Detection of Concrete Cover of Reinforcements in Reinforced Concrete Wall by Microwave Thermography with Transmission Approach

Round 1

Reviewer 1 Report

In the Reviewer opinion the research paper entitled “Detection of concrete cover thickness of steel reinforcements in reinforced concrete wall by microwave thermography: the transmission approach with one-layer reinforcements” is good.

The present paper propose an innovative methodology with microwave thermography for determining the concrete cover thickness of one-layer reinforcements in a RC wall. By using the transmission approach with five angles of microwave antenna direction, the Snell-Descartes law and linear law, the methodology leads to deduce the approximate value of the concrete cover thickness  which is close to the real value. The spacing of the steel bars and dielectric constant of the concrete are also deduced.

Some comments which greatly enhance the understanding of the paper and its value are presented below. Specific issues that require further consideration are:

1. The title of the manuscript is matched to its content, but it is too long.
2. The Introduction generally covers the cases.
3. The methodology was clearly presented.
4. In the Reviewer’s opinion, the current state of knowledge relating to the manuscript topic has been presented, but the author's contribution and novelty are not enough emphasized.
5. Experimental program and results looks interesting and was clearly presented.
6. In the Reviewer’s opinion, the bibliography, comprising 24 references, is more less representative.
7. An analysis of the manuscript content and the References shows that the manuscript under review constitutes a summary of the Author(s) achievements in the field.
8. In the Reviewer’s opinion the manuscript is well written, and it should be published in the journal after minor revision.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript entitled: "Detection of concrete cover thickness of steel reinforcements in reinforced concrete wall by microwave thermography: the transmission approach with one-layer reinforcements" is relevant for the Applied Science journal. The article is based on original experimental research. Overall, the paper is well prepared. Nevertheless, the article required some improvements:

 

·         General note: in all equations, there should be a multiplication symbol, not a regular dot - the symbol should be level with other signs, such as plus or minus

·         Line 115 - Please check if it is used correctly: waves and wave. Now we have several incident waves, but only one reflected wave. I don't think it should be like that.

·         Equations 2 and 3 - The formulas are correct and shown in line notation. Why wasn't the equation editor from MS Word used? If we have an editable template in this program, it is much easier to create equations with a fraction of a slash.

·         Equations 4-6 - See general note

·         Line 161 - Please write down the manufacturer and the type of the infrared camera used.

·         Figure 5 - Please try to change the order of the legend. Now we have 6 => 4.5 => 8 etc. However, the graph is according to the increasing dielectric constant, i.e. 4.5 => 6 => 8 etc.

·         Line 223 - Have you tried to use other periods? Why was period 5 used? Have you looked for other fit functions?

·         Figure 7 and 8 - Please change the unit on the horizontal axis to [cm], how it is used in the manuscript's text.

·         Line 238 - Equal? Has the center of each fit peak been determined (local minimum where the reinforcement is supposed to be), and is the distance between the steel bars determined? Are there any measurement uncertainties?

·         Figure 9 - equation in the frame - Please see the general note

·         Line 268 - e is not a power of 1424, and the square root of that number gives us 37.74. Therefore, it needs to be corrected. If you stick to this, raise the number to the 1/2 power, or as it was written elsewhere, to 0.5

·         References - Please check and prepare references following the template appropriate for the journal, available at:

https://www.mdpi.com/journal/applsci/instructions

 

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Authors

The manuscript is a good presentation of a very interesting subject. The abstract, introduction, and conclusions are well prepared.

But two main points need an analytical clarification:

(1)The step 4 of the methodology "Deduce the values of the shifts...". How you deduce the values? Please describe.

(2) How you calculated the Δi in table 1 from the Figure 8 moving average temperatures. Please explain analytically because  the calculation of Δi  is unclear

I would also to provide some minor remarks:

Line 61: "detected materials detected..." please correct

Line 65: "seen as...", "affected..." Unclear meaning. Do you mean "such as" and "affecting"?

In Figure 8, in the moving average figures please change the Greek letters in the labels of the figure

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Dear authors

The remarks and the improvements I suggested, I see that they are implemented. Therefore I have not to make some additional remark.