Confinement of Masonry Columns with Natural Lime-Based Mortar Composite: An Experimental Investigation

Round 1

Reviewer 1 Report

• In section 2.1 it is stated that FRP-confinement is nor reversible. This is absolutely not true. Authors are invited to consider the following: “Cascardi, A., Dell'Anna, R., Micelli, F., Lionetto, F., Aiello, M. A., & Maffezzoli, A. (2019). Reversible techniques for FRP-confinement of masonry columns. Construction and Building Materials, 225, 415-428”.
• The authors ask for additional future effort in the field of experimental investigation on FRCM-confinement aimed to improve predictive formulas. Anyway, a large part of literature was neglected in the proposed paper, lastly “Aiello, M. A., Bencardino, F., Cascardi, A., D'Antino, T., Fagone, M., Frana, I., ... & Verre, S. (2021). Masonry columns confined with fabric reinforced cementitious matrix (FRCM) systems: A round robin test. Construction and Building Materials, 298, 123816.” A large group of authors state the validity of the CNR-proposal.
• The FRCM-matrix adopted in the proposed experimental tests is very low and so definitely not consistent with the theory put in contrast with. Moreover, the lime-based mortar is far what is used in real case applications. The authors are invited to deeply discuss the consistency of the comparison or produce different validation. Maybe there is a lower bound value for the k’?
•   From the mechanical point of view an explanation is missed. The authors seem to have demonstrated that the matrix contribution is null in FRCM-confinement. Is it possible to confine without?
•  The matrix effect was demonstrated by the authors in the tensile tests: tensile strength of FRCM is lower than dry fabric. Why is this aspect not attained to be reflected in confinement? This aspect needs deep comment.
•   Please show the constitutive law of the FRCM and the dry fabric experimentally met.
•   Fig 5 shows both rounded and unrounded cross-section. It is a misunderstanding.
• Were the tests displacement controlled?
•  In fig 10 is shown two samples have the same peak load of the unconfined sample. After an unexpected hardening behaviour was observed. In principle the confinement had a main ductile gain effect. This is in-line with the CNR-model.
•  The conclusions cannot be supported by this very limited amount of data. Authors are invited to integrate with references in order to have more confidence with the phenomenon. 

Author Response

Please, see the attachement.

Best regards,

STEFANO GALASSI

Author Response File: Author Response.pdf

Reviewer 2 Report

The topic of the paper is interesting, the reviewer only has a few suggestions to improve the paper.

• The specimens with the height of 500 mm are called “full-scale columns”. The reviewer disagrees with this definition, these are only small specimens, not columns at all.
• Table 3 – there are quite big differences between data obtained from experiment and from manufacturer datasheet. This discrepancy should be explained in the text.
• Figure 5 b) – the text is unreadable.
• There are few spell-check mistakes in the text, e. g. pression = pressure, …

Author Response

Please, see the attachement.

Best regards,

STEFANO GALASSI

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper proposes a study on the Confinement of Masonry Columns with natural lime-based mortar composites: an experimental investigation. The paper is clear and concise and it addresses an interesting and relevant problem. The experimental tests developed in the manuscript are a good contribution to the field, but the Authors should explain some of their choices.

In what follows, I list some comments and suggestions that can be addressed by the authors while finalizing the manuscript in a major revision process. 
Line 78: it is the reviewer's opinion that work on confining columns cannot be limited to only 3 papers. Authors are invited to extend the bibliographic section. 
Line 226: What standard is used to evaluate the mechanical properties of brick? the cited standard refer only to mortars; 
Table 3: Why did the Authors report values from data sheet and those evaluated experimentally? In the analytical model which ones have been considered?
Line 261-164: The authors are invited to give more information on the evaluation of PBO fiber area calculation. How many yarns are involved in the specimen width? Why did the authors not multiply the area of the single yarn by the number of yarns considered?;
Figure 4: The authors are invited to describe the test setup photographed in Figure 4. In addition, the authors are invited to explain the positioning of the extensometer that is not centered with respect to the axis of the specimen. What measurement base does the extensometer have? As evidenced by Figure 4b, the placement of the extensometer will never catch the crack highlighted in the Figure. Finally, it is the reviewer's opinion that it is useful to report the diagrams obtained from the test.
Line 278: The round corner has also been investigated in the literature in the paper Sneed, L. H., Baietti, G., Fraioli, G., & Carloni, C. (2019). Compressive behavior of brick masonry columns confined with steel-reinforced grout jackets. Journal of Composites for Construction, 23(5), 04019037. 
Line 293-295: Authors are invited to provide more information about the type of evidence conducted. Was the test conducted in displacement or load control? What load rate or displacement rate was used?
Table 5: Authors are invited to justify the choice of only one specimen for parameter investigated. 
Line 354: Authors are invited to report at least one table with the values obtained using the analytical formulation given in the paper. In such a way as to facilitate reading for the reader.

Author Response

Please, see the attachement.

Best regards,

STEFANO GALASSI

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper was significantly improved

Reviewer 3 Report

Authors are asked to correct the unit of measure in the new Figure 4. Authors are invited to remove the dot and leave the MPa or not remove the dot but change the MPa to GPa.