The Influence of Water/Binder Ratio on the Mechanical Properties of Lime-Based Mortars with White Portland Cement
Round 1
Reviewer 1 Report
CRYSTALS-1324904-The influence of water/binder ratio on the mechanical properties of lime-based mortars with white Portland cement
General comments
The manuscript reports on the maintenance of heritage masonry, by experimenting on the influence of water/binder ratio of lime mortars incorporating low quantities of Portland cement. The authors have used White Portland cement, but they have not provided a justification for the use of this specific variety of cement. The manuscript may generate interest to researchers into cementitious systems in general, and especially to those with special interests in mortars and into heritage mortars. It is however not very well-written and there are far too many issues that have commulatively reduced the quality of the manuscript significantly.
In the abstract, the authors have referred to the water/binder (w/b) ratio of the composite mortar containing both lime and cement as w/b=water/lime + water/cement. It is suggested that this wrong, and it is not the same as w/b=water / (lime + Cement) which this reviewer deems to be the correct version. Some simple arithmetic using a hypothetical or real composite mortar mix will prove this is the case.
The authors have not introduced some of the figures in the text, for example Figure 1, before their presentation. For Figure 1 for example, the authors have not directed the reader to the features that are to be observed from the figure. Also, on figures, the graphs in the manuscript do not have axis titles, and only units are offered.
The authors have mixed present and past tenses in their narrative. It is recommended that for work already carried out, past tenses be adopted throughout the manuscript. There are error messages throughout the manuscript, which could have been rectified before submission.
In reporting compressive strength results, or indeed any other results on hydrated or hydraulic or cementitious mixtures, it is always necessary to mention the age at which the results are being reported. Hence, in Section 3.1, it would have been appropriate to state that the strength referred to here is at 28 days of curing.
Most of the issues of concern may be deemed minor, but the damage is cumulative, and eventually takes a toll on overall quality. An annotated copy is attached to illustrate some of the areas where issues of concern were observed.
Special comments
- Figure 1. Ideally this figure should compare the appearance of the same location, and at the same scale. Fig. 1(a) shows about four courses of masonry, while Fig 1 (b) shows only about 3 courses. There is no way the two can be related in order to see the “before” and “after” effects. The situation is exacerbated by the authors’ lack of reference to the figure and/or offering a discussion on the same to compare the effects.
- Line 88. It is helpful to the reader to get a justification, no matter how trivial, for the use of White Portland cement.
- Figs 2-7 – y-axis title is necessary.
- Line 158. It is likely that the figure referred to here is Figure 2 rather than Figure 1. Please confirm.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
The article presents the results of tests of lime mortar used for repairs of historic buildings. The authors conducted a study of the influence of the water / binder ratio on the mortar strength and permeability. An air-entraining agent was used to improve permeability. It was confirmed that the addition of small amounts of cement and the reduction of the w / b ratio improved the compressive strength without affecting the water permeability. In contrast, the addition of small amounts of AEG had no effect on strength and permeability. Below I present my comments, the inclusion of which should improve the quality of the publication:
1. Chapter 1: The State of the Art Overview is good. There is no clearly formulated goal of the work. It is necessary to emphasize one's own research achievement filling the gap in the state of knowledge.
2. Chapter 2: The test program lacks information on the number of samples tested.
3. Chapter 3: Test results should be supplemented with information on the scattering of results. Why the tests were not done after 2 days 3 days 14 days. This information is important for maintenance work. There is no statistical analysis showing that the obtained strengths differed significantly. Comparing the mean results does not reflect the reality, especially with a limited number of samples. The effect of carbonation was investigated using the index method. In addition to photography, it is essential to compare the results with the pattern. The proposed method, although the fastest, is the least accurate. The authors should add a comment about the method used and at least mention the literature about what and other methods can be used to test carbonation. Statistical analysis should also include the results of absorption studies.
4. Chapter 4: The discussion of results lacks information on the change in plow structure resulting from the use of variable proportions of components. I understand that the authors do not have SEM images, but the high-magnification structure has been studied and the lattice changes are fairly well understood.
5. Chapter 5: There are no directions for further research. I believe that the most appropriate would be to test the adhesion of the mortar to masonry units, and even small samples of masonry according to EN 1052-1. Additional testing of other air entrainers may also be performed.
General attention!
In many places (e.g. lines 100, 135 etc.) there were used automatic references that were not associated with the list of publications. It is impossible to check the correctness of references !!!
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
CRYSTALS-1324904R1-The influence of water/binder ratio on the mechanical properties of lime-based mortars with white Portland cement
General comments
The authors have taken reviewer comments constructively and effected all the recommendations made. The quality of the revised manuscript is far better than that of the original submission. A few minor issues have been noticed as shown in the special comments section, and also an annotated copy is attached.
Special comments
- Line 63/64. It is recommended that “The Figure 1(a) was taken….” be changed to “Figure 1(a) was taken…..”
- Line 72. It is recommended that “The Figure 1(b)…..” be changed to “Figure 1(b)…..”
- The first bullet point still needs further revision. It is not clear what “these small amounts actually degrade material” means or refers to. Small amounts of what?
Comments for author File: Comments.pdf
Author Response
- Line 63/64. It is recommended that “The Figure 1(a) was taken….” be changed to “Figure 1(a) was taken…..”. Remark is accepted and the text is corrected.
- Line 72. It is recommended that “The Figure 1(b)…..” be changed to “Figure 1(b)…..”. Remark is accepted and the text is corrected.
- The first bullet point still needs further revision. It is not clear what “these small amounts actually degrade material” means or refers to. Small amounts of what? Remark is accepted. The sentence is corrected to read as follows: “these small amounts of WPC actually degrade material”.
In the Table 3, we noticed one typo: for the specimen KC20, the value t was entered as 050 - now it is corrected as 150 minutes.
The authors would like to thank the Reviewer for the effort and remarks that significantly improved the manuscript.
Reviewer 2 Report
After the changes and comments made, I have no comments.
Author Response
In the Table 3, we noticed one typo: for the specimen KC20, the value t was entered as 050 - now it is corrected as 150 minutes.
The authors would like to thank the Reviewer for the effort and remarks that significantly improved the manuscript.
