Assessment of the Chemical Reactivity of Brazilian Stone Cutting Plant Waste into Cementitious Matrices
, Paulo Ricardo de Matos 3, Tatiane Benvenuti 1, Laurence Colares Magalhães 4, Antonio Pedro Novaes de Oliveira 5, José Renato de Castro Pessôa 1, Lisandro Simão 6 and Marcelo Tramontin Souza 1,*
Round 1
Reviewer 1 Report
1- Abstract: focus on the ornamental stone wastes located in brazil and compared with calcium carbonate as well as quartz, where the results prove that 10 % was positively enhance and workability as well as compressive strength. Why authors did not try 5 % which may results in more enhancement.
2- Introduction section is too long and need for shortening
3- Section 3; table 2; I think this table is not important as its place should be in the introduction rather than results.
4- Section 3.2; line 281; replace “ stress of the pates ----“ into “stress of the pastes ---“
5- Page 11; line 322 and 323; should be In English
6- The XRD peak of calcite at 29.4 not 29. 3o
7- Conclusion; is too long and need to be concise with the main findings resulted from the paper.
Author Response
Dear reviewer, thank you for your careful reading and contributions. The comments and suggestions were constructive in improving our manuscript. We feel that we have addressed the reviewer's concerns, and as a result, the manuscript quality was improved, now meeting the quality requirements of the Sustainability journal. Changes are highlighted throughout the manuscript. This document follows our responses to reviewer comments and questions.
Abstract: focus on the ornamental stone wastes located in Brazil and compared with calcium carbonate as well as quartz, where the results prove that 10 % was positively enhance and workability as well as compressive strength. Why authors did not try 5 % which may result in more enhancement.
Reply: Note that we’ve tried 5 wt.% (see Fig. 8b). Compressive strength tests showed similar results with 10 wt.% of both both DSW-d and DSW-m.
2- Introduction section is too long and need for shortening
Reply: Agreed. We shortened the section.
3- Section 3; table 2; I think this table is not important as its place should be in the introduction rather than results.
Reply: We moved Table 2 to the Materials and methods section right after mentioning the X-ray fluorescence and X-ray diffraction.
4- Section 3.2; line 281; replace “stress of the pates“ into “stress of the pastes“
Reply: Done! Thank you!
5- Page 11; line 322 and 323; should be In English
Reply: Thank you! The language was updated.
6- The XRD peak of calcite at 29.4 not 29.3°
Reply: It was corrected. Thank you! Please note that the diffracted peak position may vary slightly from its theoretical position due to sample shift (or sample displacement).
7- Conclusion; is too long and need to be concise with the main findings resulted from the paper.
Reply: The conclusion was shortened, as suggested.
Reviewer 2 Report
The paper explores a very important research gap that exists in literature regarding the interaction of marble waste with cement. However, the sample chosen for this purpose does not provide the authors with the right opportunity to completely explore this domain. Had the sample been a pure marble waste product then this work will reach places after publication. Nevertheless, the paper has to be improved in the following aspects before its publication:
The keywords used like circular economy, sustainability, recycling do not do justice here. The article largely deals with chemical interaction of marble waste with cement. So, the authors must consider rephrasing the title and keywords.
The language of the paper can be improved. Usage of words is inappropriate at a few places in the manuscript.
Line 68 – 69: There are 5 stages mentioned.
Please provide a citation for Lines 89 to 95.
What has the reference number 11 got to do with the source of the waste?
The study never explicitly mentions that the DSW used in this study used is of marble origin until section 2.1. Why?
Reference 22 is a work where marble waste was used as a replacement of cement. But it has been discussed under section 1.2.1. Why?
The summation of the mineralogical compounds for cement mentioned in table is very far off from a value of 100%. Why?
There is a typo if Fig. 6A regarding DSW.
Check line 322.
Rephrase line 340 – 341.
Please mention the limitations and future scope of work at the end of the paper.
Author Response
Dear reviewer, thank you for your careful reading and contributions. The comments and suggestions were constructive in improving our manuscript. We feel that we have addressed the reviewer's concerns, and as a result, the manuscript quality was improved, now meeting the quality requirements of the Sustainability journal. Changes are highlighted throughout the manuscript. This document follows our responses to reviewer comments and questions.
The paper explores a very important research gap that exists in literature regarding the interaction of marble waste with cement. However, the sample chosen for this purpose does not provide the authors with the right opportunity to completely explore this domain. Had the sample been a pure marble waste product then this work will reach places after publication. Nevertheless, the paper has to be improved in the following aspects before its publication:
You are right. In Brazil, granites are predominant as marble is in Europe. To overcome this limitation, we compared with pure calcium carbonate (considering the particle size effect) to simulate the behaviour of cement pastes with pure marble waste.
The keywords used like circular economy, sustainability, recycling do not do justice here. The article largely deals with chemical interaction of marble waste with cement. So, the authors must consider rephrasing the title and keywords.
Thank you for the suggestion! We changed the article title to “Assessment of the chemical reactivity of Brazilian stone cutting plant waste into cementitious matrices” and included the keyword “chemical reactivity”. The terms circular economy, sustainability, and recycling are chosen to get visibility since these are among the most search terms linked to the field. Even so, we eliminate such keywords to attempt the reviewer's concern.
The language of the paper can be improved. Usage of words is inappropriate at a few places in the manuscript.
We carefully proofread the manuscript and corrected typos, articles, punctuation, and the use of inappropriate words in the text.
Line 68 – 69: There are 5 stages mentioned.
We eliminate sawing as it is analogous to cutting.
Please provide a citation for Lines 89 to 95.
Ok! Citation was inserted.
What has the reference number 11 got to do with the source of the waste?
We eliminated it. Thank you!
The study never explicitly mentions that the DSW used in this study used is of marble origin until section 2.1. Why?
Actually, the DSW used in this study is mostly granite, as the carbonate phase is secondary. Quartz, mullite and anorthoclase are predominant. This has motivated us to compare our DSW with pure calcium carbonate – considering the particle size – to simulate DSW mainly composed of marble.
Reference 22 is a work where marble waste was used as a replacement of cement. But it has been discussed under section 1.2.1. Why?
You are right. We changed to the next section (DSW replacing the cement).
The summation of the mineralogical compounds for cement mentioned in table is very far off from a value of 100%. Why?
We corrected the mineralogical composition. The previous measure was made on a cement paste (tested for in-situ X-ray diffraction) from an earlier study using the same cement. The updated composition disregards the water presence (anhydrous cement).
There is a typo if Fig. 6A regarding DSW.
Thank you! The typo was corrected.
Check line 322.
The phrase was translated. Thank you!
Rephrase line 340 – 341.
Ok! The original sentence
“As the amount of reacted calcite to form carboaluminates is limited by the availability of the alumina, an excess of calcium carbonate will not be reactive with aluminate (C3A)”
was altered to
“Excess calcium carbonate will not be reactive with aluminate (C3A) since the formation of carboaluminates is limited by the availability of alumina.”
Please mention the limitations and future scope of work at the end of the paper.
All right! A new statement was written at the end of the conclusion, as follows:
“Lastly, these findings need to be validated in concrete mixtures, since the presence of aggregates can interfere in the rheological and mechanical properties.”
Reviewer 3 Report
The paper in question raises an interesting issue of repurposing landfill material as a component of cementitious composites. However, several revisions need to be made in order to improve the quality of the article. Most notably, the Authors did not include a table with compositions of cement pastes. Table 2 is quite difficult to read and needs to be reorganized. And most of all, the section about rheological tests performed by Authors needs to be improved. Specific comments are included in the attached pdf.
Comments for author File: 
Comments.pdf
Author Response
Dear reviewer, thank you for your careful reading and contributions. The comments and suggestions were constructive in improving our manuscript. We feel that we have addressed the reviewer's concerns, and as a result, the manuscript quality was improved, now meeting the quality requirements of the Sustainability journal. Changes are highlighted throughout the manuscript. This document follows our responses to reviewer comments and questions. As the suggestions were made directly in the pdf version, we provided answers indicating the lines where the same suggestions are inserted.
Line 24-26
The statement was updated:
“The problems generated by the ornamental stone extraction and processing industry caused by the inadequate disposal of this waste can negatively affect rivers, lakes, streams, and even natural water reservoirs.”
Line 29
The statement was updated:
“The results showed that DSW can be used in cement formulations, and its reactivity is governed by the size of the particles.”
Line 49-60
In order to address the reviewers' suggestions about the long introduction section, these lines have been deleted.
Line 105-106
To avoid mentioning all references highlighted in the following sections, which would make it repetitive, we changed the sentence to “Detailed in the sequence, the literature survey shows that the ideal SW content relies on its specific surface area, particle size distribution, and chemical composition.”
Line 130-131
The statement was updated:
“Corinaldesi et al. [23] achieved maximum mechanical strength (~52 MPa) with 10% DSW instead of sand in cement mortars (w/c of 0.5), especially due to the filler effect. For Vardhan et al. [24], the substitution level for maximum strength and lowest permeability in concrete mixtures with DSW replacing the fine aggregates was 40%.”
Line 193
A table was added.
Table 2. Formulations tested.
|
Samples |
Cement |
w/c |
DSW-d |
DSW-m |
Quartz |
Calcium carbonate |
|
1 |
95 |
0.4 |
5 |
|||
|
2 |
95 |
0.4 |
5 |
|||
|
3 |
90 |
0.4 |
10 |
|||
|
4 |
90 |
0.4 |
10 |
|||
|
5 |
90 |
0.4 |
10 |
|||
|
6 |
90 |
0.4 |
10 |
|||
|
7 |
80 |
0.4 |
20 |
|||
|
8 |
80 |
0.4 |
20 |
|||
|
9 |
70 |
0.4 |
30 |
|||
|
10 |
70 |
0.4 |
30 |
Line 198
Flow curves coupled with models such as Bingham and HB are not as accurate for determining yield stress as the shear test growth adopted in the manuscript, especially for time-resolved measurements. This is because fitting the flow curve (with the models mentioned) to determine the yield stress relies on the extrapolation of the shear rate down to a “zero shear rate”, and the system is under a dynamic (flow) state. In this scenario, the internal structuration of the sample (due to surface interactions and/or the formation of hydrated products) is destroyed by shearing, so part of the increase in yield stress over time is actually lost. In turn, flow curves are best for calculating viscosity or thixotropy/hysteresis area. We emphasize that we focused on the yield stress parameter to assess the chemical interaction of materials over time.
We included additional information in the text concerning the previous preparation of samples and references which used this method.
“The pastes were previously stirred for 3 min at 500 rpm before being cast in the viscosimeter. The test was initiated by applying a pre-shear of 100 s-1 for 1 min to equalize the pastes, followed by 1 min of rest.”
Line 213
“The mechanical performance was evaluated by compressive strength tests following the ABNT NBR 5739 Brazilian standard.” We added the Brazilian standard.
As we were working with cement pastes, and only with fine materials (no course aggregates), there was no need for large specimens, which would require the preparation of larger amounts of raw materials.
Line 223
We changed the section title to “Physicochemical characteristics of the raw materials”.
Line 230
The nomenclatures were described in the lines 171 “The collected sample was dried at 110 ºC for 24 h and de-agglomerated (named DSW-)…” and 182 “The waste was also evaluated after milling (named DSW-m)…”
Table 1: We changed the density symbol and added the type of density.
Table 2 was rearranged.
Line 262-263
As an inert material, quartz was used and compared to DSW-d to evaluate the cement replacement. It would not be fair to compare pastes with DSW-d to pastes with only cement since the content of cement is different. That was the role of quartz.
Calcium carbonate was compared to DSW-m, with similar particle sizes. Calcium carbonate is known to be reactive when particle sizes are small enough (<30 um), and thus, it was compared to assess how reactive is DSW when milled (DSW-m). The mineralogical changes in cement were also carefully investigated since carbonate phases is secondary in DSW.
“Quartz, as an inert material and with a similar particle size, will allow determining if DSW-d is reactive (with “as received” particle size). On the other hand, calcium carbonate tends to be reactive with cement (for very small particle sizes), which will be compared to DSW-m. Thus, DSW-m was processed to match the fineness of calcium carbonate.”
Line 276
Yield stress was not calculated, but measured. The slurry is placed into the viscometer using plate-to-plate geometry. The shear rate is constant at the minimum possible (~0.02 s-1), and the shear stress is recorded over time. A minute and a half are usually enough to record the maximum shear stress, which represents the yield stress (see figure below). This is the most accurate method for measuring the yield stress of cement pastes; please see above the comments for “Line 198”. As the shear rate is very low, it is possible to use the same sample after the recovery time between each measurement. For the first measurement, pre-shearing was performed on the equipment to break up the agglomerates and standardize/erase the shear history of the samples.
Additional information can be found in the following paper:
“On the measurement of evolution of structural build-up of cement paste with time by static yield stress test vs. small amplitude oscillatory shear test”
http://dx.doi.org/10.1016/j.cemconres.2017.05.014
Line 294
“The test consisted of applying a very low shear rate (in this, case 0.02 s-1 – the lowest shear rate allowed by the equipment) while the shear stress is recorded for 180 s. The pastes were previously stirred for 3 min at 500 rpm before being cast in the viscosimeter. The test was initiated by applying a pre-shear of 100 s-1 for 1 min to equalize the pastes, followed by 1 min of rest. Five measurements were recorded at 5 min intervals in each paste over a limited period of 60 min of analysis.”
We added additional information to make it clearer.
Line 300
The sentence was rewritten with the compositions as suggested.
“Furthermore, the heat flow is reduced with increasing waste contents (from 10% to 20% DSW-d).”
Line 307
References were inserted.
Line 310-312
The sentence was rewritten as follows:
“In this sense, it is assumed that DSWs from marble processing (higher CaCO3 content) are also capable of accelerating the hydration process, if they are fine enough.”
Line 322
The sentence was translated.
Figure 8. The red line represents the average compressive strength for a standard sample at 28 days of hydration. We added information in the figure caption.
References were updated.
Round 2
Reviewer 3 Report
The authors have revised the article sufficiently. However, additional information needs to be added to table 2 - water content and how it was calculated - in other words, was w/c calculated as cement-to-water ratio or (cement + DSW/quartz/calciumcarb.)/ water?
Also, the mass amount of all components per m3 is missing. I assume due to differences in the density between cement and DSW, the mass amount of water is going to differ between different series. As the Authors did not modify viscosity with plasticizers, the difference in the water amount between different series probably contributed to differences in the yield stress. I believe that the addition of the short paragraph about this issue (and why the Authors decided to design w/c in a specific way) would add additional merit to the paper.
Author Response
The response is in the attached document.
Author Response File: Author Response.pdf
