Feasibility of using Waste Brine/Seawater and Sea Sand for the Production of Concrete: An Experimental Investigation from Mechanical Properties and Durability Perspectives
Round 1
Reviewer 1 Report
The study presented an interesting exploration/investigation about the effect of brine water, sea water and sea sand for producing concrete which becomes the need of the hour. The study provided the effect of the above-mentioned ingredients by testing the fresh property (workability), mechanical property (only compressive strength) and microscopic aspects (MIP, TGA, XRD and SEM). The efforts of the authors are highly appreciated.
1. The importance provided for macro level observations seems much lesser in par with the micro level observations. Hence, it is recommended to avoid inclusion of macro level investigation in the title or to include more discussions about the macro level investigations in the content of the paper.
2. Figure 2 highlighting the Gradation of sea sand is wrong. At present, the figure indicates the passing (%) for larger sieve size is lesser in comparison with smaller sized sieve which is not practically possible. It should be noted that the correct form of gradation curve will be similar to a mirror image of what is provided in the figure (an S- shaped curve).
3. Figure 2: Explain why the lower limit of Grade II does not meet 100% passing anywhere in the graph.
4. Line 197-198: It is suggested to highlight the reason (acceleration of cement hydration) along with the citing of reference. This can improve understanding.
5. Section 4.2: The study discussed that the compressive strength decreased due to the salinity effect. However, the effect of seawater cannot be simply explained by mentioning the salinity effect. The effect of leaching of the hydration products and the salt crystallization should be included as they play a predominant role.
6. Please explain how the compressive strength increases with the replacement of natural river sand with sea sand, sea water and brine water by microscopic observations.
7. Line 269: ‘The pore volume of gel pores in BSC with w/c’ does not provide any meaning. The sentence should be completed properly.
8. Line 427: ‘Among the three types of concrete, the calcium carbonate content was comparatively high’. The sentence seems incomplete.
9. Line 468: ‘The compressive strength difference was minor for BSC and SSC to OC, with the w/c ratio between 0.51 and 0.65’. The sentence requires rewriting to convey the information properly.
10. Give the expanded form for AFm. What is its significance in this context?
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Regarding to the paper entitled “Feasibility of using waste brine/seawater and sea sand for the production of concrete: An experimental investigation from macro and micro perspectives” that has been submitted to sustainability, here in follow some explanations in this matter are presented.
• Article innovation should be more explained clearly in comparison with other research works in this field.
• Explain more about executive applications, advantages, and disadvantages of using waste brine/seawater and sea sand for the production of concrete in Civil Engineering.
• Explain more about Section 3.2 Mercury intrusion porosimetry (MIP) and the device of the American Mike automatic mercury porosimeter.
• Present Figures with the better forms with more details.
• Present and compare implementation costs of using waste brine/seawater and sea sand for the production of concrete in Civil Engineering.
• Explain more interpretation and conclusion of results.
• Provide more references from recent years in relation to this topic.
• The English language of this manuscript should be improved.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors investigated the mechanical properties, durability performances, and microstructure characterizations of brine-sea sand concrete (BSC), seawater-sea sand concrete (SSC), and ordinary concrete (OC) with three different water-cement ratios. The topic is straightforward and potentially quite interesting to the readership with potential engineering applications. The experiments were carefully designed and carried out. The results can support the conclusions. It is recommended for publications given that the following comments are sufficiently addressed.
Technical:
1. Abstract. The abstract can be further improved. As it is now, the abstract is about 250 words, which is verbose. It should be more concise, specific, and better organized.
2. Page 5. Line 148. NYT 1377 is a method to test pH value for soils. Can it be applied to concrete? And how is a concrete pH value useful? A more traditional and accurate method would test the pH value of extracted pore solution. However, it might also not applicable for concrete at longer age.
3. Page 6, line 176. If the temperature range for TGA was up to 1000C (as shown in Figure 10), there is no way an alumina crucible would hold up. It has to be a platinum one. Please double check.
4. Section 4.5, 4.6 need better tiles. TGA and XRD are not “properties” of concrete. What they reveal (such as hydration product identification etc) matters. It is suggested the to merge 4.5 and 4.6, and change the title to “hydration product analysis and microstructures”.
5. Fig 14. I can see Figure 14 can be quite useful informative. However, it can be better executed. For example, what does alkali environment mean? More description is need in the text.
Editorial:
1. Overall image qualities need to be improved with lager fonts. Some of them are just hard to read…
2. Figure 13. In the Y-axis, anything about 100% does not make sense. Please make corrections. In addition, the legends are impossible to read, please use larger fonts.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
- The issues of English language grammar to be re-checked carefully.
