Evaluating the Printability and Rheological and Mechanical Properties of 3D-Printed Earthen Mixes for Carbon-Neutral Buildings

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1.     Figure 2: Please improve the quality of Figure 2.

2.     In section 2.2, the parameters used for the four different materials must be explained clearly; Considering the combination of several materials, whether it has a greater impact on the structure of the 3D print.

3.     In section 2.4.3, Symbols in formulas should have unit.

4.     Figure 10: Please improve the quality of Figure 10.

5.     The introduction must be improved. Some latest reference like: Gaili Xue, Erol Yilmaz, Guorui Feng, Shuai Cao, Lijuan Sun. Reinforcement effect of polypropylene fiber on dynamic properties of cemented tailings backfill under SHPB impact loading. Construction and Building Materials, 2021, 279: 122417. https://doi.org/10.1016/j.conbuildmat.2021.122417 should be added.

 6.     If you think that lime and volcanic ash are not satisfactory, please make suggestions for improvement in the conclusion section. 

 

Comments on the Quality of English Language

 Minor editing of English language required

Author Response

Please check the attached document. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present the results of a study regarding the potential for using on-site materials (i.e., soil) for 3D printing of structures.  The paper addresses a timely problem and outcomes are clearly stated.  In general, the paper is well-written and the conclusions seem well-supported by the test methods and associated data.  However, several changes are required before consideration for publication:

With regards to English language, there are several places throughout the paper with extra or missing spaces (e.g., line 4 of the 4th full paragraph on page 2 - extra space, second-to-last line in the large paragraph at the bottom of page 3 - missing space, between the variable definitions and the first paragraph on page 8 - missing line space).  More problematic is the fact that in multiple spots in the paper, information is repeated verbatim, or nearly so.  For example: page 5, two nearly identical statements about fibers being chopped with a leaf blower; bottom of page 9, two different statements repeated 3-4 times each (verbatim - including the fact that '6b' is missing from, 'following the printer geometries shown in...') to make a paragraph; bottom of the large paragraph on page 11, the second half of the paragraph is a direct copy of parts of the first half.  Other minor grammatical edits (missing parentheses, capitalization, wording, etc.) are suggested.

On page 6, Kitchen Aid should be capitalized.

At several points in the manuscript, a reference is replaced with 'Error! Reference source not found.'

The '2 theta' label below Figure 7 is small and faint.

The legend below the plot in Figure 9 is unnecessary and duplicative of the caption.

In Table 6, the flow value appears to be misreported.  Referring to ASTM C230 and ASTM C1437, the flow value should be reported in % rather than length.  If an alternate approach is being used, that should be clarified.

Near the bottom of page 16, the reference to SLF and SLFP curves in Figure 14 claims they are brittle.  Qualitative observation appears to show that ~half of the area under these curves occurs beyond the peak, a significant difference from the clearly brittle behavior of S and SL samples.  What is the definition of 'brittle' that is being applied in this case that would also include SLF and SLFP?

Why does Figure 15 list units in quotes rather than in parentheses as was done in other figures?  Same for Figure 10.  It appears the font on axis labels on some figures is bolded (e.g., 13 and 14) and on some is not (e.g., 7-10, 15) - choose a consistent format.  Why the is x-axis of Figure 15 not labeled 'Mix IDs' as with Figure 13?

In Table 8, how was the maximum number of stacking layers determined?  Was this by onset of total collapse?  Specified deformation in the base layer?  Something else?  Please clarify.

Comments on the Quality of English Language

As stated above, the paper is generally well-written.  Various specific necessary changes are noted in the preceding section.  Additional grammatical edits would also improve readability but are less significant.  

Author Response

Please check the attached document: 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript is well written even though it opens a lot of further questions on the soil stability and mechanical properties. I have just some minor comments mainly to to the "materials" aspects.

1. In Abstract: it is somewhat confusing to say that 6 soils were tested and than provide one specific mineral composition (it is not clearly said in abstract that this one was the best and further studied).

2. Type S lime is not "hydraulic lime" but hydrated lime or lime hydrate - in this case it is mixture of Ca(OH)2 and Mg(OH)2. Hydraulic lime is lime containing hydraulic oxides. Further - in Abstract - lime is not "natural stabilizer" - it is industrial product.  

3. Chapter 2.2: Do I understand well that studied mixtures are based on S6 from table 1?

4. Table 4: to have 13.5 % of "others" is too much - be more specific.

5. Table 5: write the formulas properly. Are you sure that your XRD results enable to be such precise to say 14.57 % of nontronite? I guess to say 15% would be more realistic.

Author Response

Please check the attached document. 

Author Response File: Author Response.pdf