Effect of Additives, Cement Type, and Foam Amount on the Properties of Foamed Concrete Developed with Civil Construction Waste
, Patrícia Favaretto 1, Rodrigo de Almeida Silva 1,*, Gelsa Edith Navarro Hidalgo 2, Rejane M. C. Tubino 3 and Francieli Tiecher 1Round 1
Reviewer 1 Report
In this paper the mechanical and thermal properties of foam concrete have been investigated. The topic is interesting and worthy of investigation. However, there are several issues within the manuscript which should be addressed appropriately. Discussion on the results needs further expansion with reference to the similar literature published earlier. Also, the Introduction is not well up to date and many very old papers have been cited.
Following bulleted points summarize the major and minor comments on the paper.
1. Reference 1 is inaccessible and more importantly, irrelevant. Instead, please consider citing Hu W. et al. Investigation of the strength development of cast-in-place geopolymer piles with heating systems. Journal of Cleaner Production 2019;215:1481–9. Also, mention the associated carbon dioxide emissions with concrete.
2. Line 45 page 1, Please also note that these inferior properties are attributed to the adhered or bonded mortar (Kim Y. et al. Influence of bonded mortar of recycled concrete aggregates on interfacial characteristics – Porosity assessment based on pore segmentation from backscattered electron image analysis. Construction and Building Materials 2019;212:149–63) and must be mentioned.
3. Instead of reference 10, (line 57 page 1), please cite a review paper on LWA.
4. The Introduction section fails to emphasize the research gap which motivates this study. Please revise appropriately.
5. The chemical properties of cements should better be indicated in term of Bogue composition. The effects of dicalcium silicate and tricalcium silicate on the hydrated concrete properties will then be easily indicated.
6. Figure 1; please indicate the standard for the limits in the legend or caption.
7. Line 121-122; please mention the brand/mark and manufacturer of amide 90.
8. The heading of Section 2.4 should be changed to “Experimental Design”.
9. The most critical issue is the extremely meagre strength with high density and adequate thermal conductivity, for these concrete specimens. Please check the following two papers where better strength and thermal conductivity results were obtained. These should be mentioned and discussed in the results section as well. The usefulness of a research is corroborated only if it adds something to the existing knowledge base. If something better already exists, it deceits the purpose of current research.
i. Hanif A. et al. Green lightweight cementitious composite incorporating aerogels and fly ash cenospheres - Mechanical and thermal insulating properties. Construction and Building Materials 2016;116:422–30.
ii. Morales-Conde, M. J. et al. Physical and mechanical properties of wood-gypsum composites from demolition material in rehabilitation works. Construction and Building Materials 2016;114:6–14.
iii. Abbas N. et al. Silica aerogel derived from rice husk: an aggregate replacer for lightweight and thermally insulating cement-based composites. Construction and Building Materials 2019;195:312–22.
10. Water absorption and Air void results should be further explained with reference to adhered or bonded mortar (as already mentioned in comment # 3 above).
11. Currently, the Conclusions are merely summarizing the results which is just the repetition. Please revise thoroughly, this section. Please include the applicability, and future work for further improvement.
Author Response
Author's Notes to Reviewer are in the attached file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Although the article deals with an interesting topic " Effect of additives, cement type and foam amount on the properties of foamed concrete developed with civil construction waste". the way the article is currently presented need to be improved for acceptance. The authors must make a review of the following aspects:
- You must foreground the new features of your paper that improve the state of knowledge regarding (at the final of the introduction)
- Please, revise the terminology, i.e. specimen instead samples, test instead essay, etc… - It is necessary to indicate units in table 2.
- In the results and discussion paragraph you must compare the results obtained with the obtained in another works that have already been published.
The principal question is that the discussion paragraph must make comparing their results with the results obtained in two or three relevant papers for each property evaluated. There are many papers published about concrete manufactured with recycled aggregates from constructions and demolition waste. In that papers the compressive strength, the density, the water absorption and the air void are analysed. The authors must compare the results obtained for the properties previously mentioned with those obtained in two or three relevant papers.
Author Response
Author's Notes to Reviewer are in the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper has been revised appropriately. I recommend that it is accepted in current form
Reviewer 2 Report
Accept in present form
