Numerical Assessment and Repair Method of Runway Pavement Damage Due to CBU Penetration and Blast Loading
Round 1
Reviewer 1 Report
Reviewer appreciates the effort went into the study. The topic is novel and the scope of the study is interesting. However, there are some minor revisions which has to be handled and those are given below:
- Abbreviations are to be define when they are used for the first time in the manuscript.
- The quality of some images should be improved.
- Kindly state implications of your study for industry, policy and research in the conclusion section.
- Conclusion should be refined, the valuable data and useful results of the research should be accurately presented.
Author Response
This is a revised version, please review thank you.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Journal: Applied Sciences
Manuscript ID: APPLSCI-1546712
Title: Experimental and Numerical Assessment of Runway Pavement Damage Resulted by CBU Penetration and Blast Loading
Summary:
The paper titled "Experimental and Numerical Assessment of Runway Pavement Damage Resulted by CBU Penetration and Blast Loading" has been critically reviewed. The study considers rigid concrete pavements over asphalt concrete flexible pavements for operation of jet planes on runways. The cluster bomb units (CBUs) are delivered using ballistic missiles. The CBUs are dispersed from height of 20 km towards the ground surface. The CBUs undergo free fall and attain high velocities before hitting the ground surface. This allows the CBUs to penetrate the concrete pavements up to a certain depth prior to the detonation. The study investigates this phenomenon experimentally and also performs a finite element based numerical investigation. The study finally reports comparison between the experimental and numerical results and make suggestions for fast repair of the runways using quick hardening concrete.
Technical comments:
In section 1, line 48, the authors have not mentioned which exact formula is used to compute the relationship between the height at which CBU is dispersed and the depth of penetration into concrete pavement.
In section 1, line 55, the depth of installation of equivalent of TNT is not mentioned.
In section 1, line 63, need attention to re-write, clarifying field test results and numerical results separately. Currently, it mentions "when running a model in field test", which needs to be rephrased.
In section 1, line 70, it is not clear what shape of charge has been used and need to be clarified. Detonation of spherical charge and cylindrical charge are not comparable. In a spherical charge the stress waves and the wave front would be radially outward whereas for a cylindrical charge the stress waves would have radial and axial components.
In section 2, lines 78 and 79 appear to be repetitive. If there is altered intent by the authors then that is required to be clarified explicitly. ‘Conwep’ is not a word but an abbreviation for ‘Conventional Weapons’, authors need to correct it by either writing the full name or by writing the short name, i.e., ‘ConWep’.
In section 2, line 82, the authors mention "this thesis", which needs to be corrected.
In section 2.1, line 89, do the authors mean: one missile carries 15-40 cluster bomb units, or one cluster contains approximately 15-40 bombs. Please clarify in the sentence by rephrasing it as well as splitting the details for clarity.
In Table 1, total weight of munition, total length of munition, density of explosive, and velocity of explosion velocity can be mentioned separately. Representation of information in the table should be consistent. HE needs to be defined as 'high explosive' before using the abbreviation 'HE'. 1st column - last row mentions number of munitions. Does this mean number of munition used in the test or number of CBUs in one missile? Please clarify through rewriting this portion.
In Figure 2, thickness of concrete slab mentioned is different to that mentioned in section 3.1, line 127. Such lapses may carefully be avoided.
In section 3.1, line 120, the statement is contradictory. It is not clear if the authors want to report a penetration depth in the field tests or not. The statement needs to be clarified by rearticulation.
In section 3.1, line 130, authors need to justify why the explosion wave front is in a spherical shape as it was previously mentioned that the explosive used is in cylindrical shape.
In section 3.1, line 131, it is mentioned, "The completed site simulated runway", this phrase needs to be explained properly. In line 134, what kind of industrial explosive is considered? Is it PBXN-109 as mentioned in Table 1? If not, it needs to be specified clearly. If it is that, then continuity must be ensured while specifying names.
In section 3.1, line 135 is BAP - 100 a runway or an explosive? The authors mention “CBU BAP - 100 to be HE in section 2.1, line 94 therefore such ambiguity arises.
In Figure 3, the dimensions are not clearly visible. What does "S = NONE" mean in the figure is not mentioned. The same is mentioned in Figure 1 as well.
In section 3.2, lines 142 to 144, need to be rephrased to make the meanings clearer.
In Figure 4(a), authors need to clarify what they mean by "initial explosion process". In Figure 4(b), is the maximum fragment height analytically calculated or digitally recorded? Require to mention details thereof.
In section 3.2, line 163, it is not clear how the cracks were ascertained to be tensile in nature.
In Figure 7, it is not clear why the cracks are tensile.
In section 3.2, line 171, it is not clear how the dimensions for restoration were established to be 1.8 x 1.8 m. Is it based on any guidelines or based on experimental findings? Need clarification on whatsoever has been mentioned in the manuscript.
In section 4.1, line 198, the authors mention "a pressure pulse occur", the meaning of this statement is not clear.
In Figure 8, the point of explosion is not shown as mentioned in the text in line 200.
In section 4.1, line 201, "RHT concrete model" elaboration and citation for material properties is missing.
In section 4.1, the numerical model is not explained properly. The types of elements used, the mesh size, convergence and boundary conditions need to be mentioned. The strain rate, type of loading and EoS needs to be mentioned in text.
In section 4.2, line 225, what concrete surface is being mentioned here? This may be shown in the figure correspondingly.
In Figure 9(b) and Figure 10, the legend and scale are not visible.
In section 4.3, line 258, why wasn't the same explosive used in the numerical model as that used in the field test? Are the characteristics of the explosives the same? If not please elaborate.
In section 4, is the numerical model validated? If yes, then the validation results are missing. If not, then the authors need to explain how they are comparing the numerical model with the field test data. If the field test data is being used to validate the numerical results, then the results are vastly varying. The authors need to comment on this with greater details.
In references section, [16], [17] and [18] have not been cited anywhere in the paper.
The references are not in any particular format. The authors are advised rewrite the references in required format of the Journal, Applied Sciences.
Recommendation:
The authors are advised to showcase validation for their finite element based numerical model and then establish a proper comparison between numerical and field results. Furthermore, comparison of asphalt concrete surface with rigid concrete surface when subjected to similar kind of explosives would be a good addition to this paper.
Author Response
This is a revised version, please review thank you.
Author Response File: Author Response.docx
Reviewer 3 Report
The experiment, its results and simulation are interesting and beneficial. However, the article has a number of formal errors. The article needs to be edited according to the template. The article needs to be reworked and formal errors corrected (missing spaces between the text and the link or between the value and its unit, etc.), redundant parentheses, table format, etc.
Add to the article how (on what basis) the dimensions of the tested area (paving) were determined.
Line 262 - it may be appropriate to add references to studies that deal with the effect of charge shape on the destructive effect.
The whole study should be supplemented with references.
Author Response
This is revised version, please review thank you.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
No comments at this stage. The revised manuscript is improved.
Author Response
- Mpa는 MPa의 철자 오류입니다(표 4의 216행 뒤) --------> MPa
- Kg는 kg의 철자 오류입니다(표 3의 157행 뒤) --------> kg
- 일부 수치가 좋지 않거나 해상도가 낮습니다. --------> 고품질 및 고해상도.
- 그림의 많은 텍스트에는 빨간색 밑줄이 있으므로 제거해야 합니다. --------> 빨간색 밑줄 삭제
- "cos"는 기울임꼴 형식이 아니어야 합니다( 방정식 8 ) ---------> "cos" 수정 기울임꼴 형식
- "(->near?) "는 부적절합니다. (in line 123) -------->"(->near?)" 삭제
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