Application of Bilinear Softening Laws and Fracture Toughness of Foamed Concrete
Tia Mang
Round 1
Reviewer 1 Report
An abstract needs to be self-explanatory, and should not refer to some mix designation such as "GF-30". A reader would not understant what "GF-30" is unless he/she reads the paper.
The paper needs improvement in clarity and organization, and in the proper use of technical English.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript must necessarily include nomenclature - a full list of abbreviations, symbols, and designations that have appeared in the paper. You can add it at the end of your paper.
Authors should shorten the abstract – it should be concise, without giving any numerical values.
The introduction is an excellent review of the literature.
In the paper, the authors should indicate how many specimens of a given type they tested in their experiments. We are dealing with the mechanics of cracking, the process of unstable crack growth is taking place. At least three specimens should be tested in both the compression and bending tests with and without notching. For each dimension of the notch and the sample without notch, the authors should present a summary, show the dispersion, and perform a statistical analysis of the obtained results. Without it, we don't know anything about scatter, we don't know if the tests are reproducible. Please explain this fact. It seems to me that it is wrong to draw conclusions based on one specimen in the experiment.
In the manuscript, there is a quantity marked as "f" and it is nowhere explained at the beginning of the paper. Please also check the notation of many markings and symbols - there are inaccuracies - once the quantities appear in the subscript or superscript, and in another place in the text the subscript / superscript is not used (e.g. .line 171)
Please check the text on line 71 - something is blending and unclear.
Line 82 - citation of literature glued with the text of the manuscript - please correct it and check the whole paper in this respect.
Please check the paper for editing ambiguities.
What do the authors mean by "Tensile strength"? Where are the stretching tests to talk about "tensile strength"? Such language cannot be used - the work in this area contains a lot of factual errors. The authors create graphs that do not correspond to the conducted experiments, they confuse concepts and quantities. Yes, you can qualify "The flexural strength which would be the same as the tensile strength if the material were homogeneous." But it must be clearly demonstrated and written in the manuscript. This must be clearly defined. Please improve your manuscript in this regard.
The part describing the conducted experiments in the manuscript should be very specifically changed and edited, supplemented with graphs, tables and figures. It is ready for publication in its current form.
What is the interpretation of a1, a2, w1, w2, sigma1, sigma2? Please describe and explain (see Table 3).
Entries like "(see Figure 4 (b) at ultimate load = 0.07 mm)" are not allowed in the paper - please change it in the entire.
In the description of the FEM model, please provide the final number of finite elements and nodes in the model, please specify the number of integration points in the finite element. Did the authors compare the results obtained on the model with "shell" elements with "2D solid" or "3D solid" elements? At manuscript, we deal with large specimens - a cross-section of 100x100mm. It is advisable to perform FEM 2D solid for plane strain state calculations and calculations for the 3D model. This is not in the paper - please add arguments to the manuscript that the authors' approach is correct.
Figures - especially graphs with isolines require specifying units with the data presented, this is not the case.
I have the impression that the authors put together the manuscript quickly - they made a lot of mistakes, there are some shortcomings. Please correct the paper, complete it and send it for review again.
I suggest a major revision.
Minor editing of English language required.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper studies using bilinear softening laws and fracture toughness to predict the behavior of foamed concrete.
I think the idea is original and relevant. The topic is important and timely, considering the importance of developing models for unconventional concrete, including foamed concrete.
Fracture mechanics have been used extensively to understand the behavior of concrete elements. In the same way, the current study tries to propose modeling techniques for foamed concrete. Studying the behavior of foamed concrete using softening laws and facture toughness is one of the main significances of the study.
The manuscript will benefit from an editorial review to make sure about the quality of English and consistency of language to improve the reading experience. I have taken two examples from the abstract as follows:
1-In the following sentence: “two-dimensional FEA Modelling of fracture was carried out using a Traction Separation Law (TSL), incorporating extended finite element method (XFEM) and cohesive zone (CZM) techniques.” FEA should be defined. If FEA means finite element analysis, what is the difference between FEA and FEM (finite element modeling)?
2-The last sentence of the abstract might be rewritten as follows: “Furthermore, a comparison between the results of the DIC experiment and FEM shows a good agreement in terms of simulation of crack propagation.”
Element size dependency is one of the concerns of the modeling of the study. In this respect, the authors touched on fracture mechanic-based approaches. Authors may want to test other approaches like: “Element size effects in nonlinear analysis of reinforced concrete members” DOI: https://doi.org/10.1016/S0045-7949(96)00007-7.
It would be great if authors could explain further how ABAQUS accounts for cracking. To my understanding, LEFM can not take the cracking of concrete into account.
I think the title of sections should be selected more carefully. I suggest subsection 2.2 be called ‘Experimental Results’ and section 3 be called ‘Finite Element Study.’
I believe the conclusion section could be expanded. For example, authors may want to include their plans to expand and improve their study.
References are adequate.
The figures and tables look good to me.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors included all my suggestions in the revised version of the paper. I recommend the manuscript for publication.
Minor editing of English language required.
