Strength, Porosity and Permeability Properties of Porous Concrete Made from Recycled Concrete Aggregates

Round 1

Reviewer 1 Report

The paper presents “Strength, Porosity, and Permeability Properties of Porous Concrete Made from Recycled Concrete Aggregates.” In the initial judgment process, it was noticed that the paper content was insufficient. So, I recommend improving the paper’s structure and highlighting the paper’s novelty. There are additional comments:

1-      In the abstract, the authors stated, “The optimum replacement percentage of recycled aggregate for porous concrete in terms of strength is 30%, with 28^th-day compressive strength of 17.37 MPa”. This concrete is described as “structural concrete”; therefore, I suggest adding this description in the abstract and keywords.

2-      The introduction must be strengthened with previous studies.

3-      The research significance is not clear. It must be included in the subtitle.

4-      The methodology needs to rewrite professionally.

5-      It should state the main aim of using cement 32.5R in the text.

6-      Define the coarse aggregate as “Normal coarse aggregate” rather than “conventional coarse aggregate”.

7-      Fig. 3 was missing in the text. It must reveal the particle size of RCA.

8-      Why choose the replacement ratios of RCA from 15% to 60%? Respond in the text.

9-      Merge Figs. 1 and 2 in one figure. The figure must be presented from left to right.

10-  Improve the quality of all the figures.

11-  Check for the written number as superscript (kg/m³) for all manuscripts.

12-  Present the average values of how many samples are presented for each test. And calculate the standard deviation and insert the error bar on the compressive result figure.

13-  It is interesting to reinforce the discussion of the results in the fresh and hardened states with references.

Author Response

Dear Editors and Reviewers,

I am very grateful for the time and energy spent in shaping this article with your constructive comments and suggestions. I’ve attempted to address all the comments and suggestions forwarded to me. in the attached response, I have marked with red color to reply to your comments and suggestions. In the revised manuscript the modified areas are shown in marked-up using the “Track
Changes”. Also, all graphs are re-drawn in the new version of the manuscript. 

Sincerely,

The Authors.

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper is a useful characterization of a Porous Concrete made from Recycled Concrete Aggregates and is potentially worthy of publication. However, before acceptance requires minor changes, whose suggestions are described below:

1.       Abstract. The use of the term fabric applied to aggregates is not clear

2.       Abstract. Workability must be in lowercase.

3.       Introduction. Some references ([1], [4], [5]…) are about well-known characteristics of concretes that do not need to be cited.

4.       Introduction. It is recommended to include a paragraph indicating the problems generated by impermeable pavements (floods, loss of aquifers, alteration of the hydrological balance).

5.       Line 90. 2.0mm

6.       Figure 1. Is better use coarse aggregate than gravel.

7.       It is important that the grain size distribution curve of the conventional coarse aggregate and recycled concrete aggregate are similar so that the results are comparable. Figures 1 and 2 should be put together for this comparison.

8.       Figure 3. The source of the image must be indicated.

9.       Table 3. What is mix proportion?

10.   Line 161. Units are N.

11.   Line 162. Units are mm².

12.   Porosity test. It should be noted that this method is for pervous concrete, it is not valid for normal concrete, because it does not consider closed pores into account.

13.   Line 175 and 176. Is weight, not mass.

14.   Line 236 and 238. Value must be in lowercase.

15.   Line 245. This statement should be referenced.

16.   Line 300. Check the punctuation.

17.   Figure 9. The graph is not understandable. Why are such disparate values such as compressive strength, permeability and porosity superimposed? Why do all the columns have the same height if they add different values?

18.   Line 359. It must be indicated that it is for non-structural construction applications

19.   References. [24] Missing quotation marks.

20.   References. [30] Missing journal.

Author Response

Dear Editors and Reviewers,

I am very grateful for the time and energy spent in shaping this article with your constructive comments and suggestions. we've attempted to address all the comments and suggestions forwarded to me. we have incorporated all your comments and suggestion in the new version of the manuscript. In the attachment we wrongly attached the response for the reviewer 3 also. That is our mistake. For your response please refer the file "Response for  reviewer_2- MDPI"

Sorry for the incomitance.

Best Regards

The authors

Author Response File: Author Response.pdf

Reviewer 3 Report

Title: Strength, Porosity, and Permeability Properties of Porous Concrete Made from Recycled Concrete Aggregates

Sufficient tests have been carried in this study, however, no sufficient discussions were reported, also there is no novelty where existing works in the literature have reported the same.

1-      What is innovative in this work. Many studies have been carried out in the previous concrete properties with RCA. (e.g. Properties of porous concrete from waste crushed concrete (recycled aggregate) https://0-doi-org.brum.beds.ac.uk/10.1016/j.conbuildmat.2013.06.022)

2-      In the abstract, more than half of the abstract is a detailed summary of the problem statement, while I think it should focus more on what the reader is going to read in the paper, i.e. the research problem/gap and the kind of experimental tests and the results as well as the conclusion.

3-      The permeability results are not highlighted in the abstract.

4-      Introduction needs to be enriched with the latest existing studies in the field.

5-      Please show the gap/novelty of the study by the end of the introduction.

6-      Please write the standard followed to perform all the tests in the text. Not just citing them.

7-      Complementary discussion in comparison to literature is needed.

Author Response

Dear Editors and Reviewers,

I am very grateful to the time and energy spent in shaping this article with your constructive comments and suggestions. I've attempted to address all the comments and suggestions forwarded to me.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper language need to revise professionally. 

Reviewer 3 Report

Authors almost revised the manuscript according to the reviewer comments.