Review of the Strengthening Methods and Mechanical Properties of Recycled Aggregate Concrete (RAC)
Round 1
Reviewer 1 Report
This article provides a review of strengthening methods and mechanical properties of recycled aggregate concrete. The detailed comments are as follows:
1. Abstract is not well-written. What are the outputs of this study?
2. There are a lot of review articles available in the literature on RAC. Why another article is needed?
3. Article is not well-structured. There are various strengthening methods. However, the authors have only focused on limited methods. Is there any specific scope of this article?
The article is not suitable for publication. The topic is too vast. Authors have provided very limited works. It seems more like an introduction section of the thesis rather than a review article.
Author Response
Dear Professor ,
Thank you for your kind consideration on our manuscript entitled “Review of the Strengthening Methods and Mechanical Properties of Recycled Aggregate Concrete (RAC)”. We are very grateful for the second chance to revise it. We greatly admire the rigorous attitude of the two experts towards scientific research. We have studied comments carefully and made some corrections which we hope meet with approval. The main corrections in the paper and the responds to your comments are as follows:
The comments:
Reviewer #1.1 Abstract is not well-written. What are the outputs of this study?
Response:
Thank you very much for your helpful comments, which is very important to
improve our writing level.
This paper is a review of the recent research, including the following aspects: the
mixture design of RAC; the improved mechanical properties of recycled concrete
with steel fibers; the performance of the main components. In addition, the primary composition materials, properties, and calculation methods of the mixture ratio of RAC are summarized. The mechanical properties, durability and microscopic analysis of RAC are also discussed. The accurate calculation of mixture proportion can significantly facilitate the work of preparing a test mix of RAC. Through the mixture-ratio optimization and physical and chemical strengthening of RA, the mechanical properties of RAC can be improved to promote the wider application of this eco-friendly material.
The general idea of this article is to study the mechanical properties and durability of recycled concrete through the latest and quantifiable mix proportion design method, and to prove the feasibility of the mix proportion design method of recycled concrete from the micro level.
The comments:
Reviewer #1.2 There are a lot of review articles available in the literature on RAC. Why another article is needed?
Response:
Thank you very much for your helpful comments, which is very important to
improve our writing level.
There are a lot of review articles available in the literature on RAC. Before writing
this review, we carefully studied and read these precious documents, but there is no review on the mix proportion method and feasibility study of recycled concrete. In order to enable scholars to more conveniently understand the mix proportion design and corresponding mechanical properties of recycled concrete, we wrote this review.
The comments:
Reviewer #1.3 Article is not well-structured. There are various strengthening methods. However, the authors have only focused on limited methods. Is there any specific scope of this article?
Response:
Thank you very much for your helpful comments, which is very important to
improve our writing level. Its a complex scientific work，the group of researchers and the professor who coordinated the writing of the manuscript. The replacement of natural aggregates (NA) with recycled ones (RAC) is studied by many researchers, especially when the history of the RAC aggregate is not known. The manuscript deals with the possibilities of improving the new concrete mix by treating the aggregate by several methods.Your valuable suggestions have provided great help to improvement of the writing level of our entire team. Thank you very much.
Reviewer 2 Report
Its a complex scientific work and you need more time to complete it, but it is worth it! I congratulate the group of researchers and the professor who coordinated the writing of the manuscript. Observations/Additions can be found in the comments inserted in the manuscript. These are minor issues that need to be dealt with. These are minor issues that need to be dealt with.
The replacement of natural aggregates (NA) with recycled ones (RAC) is studied by many researchers, especially when the history of the RAC aggregate is not known. The manuscript deals with the possibilities of improving the new concrete mix by treating the aggregate by several methods, it is very good for a research but it must be thought of not to become expensive.
Comments for author File: 
Comments.pdf
Author Response
The comments:
Reviewer #2: Its a complex scientific work and you need more time to complete it, but it is worth it! I congratulate the group of researchers and the professor who coordinated the writing of the manuscript. Observations/Additions can be found in the comments inserted in the manuscript. These are minor issues that need to be dealt with. These are minor issues that need to be dealt with.
The replacement of natural aggregates (NA) with recycled ones (RAC) is studied by many researchers, especially when the history of the RAC aggregate is not known. The manuscript deals with the possibilities of improving the new concrete mix by treating the aggregate by several methods, it is very good for a research but it must be thought of not to become expensive.
Response:
Thank you very much for your affirmation of this article. We have carefully studied the valuable suggestions you put forward to us.
The comments:
Reviewer #2.1: “using two-stage mixing approach”[91,92],The water added twice pouring,not “improve the strenght” please redo the sentence for a clear meaning.
Response:
Thank you very much for your affirmation of this article. We have carefully studied the valuable suggestions you put forward to us.The revised content has been marked in red in the manuscript.
In the latter method, to improve the strength of RAC,water is added twice when pouring RAC [91,92].
The comments:
Reviewer #2.2: 3.7 Annexing agent. “Is not correct. It is known that the pozzolanic reaction of the fly ash cement paste is the chemical reaction bet ween reactive silica or
Alumina in the fly ash particles and calcium hydroxide(Ca(OH)2-CH) formed form cement hydration in the presence......”
Response:
Thank you very much for your affirmation of this article. We have carefully studied the valuable suggestions you put forward to us.The revised content has been marked in red in the manuscript.
the pozzolanic reaction of the fly ash cement paste is the chemical reaction bet ween reactive silica or Alumina in the fly ash particles and calcium hydroxide(Ca(OH)2-CH) formed form cement hydration.
The comments:
Reviewer #2.3: Sentences 376. “1.5ï¼… of the cementitious material”
Response:
Thank you very much for your affirmation of this article. We have carefully studied the valuable suggestions you put forward to us.The revised content has been marked in red in the manuscript.
1.5% of the weight cementious material
The comments:
Reviewer #2.4: Table 6. “ C /W : the water-cement”
Response:
Thank you very much for your affirmation of this article. We have carefully studied the valuable suggestions you put forward to us.The revised content has been marked in red in the manuscript.
C /W : the water/cement
The comments:
Reviewer #2.4: 7. Conclusion “2.There is no unified understanding of the replacement rate of RA with different qualities. It is necessary to define the upper limit of the replacement rate of RA with different qualities and the effect of enhancing the mechanical properties of auxiliary materials, so as to promote the extensive application of RAC. ”
Response:
Thank you very much for your affirmation of this article. We have carefully studied the valuable suggestions you put forward to us.The revised content has been marked in red in the manuscript.
There is no unified understanding of the replacement rate of RA with different qualities. It is necessary to define the upper limit of the replacement rate of RA with different qualities and the effect of enhancing the mechanical properties of auxiliary materials, so as to promote the extensive application of RAC.In order not to be expensive to use them through various chemical or physical treatments,the effective water in the recipe must be established and quality of RA aggregates should be checked more frequently compared to NA.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The reviewer is not satisfied with the response of the authors. There is no significant contribution of this article to existing literature. Therefore, it is not suitable for publication.
