Analysing the Influence of Fibers on Fresh Concrete Rheometry by the Use of Numerical Simulation

Round 1

Reviewer 1 Report

The paper concerns the issue of fiber influence on rheology of cement mixes and it is an experimental and theoretical analysis - very interesting and deep from the point of view of modeling the rheological parameters of the mixture.

Nevertheless, I have to express my astinishment by the fact, that in all the analysis the issue of material properties of fibers is omitted. Even in cited works and results there is frequently no info about the material of used fibers. In my opinion this is an important element of the influence of fibres on the rheology. Deformation susceptability of fiber depends not only on d/l but also on the elasticity of the fiber.

I think that this aspect should be discussed in relation to the models presented in the article, or a limitation should be included already at the Introduction chaptere, that the considerations concern, for example, only plastic fibers. In this context, the practical purpose of the analyzes undertaken is not clear - I would suggest supplementing it in the Introduction, especially taking into account the fact that the fiber dosages considered are very large (5% of the mass!) and differ from the technological practice of fiber concrete.

Author Response

Thank you very much for your review. Since we come from the field of fluid mechanics, we are usually very specialized in this subject area and the details of, for example, the materials used tend to get lost, which is why we are very grateful for exactly your perspective and comments.

We have incorporated the materials we used (concrete and fibers) and their parameters into the text and added an additional source.

With regard to elasticity, we have clarified in several places in the text that no elasticity of the fiber was taken into account in the numerical investigation. We have added an additional source that confirms that no bending of the fibers could be detected in our previous tests. In the last chapter, we have again listed the limitations of our model to avoid misunderstandings.

In order to better classify our work in which area the greatest strength of the components is generated, we have included an additional source in the introductory chapter that provides an assessment of this.

So that you can quickly see how the paper has changed, in the current version we have highlighted and commented on all the changes we have made as a result of your review. (See appendix)

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript presents an extensive study on the numerical simulation of the influence of fibers content and orientation in the flow properties of fresh concrete. For this, a numerical model of a ball probe rheometer, previously presented by the authors, is used to perform numerical simulations to determine the fiber orientation process during the measurement of the flow properties and its influence on the measured variables. The results are presented and discussed, and also compared with experimental measurement results in order to validate the used constitutive law accounting for the fiber orientation.

The advanced topic of the manuscript is very interesting and important. Such numerical studies are still scarce in the literature. The presented results could constitute a very good contribution to help researchers for future numerical studies and also assist designers in using advanced numerical tools. The authors presented a very comprehensive article.

I made few comments/suggestions in order to improve the manuscript. The authors should take the comments into account and revise their manuscript.

Specific Comment 1

In the end of the introduction section, please clarify better what is the need and novelty of your study, in relation with the presented literature review and also with you own previous studies.

Specific Comment 2

Throughout the manuscript, all presented equations must be justified with an appropriate reference.

Specific Comment 3

Please check the references in the text. For instance, at page 5 the reference “Advant and Tucker” has no reference number associated.

Specific Comment 4

I suggest to reorganize Section 4. After an introductory paragraph, the main findings should be summarized in point-by-point format. Then, the limitations and future needs should be presented.

Author Response

Thank you very much for your review. The comments on the sources of the equations helped us a lot to make it clearer in some places in the text from which source which equation is used. (Comment 2) We have also made sure that all sources are cited correctly. (Comment 3)

We have taken more time to comment 1 and 4, as we have also seen that the paper can be better integrated into current research and that a structured conclusion with future needs and limitations avoids misunderstandings and makes it easier for the reader to understand.

So that you can quickly see how the paper has changed, in the current version we have highlighted and commented on all the changes we have made based on your review. (See appendix)

Author Response File: Author Response.pdf