Multi-Response Optimization of Semi-Lightweight Concrete Incorporating Expanded Polystyrene Beads
Round 1
Reviewer 1 Report
This paper revealed how the mix design parameters including the binder content, water-to-binder ratio, EPS content, and silica fume additions affect the mechanical properties and durability of SLC mixtures.
Overall of this paper is well-written. Only some of the comments on the point of what is new and the innovation points of this study to be revealed to all reader. Also, how reliable of specific method that you used to identified the relationship of the investigated factors? In case of the other cementitious mixtures, how effectiveness of this study method and factors ?
Minor correction
Author Response
The authors express their gratitude to the reviewer for providing valuable feedback and comments. The study's innovative aspects are centered on the relevance of considering multiple mix parameter criteria in order to enhance the performance and durability of semi-lightweight concrete mixtures. The authors have emphasized the novelty of this work in the Abstract section as well as at end of the Introduction…. such as noted in lines 131-134: “These findings can be of interest to civil engineers and contractors as they showcase the advanced performance of EPS-modified SLC while promoting its use as a sustainable lightweight material in structural applications.”
Regarding the reliability of the methods, the authors have incorporated several references from the literature to reinforce the efficiency and reliable use of the TOPSIS method to assess the multi-responses of cementitious materials used in the industry. For example, please refer to lines 116-122: “As such, multicriteria optimization methods, such as technique for order of preference by similarity to ideal solution (TOPSIS), have been successful in finding the optimal scenarios for designing engineering materials while considering various operation criteria and saving testing costs and time [31–33]. Despite the effectiveness of these methods, no research has yet explored the optimization and performance of lightweight concrete incorporating EPS as aggregate materials.”
Also, for example, throughout lines 112-114, the authors used this method to assess the multi-responses of geopolymer mortars including the optimization of their properties. Through these investigations, it was concluded that such methods can be successfully used to optimize the performance of geopolymer concrete/mortar while minimizing costs and reducing the number of required specimens. Please refer to lines 112-114: “The method uses orthogonal arrays to optimize these experiments systematically and efficiently, thus reducing the number of experiments needed to obtain meaningful results [29,30].”
Reviewer 2 Report
The article is well written and easy to read, in some places it is difficult to understand the explanation of the results specifically for a non-expert (especially in the final ANOVA part) however I would recommend publication after major revisions:
The Taguchi table and the 9 experiments are not well clarified in the text. I would suggest making a colored table similar to the one in the article: 10.1016/j.cemconcomp.2018.02.007, so that each parameter for each sample produced is clearly clarified
Figure 2 is complex to identify as a trend, I would suggest using a dot plot for both compression and density so as to highlight how there is no clear correlation between the two.
I would ask for a table with numerical results for all samples tested for Taguchi. It is not clear whether the best sample according to the criteria used in the experimental design was prepared or not.
In relation to figure 9, I would suggest writing in the text that in any case the best result is always at the top, because even if the wording is "smaller is better" in any case from the calculation usually takes the highest point.
Have you considered using another correlation method for the parameters you have chosen to observe which of them has weight relative to others such as Spearman's rank correlation coefficient?
Line 271 there is a typos m3
Author Response
1-Response: The authors thank the reviewer for the positive feedback and constructive comments. The authors hope that the revised manuscript addresses the reviewer’s comments. The line numbering mentioned in the response refers to that in the annotated revised manuscript.
2-Response: The authors express their gratitude to the reviewer for his/her valuable suggestions. Nevertheless, they implemented a mix codification system to ensure that each parameter is identifiable. Please refer to:
L166-170: “The proportions of SLC mixtures are summarized in Table 2; the mixtures are labeled xC-yW-vE-zS, where x is the binder content (kg/m3), y is w/b, v is EPS content (kg/m3), and z is the SF replacement rate (% of cement mass). For instance, mix 3 (325C-0.45W-3E-8S) represents a concrete mix made with a binder content of 325 kg/m3, w/b of 0.45, EPS content of 3 kg/m3, and SF replacement rate of 8%.”
3-Response: Thank you for your suggestion. As a matter of fact, the authors objective was to reduce the number of illustrations in the manuscript by combining the f'c and density measurements in 1 figure. Yet, it is seen when the EPS content increases to 3 kg/m3 that both measurements start to significantly decrease. In addition, the authors have introduced in Eq. 3 the relationship that link f'c to density.
4-Response: We appreciate your comment. The outcomes of the Taguchi and control mix experiments are all summarized in Table 3. The TOPSIS multicriteria method was utilized to identify the optimal mixture. Furthermore, the regression equations presented in section 3.6.2 can be used to predict the mechanical properties and durability of the optimal mixture.
5-Response: We appreciate your suggestion, and in response, we have updated the text to provide clarification on the best results. The revised text now reads:
L373-374: “It is important to mention that the optimal level of each factor corresponded to the "larger is better" approach.”
6-Response: Thank you for your question. We have explored various statistical methods in our study, including Spearman's rank correlation coefficient, to determine the weight and significance of the observed parameters relative to each other. However, based on our analysis, we have found that the TOPSIS multicriteria method was the most appropriate approach to address the research objectives and achieve the desired outcomes.
7-Response: Thank you for bringing that to our attention. The typos have been corrected.
L290: “3 kg/m3 of EPS. In general, the mixtures can be ranked as good to excellent [55,56].”
Reviewer 3 Report
This is an interesting manuscript which investigates the effect of various mix design parameters on the mechanical properties and durability of expanded polystyrene modified semi-lightweight concrete.
Although the English language used in the article is not bad, a revision would be advisable because the manuscript is difficult to follow.
Descriptions of the references should be extended. For example: “Concrete is widely used in the building industry; its strength and durability make it 29 suitable for a wide range of applications requiring resistance to heavy loads and harsh 30 weather conditions [1–3].” there are 3 references, but the reader does not know what they refer to; the same for [4-6]; [6, 11, 12]; [13-15]…
You should introduce all the abbreviations used in the paper in the nomenclature; nomenclature should be listed between the abstract and the introduction.
From these reasons, I think that this manuscript, after a minor revision, could be accepted to be published by the Sustainability journal.
Although the English language used in the article is not bad, a revision would be advisable because the manuscript is difficult to follow.
Author Response
1-Response: The authors thank the reviewer for the constructive feedback and comments. The authors have addressed the comments in the revised manuscript and hope that the changes made warrant its acceptance for publication. The line numbering in the response refers to those in the revised manuscript.
2-Response: Thank you for your feedback. We acknowledge that the manuscript may be difficult to follow at times and we appreciate your suggestion to revise the language. We will take your feedback into consideration and make the necessary improvements to enhance the readability and coherence of the article.
3-Response: In agreement with the reviewer, the authors updated several references in the text, and the revised text now reads:
L44-45: “In fact, extending the service life of concrete structures is an essential strategy to meet the requirements of the construction sector [3].”
L50-52: “Compared to traditional concrete, lightweight concrete offers several advantages, such as high energy dissipation under impact loading and a high tensile strength-to-weight ratio [6].”
L65-67: “EPS aggregates have lower mechanical properties and stiffness, causing lightweight concrete with EPS to have a higher drying shrinkage compared to normal-weight concrete [15].”
4-Response: Thank you for the suggestion. A nomenclature is added to the manuscript.
5-Response: Thank you for your positive feedback on the manuscript. We appreciate your suggestion that the manuscript be accepted for publication in the Sustainability journal after a minor revision.
Round 2
Reviewer 2 Report
Acceptable.
