Flexural Performance of Steel-Continuous-Fiber Composite Bar and Fiber-Reinforced Polymer Bar Hybrid-Reinforced Sustainable Sea-Sand Concrete Beams: Numerical and Theoretical Study
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript „Investigation on the flexural performance of green SFCB and FRP bars hybrid-reinforced sustainable seawater sea-sand concrete beams“ is interesting, and the theme is novel. The authors developed three-dimensional refined FE models for SWSSC beams with hybrid reinforcement of SFCB and FRP bars. The model accounts for FRP fracture behavior and the bond-slip behavior between the tensile bars and concrete. Based on the validated model, parametric studies were conducted to analyze the effects of SWSSC strength, sectional steel ratio, and yield strength, as well as the out-wrapped FRP elastic modulus and ultimate tensile strength of SFCB, on the flexural performance of the beams. Three failure modes were defined based on reasonable assumptions, and formulae for bearing capacity were proposed.
There are certain flaws that have to be corrected before the manuscript is reconsidered for publication:
The title is very confusing. Maybe it is due to the translation, but the title has to be rewritten and redefined to precisely represent the conducted study.
Why is the term ‘green’ used? In building materials studies ‘green’ usually represents ‘fresh’ (as in the properties of fresh concrete).
The term ‘sustainable seawater sea-sand concrete beams’ is also slightly problematic. This sounds like concrete prepared with seawater. It should be stated (in the Materials section) that the sand originates from the sea floor.
There is neither a description of the materials used nor their characterization. There is no mix-design provided. Also, if authors are using abbreviations for samples or designed materials, there should be ‘nomenclature’ included.
Introduction The chapter covers all the main references from the field. The applied methodology is adequate. However, the part about materials and concrete specimens is missing, which seriously decreases the strength of the study. The manuscript looks like it is part of a wider study, but not all details are presented in this work.
The list of references is rather short. It would be interesting to compare the results achieved with those of other authors (in the Experimental section).
Comments on the Quality of English LanguageThe text should be checked by English language native speaker or a proofreader. There are terms and sentences that are not completely clear.
Author Response
Authors' response to comments raised by editor and reviewers
Title: Flexural performance of SFCB and FRP bars hybrid reinforced sustainable seawater sea-sand concrete beams: numerical and theoretical study
Authors: Anlian Wang, Zhiwen Zhang, Yan Liu*
Manuscript ID: sustainability-2789260
The authors would like to thank the editor and reviewers for the time and efforts they devoted in reviewing our manuscript, which are vital to improve the quality of the manuscript. The authors' responses to the comments are listed below. All revisions are marked in red in the revised manuscript.
Reviewer 1:
|
General comment: The manuscript "Investigation on the flexural performance of green SFCB and FRP bars hybrid-reinforced sustainable seawater sea-sand concrete beams" is interesting, and the theme is novel. Author’s response: Thanks for your positive comments, the manuscript has been revised accordingly. |
|
1. Comment: There are certain flaws that have to be corrected before the manuscript is reconsidered for publication: The title is very confusing. Maybe it is due to the translation, but the title has to be rewritten and redefined to precisely represent the conducted study. Author’s response: The title has been revised to "Flexural performance of SFCB and FRP bars hybrid reinforced sustainable seawater sea-sand concrete beams: numerical and theoretical study". |
|
2. Comment: Why is the term ‘green’ used? In building materials studies ‘green’ usually represents ‘fresh’ (as in the properties of fresh concrete). Author’s response: Thanks for your comments. The use of FRP offers numerous advantages, including high tensile strength, exceptional resistance to corrosion, and environmental sustainability [3]. Incorporating FRP as a reinforcement for concrete structures not only enhances overall structural stiffness and durability but also mitigates building-related pollution and carbon emissions. Hence, the term "green" was aptly used to describe FRP materials. In order to avoid reader confusion, we made the decision to remove the term 'green' from the title and incorporate relevant explanations in the introduction. (Lines 47~53) |
|
3. Comment: The term ‘sustainable seawater sea-sand concrete beams’ is also slightly problematic. This sounds like concrete prepared with seawater. It should be stated (in the Materials section) that the sand originates from the sea floor. Author’s response: Thanks for your comments. The term ‘seawater sea-sand concrete’ has been revised to ‘sea-sand concrete (SSC)’ throughout the manuscript. To strengthen the link with sustainability principles, the term ‘sustainable’ was retained. |
|
4. Comment: There is neither a description of the materials used nor their characterization. There is no mix-design provided. Also, if authors are using abbreviations for samples or designed materials, there should be ‘nomenclature’ included. Author’s response: The related description and figures on the materials have been added. (Lines 129~138 and Fig. 3) |
|
5. Comment: Introduction: The chapter covers all the main references from the field. The applied methodology is adequate. However, the part about materials and concrete specimens is missing, which seriously decreases the strength of the study. Author’s response: Thanks for your comments. Related discussion on the mechanical properties and hydration behavior of sea-sand concrete has been added in Introduction. (Lines 30~41) |
|
6. Comment: The manuscript looks like it is part of a wider study, but not all details are presented in this work. The list of references is rather short. It would be interesting to compare the results achieved with those of other authors (in the Experimental section). Author’s response: We very much agree with your point of view. However, the numerical method employed in this paper is utilized for the theoretical analysis on SSC beams hybrid reinforced with FRP bars and SFCB. Future work will focus on conducting related experimental research. Besides, the extra references have been added as followed. [2] Li P.R., Li W.G., Yu T., Qu F.L., Tam V.W.Y. Investigation on early-age hydration, mechanical properties and microstructure of seawater sea sand cement mortar [J]. Constr. Build. Mater. 2020, 249: 118776. [3] Li P.R., Li W.G., Sun Z.H., Shen L.M., Sheng D.C. Development of sustainable concrete incorporating seawater: A critical review on cement hydration, microstructure and mechanical strength [J]. Cem. Concr. Compos. 2021, 121: 104100. [4] Etxeberria M., Gonzalez-Corominas A., Pardo P. Influence of seawater and blast furnace cement employment on recycled aggregate concretes’ properties [J]. Constr. Build. Mater. 2016, 115: 496-505. [5] Montanari L., Suraneni P., Tsui-Chang M., Khatibmasjedi M., Ebead U., Weiss J., Nanni A. Hydration, pore solution, and porosity of cementitious pastes made with seawater [J]. Mater. Civ. Eng. 2019, 31: 04019154.1-04019154.11. [6] Sun Y.J., Zhang Y.Y., Cai Y.M., Lam W.L., Lu J.X., Shen P.L. Poon C.S. Mechanisms on accelerating hydration of alite mixed with inorganic salts in seawater and characteristics of hydration products [J]. ACS Sustain. Chem. Eng. 2021, 9 (31). [7] Yaseen S.A., Yiseen G.A., Poon C.S., Li Z.J. Influence of seawater on the morphological evolution and the microchemistry of hydration products of tricalcium silicates (C3S) [J]. ACS Sustain. Chem. Eng. 2020, 8 (42). [8] Wang J.J., Liu E.G., Li L. Multiscale investigations on hydration mechanisms in seawater OPC paste [J]. Constr. Build. Mater. 2018, 191: 891-903. [9] Xiao S.M., Zhang M., Zou D.J., Liu T.J., Zhou A., Li Y. Influence of seawater and sea sand on the performance of Anti-washout underwater concrete: The overlooked significance of Mg2+ [J]. Constr. Build. Mater. 2023, 374: 130932. [10] Ghorab H. Y., Hilal M. S., Antar A. Effect of mixing and curing waters on the behaviour of cement pastes and concrete part2: microstructure of cement pastes [J]. Cem. Concr. Res. 1990, 19: 868-878. [11] Akinkurolere O.O., Jiang C., Shobola O.M. The influence of salt water on the compressive strength of concrete [J]. Eng. Appl. Sci. 2007, 2: 412-415. [12] Zhao Y.F., Hu X., Shi C.J., Zhang Z.H., Zhu D.J. A review on seawater sea-sand concrete: Mixture proportion, hydration, microstructure and properties [J]. Constr. Build. Mater. 2021, 295: 123602. |
Reviewer 2 Report
Comments and Suggestions for AuthorsThe following comments need to be addressed:
1- The author stated that the tested beams had 10 mm transverse stirrups with a spacing of 100 mm however in Figure 1a more spacing is present in the middle zone of the beam.
2- In section 2.2, please clarify the difference between the cube strength and axial compressive strength. Do you mean that the strength was obtained from both cubic and cylindrical specimens?
3- The stress-strain curve of SWSSC presented in Fig.3a shows that the used compressive strength is less than 20 MPa which is not recommended by most design standards.
4- More data concerning the parameters of the plastic damage model used in the current study should be provided.
5- Please clarify if the used model that describes concrete behavior in tension and compression (Equations 1-5) has any limitations. Also, is there a relation between the compressive and tensile strengths of concrete according to the used model?
6- Please clarify how was the energy dissipation and ductility coefficient determined.
7- I recommend adding a flow chart summarizing the theoretical part in section 6.
8- Some ratios of improvement need to be added to the abstract and conclusion sections.
9- More references need to be included.
Author Response
Authors' response to comments raised by editor and reviewers
Title: Flexural performance of SFCB and FRP bars hybrid reinforced sustainable seawater sea-sand concrete beams: numerical and theoretical study
Authors: Anlian Wang, Zhiwen Zhang, Yan Liu*
Manuscript ID: sustainability-2789260
The authors would like to thank the editor and reviewers for the time and efforts they devoted in reviewing our manuscript, which are vital to improve the quality of the manuscript. The authors' responses to the comments are listed below. All revisions are marked in red in the revised manuscript.
Reviewer 2:
|
1. Comment: The author stated that the tested beams had 10 mm transverse stirrups with a spacing of 100 mm, however, in Figure1a more spacing is present in the middle zone of the beam. Author’s response: The related sentence has been revised. (Lines 103~105) |
|
2. Comment: In section 2.2, please clarify the difference between the cube strength and axial compressive strength. Do you mean that the strength was obtained from both cubic and cylindrical specimens? Author’s response: Thanks for your comments. The cube compressive strength fcu refers to the strength of a specimen measuring 150 × 150 × 150 mm, while the axial compressive strength refers to the strength of a specimen measuring 150 × 150 × 300 mm. The axial compressive strength fc (= 0.76fcu) and tensile strength ft (= 0.395fcu0.55) were calculated with the Chinese code GB 50010-2010. (Lines 139~138) |
|
3. Comment: The stress-strain curve of SWSSC presented in Fig.3a shows that the used compressive strength is less than 20 MPa which is not recommended by most design standards. Author’s response: The comments you provided are greatly appreciated. Your viewpoints are in line with our perspective. In the study conducted by Xiao et al [9], all SSC strengths were found to be relatively low. Therefore, this research aims to further investigate hybrid reinforced SSC beams with varying axial compressive strengths fc of 10 MPa, 20 MPa, 30 MPa and 40 MPa, respectively. The objective is to provide a theoretical foundation for their practical application in engineering. |
|
4. Comment: More data concerning the parameters of the plastic damage model used in the current study should be provided. Author’s response: More information of the concrete damaged plasticity model (CDPM) has been added. (Lines 170~175 and Table 2) |
|
5. Comment: Please clarify if the used model that describes concrete behavior in tension and compression (Equations1-5) has any limitations. Also, is there a relation between the compressive and tensile strengths of concrete according to the used model? Author’s response: Thanks for your comments. According to the Chinese code GB 50010-2010 [10], the compressive and tensile stress-strain relationships for SSC can be obtained. The constitutive model of SSC is applicable only to concrete with cubic compressive strength less than 80 MPa. It should be noted that this model does not consider the deterioration behavior of concrete strength under long-term chloride corrosion. Therefore, the constitutive model presented herein is capable of accurately characterizing the flexural behavior of beams subjected to short-term loads, while its ability to predict the flexural performance under long-term loads remains limited. (Lines 153~159) Besides, the relation between the compressive and tensile strengths of SSC has been added in Sec. 3.1.1. (Lines 139~138) |
|
6. Comment: Please clarify how was the energy dissipation and ductility coefficient determined. Author’s response: The explanation of the energy dissipation at normal service condition Escr, the energy dissipation at the ultimate state Eu and ductility μ have been added. (Lines 306~315) |
|
7. Comment: I recommend adding a flow chart summarizing the theoretical part in Section 6. Author’s response: Thanks for your comments. The flow chart has been added. (Fig. 22) |
|
8. Comment: Some ratios of improvement need to be added to the abstract and conclusion sections. Author’s response: The abstract and conclusion have been modified. |
|
9. Comment: More references need to be included. Author’s response: These references have been added as followed. [2] Li P.R., Li W.G., Yu T., Qu F.L., Tam V.W.Y. Investigation on early-age hydration, mechanical properties and microstructure of seawater sea sand cement mortar [J]. Constr. Build. Mater. 2020, 249: 118776. [3] Li P.R., Li W.G., Sun Z.H., Shen L.M., Sheng D.C. Development of sustainable concrete incorporating seawater: A critical review on cement hydration, microstructure and mechanical strength [J]. Cem. Concr. Compos. 2021, 121: 104100. [4] Etxeberria M., Gonzalez-Corominas A., Pardo P. Influence of seawater and blast furnace cement employment on recycled aggregate concretes’ properties [J]. Constr. Build. Mater. 2016, 115: 496-505. [5] Montanari L., Suraneni P., Tsui-Chang M., Khatibmasjedi M., Ebead U., Weiss J., Nanni A. Hydration, pore solution, and porosity of cementitious pastes made with seawater [J]. Mater. Civ. Eng. 2019, 31: 04019154.1-04019154.11. [6] Sun Y.J., Zhang Y.Y., Cai Y.M., Lam W.L., Lu J.X., Shen P.L. Poon C.S. Mechanisms on accelerating hydration of alite mixed with inorganic salts in seawater and characteristics of hydration products [J]. ACS Sustain. Chem. Eng. 2021, 9 (31). [7] Yaseen S.A., Yiseen G.A., Poon C.S., Li Z.J. Influence of seawater on the morphological evolution and the microchemistry of hydration products of tricalcium silicates (C3S) [J]. ACS Sustain. Chem. Eng. 2020, 8 (42). [8] Wang J.J., Liu E.G., Li L. Multiscale investigations on hydration mechanisms in seawater OPC paste [J]. Constr. Build. Mater. 2018, 191: 891-903. [9] Xiao S.M., Zhang M., Zou D.J., Liu T.J., Zhou A., Li Y. Influence of seawater and sea sand on the performance of Anti-washout underwater concrete: The overlooked significance of Mg2+ [J]. Constr. Build. Mater. 2023, 374: 130932. [10] Ghorab H. Y., Hilal M. S., Antar A. Effect of mixing and curing waters on the behaviour of cement pastes and concrete part2: microstructure of cement pastes [J]. Cem. Concr. Res. 1990, 19: 868-878. [11] Akinkurolere O.O., Jiang C., Shobola O.M. The influence of salt water on the compressive strength of concrete [J]. Eng. Appl. Sci. 2007, 2: 412-415. [12] Zhao Y.F., Hu X., Shi C.J., Zhang Z.H., Zhu D.J. A review on seawater sea-sand concrete: Mixture proportion, hydration, microstructure and properties [J]. Constr. Build. Mater. 2021, 295: 123602. |
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manusript is corrected and improved. It can be accepted for publication.
