Study on the Eccentric Compressive Performance of Steel Fibre Reinforced Coal Gangue Concrete Columns

Round 1

Reviewer 1 Report

The present manuscript investigates the eccentric compressive capability of steel fibre-reinforced coal gangue concrete columns. The paper is well written and organized however some parts should be revised before acceptance for publication.

First of all the authors should highlight the novelty of this work. As mentioned in the literature using gangue cannot be used more than 50% of volume fraction and in this study, they show that the efficient percentage of using coal gangue is less than 30%. Moreover, the use of coal gangue in concrete has some benefits. It can help to reduce the cost, improve the workability, improve the durability, and provide thermal insulation. It can also help to reduce the environmental impact of concrete production. These above-mentioned parameters should be addressed in the introduction of this work otherwise using a coal gauge in terms of increasing the mechanical properties is not a good choice ( as compared with the results of sample S-0-1).

Figure 4 needs a more detailed explanation of the cracking pattern and why by increasing the percentage of coal gangue the crack propagation had different behaviour in test samples.

I look forward to receiving the revised manuscript after minor corrections.

Author Response

We have revised the reviewers’ suggestions on editorial issues in the resubmitted manuscript, which are shown in yellow font. Additionally, we have supplemented the content according to the requirements of the reviewers. This article has been edited with the help of native English speakers and highlighted in yellow.

Responds to Reviewer 1 for the questions:

Q1：First of all, the authors should highlight the novelty of this work. As mentioned in the literature using gangue cannot be used more than 50% of volume fraction and in this study, they show that the efficient percentage of using coal gangue is less than 30%. Moreover, the use of coal gangue in concrete has some benefits. It can help to reduce the cost, improve the workability, improve the durability, and provide thermal insulation. It can also help to reduce the environmental impact of concrete production. These above-mentioned parameters should be addressed in the introduction of this work otherwise using a coal gauge in terms of increasing the mechanical properties is not a good choice (as compared with the results of sample S-0-1).

A1: Due to the gangue selection, the material properties of the gangue used in this paper and other literature selected gangue has a certain error, and in the final determination of the effective utilization rate, we take a conservative selection value, which is to prevent when the gangue selection error leads to 50% replacement rate of gangue concrete strength is too low. A description of some of the benefits offered by the use of gangue in concrete has been added to the introduction in this paper and is highlighted.

Q2：Figure 4 needs a more detailed explanation of the cracking pattern and why by increasing the percentage of coal gangue the crack propagation had different behaviour in test samples.

A2: Because of the small number of samples in this test, the final results are highly discrete and the pattern of crack development cannot be determined in relation to the percentage of coal gangue.

Reviewer 2 Report

Manuscript ID: buildings-2362696

Title:    Study on the eccentric compressive performance of steel fibre reinforced coal gangue concrete columns

The following amendments are recommended:

1.      The novelty statement that was written at the end of the introduction is not satisfactory, so it should be improved.

2.      The chemical composition and physical properties of cement should be given.

3.      Please mention the detailed mixing procedure for concrete ingredients.

4.      Please indicate based on which standard (or reference) the columns were designed.

5.      The results, in general, need to be improved and more comparisons with the literature should be added.

6.      The conclusions section must be supported by the numbers (the increase or decrease in values) obtained. 

Author Response

We have revised the reviewers’ suggestions on editorial issues in the resubmitted manuscript, which are shown in yellow font. Additionally, we have supplemented the content according to the requirements of the reviewers. This article has been edited with the help of native English speakers and highlighted in yellow.

Responds to Reviewer 2 for the questions:

Q1：The novelty statement that was written at the end of the introduction is not satisfactory, so it should be improved.

A1: We have improved the novelty statement at the end of the introduction and highlighted it.

Q2：The chemical composition and physical properties of cement should be given.

A2: Tables 2 and 3 have been added to illustrate the chemical composition and physical properties of the cement and the additions are highlighted.

Q3：Please mention the detailed mixing procedure for concrete ingredients.

A3: We have added Figure 3, which details the mixing process of the concrete components and is highlighted.

Q4：Please indicate based on which standard (or reference) the columns were designed.

A4: We have included the reference specifications used in the design of the columns and highlighted them in the document.

Q5：The results, in general, need to be improved and more comparisons with the literature should be added.

A5: We have added comparisons and analyses with other literature and highlighted them in the results section of the paper.

Q6：The conclusions section must be supported by the numbers (the increase or decrease in values) obtained.

A6: We have added figures to support these findings and highlighted them.

Reviewer 3 Report

This paper presents an experimental study on reinforced gangue concrete columns under eccentric compression. The effects of steel fiber content, the eccentricity, and the replacement of gangue aggregate were investigated. The paper can be improved by addressing the following comments:

1. The concrete mix proportation is not clear. What was the total volume for the mixs listed in Table 3?

2. Details in Figure 2b should be described.

3. How was the hinge support connected to the columns？ The authors can refer to test set-up for eccentrically loaded RC columns documented in existing studies on behavior of large-scale FRP-confined rectangular RC columns under eccentric compression.

4. The strain profiles in Figure 6 fail to verify the plain section assumption at the latter loading stages.

5. Please explain the overestimation of crack widths for the specimens such as S-30-1.

Spell check should be conducted and the English can be improved. Avoid mistakes such as 'Xiao et al. Xiao'.

Author Response

We have revised the reviewers’ suggestions on editorial issues in the resubmitted manuscript, which are shown in yellow font. Additionally, we have supplemented the content according to the requirements of the reviewers. This article has been edited with the help of native English speakers and highlighted in yellow.

Responds to Reviewer 3 for the questions:

Q1：The concrete mix proportation is not clear. What was the total volume for the mixs listed in Table 3?

A1: We have reorganised the concrete mix table and highlighted it.

Q2：Details in Figure 2b should be described.

A2: We have described the details in Figure 2b in more detail and highlighted it.

Q3：How was the hinge support connected to the columns？ The authors can refer to test set-up for eccentrically loaded RC columns documented in existing studies on behavior of large-scale FRP-confined rectangular RC columns under eccentric compression.

A3: We have made reference to the literature (Behavior of large-scale FRP-confined rectangular RC columns under eccentric compression) for an illustration and highlighted it.

Q4：The strain profiles in Figure 6 fail to verify the plain section assumption at the latter loading stages.

A4: This was due to cracking and slight spalling of the concrete on the surface of the specimen during the later stages of loading, which interfered with the strain gauge data collection. This resulted in some errors in the strain distribution at the end of the loading period.

Q5：Please explain the overestimation of crack widths for the specimens such as S-30-1.

A5: There were errors in the experimental measurements and when fitting the data, some of the too discrete data interfered with the results, which led to the final formulae calculating results that overestimated the crack resistance of the specimens.

Q6：Comments on the Quality of English Language

Spell check should be conducted and the English can be improved. Avoid mistakes such as 'Xiao et al. Xiao'.

A6: We have fixed the error in (Xiao et al.), which is highlighted in the text, and have checked the English spelling and grammar throughout.

Round 2

Reviewer 2 Report

The authors' manuscript has been improved. There is no need for further modifications.

Reviewer 3 Report

The authors have addressed the comments properly.

English language is fine. Minor editing of English language required.