The Counterbalance of the Adverse Effect of Abrasion on the Properties of Concrete Incorporating Nano-SiO₂ and Polypropylene Fiber Based on Pore Structure Fractal Characteristics

Round 1

Reviewer 1 Report

 

Journal             Fractal Fract (ISSN 2504-3110)

Manuscript ID    fractalfract-1800364

Type                 Article

Title                  The Counterbalance of the Adverse Effect of Abrasion on the Properties of Concrete Incorporating Nano-SiO2 and Polypropylene Fiber Based on Pore structure Fractal Characteristics

Authors in this work indicate about a study attempting to clarify the combined influence of the nano-SiO2 and polypropylene fibers on the performance of concrete subjected to abrasion. Our primary aim is to find a proper dosage of nano-SiO2 and polypropylene fibers to enhance the actual anti-abrasion resistance of concrete. In this context, five dosages of nano-SiO2 and three dosages of fibers are selected to evaluate and analyze the modification effect of nano-SiO2 and polypropylene fibers on the abrasion resistance of concrete.

The structure of the manuscript is very good, and well presented too.

An adequate number of tables and figures of quality were presented.

May have to increase the discussion part,

A comparative table is missing so that the audience can easily understand

References are just within 3 years 2019-2022, at least a decade has to be referred. This will also be useful for the comparison and preparation of the table.

Conclusions must be elaborated.

Manuscript can be accepted for publication after minor mandatory changes.

 

Author Response

Title: The Counterbalance of the Adverse Effect of Abrasion on the Properties of Concrete Incorporating Nano-SiO₂ and Polypropylene Fiber Based on Pore structure Fractal Characteristics

Manuscript Number: fractalfract-1800364

Author(s): Kun Wang, Jinjun Guo*, Peng Zhang, Qingxin Meng

Response to reviewers' comments：

Dear Editors and Reviewers:

Thank you for investing your valuable time in reviewing the manuscript and providing comments and suggestions. Those comments were found convenient and helpful for improving the content and quality of the manuscript. According to your comments, we have revised the manuscript thoroughly. The changes in the manuscript have been highlighted in order to facilitate its identification. The main corrections in the manuscript and the responses to the Reviewer’s comments are the following:

 

Response to Reviewer #1:

Comment 1: May have to increase the discussion part.

Response to Comment 1: We thank you very much for your reminder and suggestion, according to the valuable and helpful comment 1, we have enlarged the discussion scope concerning fractal characteristics of concrete incorporating nano-SiO₂ and polypropylene fiber, then reorganized the section 3.5.

“Firstly, when the dosage of nano-SiO₂ is too high (7%), too much nano-materials agglomerate in the concrete, and the wrapped water molecules hinder the hydration of the cement, so that the fibers are not firmly bonded to the matrix in the concrete, and the internal structure of the concrete is weakened. Secondly, under the synergistic effect of nanomaterials and fibers, the proportion of harmful pores and harmful pores in concrete with 3% nano-SiO₂ dosage is relatively high, and the complexity of pores is relatively low, so its fractal dimension is relatively low compared with specimen incorporating 3% nano-SiO₂.”

 

Comment 2: A comparative table is missing so that the audience can easily understand

Response to Comment 2: We thank you very much for your reminder and suggestion, according to the valuable and helpful comment 2, we have added the comparative table of the results declared in figure 3.

Table 4. Abrasion resistance strength of selected sample.

Code	Curing for 28 days	Curing for 60 days
NC	0.1	0.117
PFC	0.141	0.154
PF-NS1	0.325	0.304
PF-NS3	0.315	0.36
PF-NS5	0.364	0.334
PF-NS7	0.094	0.094
PF6-NS3	0.173	0.203
PF12-NS3	0.182	0.188
L-PF-NS3	0.223	0.232
H-PF-NS3	0.14	0.153

 

Comment 3: References are just within 3 years 2019-2022, at least a decade has to be referred. This will also be useful for the comparison and preparation of the table.

Response to Comment 3: Thank you very much for your carefulness, which helps us to improve the quality of our manuscript. The cited published references are as below:

[4] Sabet, F.A.; Libre, N.A.; Shekarchi, M. Mechanical and Durability Properties of Self Consolidating High Performance Con-crete Incorporating Natural Zeolite, Silica Fume and Fly Ash. Constr. Build. Mater. 2013, 44, 175–184

[5] An, Q.; Ming,W.; Chen, M. Experimental Investigation on Cutting Characteristics in Nanometric Plunge-Cutting of BK7 and Fused Silica Glasses. Materials 2015, 8, 1428–1441.

[6] Ferraris, C.F.; Obla, K.H.; Hill, R. The Influence of Mineral Admixtures on the Rheology of Cement Paste and Concrete. Cem.Concr. Res. 2001, 31, 245–255.

[10] Taengua, E.J.G.; Sonebi, M.; Hossain, K.; Lachemi, M.; Khatib, J.M. Effects of the addition of nanosilica on the rheology, hydrationand development of the compressive strength of cement mortars. Compos. Part B Eng. 2015, 81, 120–129.

 

Comment 4:

Conclusions must be elaborated.

Response to Comment 3: We gratefully thank you for your reminder. and question, according to the valuable and helpful comment 4, we have enlarged the conclusion scope.

“In general, the incorporation of nano-SiO₂ and polypropylene fibers in concrete improves the abrasion resistance of concrete Nano- SiO₂ can promote cement hydration, compact the microstructure of concrete, and enhance the bond between the cement matrix and the fibers, so that the fibers can fully exert the restraint effect on the broken cement blocks. Besides, the polypropylene fiber in the concrete will also play a role in controlling the cracks that are easily generated in the early stage after the incorporation of nano-SiO₂. The results derived show that when the content of nano-SiO₂ and polypropylene fiber is 3% and 0.9 kg/m³, the effect of improving the abrasion resistance of concrete is the best. In practical engineering, it is recommended to use the mix proportion of PF-NS3 specimen to improve guidance on mixture design of concrete when exposure to abrasion is expected in the field.”

Author Response File: Author Response.pdf

Reviewer 2 Report

The article entitled "The Counterbalance of the Adverse Effect of Abrasion on the Properties of Concrete Incorporating Nano-SiO2 and Polypropylene Fiber Based on Pore Structure Fractal Characteristics" presents a research whose methodology is in line with the requirements of a scientific paper.

The research topic is of interest to specialists in the field.

The conclusions are in line with the research conducted. The multiple aspects resulting from the observations made in the research activities are highlighted.

In the paper it is necessary for the authors to specify:

- what was the reason for using polypropylene fibers in the analyzed compositions;

- which is the cause that led to the decrease of the abrasion resistance of the PF-NS5 specimens at 60 days compared to the value declared at 28 days in figure 3;

- how to explain the decrease of the values ​​for the PF-NS7 specimens compared to the PF-NS5 specimens, as well as for the PF-NS1 specimens compared to the PF-NS3 specimens, values ​​presented in table 4;

- what has changed in the L-PF-NS3 and H-PF-NS3 specimens compared to the PF-NS3 specimens.

The authors must specify if the values ​​declared in the tables and figures are average values ​​obtained on several specimens with the same composition, and if so how many specimens were tested for each composition?

It is necessary for the authors to use the same notations used in table 4 for the explanations in figure 5, e.g. (i) L-NS3 in Figure 5 should be L-PF-NS3, and if not then explain this by highlighting differences between specimens.

It is recommended to the authors that the equations be written in accordance with the drafting requirements specified in the instructions.

The paper needs a revision.

Author Response

Response to Reviewers

Title: The Counterbalance of the Adverse Effect of Abrasion on the Properties of Concrete Incorporating Nano-SiO₂ and Polypropylene Fiber Based on Pore structure Fractal Characteristics

Manuscript Number: fractalfract-1800364

Author(s): Kun Wang, Jinjun Guo*, Peng Zhang, Qingxin Meng

Response to reviewers' comments：

Dear Editors and Reviewers:

Thank you for investing your valuable time in reviewing the manuscript and providing comments and suggestions. Those comments were found convenient and helpful for improving the content and quality of the manuscript. According to your comments, we have revised the manuscript thoroughly. The changes in the manuscript have been highlighted in order to facilitate its identification. The main corrections in the manuscript and the responses to the Reviewer’s comments are the following:

Response to Reviewer #2:

Comment 1: what was the reason for using polypropylene fibers in the analyzed compositions

Response to Comment 1: We thank you very much for your reminder and suggestion, and we also paid attention to the influence of polypropylene fibers on properties of concrete. In fact, the explanation is implicitly given in the third paragraph of section 1.

“Polypropylene fiber has the advantages of light weight, high toughness, low price and chemical resistance, and has been widely used in cement-based composite materials in recent years. At the same time, polypropylene fibers can effectively inhibit the growth and development of internal cracks in the early stage of concrete, thereby enhancing the tensile strength and plasticity of concrete.”

 

Comment 2: which is the cause that led to the decrease of the abrasion resistance of the PF-NS5 specimens at 60 days compared to the value declared at 28 days in figure 3

Response to Comment 2: We gratefully thank you for your reminder and question. Although the abrasion resistance of concrete cured for 60 days is lower than that for 30 days, the difference of two values are barely noticeable. In general, the derived results show that the longer the curing time, the stronger the abrasion resistance of concrete. Consequently, the decrease of the abrasion resistance of the PF-NS5 specimens at 60 days compared to the value declared at 28 days may be due to the discrete nature of the experimental data. Thanks again for your rigorous consideration.

 

Comment 3: how to explain the decrease of the values for the PF-NS7 specimens compared to the PF-NS5 specimens, as well as for the PF-NS1 specimens compared to the PF-NS3 specimens, values ​​presented in table 4;

Response to Comment 3: We thank you very much for your reminder and question, and we also paid attention to the influence of dosage of nano-SiO₂ on properties of concrete. In fact, the explanation is implicitly given in the third paragraph of section 3.5.

“Firstly, when the dosage of nano-SiO₂ is too high (7%), too much nano-materials agglomerate in the concrete, and the wrapped water molecules hinder the hydration of the cement, so that the fibers are not firmly bonded to the matrix in the concrete, and the internal structure of the concrete is weakened. Secondly, under the synergistic effect of nanomaterials and fibers, the proportion of harmful pores and harmful pores in concrete with 3% nano-SiO₂ dosage is relatively high, and the complexity of pores is relatively low, so its fractal dimension is relatively low compared with specimen incorporating 3% nano-SiO₂.”

 

Comment 4: what has changed in the L-PF-NS3 and H-PF-NS3 specimens compared to the PF-NS3 specimens.

Response to Comment 4: We gratefully thank you for your reminder and question. The difference between the three groups of specimens mentioned above lies in the difference in water consumption. The mix proportion of concrete are listed below:

Table 3. Mix proportion of concrete (kg/m³).

Code	Water	Cement	Sand	Aggregate	Fly Ash	Nano SiO2	Polypropylene Fiber	superplasticizer
PF-NS3	165	317.625	674.1	1198.4	82.5	12.375	0.9	1.25%
L-PF-NS3	150	317.625	674.1	1198.4	82.5	12.375	0.9	1.35%
H-PF-NS3	180	317.625	674.1	1198.4	82.5	12.375	0.9	1%

 

Comment 5: The authors must specify if the values declared in the tables and figures are average values obtained on several specimens with the same composition, and if so how many specimens were tested for each composition?

Response to Comment 5: We gratefully thank you for your reminder and question. We added the sentence: “Each group consisted of three replicate specimens”, in the revised manuscript.

 

Comment 6: It is necessary for the authors to use the same notations used in table 4 for the explanations in figure 5, e.g. (i) L-NS3 in Figure 5 should be L-PF-NS3, and if not then explain this by highlighting differences between specimens.

Response to Comment 6: We thank you very much for your reminder and suggestion. Correction have been made in the revised manuscript.

 

Comment 7: It is recommended to the authors that the equations be written in accordance with the drafting requirements specified in the instructions.

Response to Comment 7: We thank you very much for your reminder. According to the valuable and helpful comment, we have revised the format of equations in the Revised Manuscript and highlighted it.

“After performing the removal process by k times, the remaining cube size is r_k = R/m_k, and its number can be calculated using Equation (2):

(2)

where D is the volume fractal dimension of the geometry. D is obtained using Equation (3).

(3)

The volume of the solid structure is then calculated using Equation (4).

(4)

When K → ∞ or r_k → 0, V_k → V(r), and we can obtain Equation (5).

(5)

According to the pore volume of the concrete V_p(r) = R³－V(r), we obtain Equation (6):

(6)

where V_p is the cumulative invasion volume of mercury under pressure P, r is the pore radius of the concrete specimen, and D is the fractal dimension.

The pore volume of concrete was measured using the MIP method, and the fundamental principle was expressed using the Washburn equation and calculated using Equation (7):

(7)

where T is the surface tension of mercury, θ is the contact angle between mercury and the solid, and P is the pressure exerted when mercury invades.

Equations (6) and (7) were used to establish the relational expression of the fractal dimension, as expressed in Equation (8).

(8) ”

 

The authors once again gratefully thank the editors' and reviewers' suggestions and comments on this paper. The pneumonia caused by the COVID-19 has been widely spread in the world, we hope you are safe and healthy during this extraordinary time. Thank you very much for your consideration of our manuscript, I’m looking forward to hearing from you soon. If you have any queries, please don’t hesitate to contact me.

Best wishes,

Yours sincerely

Jinjun Guo

Zhengzhou University, School of Water Conservancy Engineering

E-mail: [email protected]

Author Response File: Author Response.pdf