questionable simulation assumptions, and (21) lacks any correlation between the simulation and the "pilot project". The manuscript does not have the technical merit and the rigor to be considered as a technical journal article.

Response 1: Noted. This is a case study complied with software simulation and empirical studied in-situ in parallel. The paper structure has been revised and further study for other perspectives of life cycle sustainability assessment is needed complied with the progress of projects. Rural studies, particularly focusing the cross-disciplinary studies of the life cycle approached analysis for rammed earth renovation in low resources settlement is significant to push the carbon neutrality of rural building construction in Chinese context and it can provide a great reference for under developing countries / regions. 

Comment 2: May I suggest the following. In my opinion, this manuscript fits very nicely in a conference presentation.

Response 2: Noted. 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

My comments have been addressed. The manuscript is acceptable. 

Comments on the Quality of English Language

English writting is generally well. 

Author Response

Comment 1:This paper discusses the ecological sustainability of construction using locally sourced earth materials and environmentally friendly demolition methods. The study evaluates three construction scenarios: cement-stabilized rammed earth walls, fired brick walls, and localized reinforced concrete frame structures. It compares their quantitative environmental impacts and qualitative differences in adaptation, economic sustainability, and other factors within the context of rural development in China. The results indicate that cement-stabilized rammed earth walls have higher embodied carbon emissions compared to reinforced concrete frames but lower emissions than fired brick walls, while still meeting structural requirements effectively.

Response 1: Noted.

Comment 2: The subject under investigation is of interest and comprehensive but lacks well designing and writing for the scientific significance and purpose. I recommend this paper a major revision.

Response 2: Noted.

Comment 3: Figures 4 and 7(a) in the manuscript require improvement in clarity. It is recommended to enhance the readability;

Response 3: Noted. The data with high resolution is available when requested. 

Comment 4: Does the discrepancy between the building model depicted in Figure 2 and the actual building structure illustrated in Figure 5 impact the analysis results of hidden energy consumption?

Response 4: Noted. The model shown in Figure 2 has been formed based on three structural forms already in common use in the local area, which to some extent represent a high degree of acceptance by the local population and is therefore a choice that relies on a context that is actually acceptable to the users. Of course, from a professional structural calculation point of view, the thickness of the building walls and the choice of materials used will have a greater impact on the whole-life carbon emission results and the construction costs when dealing with the challenges of non-subjective factors such as nature, but also the actual acceptance of the local villagers.

Comment 5: There is no explanation for the tool One Click LCA database used in the manuscript. Please provide a brief explanation;

Response 5: Noted. Please refer to the revised version in details. 

Comment 6: Line 400-401: Based solely on the carbon consumption shown in Figure 4, “the adverse effects of cement-based materials on the environment” cannot be directly inferred. Suggestions include quantifying adverse gas emissions and waste to confirm the potential adverse environmental impacts of cement-based materials;

Response 6: Noted. The software simulation is a reference to supplement the research. Site observation and monitoring results are the most considered portion of this case study.

Comment 7: There are some low-level writing errors in the paper, such as forgetting to delete the words on the template in Line 268-270, and what does the “3.1.1. Subsubsection” mean? Please carefully review the entire paper.

Response 7: Noted.

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

the revised version takes into account my comments

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Editor,

1. The authors have not addressed the second part of my first comment (The research lacks any correlation between the simulation and the "pilot projec"). The manuscript lacks the technical merit and the rigor to be considered as a technical journal article.

2. Per the authors' response to my comment 2, it seems that the authors agree with my comment (Comment 2: May I suggest the following. In my opinion, this manuscript fits very nicely in a conference presentation.) 

THE END