Utilizing Industrial By-Products for Sustainable Three-Dimensional-Printed Infrastructure Applications: A Comprehensive Review†
Round 1
Reviewer 1 Report
The use of industrial by-products in green cementitious composites for casting and 3D printed applications is not a novel idea. Despite numerous review papers on the topic, the authors failed to highlight any new contributions in their reviews.
· Sections 2.1 to 2.3: More information is needed to clearly introduce these alternative materials.
· A separate section is needed to introduce the 3D printing as well as the dis/advantage of 3D printing over conventional cast methods.
· Section 3: The authors should explain the effect of each by-product on the fresh property of the Cementous composites in a comprehensive way. For instance, how GGBS can enhance the buildability of the mixtures. What are the negative effects of using GGBS?
· The authors declared this to be a comprehensive review of the title. Consequently, it is expected that they provide distinct justifications for all the fresh and hardened properties. Authors are advised to utilize the following references:
https://doi.org/10.1016/j.cscm.2022.e01818 https://doi.org/10.1016/j.matdes.2021.109574
· The utilization of industrial by-products is particularly significant in the development of alkali-activated materials. However, the authors of the review neglected to mention or discuss this type of cementitious composites.
· The authors are suggested to add a sub-section on the application of 3D printing on the building renovation. Authors are advised to utilize the following references:
https://doi.org/10.1007/978-3-031-32309-6_7
The manuscript, in its current format, is inadequate and requires extensive revisions before it can be published
Moderate editing of English language required
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper reviews the use and effectiveness of supplementary cementitious materials (SCMs) in 3D printing of concrete. The authors started by introducing the three major SCM species, FA, slag, and SF, going through each of their physical and chemical properties, talked about their influence on both fresh and hardened concrete and 3D printability, visited example applications of 3D-printed concrete, and finally mentioned environmental and economic considerations. However, the depth of discussion requires improvement.
Besides, the English language may be improved to express the meaning of each sentence more clearly and precisely and to enhance the coherence between sentences. Multiple places seem to be missing references.
Specific comments include:
Line 35: 0.9% does not make sense.
Line 38-40: references are needed to support the statement “Many researchers ….”
Line 48: three?
Line 55: I don’t understand what “keeps getting better” means here.
Line 58-59: the sentence “Combining benefits from two solutions …” is confusing.
Line 74: the sentence "It is supported by the requirement” does not make sense in the sentence.
Line 77: may be better to phrase “Chemical properties” as chemical composition instead. The table is suggested to list other minor components so that the total wt% can sum to 1. Similar suggestions may apply to Table 4.
Line 101: are there other benefits of densifying SF?
Line 107: (un)densified density for cement may be removed.
Line 115: it is suggested to plot the five real compositions for SF as it is done for FA and slag.
Line 141: “somehow has the reserved effect” is confusing.
Line 144: usually, increasing w/b decreases the strength. Could you elaborate on the opposite trend here?
Line 154: “decelerates” is confusing.
Line 157: “reducing the amount of water” for what or so what? The logic flow does not feel complete.
Line 189: “the filament’s surface sticks to other ones” is confusing.
Line 195: it is suggested to mention the range of the “time gap.” Is it a few seconds, minutes, or hours?
Line 197: the before and after paragraphs may be more understandable if the authors indicate the printing path in the figure.
Line 200-215: this paragraph seems to be missing multiple references. Please fix the problem.
Line 207: how is the mass loss measured? Is the mass loss due to water loss or else?
Line 348-349: “promotes” and “the total EP category” are both confusing. Please rewrite the sentence.
Line 350-351: please provide a reference for “formwork gives a negative value to GWP because it is made of timber and is considered to absorb carbon dioxide from the trees.” This statement is counterintuitive to me because, in my understanding, formworks would eventually decommission, and the material would decay to release the absorbed CO2, not to mention the additional embedded CO2 from manufacturing, transportation, and other processes during its lifetime.
Line 352: “performs more” is confusing.
Line 353: per 1 kg concrete?
Line 371: wouldn’t increasing aggregate/binder decrease the strength?
There seem to be many misuses of words and sentences with confusing meanings.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript under the title: “Utilizing Industrial By-products for Sustainable 3D Printed Infrastructure Applications: A Comprehensive Review” is in line with the Infrastructures journal. The topic of the article is up-to-date and attractive to potential readers. Overall, the manuscript is well-composed but requires additional improvements before publication. The following elements required to be improved:
· Introduction: reference [1] is form 2013 and presents old data; this part requires to be updated;
· Last paragraph of the Introduction - the information on methodology and research methods is very generic. Add the short information about used keywords, databases or general methodology for the literature.
· Part 2.1., What about other useful properties of fly ash, please see: https://doi.org/10.3390/ijms23042023?
· Part 2.3. What kind of amount of silica fume is usually applied?
· What about additives to this kind of composition https://doi.org/10.3390/ma14226874; please consider also another type of by-product as mine tailing or CDW.
· Part 3. Very generic information about specific properties of additives technology, such as interlayer bonding, and others.
· Part 4. Could you supplement this part about some recent applications, https://doi.org/10.32933/ActaInnovations.48.2 ?
· Add some information about further applications and trends.
· What about the advantages and disadvantages of presented technologies?
· References: The number of references, taking into consideration the type of the article is quite small.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The manuscript has been significantly improved.
Reviewer 3 Report
The authors implemented all required changes. The manuscript is ready to publication.
