Ontology Framework for Sustainability Evaluation of Cement–Steel-Slag-Stabilized Soft Soil Based on Life Cycle Assessment Approach

Round 1

Reviewer 1 Report

The research studied the environmental impact of partially replacing the stabilizing cement with Steel Slag on the cost and the behavior of soft marine soils. the study presents an ontological framework using a free software called Protégé. the developed framework is verified using case study from China

The research is valuable, well organized and written in good English, however there are minor comments should be considered before acceptance as follows:

1- The introduction should be contains recent references regarding different soil stabilizing materials besides the steel slag, the following references are recommended 

     doi.org/10.1007/s40515-021-00199-y

     doi.org/10.3390/su14127403

2- Add vertical axis titles and units for figures 9, 10

3- Replace "basic oxygen furnace slag (BOFS)" with steel slag.

4- Add a map showing the location of the case study and grain size distribution for the used soft soil

5- The text in Figures 4, 8, 11 are not readable 

6- Add a comparison with other stabilizing materials from literature (if possible) 

7- Conclusions section must include the limitation of the study

 

     

Author Response

Reviewer #1:

Dear Reviewer #1:

Thank you for your careful review and helpful suggestions regarding our manuscript. Based on your valuable comments, we have carefully and thoroughly revised the manuscript. The corrected sections and supplemental materials are marked in red in the revised manuscript. Moreover, our response to your comments is as follows:

Q1: The introduction should be contains recent references regarding different soil stabilizing materials besides the steel slag, the following references are recommended

doi.org/10.1007/s40515-021-00199-y

doi.org/10.3390/su14127403

doi.org/10.1080/17486025.2022.2090621

doi.org/10.1093/ijlct/ctac058

A1: Thank you for your suggestion, we have supplemented lines 39−42, and 46−48 with a description of other stabilized materials. References 5,8,11 cited on your suggestion,

Q2: Add vertical axis titles and units for figures 9, 10

A2: Thank you for pointing this out. We have added vertical axis titles and units for Figures 8,9 (Figures 9, 10 in the original manuscript)

Q3: Replace "basic oxygen furnace slag (BOFS)" with steel slag.

A3: We have made the modifications you suggested, which can be seen in line 305.

Q4: Add a map showing the location of the case study and grain size distribution for the used soft soil

A4: Thank you for your suggestion, the grain size distribution of soft soils has been supplemented in Table 4. The case is carried out at the experimental scale, so there is no need to add a map.

Q5: The text in Figures 4, 8, 11 are not readable

A5: Thank you for your comment. These figures are regularly displayed in the literature in the field of ontology, and relevant researchers will want to see these figures.

Q6: Add a comparison with other stabilizing materials from literature (if possible)

A6: Thank you very much for your comments, we will discuss the comparison of different stabilized materials in the next paper.

Q7: Conclusions section must include the limitation of the study.

A7: Thank you for your comments, we have supplemented our conclusions with study limitations, which can be found in lines 461−464.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper tries to report an ontology framework to assess, from a sustainability point of view, several chemical stabilization alternatives of soft soils, mainly by adding cement and steel slags. The focusing of the paper is a current issue in many construction researches and it could be of great interest for readers. Although the goal of the paper is relevant and the experimental results look nice, the structure and organization of the document is very confused, some sections are really hard to understand and following. Some relevant parts have not been properly described and they should be rewritten. Some items and hypothesis along the research must be justified properly. From this reviewer’s point of view, the present form of the paper is not acceptable and its publication is not recommended. The main drawbacks are detailed below:

1) The title does not exactly reflect the content of the paper, which is focused on a particular case of ‘Marine Soft Soils’. This aspect should be emphasized to avoid misunderstandings. 

2) The structure of the abstract is not appropriated for a scientific document. The beginning as ‘Our previous study’ is not suitable at all. Some information included in the abstract cannot be understood if the paper has not been previously read (e.g. ‘knowledge base with semantic web rule language’…). The abstract should be rewritten according to the usual structure for a scientific document.

3) In general, the main idea and novelty of the paper are not well stablished. Several topics have been included and superposed, but it is not clear the main goal of the paper. Please clarify them in the abstract and also at the end of the introduction.

4) Moreover, the main items of methodology carried out should be also clearly presented from the beginning, i.e. comparison with cement (section 2) and why, because in the results and discussion, this comparison is scarcely considered; GWP evaluated in terms of equivalent CO2, instead of other greenhouse gas (this is included in lines 102-105, but this is so relevant that it should be exposed clearly from the beginning). In general, the description of the methodology is very confused. They should be reviewed.

5) Please review the references: 1, 4, 15, 38, 45, 47 and 49. They seem to be out of the scope of the paper (‘dynamic', 'vibration’, ‘pile foundations’, ‘analytical solutions’, ‘numerical modelling’…).

6) Line 40: the chemical soil stabilizations have been employed from decades, mainly with cement. This is not a recent popular trend. Moreover, other alternative chemical stabilizers, apart from cement, are usually employed. Please review it and include proper references.

7) Line 51: the sentence ‘our laboratory’ is not appropriated for a scientific document. Please, review lines 55-58 because the sentence ‘The use of carbonated steel slag is promising to reduce the CO2 emission and cost of stabilized soils’ and the assertion ‘a large amount of electrical energy can be consumed in the complex steel slag preparation process, such as grinding and high-temperature/high-pressure carbonation treatment’ are contradictory. Moreover, the first one is not addressed yet. Lines 67-70 linked to LCA should be moved upwards, up to the end line 61. Line 65: please define ‘MWhel’. Lines 82-84 should be included in the previous paragraph.

8) Section 2: LCA description included in this section is specific for this research, so the titles and subtitles should be described in detail, avoiding generalization expressions of this methodology. Section 2.2 could be included in section 2.1, since it would be very convenient to describe previously the three stages (line 129). Along the document, it is not clear if the energy consumption because of carbonation of steel slags is included (please, review and clarify it in the text, also in figure 1, and compare with legend in figure 7). The energy consumption due to the mixture of cement and steel slag to obtain the 'stabilizer' has been considered? In table 1, which procedures have been included in ‘Electricity’?

9) For consistency, the order of equations 1-4 should be in agreement with the stages described in line 130. Moreover, since equations 1-3 have been written in an extended form, the equation 4 should be written too, instead of summation notation. The parameter 'Wi' should be defined. Respect to the last term in equation 3 ('Co2uptake'), the units obtained (tons?) are not in agreement with kgCO2-eq resulting in the rest of the terms?, please review. The term 'CO2uptake' is not clear, neither the physical meaning nor the measure procedure. Please, rewrite and complete with the corresponding references. 

10) Line 160, respect to the cost figures considered, it should be clarified that they correspond to China, and the information of the corresponding year and exchange rate used should be also included, in sake of comparison with other locations or years. The equation to obtain 'Cost_a' and the term 'Wi' (equation 6) have not been defined.

11) The idea in lines 181-182 seems another objective of the paper?. It should be clarified from the beginning. Lines 184-185 are repeated. The definitions of 'SUI environment' ratios are not well explained. Please, rewrite this part (line 185-190). The procedures or equations to normalization of CO2, cost and UCS have been omitted. How has been included the reference S-C case in both ratios?

12) Regrettably, after several readings of section 3, this reviewer has hardly extract the main idea of this part, in spite of its relevance for the general scope of the paper. ‘Database layer’, ‘knowledge base layer’, ‘user layer’ are not clear. Line 205 is confused. What information is contained in each part should be clarified. The acronym LCI is not defined previously, and neither the software used. Lines 264 – 267 and tables 2 to 6, and 10, are too specific for the general objective of the paper, therefore, they could be moved to an annex. ‘OntoESS’ should be defined at least in the title of the section. Finally, the main advantage of this ontology framework to the scope of this research should be highlighted. 

13) Section 4-case study: For simplify, the geotechnical properties of the clay soil and stabilizers materials could be summarized in a table. Respect to the sample preparation at lab (line 288), why the moisture content of the mixture has been removed from the research considering a constant value of 1.5 of LL-moisture content? The optimum moisture content could significantly vary depending on the % of additive and could have a great influence in the UCS. This hypothesis should be properly justified. The criteria followed in lines 306-309 is not justified. Line 315 is not understood, please rewrite. The %-cement or %-stabilizer respect to the amount of dry soil should be included. It is not possible to know the %cement or %steel slag used in these stabilizations. However, this is the usual procedure to define a chemical stabilization in geotechnical engineering. Line 317, the curing conditions of the samples have been detailed, but the corresponding energy-consumption during curing stage in practice soil applications has been considered? They could vary depending on the type of mixture applied or not? why?

14) As it can be observed in table 9, the UCS results are not similar for the all dosages tested, so, the environmental comparative assessment of soils with different strength properties after stabilization cannot be comparable (from 2MPa to 0.85 MPa)? since the ‘quality’ or 'goodness' of the stabilized soil is different in each case. How the authors considered this issue? 

15) According to lines 327-328, these results are scarcely addressed in figure 6. Please review. 

16) Results and discussion of results: figure 7, the total sum of GWP and each part values should be included in the graph (o even change this graph by a table). Discussion in line 336 is not so evident from results in figure 7. In general, the discussion of the results is not strongly supported by the graphical results plotted.

17) Title of section 4.2.2 is uncompleted, please compared with 4.2.1.

18) It is impossible to understand anything in figure 8, because of the font size and because the information is coded. Only, the programmer can understand. Please, remove this figure and extract the main results into a table. Also for figure 11.

19) Bar-graphs have been used in figures 9 and 10. Please complete these figures with the corresponding axe labels (which correspond to GWP or to Cost?). The exact data plotted on each bar would be of great interest for comparative purposed. In figure 10, why UCS results and SUI ratios have been plotted together when they are not directly linked to? From this reviewer’s point of view, both graphs are not the best way to depict the results and support any discussion, because it is very difficult to compare between different cases. For instance, discussions in line 361 or line 362 are not supported by this graphs.

20) Section 4.2.3 should be renamed since this not correspond to a genuine sensitivity analysis.

21) Along the whole document, names and labels should be kept for consistency: ie. ‘steel slag’ or ‘carbonated steel slag’ or ‘BOFS’; ‘CO2’ or ‘Equivalent CO2’; samples name used in table 9 are not consistency with the names used in the figures.

 

Minor editing of English language required

Author Response

Reviewer #2:

Dear Reviewer #2:

Thank you for your careful review and helpful suggestions regarding our manuscript. Based on your valuable comments, we have carefully and thoroughly revised the manuscript. The corrected sections and supplemental materials are marked in red in the revised manuscript. Moreover, our response to your comments is as follows:

Q1: The title does not exactly reflect the content of the paper, which is focused on a particular case of ‘Marine Soft Soils’. This aspect should be emphasized to avoid misunderstandings.

A1: Thank you for your comments, the title of this manuscript has been modified to:“Ontology Framework for Sustainable Evaluation of Cement-Steel Slag Stabilized Soft Soil Based on LCA Approach”

Q2: The structure of the abstract is not appropriated for a scientific document. The beginning as ‘Our previous study’ is not suitable at all. Some information included in the abstract cannot be understood if the paper has not been previously read (e.g. ‘knowledge base with semantic web rule language’…). The abstract should be rewritten according to the usual structure for a scientific document.

A2: Thank you for your advice. The abstract of this manuscript has been rewritten.

Q3: In general, the main idea and novelty of the paper are not well stablished. Several topics have been included and superposed, but it is not clear the main goal of the paper. Please clarify them in the abstract and also at the end of the introduction.

A3: Thank you for pointing this out. This comment made us realize that the innovation of this study had not been fully expressed in the original manuscript. Hence, we have supplemented and highlighted the novelty in the abstract and introduction, which can be seen in the revised manuscript line 21-24, 52-56, 84-88.

Q4: Moreover, the main items of methodology carried out should be also clearly presented from the beginning, i.e. comparison with cement (section 2) and why, because in the results and discussion, this comparison is scarcely considered; GWP evaluated in terms of equivalent CO2, instead of other greenhouse gas (this is included in lines 102-105, but this is so relevant that it should be exposed clearly from the beginning). In general, the description of the methodology is very confused. They should be reviewed.

A4: Thank you for your suggestions, which made us realize that the main items of the research methodology were not clearly stated at the beginning of the manuscript, regarding the comparison with cement we have supplemented in the introduction, which can be seen in the revised manuscript line 94, and regarding GWP we have supplemented in line 84.

Q5: Please review the references: 1, 4, 15, 38, 45, 47 and 49. They seem to be out of the scope of the paper (‘dynamic', 'vibration’, ‘pile foundations’, ‘analytical solutions’, ‘numerical modelling’…).

A5: Thank you for pointing this out. We have removed these references from the manuscript.

Q6: Line 40: the chemical soil stabilizations have been employed from decades, mainly with cement. This is not a recent popular trend. Moreover, other alternative chemical stabilizers, apart from cement, are usually employed. Please review it and include proper references.

A6: Thank you for pointing this out. We have revised the description of the chemical stabilization method and supplemented the description of other chemical stabilizers, which can be seen in lines 39-48 of the Introduction.

Q7: Line 51: the sentence ‘our laboratory’ is not appropriated for a scientific document. Please, review lines 55-58 because the sentence ‘The use of carbonated steel slag is promising to reduce the CO2 emission and cost of stabilized soils’ and the assertion ‘a large amount of electrical energy can be consumed in the complex steel slag preparation process, such as grinding and high-temperature/high-pressure carbonation treatment’ are contradictory. Moreover, the first one is not addressed yet. Lines 67-70 linked to LCA should be moved upwards, up to the end line 61. Line 65: please define ‘MWhel’. Lines 82-84 should be included in the previous paragraph.

A7: We apologize for the confusion caused by the unclear descriptions in our manuscript and have rewritten the unclear descriptions. The revised text can be found in lines 52-56. The positions of lines 67 and 82-84 in the original manuscript have been adjusted, which can be seen in the revised manuscript lines 59, 79−82.

Q8: Section 2: LCA description included in this section is specific for this research, so the titles and subtitles should be described in detail, avoiding generalization expressions of this methodology. Section 2.2 could be included in section 2.1, since it would be very convenient to describe previously the three stages (line 129). Along the document, it is not clear if the energy consumption because of carbonation of steel slags is included (please, review and clarify it in the text, also in figure 1, and compare with legend in figure 7). The energy consumption due to the mixture of cement and steel slag to obtain the 'stabilizer' has been considered? In table 1, which procedures have been included in ‘Electricity’?

A8: Thanks for your kind suggestion. We have revised the title of the manuscript. We apologize for the confusion regarding the unclear description of section 2.2, we have rewritten section 2.2. The modification regarding the description of energy consumption is in lines 128-133 of the manuscript and corresponds to that of Figure 7 (Figure 7 has now been replaced by Table 8) of the original manuscript.

The electricity consumption in the preparation of the stabilizer comes from the grinding of the steel slag. The carbonation of steel slag is a self-heating reaction without external heat source, so there is no energy consumption.

Q9: For consistency, the order of equations 1-4 should be in agreement with the stages described in line 130. Moreover, since equations 1-3 have been written in an extended form, the equation 4 should be written too, instead of summation notation. The parameter 'Wi' should be defined. Respect to the last term in equation 3 ('Co2uptake'), the units obtained (tons?) are not in agreement with kgCO2-eq resulting in the rest of the terms?, please review. The term 'CO2uptake' is not clear, neither the physical meaning nor the measure procedure. Please, rewrite and complete with the corresponding references.

A9: Thank you for your helpful suggestions, we have adjusted the order and formatting of the equations in the manuscript as you suggested and supplemented the equation for CO₂ uptake, the modifications are in Eqs. (1)-(6) in the manuscript.

Q10: Line 160, respect to the cost figures considered, it should be clarified that they correspond to China, and the information of the corresponding year and exchange rate used should be also included, in sake of comparison with other locations or years. The equation to obtain 'Cost_a' and the term 'Wi' (equation 6) have not been defined.

A10: Thank you for your suggestions, we have supplemented the exchange rate in lines 182-183, and the modification to the equations can be seen in Eqs. (9) and (11).

Q11: The idea in lines 181-182 seems another objective of the paper?. It should be clarified from the beginning. Lines 184-185 are repeated. The definitions of 'SUI environment' ratios are not well explained. Please, rewrite this part (line 185-190). The procedures or equations to normalization of CO₂, cost and UCS have been omitted. How has been included the reference S-C case in both ratios?

A11: Thank you for your comment, we realize that the description of this section is not clear enough and we have rewritten section 2.5, which can be found in lines 210−220. The normalized equations for CO₂, cost, and UCS have been supplemented, which can be found in Eqs. (14)−(16).

Q12: Regrettably, after several readings of section 3, this reviewer has hardly extract the main idea of this part, in spite of its relevance for the general scope of the paper. ‘Database layer’, ‘knowledge base layer’, ‘user layer’ are not clear. Line 205 is confused. What information is contained in each part should be clarified. The acronym LCI is not defined previously, and neither the software used. Lines 264 – 267 and tables 2 to 6, and 10, are too specific for the general objective of the paper, therefore, they could be moved to an annex. ‘OntoESS’ should be defined at least in the title of the section. Finally, the main advantage of this ontology framework to the scope of this research should be highlighted.

A12: Thank you for your suggestion and we have rewritten this section in lines 233-244 of the manuscript. Tables 2−6, and Table 10 in the original manuscript have been moved to Appendix A as you suggested. OntoESS has been defined in line 234.

Q13: Section 4-case study: For simplify, the geotechnical properties of the clay soil and stabilizers materials could be summarized in a table. Respect to the sample preparation at lab (line 288), why the moisture content of the mixture has been removed from the research considering a constant value of 1.5 of LL-moisture content? The optimum moisture content could significantly vary depending on the % of additive and could have a great influence in the UCS. This hypothesis should be properly justified. The criteria followed in lines 306-309 is not justified. Line 315 is not understood, please rewrite. The %-cement or %-stabilizer respect to the amount of dry soil should be included. It is not possible to know the %cement or %steel slag used in these stabilizations. However, this is the usual procedure to define a chemical stabilization in geotechnical engineering. Line 317, the curing conditions of the samples have been detailed, but the corresponding energy-consumption during curing stage in practice soil applications has been considered? They could vary depending on the type of mixture applied or not? why?

A13: Thank you for your comment, we realize that the description of sample preparation was not clear enough and we have rewritten this section as seen in lines 327-334. The physical properties of soft soils have been listed in Table 1. This study currently only considers the energy consumption of stabilizer preparation at the laboratory scale, issues concerning the practical application of stabilized soils will be discussed in the next paper.

Q14: As it can be observed in table 9, the UCS results are not similar for the all dosages tested, so, the environmental comparative assessment of soils with different strength properties after stabilization cannot be comparable (from 2MPa to 0.85 MPa)? since the ‘quality’ or 'goodness' of the stabilized soil is different in each case. How the authors considered this issue?

A14: Thank you for raising this point, we have supplemented the mechanistic analysis on the strength of the stabilized soil in section 4.1, which can be found in lines 335−344.

With regard to evaluating the quality of stabilized soils, this study is based on the sustainability of the stabilized soil as a perspective and compares the sustainability of different scenarios using pure cement stabilized soil (S-C) as a benchmark to obtain the design solution with the best overall benefit. There is a strong correlation between the strength and sustainability of the stabilized soil, Fig.9 shows the UCS_60d and sustainability indexes of each scheme. Although steel slag as a SCMs can effectively reduce the GWP and production cost of stabilized soil by partially replacing cement, cement is the main source of its strength, and excess steel slag can cause insufficient strength of stabilized soil, thus leading to a high sustainability index of stabilized soil, which is not conducive to engineering applications. The stabilized soils with low-content steel slag have better sustainability than S-C, and the strength is not less than 90% of S-C, which can meet the engineering performance requirements.

Q15: According to lines 327-328, these results are scarcely addressed in figure 6. Please review.

A15: Thank you for pointing out the problem, this section has been revised in lines 350-353 of the manuscript.

Q16: Results and discussion of results: figure 7, the total sum of GWP and each part values should be included in the graph (o even change this graph by a table). Discussion in line 336 is not so evident from results in figure 7. In general, the discussion of the results is not strongly supported by the graphical results plotted.

A16: Thank you for your suggestion, we have replaced Figure 7 with Table 8 and the presentation of the data provides strong support for the results we discussed.

Q17: Title of section 4.2.2 is uncompleted, please compared with 4.2.1.

A17: We have modified the title of 4.2.2 to “Impact analysis of SCSs” according to your suggestion.

Q18: It is impossible to understand anything in figure 8, because of the font size and because the information is coded. Only, the programmer can understand. Please, remove this figure and extract the main results into a table. Also for figure 11.

A18: We appreciate your confusion about these figures and the clarity of the figures has been adjusted. These figures are regularly displayed in the literature in the field of ontology, e.g. Ref. 1, 2, and 3, and relevant researchers will want to see these figures.

Q19: Bar-graphs have been used in figures 9 and 10. Please complete these figures with the corresponding axe labels (which correspond to GWP or to Cost?). The exact data plotted on each bar would be of great interest for comparative purposed. In figure 10, why UCS results and SUI ratios have been plotted together when they are not directly linked to? From this reviewer’s point of view, both graphs are not the best way to depict the results and support any discussion, because it is very difficult to compare between different cases. For instance, discussions in line 361 or line 362 are not supported by this graphs.

A19: Thank you for pointing out these issues. We have added axe labels to Figures 8 and 9 (Figures 9 and 10 in the original manuscript). We have modified the discussion of the result of Figure 9 in lines 391-395.

Q20: Section 4.2.3 should be renamed since this not correspond to a genuine sensitivity analysis.

A20: Thank you for your comment, 4.2.3 "Sensitivity analysis" is a necessary procedure for LCA research, e.g. literature 4, 5.

Q21: Along the whole document, names and labels should be kept for consistency: ie. ‘steel slag’ or ‘carbonated steel slag’ or ‘BOFS’; ‘CO2’ or ‘Equivalent CO2’; samples name used in table 9 are not consistency with the names used in the figures.

A21: Thanks for pointing out this problem, we have standardized the naming of steel slag.

 

1. Cui CY, Xu MZ, Xu CS, Zhang P, Zhao JT (2023) An ontology-based probabilistic framework for comprehensive seismic risk evaluation of subway stations by combining Monte Carlo simulation. Tunnelling and Underground Space Technology 135: 105055, DOI: 10.1016/j.tust.2023.105055
2. Meng K, Cui CY, Li HJ, Liu HL (2022) Ontology-Based Approach Supporting Multi-Objective Holistic Decision Making for Energy Pile System. Buildings 12(2):236, DOI: 10.3390/ buildings12020236
3. Hou SJ, Li HZ, Rezgui Y (2015) Ontology-based approach for structural design considering low embodied energy and carbon. Energy and Buildings 102: 75-90. DOI: 10.1016/j.enbuild. 2015.04.051
4. Li LF, Jiang Y, Pan SY, Ling TC (2021) Comparative life cycle assessment to maximize CO2 sequestration of steel slag products. Construction and Building Materials 298:123876, DOI: 10.1016/j.conbuildmat.2021.123876
5. Shao X, Mehdizadeh H, Li LF, Ling TC (2022) Life cycle assessment of upcycling waste slag via CO2 pre-treatment: Comparative study of carbonation routes. Journal of Cleaner Production 378:134115, DOI: 10.1016/j.jclepro.2022.134115

Author Response File: Author Response.docx

Reviewer 3 Report

The paper presented an evaluation framework for environmental and economic impacts of Cement-Steel Slag in stabilisation of marine soft soil. This can be a good addition to the authors' prior study.

My biggest concern is the scientific basis of Table 1. ISO 14040:2006 is just a framework and does not include the information in Table 1. The use of data without a scientific establishment could be a falsifying bias. The CO₂ calculation for steel slag should begin from raw materials to steel and, then, steel slag as the authors want to assess the whole LCA. At this step, the authors obviously favour the slag.

Here are some minor comments:

- The impact assessment used a lot of unkown parameters (equations 1-8). Please provide scientific estimation or source of data. For example, CO_2-p and CO_2-a in equation 1 are not clearly evaluated.

- Figure 2 require better resolution as it is not readable.

- Table 2 is not well organised. "Ruel" should read "Rule". "?" must be replaced by respective symbol. The authors must show the rules and formula. Program syntax can be shown below or in appendices.

- Line 287 should be a typo and misformat.

- Table 9 raised an eye browse. The author confirmed in the abstract that their prior study showed that the substitution can improve the performance of soil. However, Table 9 showed the opposite. In general, the more binder the better bound. However, I don't want to revise the first publication as it is not my job. Just make clear lines to separate samples with different designated names.

- The conclusion does not make sense if the Table 1 was not scientifically established.

 

 

The paper is readable without the second thought. A few typos.

Author Response

Reviewer #3:

Dear Reviewer #3:

Thank you for your careful review and helpful suggestions regarding our manuscript. Based on your valuable comments, we have carefully and thoroughly revised the manuscript. The corrected sections and supplemental materials are marked in red in the revised manuscript. Moreover, our response to your comments is as follows:

Q1: The impact assessment used a lot of unkown parameters (equations 1-8). Please provide scientific estimation or source of data. For example, CO2-p and CO2-a in equation 1 are not clearly evaluated.

A1: Thank you for your suggestion, we have modified the equations in the manuscript to supplement the definition of the parameters, which can be seen in Eqs. (1)-(6).

Q2: Figure 2 require better resolution as it is not readable.

A2: Thank you for your suggestion, we have adjusted the resolution of Figure 2.

Q3: Table 2 is not well organised. "Ruel" should read "Rule". "?" must be replaced by respective symbol. The authors must show the rules and formula. Program syntax can be shown below or in appendices.

A3: Thank you for pointing this out. We have corrected typos in the manuscript. The symbols in the rules are written in accordance with the syntax specified in the Protégé software. Tables 2-6, and Table 10 in the original manuscript have been moved to Appendix A as you suggested.

Q4: Line 287 should be a typo and misformat.

A4: Thank you for pointing this out. We have corrected typos in the manuscript.

Q5: Table 9 raised an eye browse. The author confirmed in the abstract that their prior study showed that the substitution can improve the performance of soil. However, Table 9 showed the opposite. In general, the more binder the better bound. However, I don't want to revise the first publication as it is not my job. Just make clear lines to separate samples with different designated names.

A5: We apologize for the confusion caused by our unclear description, we have modified and supplemented this section which can be found in the abstract and lines 391-395.

Although steel slag as a supplementary cementitious material can effectively reduce the GWP and production cost of stabilized soil by partially replacing cement. However, cement is the main source of its strength, excess steel slag can cause insufficient strength of stabilized soil, thus leading to high sustainability index of stabilized soil, which is not conducive to engineering applications.

Q6: The conclusion does not make sense if the Table 1 was not scientifically established.

A6: Thank you for your comment, we have added to the sources of the data in Table 1, which can be seen in lines 121-124,128-133.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

After the revision made, the paper has significant improved. Most of the suggestions proposed by this reviewer have been taking into account by the authors. The scope of the paper and methodology have been clarified. The references have been updated. However, some few comments have not been attended successfully. Taking into account the improvements carried out by the authors, I recommend its publication, although the following comments should be previously reviewed:

1)     It is not convenience to use acronyms in the title, so I recommend to define ‘LCA’ completed.

2)     In the abstract, the sentence ‘With the development of steel slag treatment technology’ could be removed.

3)     In Equation 4, the units of the first term (kgCO2-eq) of the equation and the second term (t and %) seems not to be coherent, or at least, this is not clear in the text. Please, review or justify properly.

4)     The question 13 of the previous report has not been entirely attended. The moisture content of the mixture has been removed from the research considering a constant value of 1.5 of Liquid limit. The optimum moisture content is a relevant geotechnical parameter and could significantly vary depending on % of additive and affect to UCS. This hypothesis should be properly justified.

Minor editing of English language required

Author Response

Dear Reviewer #2:

Thank you for your careful review and helpful suggestions regarding our manuscript. Based on your valuable comments, we have carefully and thoroughly revised the manuscript. The corrected sections and supplemental materials are marked in red in the revised manuscript. Moreover, our response to your comments is as follows:

Q1: It is not convenience to use acronyms in the title, so I recommend to define ‘LCA’ completed.

A1: Thank you for your comments, the title of this manuscript has been modified to:“Ontology Framework for Sustainable Evaluation of Cement-Steel Slag Stabilized Soft Soil Based on Life Cycle Assessment Approach”

Q2: In the abstract, the sentence ‘With the development of steel slag treatment technology’ could be removed.

A2: Thank you for your comments. We have revised the abstract.

Q3: In Equation 4, the units of the first term (kgCO2-eq) of the equation and the second term (t and %) seems not to be coherent, or at least, this is not clear in the text. Please, review or justify properly.

A3: Thank you for pointing this out, we have modified Eq. 4.

Q4: The question 13 of the previous report has not been entirely attended. The moisture content of the mixture has been removed from the research considering a constant value of 1.5 of Liquid limit. The optimum moisture content is a relevant geotechnical parameter and could significantly vary depending on % of additive and affect to UCS. This hypothesis should be properly justified.

A4: Thank you for your comment, we have supplemented the manuscript with a description of the deep mixing method in lines 332-334.

The deep mixing method is a common method of foundation treatment and the water content of the stabilized soil is generally taken to be around the liquid limit of the soil [1-4], as shown in Table 1. In this study, the water content of the specimen preparation was set at 1.5 times the liquid limit, i.e. 57.2%, to ensure the fluidity of the stabilized soil.

 

Table 1. Summary of researchers on deep mixing of cement stabilized soil.

Reference	Liquid Limit (%)	Water content (%)
Adriana Luis [1]	40.9	49.8
Hamza Güllü [2]	41	36
Mohammad S.Pakbaz [3]	122	132
Jacques J.M.M. Hessouh [4]	38.5	50

 

[1]Luis A , Deng LJ , Shao LS, Li HZ (2019) Triaxial behaviour and image analysis of Edmonton clay treated with cement and fly ash. Construction and Building Materials 197:207-219

[2]Gullu H, Canakci H, Al Zangan IF (2017) Use of cement based grout with glass powder for deep mixing. Construction and Building Materials 137:12-20

[3]Pakbaz MS, Farzi M (2015) Comparison of the effect of mixing methods (dry vs. wet) on mechanical and hydraulic properties of treated soil with cement or lime. Applied Clay Science105:156-159

[4]Hessouh JJMM, Eslami J, Beaucour AL, Noumowe A, Mathieu F, Gotteland P (2023) Physical and mechanical characterization of deep soil mixing (DSM) materials: Laboratory vs construction site. Construction and Building Materials 368:130436

Author Response File: Author Response.pdf

Reviewer 3 Report

The author provided some good responses on the comments about the scientific basis of the study, especially Table 1.  However, there are still a few things to consider.

- The estimation of factors in equation from 1-6 are still unclear. For example, what is the value of CO_2-p and where did the author retrieve from? Value table and references are required.

- Similar comments to components in equation 7. What is the value of Da and justification to calculate it. I understand the author are providing frame work, not a case study. However, the conclusion is quantitatively in favour of the SC.

- Figures are still very difficulty to read in either electronic or printed form. 

- I still think that showing syntax in table 3 is not a good idea, but it is much better now.

- The Environmental effect makes non-sense if the UCS does not meet requirement. Please provide some references about the target UCs on Figure 9.

 

English is ok. There are some minor misuse of articles, which cause a bit confusion. But the paper is readable.

Author Response

Dear Reviewer #3:

Thank you for your careful review and helpful suggestions regarding our manuscript. Based on your valuable comments, we have carefully and thoroughly revised the manuscript. The corrected sections and supplemental materials are marked in red in the revised manuscript. Moreover, our response to your comments is as follows:

Q1: The estimation of factors in equation from 1-6 are still unclear. For example, what is the value of CO2-p and where did the author retrieve from? Value table and references are required.

A1: Thank you for your suggestion, we have supplemented the manuscript with information on the electricity consumption of steel slag grinding and the CO₂ uptake of different carbonation grades of steel slag, which can be seen in lines 316-319, and 323-325.

The transport distances and weights of the materials can be found in Tables 6 and 7 of the case study respectively.

Q2: Similar comments to components in equation 7. What is the value of Da and justification to calculate it. I understand the author are providing frame work, not a case study. However, the conclusion is quantitatively in favour of the SC.

A2: Thank you for your comment, D_a is the transport distance from the steel slag to the landfill. In Literature 1 and 2, the calculation of carbon emissions also takes into account the avoided landfill of steel slag. In this case study, D_a is 35 km, which can be seen in Table 6.

Q3: Figures are still very difficulty to read in either electronic or printed form.

A3: Thank you for pointing this out, we have increased the resolution of all figures and uploaded each one separately in the submission system.

Q4: I still think that showing syntax in table 3 is not a good idea, but it is much better now.

A4: Thank you for the suggestion that the SWRL rules in Table 3 are readable for the ontology researcher.

Q5: The Environmental effect makes non-sense if the UCS does not meet requirement. Please provide some references about the target UCS on Figure 9.

A5: Thank you for your comments, we have supplemented the relevant specifications and descriptions in lines 396-399. We set the strength of the stabilized soil to meet the strength grade 1.0 as required by GJ/T 526-2018 [3], which means that the strength of the specimen should be greater than 1MPa.

 

[1] Evangelista BL, Rosado LP, Penteado CSG (2018) Life cycle assessment of concrete paving blocks using electric arc furnace slag as natural coarse aggregate substitute. Journal of Cleaner Production, 178:176-185

[2] Shao X, Mehdizadeh H, Li LF, Ling TC (2022) Life cycle assessment of upcycling waste slag via CO₂ pre-treatment: Comparative study of carbonation routes. Journal of Cleaner Production 378:134115

[3] GJ/T 526-2018 (2018) Stabilizer for soft soil. Ministry of Housing and Urban-Rural Development of the People's Republic of China, Beijing, China

Author Response File: Author Response.pdf