Nanomodified Basalt Fiber Cement Composite with Bottom Ash

Round 1

Reviewer 1 Report (Previous Reviewer 2)

1. The first sentence of the introduction is an improvement, but needs rephrasing. There is no need to mention what reinforced concrete is. It needs to be explained that it is evolving into a more complex material with superior performance.

2. "It does not shrink significantly without creating visible cracks, i.e. does not crack when cured" should be rephrased

3. "...due to the evenly strong distribution of the fiber but fibers are not necessarily uniformly distributed [25], the material is not afraid of chips and cracks..." should be rephrased

4. instead of "And a durability period for..." only "The durability of..."

5. Do you have a reference to "Nanoadditives applied to microfiber provoke the growth of crystals in the mineral substance, and their rays, growing and intertwining with each other, give the material higher strength. This process is called dispersed self-reinforcement."? This is an interesting issue for the concrete research community, so it must be accompanied by a reference. 

6. "Pozzolanic additives and basalt fiber have a high water demand and affect concrete mixtures..." the "mixture" should be replaced with "workability" or "slump".

7. If you do not use ANOVA, you do not have to include it in the introduction. If you do, the paragraph needs English editing. 

8. change "The error of all obtained experimental results was no more than 5%." into "The error of all obtained experimental results was less than 5%." It will be even better to add the standard deviation for each number in the results.

9. You answered that the air content is in the normal range, but each 1% of air is like 10 liter/m³ of water for the W/C ratio. Hence, it may play a role in compressive strength. calculate the air content from the composition and the density. It may explain why the 45 series is weaker than the 30 series.

10. An increase in the ratio of flexural and compressive strength does not necessarily mean a longer plastic zone. In order to claim plasticity you have to show that the strain increases without a proportional increase of the stress.

11. there are statistical procedures to find whether a combined effect exists (ANOVA for example, for the case of linear relation). Another way is to use the proposed function (i.e. mathematical model) and draw the results against the measured result. Then, calculate the p-value, to assess if it is a random correlation or a significant one. As scientists and engineers, we have to use one of these methods. We cannot just say "...explained by the combined structure-forming action..." One may say that he assumes that it can be "explained by the combined structure-forming action..." and offer an experiment to check it out.

12. Subsection 3.5, how can I see these things in the SEM images? There are many hexagonal crystals in the cement paste which are not portlandite.

The main problems of the paper as it is are: 1) the air content was ignored, and 2) No quantitative model for the effect of BA and BNF was offered (you may claim to report results only, without analysis interactions)

Author Response

Dear Reviewer 1!

Thank you for your interest in our manuscript. Your valuable comments helped make the manuscript even better. All corrections in the manuscript are highlighted in blue.

Comment 1: The first sentence of the introduction is an improvement, but needs rephrasing. There is no need to mention what reinforced concrete is. It needs to be explained that it is evolving into a more complex material with superior performance.

Response: The first sentence now look like this: « By the beginning of the 21st century, traditional reinforced concrete had evolved into a cementitious composite, which, with the addition of pozzolanic additives and reinforcing fibers, was transformed into a more complex material with superior performance»

Comment 2: "It does not shrink significantly without creating visible cracks, i.e. does not crack when cured" should be rephrased.

Response: The sentence now look like this: « Evenly distributed throughout the volume of the fibers contribute to a significant reduction in shrinkage, and therefore does not allow the appearance of cracks»

Comment 3 "...due to the evenly strong distribution of the fiber but fibers are not necessarily uniformly distributed [25], the material is not afraid of chips and cracks..." should be rephrased.

Response: Rephrased to:  "... perfectly perceives flexural and tensile forces [25], perfectly counteracts the formation of chips and cracks..."

Comment 4:  instead of "And a durability period for..." only "The durability of...".

Response: Changed

Comment 5: Do you have a reference to "Nanoadditives applied to microfiber provoke the growth of crystals in the mineral substance, and their rays, growing and intertwining with each other, give the material higher strength. This process is called dispersed self-reinforcement."? This is an interesting issue for the concrete research community, so it must be accompanied by a reference.

Response: References have been added.

Comment 6: "Pozzolanic additives and basalt fiber have a high water demand and affect concrete mixtures..." the "mixture" should be replaced with "workability" or "slump".

Response: Replaced with workability

Comment 7 If you do not use ANOVA, you do not have to include it in the introduction. If you do, the paragraph needs English editing.

Response: All references to ANOVA have been removed.

Comment 8:  change "The error of all obtained experimental results was no more than 5%." into "The error of all obtained experimental results was less than 5%." It will be even better to add the standard deviation for each number in the results.

Response: changed "The error of all obtained experimental results was no more than 5%." into "The error of all obtained experimental results was less than 5%." Standard deviation for each number in the results have been added.

Comment 9: You answered that the air content is in the normal range, but each 1% of air is like 10 liter/m3 of water for the W/C ratio. Hence, it may play a role in compressive strength. calculate the air content from the composition and the density. It may explain why the 45 series is weaker than the 30 series.

Response: A column with the calculated air content has been added to Table 6. And below was added a paragraph with explanations of the results and their discussion

Comment 10: An increase in the ratio of flexural and compressive strength does not necessarily mean a longer plastic zone. In order to claim plasticity you have to show that the strain increases without a proportional increase of the stress.

Response: The sentence has been corrected with the words «can be caused»

Comment 11 there are statistical procedures to find whether a combined effect exists (ANOVA for example, for the case of linear relation). Another way is to use the proposed function (i.e. mathematical model) and draw the results against the measured result. Then, calculate the p-value, to assess if it is a random correlation or a significant one. As scientists and engineers, we have to use one of these methods. We cannot just say "...explained by the combined structure-forming action..." One may say that he assumes that it can be "explained by the combined structure-forming action..." and offer an experiment to check it out.

Response: In the course of addressing the comments of the reviewers, we moved away from using ANOVA for the case of a linear relationship. The combined structure-forming action has been proven by comparing the compositions and properties of the developed samples.

Comment 12:  Subsection 3.5, how can I see these things in the SEM images? There are many hexagonal crystals in the cement paste which are not portlandite.

Response: Portlandite changed with hydration products

Comment 13: The main problems of the paper as it is are: 1) the air content was ignored, and 2) No quantitative model for the effect of BA and BNF was offered (you may claim to report results only, without analysis interactions)

Response: 1) A column with the calculated air content has been added to Table 6. And below was added a paragraph with explanations of the results and their discussion. 2) The combined structure-forming action has been proven by comparing the compositions and properties of the developed samples.

Reviewer 2 Report (New Reviewer)

The present paper investigated mechanical and durability properties of cementitious materials containing different concentrations of nanomodified basalt fiber and bottom ash. The main topic of the paper is original and extensive experimental results were obtained. However, the literature review is incomplete, many methods were not provided, and English writing is poor. The authors failed to carry out the ANOVA proposed in this manuscript. Microstructural analyses were not provided (the authors only presented two SEM images that cannot be used to reach any relevant conclusion. The following issues were identified in this work:

1.     Section 1: in the literature review presented in this section, the authors stated that fiber-reinforced concrete “does not deform”, which is not technically correct. Actually, fiber-reinforced concrete may exhibit high stiffness.

2.     Section 1: the following statement must be rewritten in a more technical manner: “the material is not afraid of chips and cracks”.

3.     Section 1: The specific gravity is a dimensionless parameter. It is not expressed in units. Therefore, the following statement is incorrect: “The specific gravity of steel fiber is 7800 kg/m³, and that of basalt one is 2800 kg/m³”.

4.     Section 1: The following statement must be supported with citation of relevant references: “Nanoadditives applied to microfiber provoke the growth of crystals in the mineral substance, and their rays, growing and intertwining with each other, give the material higher strength. This process is called dispersed self-reinforcement”.

5.     Section 1: The paragraph describing the analysis of variance (ANOVA) must be supported with citation of relevant references.

6.     Section 1: quantitative information could be added to the introduction section, in order to clarify the effects associated with the incorporation of bottom ash into cementitious materials. For example, the authors should summarize the maximum increases/decreases in mechanical and durability properties due to bottom ash inclusion, according to previous works. Optimal dosage of these admixtures could be also indicated.

7.     Section 1: the authors should list previous papers that evaluated the effects of nanomodified basalt fiber on cement-based materials. In addition, quantitative information should be added to this section, in order to summarize the maximum increases/decreases in mechanical and durability properties due to inclusion of nanomodified basalt fibers, according to previous works. Optimal dosage of these admixtures could be also reported.

8.     Section 1: the paragraph regarding the different types of superplasticizer could be removed because it is disconnected from the main topic of the paper (the authors did not investigate the use of different types of superplasticizer in the present study).

9.     Section 2: Equipment and methods used to obtain the chemical and mineralogical composition of cement (Table 1) were not provided. Did you use XRF analysis? Did you use XRD analysis? Did you use Rietveld refinement?

10. Section 2: standard test methods used to determine the data of Table 2 could be listed in the table’s caption or note.

11. Section 2: Equipment and methods used in SEM/EDS analyses of Figure 2 should be presented.

12. Section 2: Percentage of different elements detected in EDS analysis could be also provided in Figure 2b.

13. Section 2: The authors must provide strong evidences that prove that the EDS results of Figure 2b are representative of any part of the ashes.

14. Section 2: Figure 3 should provide the particle size distribution of the different combinations of contents of cement and bottom ash presented in Table 4.

15. Section 2: Equipment and methods used to get the data of Figure 3 should be presented. Did you use laser diffraction analysis? Did you use some specific standard method?

16. Section 2: standard test method used to determine the fineness modulus of sand was not provided.

17. Section 2: the authors should provide a complete characterization of the aggregates. For example, the authors did not provide their specific gravity, maximum particle diameter, water absorption, composition, etc.

18. Section 2: how did you define the superplasticizer content? It should be clarified in Section 2.

19. Section 2: equipment and methods used to get the specific surface area of 400 m2/kg mentioned in the paper were not provided.

20. Section 2: description of compaction procedures used to cast the specimens must be improved. Did you use standard compaction methods?

21. Section 2: Figure 4 could be removed because it shows very simple lab equipment.

22. Section 2: temperature and relative humidity of the curing environment should be provided.

23. Section 2: standard test procedures used to determine slump and slump flow should be presented in Section 2.3.2.

24. Section 2: Section 2.3.3 should clarify the type of specimen and standard test methods used to determine the elastic modulus of the material. In addition, how did you measure the strain? Did you use strain gauges? Clip-gauges?

25. Section 2: loading rate used in compression, flexural and elastic modulus tests was not presented.

26. Section 2: test methods used to determine the crack resistance of the specimens and Equation 2 should be supported with citation of relevant literature and/or standard test methods.

27. Section 2: the authors stated that an ANOVA was carried out. However, the authors did not provide the significance level, null hypothesis, alternative hypothesis of the statistical tests.

28. Section 2: statistical tests used to check ANOVA assumptions were not indicated.

29. Section 2: sample preparation methods used in SEM analyses of cementitious materials must be added to the paper. Where did the samples come from? Are they intern fragments of a specimen after failure? The surface of the specimen? Some undamaged sample casted specifically for microstructural evaluation? How was the preparation of the surface of SEM samples? Have you used a sputter coater to cover the surface of SEM samples with gold? Did you polish the surface of the SEM samples?

30. Section 3: the authors should explain the reasons why all mixtures presented the same slump value, but they presented different slump flow values. These discussions should focus on the methodology of these tests and cover citations of relevant previous literature.

31. Section 3: points should be added to Figures 8, 9, 10, 11, 12, 13, in order to represent the location of each different mixture evaluated in this study. Since 6 replicates were used in each test, error bars should be added to the graphs, in order to represent the standard error associated with average results of each different series.

32. Section 3: coefficients of variation or standard deviation must be added to Tables 6, 7, in order to represent the natural variability of experimental data.

33. Section 3: a two-way ANOVA is able to provide a P-value that indicates if there is an interaction between the two independent variables on each different dependent variable. Then, the following statement must be provided with ANOVA statistical analyses: “Experimental results show the absence of interaction between BNF and BА at all dosages”.

34. Section 3: the interpretation of experimental results is not based on concrete evidence. Only two SEM images were used for microstructural investigation. In addition, these images cannot be used to reach any general conclusion because the microstructure of cementitious materials is so heterogeneous that you can find locally spots that will confirm or disprove any theory. Quantitative BSE-SEM image analyses were not provided. Compactness and voids

35. Section 3: Tables showing the ANOVA results were not presented (p-values of F-tests, multiple comparison tests, p-values of interactions, etc).

36. Section 3: Results of tests for verification of ANOVA assumptions were not provided.

37. Section 4: Novelty of this paper must be highlighted at the beginning of the conclusion section.

38. Section 4: limitations of the present paper were not listed at the end of the paper.

39. Comma should not be used as decimal separator in the manuscript (e.g., Figure 7, unit of Table 7).

40. English writing must be significantly improved by a native speaker. For example, the following terms must be corrected: “be divided into the following types such purified”; “Estimation of the variance (…) is estimated by”, “pierced it”, “and its one after 600 m of the abrasion circle”, etc.

Author Response

Dear Reviewer 2!

Thank you for your interest in our manuscript. Your valuable comments helped make the manuscript even better. All corrections in the manuscript are highlighted in blue.

Comment 1: Section 1: in the literature review presented in this section, the authors stated that fiber-reinforced concrete “does not deform”, which is not technically correct. Actually, fiber-reinforced concrete may exhibit high stiffness.

Response: “does not deform” changed with «may exhibit high stiffness»

Comment 2: Section 1: the following statement must be rewritten in a more technical manner: “the material is not afraid of chips and cracks”.

Response: Changed with «perfectly counteracts the formation of chips and cracks»

Comment 3 Section 1: The specific gravity is a dimensionless parameter. It is not expressed in units. Therefore, the following statement is incorrect: “The specific gravity of steel fiber is 7800 kg/m³, and that of basalt one is 2800 kg/m³”.

Response: Units have been deleted

Comment 4:  Section 1: The following statement must be supported with citation of relevant references: “Nanoadditives applied to microfiber provoke the growth of crystals in the mineral substance, and their rays, growing and intertwining with each other, give the material higher strength. This process is called dispersed self-reinforcement”.

Response: References have been added.

Comment 5: Section 1: The paragraph describing the analysis of variance (ANOVA) must be supported with citation of relevant references.

Response: In the course of correcting the comments of the reviewers, we moved away from using ANOVA for the case of a linear relationship.

Comment 6: Section 1: quantitative information could be added to the introduction section, in order to clarify the effects associated with the incorporation of bottom ash into cementitious materials. For example, the authors should summarize the maximum increases/decreases in mechanical and durability properties due to bottom ash inclusion, according to previous works. Optimal dosage of these admixtures could be also indicated

Response: Added: «Chindasiraphan et al [14] indicated that concrete with 50% bottom ash cement replacement could be classified as high-strength concrete at 7 days, achieving a compressive strength of approximately 80.9 MPa at 28 days.»

Comment 7 Section 1: the authors should list previous papers that evaluated the effects of nanomodified basalt fiber on cement-based materials. In addition, quantitative information should be added to this section, in order to summarize the maximum increases/decreases in mechanical and durability properties due to inclusion of nanomodified basalt fibers, according to previous works. Optimal dosage of these admixtures could be also reported.

Response: Added: «Depending on the content of nanomodified basalt fibers dispersion method compressive strength increases from 15.7% to 23.3%, flexural strength increases from 28.5% to 31.1%. Pozzolanic additives and basalt fiber have a high water demand and affect concrete workability, so it is necessary to use various chemical modifiers in them [41]. The optimal dosage of nanomodified basalt microfiber is 1.0-1.5% by weight of the binder [42].»

Comment 8:  Section 1: the paragraph regarding the different types of superplasticizer could be removed because it is disconnected from the main topic of the paper (the authors did not investigate the use of different types of superplasticizer in the present study).

Response: The paragraph has been removed

Comment 9: Section 2: Equipment and methods used to obtain the chemical and mineralogical composition of cement (Table 1) were not provided. Did you use XRF analysis? Did you use XRD analysis? Did you use Rietveld refinement?

Response: Added: «To study the Portland cement mineral composition, a D8 Advance AXS X-ray powder diffractometer (Bruker, Billerick, USA) was used (wavelength λ = 1.5418 Å) using Rietveld refinement.»

Comment 10: Section 2: standard test methods used to determine the data of Table 2 could be listed in the table’s caption or note.

Response: All of these methods have been added to section 2.3

Comment 11 Section 2: Equipment and methods used in SEM/EDS analyses of Figure 2 should be presented.

Response: Section 2.3.1: The morphological features of the bottom ash and concrete were studied using a MIRA3 scanning electron microscope (SEM) (Tescan, Brno, Czech Republic), which makes it possible to carry out energy dispersive spectroscopy.

Comment 12:  Section 2: Percentage of different elements detected in EDS analysis could be also provided in Figure 2b.

Response: Percentage of different elements detected in EDS analysis has been added in Figure 2b.

Comment 13: Section 2: The authors must provide strong evidences that prove that the EDS results of Figure 2b are representative of any part of the ashes

Response: Added to the end of 3-rd page: «An EDS was taken at 16 points of the sample taken, while the results shown in Fig. 2 are representative of any part of the ashes»

Comment 14: Section 2: Figure 3 should provide the particle size distribution of the different combinations of contents of cement and bottom ash presented in Table 4

Response: This information can be easily obtained from the universal Fig. 3

Comment 15 Section 2: Equipment and methods used to get the data of Figure 3 should be presented. Did you use laser diffraction analysis? Did you use some specific standard method?

Response: Added to the section 2.3.2: «A granulometry of the particles of the raw materials was evaluated using a laser analyzer Analysette 22 (Fritsch, Idar-Oberstein, Germany).

Comment 16:  Section 2: standard test method used to determine the fineness modulus of sand was not provided.

Response: Added to the section 2.3.2: « According to the Russian standard GOST 8736-2014, the sand fineness module is determined as follows. From 2 kg of sample, particles larger than 5 mm are first separated using sieves, and one kg is taken from the remaining mass and sieved sequentially through sieve cells ranging in size from 2.5 mm to 0.16 mm (5 sieves in total). The amount of sand, as a percentage of 1000 g, not sieved through each sieve, is recorded on paper. Screening during operations is stopped when the sand stops passing through the cells. Sand size modulus is calculated by the formula: Mk = (A2.5 + A1.25 + A0.63 + A0.315 + A0.16) / 100, where A ... is the total residue on five sieves as a percentage of the total weight.»

Comment 17: Section 2: the authors should provide a complete characterization of the aggregates. For example, the authors did not provide their specific gravity, maximum particle diameter, water absorption, composition, etc.

Response: Added to the section 2.3.1: « Specific gravity of sand 2600, bulk density 1400 kg/m3, maximum particle size 2.5 mm, water absorption by weight 0.5%. The composition of the sand includes a large number of minerals, the main of which are quartz, feldspars, calcite, mica. The chemical composition of the sand has 98% SiO₂»

Comment 18 Section 2: how did you define the superplasticizer content? It should be clarified in Section 2.

Response: Added to the section 2.2: « A dosage of superplasticizer has been adopted to ensure that almost equal slump and slump flows are achieved. »

Comment 19:  Section 2: equipment and methods used to get the specific surface area of 400 m2/kg mentioned in the paper were not provided.

Response: Added to the section 2.3.2: «A specific surface of bulk raw materials was studied using a PSH-11 device (Khodakov Devices, Moscow, Russia). »

Comment 20: Section 2: description of compaction procedures used to cast the specimens must be improved. Did you use standard compaction methods?

Response: Added to the section 2.2: «Standard methods were used for compaction.»

Comment 21: Section 2: Figure 4 could be removed because it shows very simple lab equipment.

Response: Figure 4 has been removed

Comment 22 Section 2: temperature and relative humidity of the curing environment should be provided.

Response: Added to the section 2.2: «After 24 hours, the samples were removed from the molds and left to harden for up to 28 days under standard temperature (18-22°C) and humidity (relative humidity 100%) conditions»

Comment 23: Section 2: standard test procedures used to determine slump and slump flow should be presented in Section 2.3.2.

Response: Added to the section 2.2: «A slump of the concrete mixture is determined by laying a metal ruler with an edge on the top of the cone and measuring the distance from the lower edge of the ruler to the top of the concrete mixture with an error of up to 0.5 cm. A slump flow of the concrete mix is determined by measuring the diameter of the spread paste with a metal ruler in two mutually perpendicular directions with an error of not more than 0.5 cm. »

Comment 24: Section 2: Section 2.3.3 should clarify the type of specimen and standard test methods used to determine the elastic modulus of the material. In addition, how did you measure the strain? Did you use strain gauges? Clip-gauges?

Response: Strain gauges were used to strain measure

Comment 25 Section 2: loading rate used in compression, flexural and elastic modulus tests was not presented.

Response: Added to the section 2.3: «The loading rate of the specimens was uniform throughout the entire test time and was 7 kN/min (compressive strength and modulus of elasticity) and 3 kN/min (flexural strength) »

Comment 26:  Section 2: test methods used to determine the crack resistance of the specimens and Equation 2 should be supported with citation of relevant literature and/or standard test methods.

Response: A critical value of the stress intensity factor was determined by Eq. (2) according to the Russian standard GOST 29167-2021.

Comment 27: Section 2: the authors stated that an ANOVA was carried out. However, the authors did not provide the significance level, null hypothesis, alternative hypothesis of the statistical tests.

Response: In the course of addressing the comments of the reviewers, we moved away from using ANOVA for the case of a linear relationship.

Comment 28: Section 2: statistical tests used to check ANOVA assumptions were not indicated.

Response: In the course of addressing the comments of the reviewers, we moved away from using ANOVA for the case of a linear relationship.

Comment 29 Section 2: sample preparation methods used in SEM analyses of cementitious materials must be added to the paper. Where did the samples come from? Are they intern fragments of a specimen after failure? The surface of the specimen? Some undamaged sample casted specifically for microstructural evaluation? How was the preparation of the surface of SEM samples? Have you used a sputter coater to cover the surface of SEM samples with gold? Did you polish the surface of the SEM samples?

Response: Added to the section 2.3.1: «The samples used in the SEM analysis of binders were internal fragments of the sample after fracture. When preparing the surface of the SEM samples, polishing was performed. »

Comment 30:  Section 3: the authors should explain the reasons why all mixtures presented the same slump value, but they presented different slump flow values. These discussions should focus on the methodology of these tests and cover citations of relevant previous literature.

Response: Added to the section 3.1: «All mixes have almost the same slump (20-22cm), but slightly different slump flow (46-52cm). These are related to the methodology of these tests and are supported by references to relevant previous literature [43,44]. »

Comment 31: Section 3: points should be added to Figures 8, 9, 10, 11, 12, 13, in order to represent the location of each different mixture evaluated in this study. Since 6 replicates were used in each test, error bars should be added to the graphs, in order to represent the standard error associated with average results of each different series.

Response: These mixes are easily identified through the rise of points with 0, 15, 30 and 45 % bottom ash. All error bars are shown in the tables preceding these figures.

Comment 32: Section 3: coefficients of variation or standard deviation must be added to Tables 6, 7, in order to represent the natural variability of experimental data.

Response: Standard deviation must be added to Tables 5, 6, (by new numbering) in order to represent the natural variability of experimental data.

Comment 33 Section 3: a two-way ANOVA is able to provide a P-value that indicates if there is an interaction between the two independent variables on each different dependent variable. Then, the following statement must be provided with ANOVA statistical analyses: “Experimental results show the absence of interaction between BNF and BА at all dosages”.

Response: In the course of addressing the comments of the reviewers, we moved away from using ANOVA for the case of a linear relationship.

Comment 34:  Section 3: the interpretation of experimental results is not based on concrete evidence. Only two SEM images were used for microstructural investigation. In addition, these images cannot be used to reach any general conclusion because the microstructure of cementitious materials is so heterogeneous that you can find locally spots that will confirm or disprove any theory. Quantitative BSE-SEM image analyses were not provided. Compactness and voids.

Response: The main conclusions are proved by the obtained results of increasing the complex of physical and mechanical properties and operational characteristics. The study of the microstructure is a secondary and complementary confirmation. The results of the calculated air content are added to Table 6.

Comment 35: Section 3: Tables showing the ANOVA results were not presented (p-values of F-tests, multiple comparison tests, p-values of interactions, etc)

Response: N

Comment 36: Section 3: Results of tests for verification of ANOVA assumptions were not provided.

Response: In the course of addressing the comments of the reviewers, we moved away from using ANOVA for the case of a linear relationship.

Comment 37 Section 4: Novelty of this paper must be highlighted at the beginning of the conclusion section

Response: Added to the beginning of the conclusion section : «The novelty of the work lies in the fact that the joint effect of nanomodified basalt fiber and bottom ash on fresh, physical and mechanical properties and durability of concrete has been studied».

Comment 38:  Section 4: limitations of the present paper were not listed at the end of the paper.

Response: Added to the end of the paper: «The limitations of this article are in compliance with the identified proportions of the components, in particular 30 wt. % bottom ash and 5 wt. % nanomodified basalt fiber, as well as the need for mechanically activating BA up to a specific surface area of 400 m²/kg»

Comment 39: Comma should not be used as decimal separator in the manuscript (e.g., Figure 7, unit of Table 7)..

Response: Comma has been used as decimal separator in the manuscript

Comment 40 English writing must be significantly improved by a native speaker. For example, the following terms must be corrected: “be divided into the following types such purified”; “Estimation of the variance (…) is estimated by”, “pierced it”, “and its one after 600 m of the abrasion circle”, etc.

Response: The entire article has been carefully checked by a native English speaker

 

Round 2

Reviewer 1 Report (Previous Reviewer 2)

Review Nanomodified basalt fiber cement composite with bottom ash, round 3

1.    English editing is needed. Some sentences are very long and complex. I other the meaning is meaningless, like “Evenly distributed throughout the volume of the fibers contribute to…” The English editor should be a scholar in engineering.

2.    A note on specific gravity. The definition of specific gravity in English is different from the definition in other languages. It is defined as the ratio of the density to the density of water (in standard conditions). Hence, it has no units, and it is a number equal to the specific gravity in units of kg/liter. So the specific gravity of steel and basalt are 7.8 and 2.8 respectively.

3.    I think you used the word poked instead of consolidated

4.    The air content looks very low for mortar. One would expect no less than 3%. The 45 series has only 0.5% air more than the 30 series. The high dosage of plasticizer may have an effect too. My advice is, if possible, to redo this series. Maybe something went wrong in the grinding. Because, all parameters improved up to 30, and then went down. So there are two possibilities: 1) there is a problem in the preparation process, or 2) there is an optimal BA content, and above it, there is a reduction in properties. (this can be measured with compression only)

5.    “Experimental results show the absence of interaction between BNF and BА at all dos-ages of bottom ash and 0, 3, and 7% nanomodified basalt fiber (Fig. 9). However, at 5% fiber and 30% BA, the critical stress intensity factor K1c increases significantly (by 25–40%), which is explained by the combined structure-forming action of BNF and BA.” An internal contradiction. If the is a real interaction, it should appear for all the mixes.

6.    The improvement of the water resistance is can indicate a change in the microstructure, not prove it. The improvement may result from micro-cracks control, before or during the test.

7.    As there are no error bars on the figures, one cannot use them to conclude whether the differences between mixes are significant.

8.    There is no mathematical analysis of interaction. For example, divide each result by the corresponding result for the mix without fibers. As it is now, interactions cannot be discussed. This comment is valid for any mention of complex effects in the conclusion too.

9.    In the methods, you mentioned that the specimens for SEM were polished, but the images are of unpolished specimens.

10. You should compare your result with the results of studies where fiber content or SCM was used.

11. The limitations of the study are: 1) not enough points to draw conclusions regarding the effect of BA in the 20-45%. 2) not enough repetitions to verify significant differences between mixes. 3) no analysis for synergistic or antagonistic effects. 4) the intention is to have 2 variables (which require a minimum of 20 different mixes), but in fact, there are 4 variables (plasticizer and air content too, so a minimum of 40 mixes is needed for reliable statistical analysis)

12. The DOI of reference 39 is erroneous. I could not verify if the information in the introduction is supported by it.

13. Reference 40 does not present an investigation of nano additives to the fibers. Furthermore, It is unethical to give an article from one of the authors’ papers as a single reference.

 

14. The pieces of evidence presented in reference 41 are not convincing. Only 2 images are presented, and one cannot conclude whether the result is random or meaningful. This area should be further investigated. Reference 42 does not mention nano additives. Hence, the claim in the introduction needs a better reference or a clear criticism to raise doubt. 

Author Response

 

Dear Reviewer 1!

Thank you for your interest in our manuscript. Your valuable comments helped make the manuscript even better. All corrections in the manuscript are highlighted in blue.

Comment 1: English editing is needed. Some sentences are very long and complex. I other the meaning is meaningless, like “Evenly distributed throughout the volume of the fibers contribute to…” The English editor should be a scholar in engineering.

Response: English edition has been completed. Long and complex sentences have been shortened. Nonsensical phrases have been removed. The English editor was an engineer scientist.

Comment 2: A note on specific gravity. The definition of specific gravity in English is different from the definition in other languages. It is defined as the ratio of the density to the density of water (in standard conditions). Hence, it has no units, and it is a number equal to the specific gravity in units of kg/liter. So the specific gravity of steel and basalt are 7.8 and 2.8 respectively.

Response: Corrected

Comment 3 I think you used the word poked instead of consolidated.

Response: Changed

Comment 4:  The air content looks very low for mortar. One would expect no less than 3%. The 45 series has only 0.5% air more than the 30 series. The high dosage of plasticizer may have an effect too. My advice is, if possible, to redo this series. Maybe something went wrong in the grinding. Because, all parameters improved up to 30, and then went down. So there are two possibilities: 1) there is a problem in the preparation process, or 2) there is an optimal BA content, and above it, there is a reduction in properties. (this can be measured with compression only).

Response: All right. All further results confirm that 30% is a rational dosage, over which there is a decrease in all properties.

Comment 5: “Experimental results show the absence of interaction between BNF and BА at all dos-ages of bottom ash and 0, 3, and 7% nanomodified basalt fiber (Fig. 9). However, at 5% fiber and 30% BA, the critical stress intensity factor K1c increases significantly (by 25–40%), which is explained by the combined structure-forming action of BNF and BA.” An internal contradiction. If the is a real interaction, it should appear for all the mixes.

Response: All right. The obtained results of the experiments prove the rational content of the components at the level of 5% fiber and 30% BA. The dosage of these components above and below this content reduces the entire complex of the studied characteristics.

Comment 6: The improvement of the water resistance is can indicate a change in the microstructure, not prove it. The improvement may result from micro-cracks control, before or during the test.

Response: Yes, we agree. But on the other hand, the improvement in water resistance indicates a compaction of the microstructure due to a decrease in the number of microcracks.

Comment 7 As there are no error bars on the figures, one cannot use them to conclude whether the differences between mixes are significant.

Response: However, information on the scatter of the results obtained is given in the tables that are given along with these figures.

Comment 8:  There is no mathematical analysis of interaction. For example, divide each result by the corresponding result for the mix without fibers. As it is now, interactions cannot be discussed. This comment is valid for any mention of complex effects in the conclusion too.

Response: We agree, however, the result of improving all characteristics for the rational composition may prove its effectiveness.

Comment 9: In the methods, you mentioned that the specimens for SEM were polished, but the images are of unpolished specimens.

Response: The information in the methods section has been corrected to indicate that polishing was not performed during surface preparation for the SEM samples.

Comment 10: You should compare your result with the results of studies where fiber content or SCM was used.

Response: The results with separate application of the components have been investigated previously by other authors. These results and comparisons are given both in the introduction and in the results and discussion section.

Comment 11 The limitations of the study are: 1) not enough points to draw conclusions regarding the effect of BA in the 20-45%. 2) not enough repetitions to verify significant differences between mixes. 3) no analysis for synergistic or antagonistic effects. 4) the intention is to have 2 variables (which require a minimum of 20 different mixes), but in fact, there are 4 variables (plasticizer and air content too, so a minimum of 40 mixes is needed for reliable statistical analysis).

Response: We agree with the reviewer that more samples can give more accurate results. However, in our study, for each test, 6 samples of the same type of each series were used, which is normative and gives adequate results.

Comment 12:  The DOI of reference 39 is erroneous. I could not verify if the information in the introduction is supported by it.

Response: Corrected

Comment 13: Reference 40 does not present an investigation of nano additives to the fibers. Furthermore, It is unethical to give an article from one of the authors’ papers as a single reference.

Response: Reference 40 replaced

Comment 14: The pieces of evidence presented in reference 41 are not convincing. Only 2 images are presented, and one cannot conclude whether the result is random or meaningful. This area should be further investigated. Reference 42 does not mention nano additives. Hence, the claim in the introduction needs a better reference or a clear criticism to raise doubt.

Response: 3 more references have been added

Reviewer 2 Report (New Reviewer)

Although the quality of the paper was improved, many serious problems were not corrected in the first review round, as follows:

1.     The values of specific gravity (e.g., 2600, 7800, 2800) provided in this manuscript do not make sense because they are very high. Did you mean 2.6, 7.8 and 2.8? The authors should revise the meaning of “specific gravity” and the calculation methods, in order to correct the values provided in the manuscript.

2.     Response to comment #6 of the first review round is incomplete because the authors only added quantitative results published in a single paper (reference [14]). The authors should summarize the maximum increases/decreases in mechanical and durability properties (and optimal contents) due to bottom ash inclusion, based on a complete and updated literature review. This information is probably available in literature review papers.

3.     Response to comment #7 of the first review round is incomplete because the authors only added quantitative results published in two papers (reference [41] and [42]). The authors should summarize the maximum increases/decreases in mechanical and durability properties (and optimal contents) due to inclusion of nanomodified basalt fibers, based on a complete and updated literature review.

4.     Response to comment #9 of the first review round is not convincing because XRD analyses do not provide oxide percentages (Table 1). Did you also use XRF analyses? Equipment and methods used to obtain the oxide contents of cement (Table 1) were not provided.

5.     Response to comment #20 is not convincing because the authors did not cite the standard (code or regulation) used to compact the specimens. In the response to this comment, the authors mentioned that “Standard methods were used for compaction”. However, this sentence was not added to the manuscript.

6.     The authors did not solve the issue identified in comment #24. Section 2 should clarify that a strain gauge was used to calculate the elastic modulus. The following problems regarding this mechanical tests were not addressed:

-        Where did you bond the strain gauge?

-        What was the standard (code or regulation) used to determine the elastic modulus of the material?

-        Elastic modulus of cementitious materials is usually estimated in compression tests. Did you determine this parameter is compression or tensile tests? Why?

-        The test procedures and the shape/size of the specimen used in this test should be supported with citation of relevant literature.

7.     Response to comment #29 is not appropriate. Polishing procedures were not detailed. The authors did not state that the samples were impregnated with resin before polishing procedures. Impregnating the samples with a low-viscosity resin is an important step to support the original microstructure of the material during the polishing process. If the authors did not carry out this step, they unfortunately affected the original microstructure of the material.

8.     The serious problem highlighted in comment #31 was not solved. Since ANOVA was not carried out, it is necessary to provide the readers with a fast evaluation of the standard deviation obtained in the experimental tests in Figures 8, 9, 10, 11, 12, in order to represent the location of each different mixture evaluated in this study. Since 6 replicates were used in each test, error bars should be added to the graphs, in order to clearly represent the standard error associated with average results of each different series.

9.     Response to comment #34 was not convincing. The compaction deduced from SEM analysis and discussed in the text (“fill the voids at the micro level and compact”, “hydration products in the interpore space”, “is explained by the compaction of the cement matrix structure”, etc) is not convincing (and should be avoided). If you want to discuss porosity, you need to access a direct porosity measurement (e.g., mercury intrusion porosimetry). The explanation provided by the authors is based on only two simple qualitative images of Figure 13, so it is not accepted as a proof.

10. The hydrates discussed in the text were not clearly indicated in the SEM images of Figure 13. Arrows should be added to all figures, according to all citations of the text of Section 3.5. In addition, did you use SEM/EDS to support the identification of these hydrates, based on their chemical composition? The authors did not cite and compare the size of the compounds indicated in the figures with those typically observed in the literature. The book “Concrete: Microstructure, Properties, and Materials” of Mehta and Monteiro describes the size and shape of cement hydrates, which may help the authors to solve some of these problems.

11. Caption of Figure 13 did not cite the image b.

12. Although ANOVA was not carried out, the standard deviation should be discussed in the comparisons of experimental results presented in the manuscript.

13. The authors should consider the replacement of the word “A” by “The” in many sentences of the paper, such as “A specific surface of bulk raw materials was studied”, “A granulometry of the particles of the raw materials was”, “A slump of the concrete mixture is”, “A slump flow of the concrete mix is”, “A compressive strength was”, “An elastic modulus was”, “A specific surface of bulk raw materials was”, etc.

14. All standards mentioned in the paper (e.g., GOST 310.4-81, GOST 29167-2021, GOST 10060-2012, etc) should be added to the reference list.

Author Response

Dear Reviewer 2!

Thank you for your interest in our manuscript. Your valuable comments helped make the manuscript even better. All corrections in the manuscript are highlighted in blue.

Comment 1: The values of specific gravity (e.g., 2600, 7800, 2800) provided in this manuscript do not make sense because they are very high. Did you mean 2.6, 7.8 and 2.8? The authors should revise the meaning of “specific gravity” and the calculation methods, in order to correct the values provided in the manuscript.

Response: Corrected

Comment 2: Response to comment #6 of the first review round is incomplete because the authors only added quantitative results published in a single paper (reference [14]). The authors should summarize the maximum increases/decreases in mechanical and durability properties (and optimal contents) due to bottom ash inclusion, based on a complete and updated literature review. This information is probably available in literature review papers.

Response: Added to the introduction section: «Chindasiraphan et al [14] indicated that concrete with 50% bottom ash cement replacement could be classified as high-strength concrete at 7 days, achieving a compressive strength of approximately 80.9 MPa at 28 days. Summarizing and analyzing the recent papers [15–17], it noted the maximum increase in mechanical properties by 20-30% (compressive and flexural strength, modulus of elasticity) as well as durability performances by 25-40% (water absorption, water resistance, frost resistance, abrasion resistance) due to the inclusion of BA. At the same time, the optimal dosage at the level of 15-20%, as well as the required degree of enrichment of the bottom ash, is important. In the case of using the original (unenriched) BA, the concrete will weaken at any dosage»

Comment 3 Response to comment #7 of the first review round is incomplete because the authors only added quantitative results published in two papers (reference [41] and [42]). The authors should summarize the maximum increases/decreases in mechanical and durability properties (and optimal contents) due to inclusion of nanomodified basalt fibers, based on a complete and updated literature review.

Response: Added to the introduction section: « During the literature search [42,43], very few works were noted on the use of nanomodi-fied basalt fibers, however, they note a high potential for the whole complex of physical and mechanical properties and durability performances. This is explained by the fact that the fiber works not only as a reinforcing element, but also as a structure-forming (reactive) component. Nanoadditives applied to microfiber provoke the growth of crystals in the mineral substance, and their rays, growing and intertwining with each other, give the material higher strength [44,45]. This process is called dispersed self-reinforcement. De-pending on the content of nanomodified basalt fibers dispersion method compressive strength increases from 15.7% to 23.3%, flexural strength increases from 28.5% to 31.1%. Pozzolanic additives and basalt fiber have a high water demand and affect concrete workability, so it is necessary to use various chemical modifiers in them [46,47]. The op-timal dosage of nanomodified basalt microfiber is 1.0-1.5% by weight of the binder [48–50]»

Comment 4:  Response to comment #9 of the first review round is not convincing because XRD analyses do not provide oxide percentages (Table 1). Did you also use XRF analyses? Equipment and methods used to obtain the oxide contents of cement (Table 1) were not provided.

Response: Added to the section 3.1: « The percentage of oxides and minerals in the Portland cement was determined by the standard method of X-ray fluorescence analysis»

Comment 5: Response to comment #20 is not convincing because the authors did not cite the standard (code or regulation) used to compact the specimens. In the response to this comment, the authors mentioned that “Standard methods were used for compaction”. However, this sentence was not added to the manuscript.

Response: Added to the section 2.2: « Compaction of the concrete mix was carried out in accordance with the requirements of the Russian Standard GOST 7473-2010.»

Comment 6: The authors did not solve the issue identified in comment #24. Section 2 should clarify that a strain gauge was used to calculate the elastic modulus. The following problems regarding this mechanical tests were not addressed:

 

-        Where did you bond the strain gauge?

-        What was the standard (code or regulation) used to determine the elastic modulus of the material?

-        Elastic modulus of cementitious materials is usually estimated in compression tests. Did you determine this parameter is compression or tensile tests? Why?

-        The test procedures and the shape/size of the specimen used in this test should be supported with citation of relevant literature.

Response: Added to the section 2.2: «To determine the modulus of elasticity of concrete by the magnitude of elastic-instantaneous deformations, tests are carried out on specimens-prisms with a size of 40×40×160 mm according to the standard method of the Russian standard GOST 310.4-81. Measurement of prism deformations is carried out with an accuracy of at least 1 × 10^-5 relative units using strain gauges installed on each face of the sample. Prior to the implementation of the stepwise loading mode of the prism, the test loads are centered along the physical axis of the sample. As a first approximation, the prism is mounted on the base plate of the press centered along the geometric axis. Then, at a speed of 0.2-0.3 MPa / s, a force is transferred to the sample up to the size of the first loading stage, the value of which is assumed to be 10% of the expected destructive (P_u). In this case, the largest difference in the increment of deformations on opposite faces should be no more than 20% of the average deformation of the sample, otherwise the centering of the load is refined by moving the prism towards the faces that deform to a greater extent. When the load is removed during the alignment process, the initial readings of the strain gauges are refined by introducing corrections to compensate for the “zero drift” of the instruments. Further loading of the sample is carried out in steps of 0.1×P_u. At each stage of the load, a constant force is maintained for 5 minutes, during which readings are taken on the instruments at the time of application of the next stage of the load (at the beginning of the stage) and after exposure (at the end of the stage). Based on these measurements, the fraction of the elastic component is separated from the total deformations of concrete, and the elastic modulus is calculated from the value of this component by the Eq. (1):

(1)

where σ₁ is the strain increment up to 30% of the breaking load; ε_1у is the increase in specimen deformation corresponding to the load level Р₁=0.3Р_b; Р_b is the breaking load; P₁ is the corresponding increase in external load.»

 

Comment 7 Response to comment #29 is not appropriate. Polishing procedures were not detailed. The authors did not state that the samples were impregnated with resin before polishing procedures. Impregnating the samples with a low-viscosity resin is an important step to support the original microstructure of the material during the polishing process. If the authors did not carry out this step, they unfortunately affected the original microstructure of the material.

Response: The information in the methods section has been corrected to indicate that polishing was not performed during surface preparation for the SEM samples.

Comment 8:  The serious problem highlighted in comment #31 was not solved. Since ANOVA was not carried out, it is necessary to provide the readers with a fast evaluation of the standard deviation obtained in the experimental tests in Figures 8, 9, 10, 11, 12, in order to represent the location of each different mixture evaluated in this study. Since 6 replicates were used in each test, error bars should be added to the graphs, in order to clearly represent the standard error associated with average results of each different series.

Response: However, information on the scatter of the results obtained is given in the tables that are given along with these figures.

Comment 9: Response to comment #34 was not convincing. The compaction deduced from SEM analysis and discussed in the text (“fill the voids at the micro level and compact”, “hydration products in the interpore space”, “is explained by the compaction of the cement matrix structure”, etc) is not convincing (and should be avoided). If you want to discuss porosity, you need to access a direct porosity measurement (e.g., mercury intrusion porosimetry). The explanation provided by the authors is based on only two simple qualitative images of Figure 13, so it is not accepted as a proof.

Response: We agree, however, that the result of improving all the characteristics of a rational composition can prove the compaction of the material.

Comment 10: The hydrates discussed in the text were not clearly indicated in the SEM images of Figure 13. Arrows should be added to all figures, according to all citations of the text of Section 3.5. In addition, did you use SEM/EDS to support the identification of these hydrates, based on their chemical composition? The authors did not cite and compare the size of the compounds indicated in the figures with those typically observed in the literature. The book “Concrete: Microstructure, Properties, and Materials” of Mehta and Monteiro describes the size and shape of cement hydrates, which may help the authors to solve some of these problems.

Response: Thank you very much for this comment! This book has been used to describe hydration products and the book has been cited

Comment 11 Caption of Figure 13 did not cite the image b.

Response: Cited.

Comment 12:  Although ANOVA was not carried out, the standard deviation should be discussed in the comparisons of experimental results presented in the manuscript.

Response: However, information on the scatter of the results obtained is given in the tables that are given along with these figures.

Comment 13: The authors should consider the replacement of the word “A” by “The” in many sentences of the paper, such as “A specific surface of bulk raw materials was studied”, “A granulometry of the particles of the raw materials was”, “A slump of the concrete mixture is”, “A slump flow of the concrete mix is”, “A compressive strength was”, “An elastic modulus was”, “A specific surface of bulk raw materials was”, etc.

Response: Replaced throughout.

Comment 14: All standards mentioned in the paper (e.g., GOST 310.4-81, GOST 29167-2021, GOST 10060-2012, etc) should be added to the reference list.

Response: All standards mentioned in the paper have been added to the reference list.

 

Round 3

Reviewer 1 Report (Previous Reviewer 2)

The air content itself cannot explain the reduction of the 45% BA properties. It is possible that the extra 15% BA is more than can react with the lime from the cement hydration during the experiment. It would help if you left this question open. In another experiment, you may have more specimens from 15% to 45% BA (compressive strength only), to see if there is an optimum. publish it in a separate brief report.

The references do not give a strong background for the claim that the nano-modification hase the claimed effect. a disclaimer is needed

Author Response

Dear Reviewer 1!

Thank you for your interest in our manuscript. Your valuable comments helped make the manuscript even better. All corrections in the manuscript are highlighted in blue.

Comment 1: The air content itself cannot explain the reduction of the 45% BA properties. It is possible that the extra 15% BA is more than can react with the lime from the cement hydration during the experiment. It would help if you left this question open. In another experiment, you may have more specimens from 15% to 45% BA (compressive strength only), to see if there is an optimum. publish it in a separate brief report.

Response: Thanks for the valuable advice. We removed the sentence about the effect of air content on compressive strength. We will explore this later.

Comment 2: The references do not give a strong background for the claim that the nano-modification hase the claimed effect. a disclaimer is needed.

Response: This information has been removed from the introduction section.

Reviewer 2 Report (New Reviewer)

All serious issues indicated in the first and second review rounds were not corrected. Therefore, the paper cannot be recommended for publication. The problems that were not corrected are listed below.

1.       The authors discussed voids and porosity based on two SEM images of mortar fragments that were not polished. The structure of cementitious materials is very heterogeneous. Without systematic quantitative SEM techniques in polished samples cast for microstructural analyses, the authors could find locally spots that could approve or reject any porosity hypothesis… All discussions regarding compactness, porosity, voids should be removed or supported by strong experimental evidences (e.g., quantitative SEM analyses, MIP analyses, etc).

2.       Response to comment #9 of the previous review round is not appropriate. The authors stated that “the result of improving all the characteristics of a rational composition can prove the compaction of the material”. Actually, the microstructural analysis (SEM) is used to prove the macroscale analyses results, and not the other way around. Then, the authors failed to explain the macroscale results based on microscale mechanisms.

3.       Response to comment #10 is inappropriate. The hydrates discussed in the text were not clearly indicated with arrows in the SEM images of Figure 13. Considering the typical morphology and chemical composition of hydrates reported in previous literature, arrows should be added to all SEM figures, according to all citations of the text of Section 3.5. In addition, the authors did not indicate that SEM/EDS was applied to support the identification of these hydrates, based on their chemical composition.

4.       Since ANOVA was not carried out, it is necessary to provide the readers with a fast evaluation of the standard deviation obtained in the experimental tests in Figures 8, 9, 10, 11, 12, in order to represent the location of each different mixture evaluated in this study. The readers will not be able to plot or imagine in this figure the error bars associated with the numerous values of standard deviation presented in the Tables. Since 6 replicates were used in each test, error bars should be added to the graphs, in order to clearly represent the standard error associated with average results of each different series.

5.       The authors did not consider the standard deviation values in all comparisons of results presented in Figures 8, 9, 10, 11, and 12. No statistical analysis of variance was carried out. Therefore, some biased conclusions were reported in this manuscript.

Author Response

Dear Reviewer 2!

Thank you for your interest in our manuscript. Your valuable comments helped make the manuscript even better. All corrections in the manuscript are highlighted in blue.

Comment 1: The authors discussed voids and porosity based on two SEM images of mortar fragments that were not polished. The structure of cementitious materials is very heterogeneous. Without systematic quantitative SEM techniques in polished samples cast for microstructural analyses, the authors could find locally spots that could approve or reject any porosity hypothesis… All discussions regarding compactness, porosity, voids should be removed or supported by strong experimental evidences (e.g., quantitative SEM analyses, MIP analyses, etc).

Response: All discussions regarding compactness, porosity, voids should have been removed

Comment 2: Response to comment #9 of the previous review round is not appropriate. The authors stated that “the result of improving all the characteristics of a rational composition can prove the compaction of the material”. Actually, the microstructural analysis (SEM) is used to prove the macroscale analyses results, and not the other way around. Then, the authors failed to explain the macroscale results based on microscale mechanisms.

Response: This sentence is missing in the current version of the article.

Comment 3 Response to comment #10 is inappropriate. The hydrates discussed in the text were not clearly indicated with arrows in the SEM images of Figure 13. Considering the typical morphology and chemical composition of hydrates reported in previous literature, arrows should be added to all SEM figures, according to all citations of the text of Section 3.5. In addition, the authors did not indicate that SEM/EDS was applied to support the identification of these hydrates, based on their chemical composition.

Response: Arrows have been added to all SEM figures

Comment 4:  Since ANOVA was not carried out, it is necessary to provide the readers with a fast evaluation of the standard deviation obtained in the experimental tests in Figures 8, 9, 10, 11, 12, in order to represent the location of each different mixture evaluated in this study. The readers will not be able to plot or imagine in this figure the error bars associated with the numerous values of standard deviation presented in the Tables. Since 6 replicates were used in each test, error bars should be added to the graphs, in order to clearly represent the standard error associated with average results of each different series.

Response: The error bars have been added for all figures

Comment 5: The authors did not consider the standard deviation values in all comparisons of results presented in Figures 8, 9, 10, 11, and 12. No statistical analysis of variance was carried out. Therefore, some biased conclusions were reported in this manuscript.

Response: The error bars have been added for all figures

 

Round 4

Reviewer 1 Report (Previous Reviewer 2)

1. What are "Perfect values of mechanical properties"? the ward perfect seems to be unperfect in this context. (abstract). This is only the first of many grammatical errors. 

2. fiber dosage should be volumetric

3. I have a problem with Russian standards. They do not have an English version. I there is an equal standard with an English version, please refer to it.

 

Reviewer 2 Report (New Reviewer)

The authors corrected the main issues identified by this reviewer and the paper can be recommended for publication.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

There are numerous errors (see the beginning page as marked in the draft paper).  The authors should revise and correct all errors before reviewing by others.

Comments for author File: Comments.pdf

Reviewer 2 Report

Review Nanomodified basalt fiber cement composite with bottom ash

1.    In the abstract, the fourth line. Bottom Ash – BA, not CB.

2.    First paragraph of the introduction. Should be rewritten. During the 21 century, steel-reinforced concrete continues to be dominantly used. Please, use Arab numbers.

3.    The 3^rd paragraph is not connected to the 2^nd. A sentence like “pozzolans often change the rheological properties of the fresh concrete” is needed to make a logical continuity.

4.    Paragraph 4, line 4, this is not true. Fiber-reinforced concrete does shrink. The shrinkage does not create visible cracks. Line 6, sometimes there is no need for additional reinforcement. Line 7, fibers are not necessarily uniformly distributed. Line 10, not warranty but durability. Line 18, not transformer but conductor. Doesn’t basalt fiber change workability? In this case, it should be mentioned, and the order of paragraphs 3 and 4 should be changed.

5.    Unfortunately not all in the field have a good background in statistics. A short review of the parameters of ANOVA and the advantage of using a statistical method in the introduction is advised.

6.    Figure 1, why not a table?

7.    Figure 2. Completely redundant, in my opinion.

8.    Please replace figure 5 with a particle distribution graph like in figure 4 (you may draw both distributions on the same graph). The fineness modulus is 2.36, not 20-40 mm.

9.    What is the importance of fulleroid-type nano additives? That should be covered in the introduction.

10. Figure 6. The data should be given in a table. The fiber length may be 6 mm, not 6 microns.

11. When no BA was used, did the cement has been ground for 30 min in the ball mill?

12. Figures 8 and 9 provide the same information. The reader is not interested in the cyanoacrylate (super-glue) container image.

13. What are “normal” conditions? Do you mean “standard” conditions?

14. How many repetitions were carried out for each test?

15. Page 9, last paragraph, concrete compositions or concrete composite?

16. Figure 10 shows lots of air bubbles on the surface of the cubes. Don’t you have measured or calculated air content?

17. Table 4, what is the confidence interval for each number?

18. Figure 13, 1) please edit the figure to have the legend in a continuous order of fiber content. 2) this is not an ANOVA result. First, ANOVA is useful only for a function with a monotonous slope, in particular linear. For the ANOVA result, one expects to see a table of probability of the linear relation between parameters.

19. The same hold for 3.3 and 3.4

20. The evidence shown in 3.5 cannot support the discussion and conclusions in this section.

21. No statistical analysis supports the claim that there is a combined effect of BA and NBF on flexural strength or any other parameter.

 

22. No evidence to support conclusion 4 (plastic zone) was shown in the paper body.