Experimental Investigation and Numerical Model for Chloride Diffusivity of Long-Age Fly Ash Cement Slurry
Round 1
Reviewer 1 Report
In this manuscript, the results of this research are conveyed thoughtfully and completely, and they are consistent with the experimental findings. However, the authors failed to explain and draw out the novelty of the work, this aspect needs to be improved. This work is worthwhile to be publish in this journal after major revision. The following issues should be addressed:
1. Introduction is well-organized but the importance and novelty of the research should be highlighted and more clearly stated. The authors should give some examples of works in the bibliography, to clear the advantage of their work in comparison with those works.
2. The novelty needs to refinement and should be highlighted in the introduction part.
3. Many spelling and formatting typos in this paper, and the authors should check and revise them thoroughly.
4. the authors should check the labeling of figure and captions.
5. All equation should be revised, which contain some typo error.
6. some references need to be updated such as ref. no. 5, 8, 11, 12, …etc, please revise all references.
7. In Introduction part, some relative reports references could be helped: https://doi.org/10.1016/j.jobe.2022.104869, https://doi.org/10.3390/math11132998.
Hence, I recommend it accepted for publication after Major revisions.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper addresses an important and practically relevant matter. By computer simulation of the microstructure of cement paste with blended fly ash and the random walk algorithm is proposed for calculating the chloride transport performance of concrete. The simulation results show a good fit with the experimental data. Overall, this is an interesting and well-organized paper which provides some new ideas for investigating the effects of fly ash supplement on chloride diffusivity of cement paste by by experiments and numerical method. Minor revision should be made before this paper can be published.
1. There are a few spelling mistakes in the paper. Thoroughly checking for the possible errors in the paper should be draw.
2. The addition of fly ash not only affects the durability of concrete, but also affects its mechanical properties. Thus, relevant research progress on the influence of fly ash on pore structural, fractal analysis and mechanical properties needs to be replenished in the section of “introduction”，such as The Influence of fly ash dosages on the permeability, pore structure and fractal features of face slab concret; Comparison between the influence of finely ground phosphorous slag and fly ash on frost resistance, pore structures and fractal features of hydraulic concrete
3. Line 145: Why the specimens should be immersed in saturated Ca(OH)2 solution? The author needs to provide necessary explanations.
4. Line 327: K0 and K1 represent the reaction rate coefficients of cement and fly ash particles. What confuses me is the definition of Kc and Kf in the Eqs. (17) and (18).
5. Line 402: What is the definition of α? Is it the degree of hydration?
The Language is good.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
In the introduction, the authors cite a number of references and should describe what the problem is. Also, it is necessary to describe what is different between this paper and previous papers in terms of novelty.
Table 2 should also include values for Na2O, K2O, and loss on ignition.
Particle size distributions for fly ash and cement should be posted.
The method for measuring the diffusion coefficient of chloride ion should not only be cited, but the details of how it was measured should be described.
Figure 2 should also describe the variability of the measurement results. Also, describe the validity of the measurement results compared to the results of previous studies.
Are the cement and fly ash particle size distributions shown in Figure 4 the same as those measured?
In Figure 6, which is calcium hydroxide and which is CSH? I have never seen calcium hydroxide in a spherical shape in experimental results.
I have never seen the word 'cement slurry'.
Figure 7 shows a comparison of some of the results with experimental results, but please compare the results for other conditions as well. Also compare the amount of calcium hydroxide, CSH, and capillary porosity with the experimental results.
What is the physical meaning of radius 'R'? Explain.
Discuss the validity of the values of Dif and Dhf in Tbale 3.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Why does Figure 1 show a particle range of only 30 µm?
In Figure 7, calcium hydroxide is still represented as a sphere. This is very different from reality.
Comparison of capillary porosity is important, but other products are also important. This is because gel porosity is included in C-S-H.
Author Response
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Round 3
Reviewer 3 Report
No.
