A Study on the Mechanical Properties of Glass-Fiber-Reinforced Defective Gypsum Boards

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article "Study on the Mechanical Properties of Glass Fiber Reinforced Defective Gypsum Boards" by Di Wu, Laiwang Jing, Shaochi Peng and Wei Jing examines the possibility of using glass fiber to improve the performance of defective gypsum boards. The subject of the study is the mechanical properties of gypsum board samples with one and two holes under single compression and under repeated loading. Through microstructural analysis, the authors showed that glass fibers reduce stress concentrations, improve integrity, and prevent brittle failure of samples. In addition, the addition of glass fiber has been shown to improve adhesion and prevent microcracks, improving the behavior of the specimen under cyclic loading. The results presented in the article will be of interest to specialists in the construction industry.

The article has only a few clarifying questions:

1) Formulas (1) and (2) are quite trivial in their mathematical form. Did the authors introduce them independently as part of their research, or is this a generally accepted assessment of the mechanical properties of samples of defective and brittle materials?

2) How was the schematic diagram of energy partitioning obtained (Figure 5)? Are these the results of calculations or experiments?

The article deserves to be published in Sustainability journal.

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Response to Reviewer 1#

1.Formulas (1) and (2) are quite trivial in their mathematical form. Did the authors introduce them independently as part of their research, or is this a generally accepted assessment of the mechanical properties of samples of defective and brittle materials?

Thanks to the reviewer for question, Formulas (1) and (2) are common methods of calculating damage factors in cyclic loading and unloading experiments, which are applicable to the evaluation of mechanical properties of defective and brittle material samples.

 

2.How was the schematic diagram of energy partitioning obtained (Figure 5)? Are these the results of calculations or experiments?

Thanks to the reviewer's question, Fig. 5 is intercepted the loading and unloading curves of the twelfth cycle of the experiment numbered DH-00 as a schematic diagram, which is the result of the data obtained by the experiment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear editor

I am grateful to you for giving me the opportunity to review this research “Study on the Mechanical Properties of Glass Fiber Reinforced 2 Defective Gypsum Boards” with manuscript number sustainability-2735519-MDPI

This article review presents an interesting subject but it needs some MAJOR modifications keeping in view the following suggestions:

Comments

1.     The abstract should be better formulated, presenting some numerical values to make it easier for readers.

2.     The introduction section is very short. The environmental and economic problems caused by glass industry must be presented more broadly, types of glass wastes and their quantities all over the world must be mentioned. Authors should read the following articles (only the introduction section) carefully to support this point and take them as references in the revised manuscript.

i.                 Mechanical properties, radiation mitigation and fire resistance of OPC-recycled glass powder composites containing nanoparticles.

ii.               Effect of high gamma radiation dosage and elevated temperature on the mechanical performance of sustainable alkali-activated composite as a cleaner product.

iii.             Investigation of the mechanical properties, morphology and the attenuation behavior of gamma rays for OPC pastes mingled with two different glass wastes.

iv.             Valorization of hazardous glass wastes via geopolymer production utilized in gamma ray shielding applications: A comparative study with Portland cement.

v.               Correlation between porous structure analysis, mechanical efficiency and gamma-ray attenuation power for hydrothermally treated slag-glass waste-based geopolymer

vi.             Synergetic effects of hydrothermal treatment on the behavior of toxic sludge-modified geopolymer: Immobilization of cerium and lead, textural characteristics, and mechanical efficiency

vii.            From dangerous wastes to green construction materials, as thermally stable-radiation blocker, in presence of meso-porous magnesia and alumina

viii.          Impact of microporous γ-Al2O3 on the thermal stability of pre-cast cementitious composite containing glass waste

ix.             Investigation of autoclave curing impact on the mechanical properties, heavy metal stabilization and anti-microbial activity of the green geopolymeric composite based on received/ thermally-treated glass polishing sludge

x.               Enhancement of fresh and hardened properties of geopolymeric composite containing toxic lead sludge: A comparative study between the effect of superplasticizer and thermal treatment of sludge

3.     What are the research gaps behind conducting this work? Authors must state the reasons in order and detail in the introduction section.

4.     Be careful that the innovation in the work is clear and condensed at the end of the introduction.

5.     Please insert the chemical composition of fiber glass and gypsum in Table 1. Mention loss of ignition (L.O.I) for each one.

6.     Please ( Page 3 lin3 117) modify this sentence “The design water-cement ratio is 0.25” to “The design water-gypsum ratio is 0.25”

7.     Please authors should display a mix design in detail in a table.

8.     Conclusion section is very long. It is recommended to formulate it in a condensed way.

9.     Some languages should be polished; grammatical correction is required.

10.  Reference section must be supported by the mentioned 10 papers.

11.  All these comments must be paid attention to and responded to point by point.

 

 

Comments on the Quality of English Language

moderate 

Author Response

Response to Reviewer 2# 

1. The abstract should be better formulated, presenting some numerical values to make it easier for readers.

   Thanks to the reviewer's comments, the abstract has been modified to add some values and highlighted in yellow, the modification is as follows: The results show that adding glass fibre can improve the compressive strength of defective gypsum boards. When the fibre concentration is 1.5%, the strength of single-hole gypsum boards increases by 77.1%. Energy evolution and residual strain evaluation after repeated loading showed significant reinforcement of the dual-hole gypsum board samples with the addition of glass fibers, improving stress distribution and elasticity, which was confirmed by damage factor analysis.See lines 10-17 for details.

 

2. The introduction section is very short. The environmental and economic problems caused by glass industry must be presented more broadly, types of glass wastes and their quantities all over the world must be mentioned. Authors should read the following articles (only the introduction section) carefully to support this point and take them as references in the revised manuscript.

Thanks to the reviewers' comments, we have cited the references mentioned in the Introduction section and highlighted them in yellow, with the modification : Ramadan investigated the mechanical properties, thermal stability and radiation mitigation capabilities of composites containing glass waste [28-37]. See specifically lines 48-49.

 

3. What are the research gaps behind conducting this work? Authors must state the reasons in order and detail in the introduction section.

Thanks to the reviewer's question, the authors' aim in carrying out this research is that the improvement of fibers on the resistance of perforated specimens to cyclic stresses has not been studied in the literature before, and that the present work can simulate the enhancement of fibers on stress-concentrated members with defects in real engineering. A description is added to the introduction section, as follows:In geotechnical structures, micropores are always distributed inside the material. On the one hand, these holes reduce the effective bearing area of the structure and lower the macro-strength of the structure. On the other hand, the porous holes can effectively improve the stress concentration phenomenon, form structural "defense holes", inhibit the expansion of cracks, and improve the stability and durability of the structure. However, there is a lack of research on the improvement of the mechanical properties of porous structures by glass fibers under cyclic loading. Therefore, it is of great engineering value to carry out cyclic loading and unloading tests of single and double holes with different glass fiber dosage to investigate the effects of glass fibers and defense holes on the improvement of structural stress distribution and damage evolution, and on the stability evaluation and durability analysis of geotechnical engineering structures.

 

4. Be careful that the innovation in the work is clear and condensed at the end of the introduction.

Thanks to your comments, we have modified and yellow highlighted the innovation of the work, as follows: The innovation of this study is the preparation of six types of defective gypsum boards with different glass fibre contents, and conducting repeated loading experiments with different stress amplitudes to observe the failure mode and energy evolution of the specimens, which provides a theoretical basis for the sustainable utilisation of glass fiber. See lines 87-90 for details.

 

5. Please insert the chemical composition of fiber glass and gypsum in Table 1. Mention loss of ignition (L.O.I) for each one.

Thanks to your comments. Since the chemical composition of gypsum is widely known, Table 1 has been modified by deleting the percentage of chemical composition and instead listing the basic mechanical parameters and loss on burn for the experimental gypsum. Relevant data have been added and highlighted in yellow in the manuscript, as shown in line 118.

 

6. Please ( Page 3 lin3 117) modify this sentence “The design water-cement ratio is 0.25” to “The design water-gypsum ratio is 0.25”

Thank you for your comments, which have been revised and yellow highlighted in the article, see line 102.

 

7. Please authors should display a mix design in detail in a table.

Thank you for your comment, the detailed mixing ratio design has been shown in list Table 3 in the article, with the modifications highlighted in yellow, see line 122.

 

8. Conclusion section is very long. It is recommended to formulate it in a condensed way.

 Thank you for your comments, which have been revised and yellow highlighted in the article, as follows:

(1) Uniaxial tests show that two-hole gypsum boards have weaker strength due to the reduced effective bearing area, leading to early cracking. Adding fiberglass can increase strength, but the effect diminishes beyond a 1.5% threshold. Balancing cost and safety is critical in engineering.

(2) Glass fibers exert influence on the recuperation of strain in gypsum boards. While their impact is negligible in single-hole (SH) samples, a substantial decrease in strain is observed in dual-hole (DH) samples. The addition of fibers leads to enhanced distribution of stress and elasticity. An analysis of damage factors affirms this enhancement, particularly fortifying structural stability and longevity.

(3) Glass fibers mitigate stress concentration, fortify sample integrity. Absence leads to brittleness, stress concentration between double pores. Low galss fiber content weakens bonding, causing slippage; higher content inhibits microcracking, acts as stress-transferring bridges, enhancing cyclic loading behavior.

 

9. Some languages should be polished; grammatical correction is required.

Thanks to your comments, we made the changes using the language modification service provided by MDPI.

 

10. Reference section must be supported by the mentioned 10 papers.

Thank you for your comments, the 10 papers mentioned above have been cited and highlighted in yellow in the introduction section, see lines 48-49.

 

11. All these comments must be paid attention to and responded to point by point.

Thank you for your suggestions, we have followed and responded to each of your comments.

 

 

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The study demonstrated that two-hole gypsum boards were more brittle due to a reduction in the effective load-bearing area, leading to early cracking. The addition of fiberglass enhances strength, but this effect diminishes beyond a certain threshold. Balancing cost and safety is crucial in engineering.

1. How does the addition of fiberglass influence the strength of two-hole gypsum boards, particularly concerning the reduction in the effective load-bearing area and early cracking?
2. What are the effects of fiberglass on strain recovery and stress distribution in one-hole gypsum board samples compared to two-hole samples, and how do these effects contribute to structural stability and durability?
3. How do fiberglass fibers operate at the microscopic level to enhance adhesion, inhibit microcracking, and act as bridges to transfer stress, and what impact does this have on the behavior of samples under cyclic loading?

Author Response

Response to Reviewer 3# 

The study demonstrated that two-hole gypsum boards were more brittle due to a reduction in the effective load-bearing area, leading to early cracking. The addition of fiberglass enhances strength, but this effect diminishes beyond a certain threshold. Balancing cost and safety is crucial in engineering.

1. How does the addition of fiberglass influence the strength of two-hole gypsum boards, particularly concerning the reduction in the effective load-bearing area and early cracking?

We thank the reviewer for his question about the effect of glass fibers on gypsum strength and early cracking, which is central to the analysis of the experimental phenomena in the manuscript. I will answer the reviewer's questions in terms of effective bearing area and early cracking:

1.Effective bearing area. Gypsum has obvious Poisson effect, when the specimen is in uniaxial compression loading condition, tensile stress exists in the centre of gypsum board. In the direction of tensile loading, the effective bearing area of a two-porous board is lower compared to a single-porous board. Therefore, the strength of two-hole gypsum board is lower than that of single-hole gypsum board in lower glass fibre dosage specimens.

2.Early cracking. From the damage factor curves of the specimens, it can be seen that the early damage factor of bi-porous gypsum board is higher than that of mono-porous gypsum board in lower glass fibre doping conditions. And this was significantly improved when the fibre doping was increased. It shows that with the addition of glass fibre, the early cracking of double-hole gypsum board is significantly controlled.

In conclusion: with the addition of glass fibers, the early cracking of the bi-porous gypsum board was controlled and the effect of the reduction of the effective bearing area was gradually reduced. Therefore, glass fibers contribute to the strength increase of the bi-porous gypsum board.

 

2. What are the effects of fiberglass on strain recovery and stress distribution in one-hole gypsum board samples compared to two-hole samples, and how do these effects contribute to structural stability and durability?

Thanks to the reviewer's question, strain recovery and stress distribution are the root causes of test damage. In response to the reviewer's question, we will analyse the following three aspects:

1. Strain recovery. At lower glass fibre doping, the strain recovery of single-hole specimens is higher than that of double-hole specimens. And when the glass fibre doping is higher, the strain recovery of two-hole gypsum board is higher than that of single-hole gypsum board. This conclusion can be obtained from Fig. 3. At lower glass fibre doping, the hysteresis loops in the stress-strain curves are more sparse for the two-hole gypsum board. This phenomenon is reversed when the glass fibre doping is higher.
2. Stress distribution. Compared with single-hole gypsum board, the effective bearing area of double-hole gypsum board is lower. But it can well improve the phenomenon of stress concentration at the hole edge, especially in the range between two holes. This is helpful to inhibit the development of cracks. Therefore, when glass fibres are added, the tensile properties of double-hole gypsum board are improved. Thanks to the beneficial effect of the two-hole structure in improving the stress concentration, the damage of two-hole gypsum boards in cyclic loading and unloading is lower than that of single-hole gypsum boards.
3. Improved structural stability and durability. Stress is the root cause of structural damage. When the structural strength meets the demand, in order to improve the durability and stability of the structure containing holes. Arranging defence holes in the direction of stress concentration can effectively relieve stress concentration and inhibit crack expansion in that direction. The application of this design already exists in the design of aerospace vehicles, and the authors are very much looking forward to the application in geotechnical engineering structures.

 

3.How do fiberglass fibers operate at the microscopic level to enhance adhesion, inhibit microcracking, and act as bridges to transfer stress, and what impact does this have on the behavior of samples under cyclic loading?

The authors are very grateful to the reviewers for their questions. The role of glass fibers in improving the bonding between gypsum particles in the microstructure is at the core of the mechanism by which glass fibres improve the mechanical properties of gypsum samples. For the reviewer's questions. The authors will answer them in terms of peak strength and damage evolution:

1. Peak strength. With the incorporation of glass fibres, the bonding effect and friction between gypsum particles gradually improved, especially improving the tensile properties of gypsum. When external loading is applied, tensile stress concentration exists at the upper and lower ends of the circular hole and tensile cracks sprout. The addition of glass fibers, on the other hand, led to the inhibition of crack development. The peak strength of the specimen under cyclic loading is improved.
2. Damage evolution. Under the effect of glass fibre filling, the stress distribution inside the specimen is more uniform. Under cyclic loading, when the fibre content is low, the energy dissipation in the specimen shows a jumping increase, whereas when the fibre content is high, the energy dissipation in the specimen has a smooth transition, indicating that the increase in fibre content contributes to the suppression of energy dissipation.

 

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The article is devoted to the study of the possibility of using fiberglass to improve the quality of building materials such as gypsum. Researchers have shown in their work that Glass fibers reduce stress concentrations, improve integrity and prevent brile failure, especially at high stress levels. Microstructural analysis demonstrates that the addition of glass fibers improves adhesion and prevents microcracking while acting as a stress transfer bridge, enhancing specimen behavior under cyclic loading. The article contains an original and simple idea, is devoted to current topics and may be of interest to a wide range of readers. Meanwhile, several questions and comments arose about the work.

1. The article does not provide the strength and geometric (thickness, length of fragments) characteristics of fiberglass.

2 Table 1 shows the mass fractions of gypsum components. It is not necessary. Everyone knows that the chemical formula of gypsum is CaSO4*2H2O.

3 The authors of the work claim that there is an optimal limit for glass fiber content. The question arises: is this limit the same for different building materials? If not, how to determine it in order to prevent the negative impact of the fiberglass additive.

4 Can fiberglass be replaced with fine broken glass powder?

Author Response

Response to Reviewer 4# 

1. The article does not provide the strength and geometric (thickness, length of fragments) characteristics of fiberglass.

Thank you for your comments, considering that glass fibre is a fine fibre, we have given its properties such as length, diameter and tensile strength in Table 2, see line 120.

2. Table1 show the mass fractions of gypsum components. It is not necessary. Everyone knows that the chemical formula of gypsum is CaSO4*2H2O.

  Thank you for your comments, we have deleted the description of each component of gypsum in Table 1 and replaced it with a description of some basic physical properties of gypsum. The modifications are highlighted in yellow, see line 118 for details.

3. The authors of the work claim that there is an optimal limit for glass fiber content. The question arises: is this limit the same for different building materials? If not, how to determine it in order to prevent the negative impact of the fiberglass additive.

Thanks to the reviewer for question. This optimum limit is different for different building materials. In the studies we have carried out, cement mortar and concrete, the optimum limit is different from gypsum, and specific experiments are needed to determine the optimum limit of glass fibers in other building materials.

4. Can fiberglass be replaced with fine broken glass powder?

Thank you for your comment. In fact it is not feasible to use finely ground glass powder instead of glass fibre. We have already carried out related research and experiments with different mesh sizes of glass powder instead of glass fibre respectively, and the results show that the glass powder performs poorly in improving the stress concentration damage of the specimen, and the result is even lower than that without adding any admixture, and the larger the diameter of the glass powder, the worse the effect is, so we gave up the related experiments with finely crushed glass powder.

 

Author Response File: Author Response.docx

Reviewer 5 Report

Comments and Suggestions for Authors

The work "Study on the Mechanical Properties of Glass Fiber Reinforced Defective Gypsum Boards" shows important results.

Glass fiber is a waste product that has attracted interest for its recycling from the engineering community. The work shows an improvement in the properties of defective gypsum boards after the inclusion of glass fiber in its composition. The addition of glass fiber can increase the compressive strength of defective gypsum boards, but within certain concentrations limited by a threshold, which is confirmed by studies of single compression, repeated loading and testing using scanning electron microscopy. Such materials strike a balance between cost and safety, which is critical in engineering. In comparison with the original gypsum boards, such material exhibits a significant reduction in residual deformation. Moreover, without glass fiber, a material with two 5 mm holes located at a distance of less than 15 mm cannot be manufactured at all due to the stress concentration between the double pores.

There are shortcomings in the work, which impair the accessibility of the material to a wide range of readers:

1.      It is not clear why samples with one and two holes were chosen for research. There may be many more of them.

2.      In the case of construction, large fragments of materials are of interest. How can these characteristics be scaled to material larger than 100mm×130mm×20mm?

3.      The conclusion needs to be revised. It contains sentences that almost repeat the abstract; moreover, the main results are not supported by numerical estimates, which are in the text of the work itself. There is no conclusion about the optimal concentration of glass fiber based on the studies conducted. What is the value of this threshold?

4.      The paper also states that any recycled glass fiber is suitable. Why are studies carried out with fiberglass that has the exact characteristics as in Table 2. Are these easier to manufacture or are they optimal?

Author Response

Response to Reviewer 5# 

1. It is not clear why samples with one and two holes were chosen for research. There may be many more of them.

The authors greatly appreciate the reviewer's comments. In response to the manuscript's shortcomings of unclear research implications, the authors have added to the introduction of the manuscript. The additions are located in lines 75-83 and are highlighted. The additions are listed below: In geotechnical structures, micropores are always distributed inside the material. These pores, on the one hand, reduce the effective bearing area of the structure and decrease the macroscopic strength of the structure. On the other hand, the porous holes can effectively improve the phenomenon of stress concentration, form structural "defence holes", inhibit the expansion of cracks, and improve the stability and durability of the structure. However, there is a lack of research on the improvement of mechanical properties of porous structures by glass fibers under cyclic loading. Therefore, the cyclic loading and unloading tests of single and double holes with different glass fibre dosages are conducted to investigate the effects of glass fibers and defence holes on the improvement of structural stress distribution and damage evolution, which are of great engineering value for the stability evaluation and durability analysis of geotechnical engineering structures.

 

2. In the case of construction, large fragments of materials are of interest. How can these characteristics be scaled to material larger than 100mm×130mm×20mm?

We thank the reviewer for asking how the extension of specimen properties to building materials is key to the manuscript's guidance for engineering practice. As the size of a material increases, the probability of distributing micropores and microcracks within it gradually increases, and therefore the strength of the material gradually decreases. Therefore, the guidance of the manuscript research content to engineering materials mainly focuses on qualitative analyses rather than quantitative analyses. Therefore, the specimen size is mainly set to give cracks more sufficient space to develop and reduce the influence of end effects and boundary effects on the damage evolution. Under this premise, the damage evolution patterns of specimens containing holes, obtained in the manuscript, under disturbed loading; as well as the conclusions on the effects of damage with respect to the number of cycles, fibre content, and pore distribution characteristics can be directly applied to construction materials. Analytical ideas are provided for the damage evolution of construction materials under disturbing loads.

 

3.The conclusion needs to be revised. It contains sentences that almost repeat the abstract; moreover, the main results are not supported by numerical estimates, which are in the text of the work itself. There is no conclusion about the optimal concentration of glass fiber based on the studies conducted. What is the value of this threshold?

Thank you for your comments. We have modified the conclusions section and explicit numerical estimates have been added to the conclusions section with a threshold of 1.5% volume fraction. The modifications are as follows: (1) Uniaxial tests show that two-hole gypsum boards have weaker strength due to the reduced effective bearing area, leading to early cracking. Adding fiberglass can increase strength, but the effect diminishes beyond a 1.5% threshold. Balancing cost and safety is critical in engineering.

(2) Glass fibers exert influence on the recuperation of strain in gypsum boards. While their impact is negligible in single-hole (SH) samples, a substantial decrease in strain is observed in dual While their impact is negligible in single-hole (SH) samples, a substantial decrease in strain is observed in dual-hole (DH) samples. The addition of fibers leads to enhanced distribution of stress and elasticity. analysis of damage factors affirms this enhancement, particularly fortifying structural stability and longevity.

(3) Glass fibers mitigate stress concentration, fortify sample integrity. Absence leads to brittleness, stress concentration between double pores. Low galss fiber content weakens bonding, causing slippage; higher content inhibits microcracking, acts as stress-transferring bridges, enhancing The higher content inhibits microcracking, acts as stress-transferring bridges, enhancing cyclic loading behaviour.

 

4.The paper also states that any recycled glass fiber is suitable. Why are studies carried out with fiberglass that has the exact characteristics as in Table 2. Are these easier to manufacture or are they optimal?

Thank you for your comments. We have selected the glass fibers with the characteristics shown in Table 2 according to the reference (Glass Fibers Reinforced Concrete: Overview on Mechanical, Durability and Microstructure Analysis), which are in the average of the range of glass fibre characteristics. These glass fibers are in the average of the range of glass fibre properties, less difficult to manufacture, easy to obtain, and more instructive for practical engineering.

 

 

 

 

Author Response File: Author Response.pdf

Reviewer 6 Report

Comments and Suggestions for Authors

The authors have presented an interesting work for the building sector. However, some issues need to be corrected before recommending the publication of the manuscript.

Some relevant numerical results could be included in the abstract.

Line 31, change references to [1-3], repeat this where necessary.

Line 106, change to 100 x 130 x 20 mm.

Line 119, clarify whether the percentages added are by weight or by volume. 

The dosages should be included, describing the mixing process of the compounds and their regulation.

How was the vibrating process? What are the setting times?

Why has it been decided to fix 28 days of curing, in general for this type of materials, according to the regulations, 7 days is enough.

How has the chemical composition of the gypsum in Table 1 been obtained, in the end it is understood that it is only dihydrate (CaSO42H2O).

Reference or indicate how the properties of the fibres have been obtained.

Table 2, change Gpa to GPa.

No image of the experimental setup is shown.

The units in the tables must be in brackets.

Indicate the reference standards used for the tests.

The discussion of the tests is very poor and should be improved. In addition, the quality of the graphs presented could be improved.

The conclusions should be improved, including limitations and future lines of work.

Several ideas are proposed to the authors to complement this study: to analyse the behaviour against fire, to study the Young's modulus by ultrasound and the hardness of the material, to measure the resistance of the material against actions such as drilling or hanging of objects or to evaluate its mechanical behaviour after humidity-dryness cycles.

Author Response

Response to Reviewer 6# 

The authors have presented an interesting work for the building sector. However, some issues need to be corrected before recommending the publication of the manuscript.

1. Some relevant numerical results could be included in the abstract.

Thank you for your comments. The abstract section has been modified and we have added numerical results which are modified as follows: The results show that adding glass fibre can improve the compressive strength of defective gypsum boards. when the The results show that adding glass fiber can improve the compressive strength of defective gypsum boards. When the fibre concentration is 1.5%, the strength of single-hole gypsum boards increases by 77.1%. Energy evolution and residual strain evaluation after repeated loading showed significant reinforcement of the dual-hole gypsum board samples with the addition of glass fibers, improving stress distribution and elasticity, which was confirmed by damage factor analysis. Based on the experimental results and cost, 1.5% glass fibre is the optimal concentration. See lines 10-17 for details.

 

2. Line 31, change references to [1-3], repeat this where necessary.

The reviewer's comment is appreciated. The citation format of the references in the text has been revised.

 

3. Line 106, change to 100 x 130 x 20 mm.

Thank you for your comments. This has been changed to 100 x 130 x 20 mm in the manuscript, see line 93.

 

4. Line 119, clarify whether the percentages added are by weight or by volume. 

Thank you for your comments.Percentages have been clarified to be calculated on a volumetric basis, see lines 103-104 for details of the changes.

 

5. The dosages should be included, describing the mixing process of the compounds and their regulation.

We thank the reviewer for comments. We have given the proportions of the mixtures in Table3, and the mixing process of the specimens is described in lines 105-114. It is as follows: The specimen preparation process is as follows. Firstly, assemble the acrylic mold one hour in advance, and use glue to adhere the molds. After the assembly is completed, fill the mold with water. If no water seeps out within half an hour, the mold assembly is qualified. Wipe the mold and dry it for later use. Then, put the weighed gypsum, water-reducing agent, and defoaming agent into a horizontal mixer and stir for 1 minute. The mixture’s base proportions are shown in Table 3. Add the glass fiber to the mixer and stir for 2 minutes, and then slowly add water and continue stirring for 2 minutes. This is to ensure that all materials can fully contact and allow the gypsum specimen to be formed. Pour the stirred gypsum mixture into the mold and use a vibration table to vibrate at the same time. This process can make the bubbles attached to the reserved defective holes and the inner wall of the mold escape, ensuring the reliability of the experimental data. After curing for 24 hours, disassemble the mold and take out the sample, place it in a curing room with a temperature of 20±2°C, and cure it for 28 days for testing. 

 

6. How was the vibrating process? What are the setting times?

We appreciate the comments of the reviewer. We placed the gypsum-filled moulds on a vibration table for 30 s. We kept adding gypsum to the moulds to ensure that the gypsum filled the moulds. After the vibration, the moulds were covered with cling film and left to rest for 24h before being dismantled.

 

7. Why has it been decided to fix 28 days of curing, in general for this type of materials, according to the regulations, 7 days is enough.

Thank you for your question. It was winter when the specimens were prepared, and to avoid the effect of ambient temperature on the specimens, it was decided to carry out a 28-day conditioning in a curing box at 25°C and 30% humidity.

8. How has the chemical composition of the gypsum in Table 1 been obtained, in theend it is understood that it is only dihydrate (CaSO42H2O).

We thank the reviewer for comments. Given that the chemical composition of gypsum is well known, we have revised Table 1 to delete the content related to its chemical composition and to add some physical properties of gypsum.

 

9. Reference or indicate how the properties of the fibres have been obtained.

We thank the reviewer for comments.We have selected the glass fibers with the characteristics shown in Table II based on the reference (Glass Fibers Reinforced Concrete: Overview on Mechanical, Durability and Microstructure Analysis), which are less difficult to manufacture and easy to obtain.

 

10. Table 2, change Gpa to GPa.

We appreciate the comments of the reviewer. The units are not written correctly due to our mistake. Gpa has been changed to GPa in Table 2, see line 120 for details.

 

11. No image of the experimental setup is shown.

We appreciate the comments of the reviewer. Images of the experimental setup have been added and are detailed in Fig 1.

 

12. The units in the tables must be in brackets.

We thank the reviewer for comments.The units in the table have been ensured to be in brackets.

 

13. Indicate the reference standards used for the tests.

Thank you to the reviewers for question. The test is based on 90% of the lowest uniaxial compressive strength of the specimen as the criterion for the maximum stress in the third stage of cycling to ensure that the following two objectives are achieved:1. to ensure that the specimen will not be destabilised and damaged during the complete cyclic loading and unloading process. 2. to be able to reflect the damage evolution law of the specimen in the cycling process. Experimenting with the above standard can meet the above two objectives at the same time.

 

14. The discussion of the tests is very poor and should be improved. In addition, the quality of the graphs presented could be improved.

Thank you for your comments. The authors added too many variables in the design of the experiments, which made the discussion of the tests too complicated. We will simplify the design of the experiments and focus on the effect of fibers on the mechanical properties of the defective structures in the subsequent studies. We will also improve the quality of the graphical presentation and choose more concise and intuitive forms of presentation in the subsequent studies.

 

15. The conclusions should be improved, including limitations and future lines of work.

  The authors are grateful to the reviewer for his suggestions. The limitations of the work expressed in the conclusions reflect the rigour of the manuscript's content; the outlook for future work highlights the completeness of the study. In this regard, we have improved the original conclusion. The changed text is located in lines 287-290 and has been highlighted.

 

16.Several ideas are proposed to the authors to complement this study: to analyse the behaviour against fire, to study the Young's modulus by ultrasound and the hardness of the material, to measure the resistance of the material against actions such as drilling or hanging of objects or to evaluate its mechanical behaviour after humidity-dryness cycles.

Thanks to the reviewer for his comments. We are working on similar aspects in our group, and your ideas have inspired us, and we will continue to add to this research in our subsequent work.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for great efforts

Reviewer 6 Report

Comments and Suggestions for Authors

The authors have made all the changes proposed by the reviewer. The article is suitable for publication in the journal.