Evaluation Residual Compressive Strength of Tunnel Lining Concrete Structure after Fire Damage Based on Ultrasonic Pulse Velocity and Shear-Wave Tomography

Round 1

Reviewer 1 Report

        Paper is focused on non-destructive evaluation of residual compressive strength after fire exposure. From investigation results can be seen, that with increasing of temperature, the ultrasonic velocity also compressive strength of the concrete decrease. But it would be appropriate to add results (ultrasonic velocity and compressive strength) for initial temperature of specimens. Tunnel lining are designed from concrete with specific parameters (compressive strength, module of elasticity,..). Comparison of initial compressive strength with compressive strength (ultrasonic velocity also) after fire damage can better understand relatively decrease their values.  

Author Response

We sincerely thank the reviewer for the comment. The UPV and ultrasonic shear wave tomography are firstly combined to measure RCS of lining concrete block and detect lining structure inner defects in this study. The structure has been revised.

Author Response File: Author Response.doc

Reviewer 2 Report

The article needs to be corrected.

1. Abstract needs to be rewritten. Example: Instructions for Authors. The annotation indicates 0-800°C. In the article, the results are for 200°C and more.

2. The structure of the manuscript does not correspond to the instructions for authors.

3. Introduction. Research needs to be justified. A lot of articles on this topic have been published over the past 5 years. They are very similar to your article (DOI: https://doi.org/10.12989/acc.2020.10.3.247, https://doi.org/10.3390/app8071107 and many more). Write the novelty of your research. State clearly the purpose and object of the study.

4. Experimental setup. There is no concrete composition. There is no description of instruments for measurement. Figure 5 shows no deviation from the mean. There are similar studies. There is no comparison with the results of other authors.

5. Post-Fire Specimen Micro-Phase. Lots of inaccuracies. There are no explanations in the pictures. Where is C-S-H gel and portlandite? "Some crystal water has evaporated". How was it understood?

6. Conclusions. It is not possible to evaluate the section at this stage. "From micro-phase SEM structure images, specimen mechanical property varied with temperature". How is this possible?

7. Reference. Need to be supplemented. Many works are like a manuscript. 

Author Response

We sincerely thank the reviewer for the comment.  I have revised the content based on the comments.

Reviewer 3 Report

Inform data of the results in the abstract or the main contributions. 

Update the bibliography, there are several studies cited that are outdated. The author should cite the most recent articles and studies possible.

Insert scales in Figure 1, Figure 2 and Figure 9.

In the discussion of the results referring to the topic "3. Post-Fire Specimen Micro-Phase", the author should indicate in Figure 6 where are the hydration products and composition of the points discussed. It would be ideal to provide a legend of the highlighted points in the SEM images.

Figure 10 should have its caption in legible scale.

In the discussion of results, the authors should compare their results with relevant and recent research. That can somehow add knowledge to the study, formulate other hypotheses of analysis and show other possible points of view. 

In the conclusion the authors should further specify the main results, placing them in specific topics and comparing quantitatively and qualitatively their results.

Author Response

We sincerely thank the reviewer for the comment.  I have added some content.

Reviewer 4 Report

abstract must contain key numerical findings

"...static loading tests[11]. " provide a space between the text and reference, please check the whole manuscript, there are many typos like that

"in the cement paste and aggregate connection zones," what do you mean by aggregate connection zone. please use more appropriate terminology. Do you mean aggregate-paste interface?

more discussion for tomography results must be added

recommendation section is missing and must be added

 

Author Response

I have revised some content based on  reviewer’s comments .

Reviewer 5 Report

Please see attached file "comments_authors.pdf"

Comments for author File: Comments.pdf

Author Response

We sincerely thank the reviewer for the comment. As you has mentioned, I have revised the manuscript based on the comments on by one.

The details in the revised PDF.

Author Response File: Author Response.doc

Round 2

Reviewer 2 Report

Add a comparison of the obtained results with the results of other authors.

Author Response

Thanks for your comments.

I have added some references.
24.    Chen, L.-H.; Chen, W.-C.; Chen, Y.-C.; Lin, H.-J.; Cai, C.-F.; Lei, M.-Y.; Wang, T.-C.; Hsu, K.-W. Using Ultrasonic Pulse and Artificial Intelligence to Investigate the Thermal-Induced Damage Characteristics of Concrete.  Appl. Sci. 2018, 8(7), 1107.
25.    Blumauer, U.;  Hozjan, T.; Trtnik, G.; Prediction of mechanical properties of limestone concrete after high temperature exposure with artificial neural networks. Adv. Concr. Constr.,2020,10(3),247-256.
35.    Ling, T. C. ; Poon, C.S. ; Kou, S. C.; Influence of recycled glass content and curing conditions on the properties of self-compacting concrete after exposure to elevated temperatures, Cem Concr Compos, 2012, 34(2), 265-272.
36.    Al-Mansour,A.; Chen,S.; Xu,C.; Peng, Y.; Wang,J.; Ruan,S.; Zeng, Q.; Sustainable cement mortar with recycled plastics enabled by the matrix-aggregate compatibility improvement, Constr. Build. Mater., 2022, 318, 125994.

And our experimental results have the same trend with the data of Chen, L.-H(2018),Blumauer, U(2020).
Residaul compressive strength values has the strong relationship with UPV. But in our study,we combined the UPV and ultrasonic shear wave tomography.

Reviewer 4 Report

the authors did all the necessary correction

Author Response

Thanks for your comments.

I have added some references.
24.    Chen, L.-H.; Chen, W.-C.; Chen, Y.-C.; Lin, H.-J.; Cai, C.-F.; Lei, M.-Y.; Wang, T.-C.; Hsu, K.-W. Using Ultrasonic Pulse and Artificial Intelligence to Investigate the Thermal-Induced Damage Characteristics of Concrete.  Appl. Sci. 2018, 8(7), 1107.
25.    Blumauer, U.;  Hozjan, T.; Trtnik, G.; Prediction of mechanical properties of limestone concrete after high temperature exposure with artificial neural networks. Adv. Concr. Constr.,2020,10(3),247-256.
35.    Ling, T. C. ; Poon, C.S. ; Kou, S. C.; Influence of recycled glass content and curing conditions on the properties of self-compacting concrete after exposure to elevated temperatures, Cem Concr Compos, 2012, 34(2), 265-272.
36.    Al-Mansour,A.; Chen,S.; Xu,C.; Peng, Y.; Wang,J.; Ruan,S.; Zeng, Q.; Sustainable cement mortar with recycled plastics enabled by the matrix-aggregate compatibility improvement, Constr. Build. Mater., 2022, 318, 125994.

And our experimental results have the same trend with the data of Chen, L.-H(2018),Blumauer, U(2020).
Residaul compressive strength values has the strong relationship with UPV. But in our study,we combined the UPV and ultrasonic shear wave tomography.