The Influence of Graphene Oxide on the Performance of Concrete: A Quantitative Analysis of Mechanical and Microstructural Properties

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. In the abstract, the exact contribution of GO to each property should be briefly explained (very brief explanation). For example, how does the 16.28% reduction in pore and crack size relate to the structural integrity of the material?
2. What are the limitations of GO in enhancing concrete properties? This should be briefly mentioned in the introduction section.
3. The novelty of the work should be clearly mentioned at the end of the introduction part.
4. In the introduction section, the following sentence needs a reference: "These cracks can originate both from internal stresses and external restraints during the hardening process. On the other hand, porosity is a determining factor in the mechanical behavior of concrete, since it influences its physical and structural properties". Refer to the following paper: https://doi.org/10.1002/suco.202000214.
5. The authors should clarify the reasons behind choosing the specific GO concentrations (0.00%, 0.05%, 0.10%, 0.15%, and 0.20%)? 
6. How was the dispersion of GO quantified to ensure uniformity in all the samples?
7. What is the rationale behind using the plasticizer in the dispersion process? I could not figure out the relation here!
8. The results show a decrease in mechanical performance at higher GO dosages (0.10% and above). Please explain the possible reasons behind this decrease? 
9. Was there any variation in the workability of the mixtures at higher GO dosages?
10. How consistent were the results of SEM and EDS across different batches of concrete? Were there any outliers or unusual observations that might affect the overall conclusion?
11. In FTIR analysis, the increase in absorbance with GO addition is noted. Clarify the potential implications of this increase?
12. Are there any implications of the reduction in portlandite content in the GO-modified concrete for long-term durability?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents an investigation into the effect of graphene oxide (GO) on concrete’s mechanical and microstructural properties. The study evaluates compressive strength, flexural strength, indirect tensile strength, and elastic modulus for different GO dosages. Microstructural assessments, including SEM, EDS, FTIR, TGA, and XRD, provide insights into the material's densification and hydration kinetics. Overall, it is well-structured, with a strong methodology and thorough experimental analysis. The detailed comments are given as follows.

1. The study identifies 0.05% as the optimal GO dosage for mechanical improvement. Could the authors provide additional validation of this finding, such as statistical confidence intervals or reproducibility tests across different mix designs?
2. The study reports a decline in mechanical performance beyond 0.05% GO. Could the authors elaborate on the specific mechanisms causing this reduction? Is it due to agglomeration, workability issues, or another factor?
3. The microstructural analysis primarily focuses on final hydration stages. Have the authors investigated early hydration effects of GO at 1–3 days? This could provide further insights into how GO affects nucleation and early-stage hydration.
4. While the paper discusses dispersion techniques using ultrasonic treatment and plasticizers, no direct quantitative analysis of dispersion quality is presented. Can the authors include dispersion measurements to confirm uniform GO distribution?
5. The EDS and XRD results suggest improved hydration kinetics and an increased Ca/Si ratio. Can the authors confirm whether GO acts primarily as a nucleation site for C-S-H formation, or if it also influences chemical reactions involving portlandite transformation?
6. The TGA results indicate mass loss due to GO decomposition at elevated temperatures. How does this impact the fire resistance of concrete? Is there a risk of performance deterioration under high-temperature exposure?

Author Response

Please see the attachment.

Author Response File: Author Response.docx