The Effect of Curing Conditions on Selected Properties of Recycled Aggregate Concrete
Round 1
Reviewer 1 Report
The paper is well written and organised. Presents a sufficient amount of results for a research paper.
There are some important aspects that should be deeply imporved before trying to publish the paper again.
The introduction is too long, and includes some ideas about the use of recycled aggregates thata are too old, as for example those presented on lines 50-52. The idea stated on line 53 is nowadays mandatory in all countries, or should be. No aggregate, neither natural nor recycled should be used if it has not passed a quality control, so this idea should be clarified in the text.
On lines 68-69 authors refer to the negative effect that the use of coarse recycled aggregate has on concrete properties, but no mention is made on the pernicious effect that the recycled fine aggregate
(RFA) also has, and that is the cause why the use of RFA is not allowed in some countries. Authors should make any mention on the effect of RFA as well.
As stated on line 82 “the absorption time should be 10 minutes”. Is this data relevant for the research here presented?
What do authors mean by “the firm and tight microstructure of concrete”? (line 96)
Bi and ci indexes are not very common and they should be explained more clearly avoiding the obvious examples that are given in the manuscript.
As a conclusion I find the introduction too long, full of unnecessary data, and I miss some other data, as for example the influence of the environment on the service properties of concrete, as a function of the cement type used. There is a huge corpus on this aspect (i.e. Ortega et al.) that could help for a better interpretation of the results obtained.
The introduction should be completely rewritten, and more focused on the aspects treated in the paper, letting know the deficiencies in the state of the art, and plan the paper as an answer to those deficiencies.
Regarding the experimental section, why did authors not use any standard for concrete mixing? Mixing times seem to be really short.
The water absorption procedure should be only referred to the standard, that is widely known, and not so much information should be given in the experimental section.
Have authors quantified from the economic/ecological point of view the influence of the carbonation procedure proposed. The amount of surface, and the time seem to be too big as to make the process efficient from the industrial point of view. It the results cannot be used at a real scale the research would be meaningless.
The lack of references might be the reason o the low level of the discussion of the results, i.e the different behaviour of each type of cement, as a function of the environment, the possible self-curing effect provided by the pre-saturated recycled aggregates, effects that have already been referred in the literature, and that are essential for the quality of the paper.
There are some aspects, i.e. the saturation degree of the concrete, that seem to be in disagreement with some other results, but no effort is made on the explanation of those differences.
The results section MUST be rewritten taking into account previous results and providing a more in deep explanation of the obtained results before trying to publish the paper.
Author Response
Please see attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
There are some weaknesses through the manuscript which need improvement. Therefore, the submitted manuscript cannot be accepted for publication in this form, but it has a chance of acceptance after a major revision. My comments and suggestions are as follows:
1- Abstract gives information on the main feature of the performed study, but some details about the test conditions (at least in a couple of sentences) and also obtained results should be added. However, a concise abstract is needed.
2- Authors must clarify necessity of the performed research. Aims and objectives of the study, and also differences with the previous researches must be clearly mentioned in concluding part of introduction.
3- Introduction should be compacted (to avoid trivial comments of justifications), and written in a more scientific way. A concise and informative introduction is needed.
4- The literature study must be enriched. As the manuscript deals mechanical properties of concrete, it is highly recommended to read and cite the relevant published paper: (DOI: doi.org/10.1016/j.advengsoft.2018.10.002)
5- Although European standards are mentioned in the text, they are not in the reference list.
6- As the manuscript presented an experimental study, it is necessary to show the specimen figure in section 2. Description without this figure is not acceptable!
7- Each formula must be typed in the text (it seems Eq. (1) is a copy). Also, the main reference of each formula must be cited.
8- Although the text (section 3.3) is described compressive strength, a figure must be added to show specimen under the test conditions.
9- Figures 3 and 5 must be presented in a high quality and with details. Moreover, main source (reference) of each equation must be mentioned.
10- In its language layer, the manuscript should be considered for English language editing. There are sentences which have to be rewritten.
11- The conclusion must be more than just a summary of the manuscript. Please provide all changes in text and reference update by red color in the revised version.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
paper should be accepted in present form
Reviewer 2 Report
The paper has been improve.
