Chloride Induced Corrosion and Carbonation in 3D Printed Concrete

Round 1

Reviewer 1 Report

This paper investigates the chloride-induced corrosion and carbonation in 3D printed concrete, and some interesting findings are presented. The content of this manuscript is very solid and high-quality results were reported. Also, the topic matches the scope of the special issue well and some information is useful for the research community. The reviewer suggests the publication of this paper in this journal after addressing the following comment.

# Please check the reference in the manuscript, as the “Error! Reference source not found” appeared many times.

Author Response

Comments are addressed in the document.

Author Response File: Author Response.docx

Reviewer 2 Report

This article investigates the interlayer bond strength and durability performance of 3D printed concrete. Experimental studies were conducted to demonstrate that the cast samples outperform printed samples. Reasonable analysis and presentation of the work are good. Following are the few concerns to be addressed:

1. Introduction Section: For wide readability, review and include the state-of-the-art sensor technologies that can monitor chloride-induced corrosion or carbonation. For example: (a) K. Thiyagarajan, S. Kodagoda, R. Ranasinghe, D. Vitanage and G. Iori, "Robust Sensor Suite Combined With Predictive Analytics Enabled Anomaly Detection Model for Smart Monitoring of Concrete Sewer Pipe Surface Moisture Conditions," in IEEE Sensors Journal, vol. 20, no. 15, pp. 8232-8243, 1 Aug.1, 2020, doi: 10.1109/JSEN.2020.2982173. (b) M. Ams et al., "Fibre optic temperature and humidity sensors for harsh wastewater environments," 2017 Eleventh International Conference on Sensing Technology (ICST), 2017, pp. 1-3, doi: 10.1109/ICSensT.2017.8304493.
2. Figure 1: spell check for "printed samples"
3. Error! Reference source not found. It repeats throughout the manuscript
4. Section 2.8: Is there a random or uniform chloride penetration? Also, any presence of aggregates in the sample?
5. Section 3.2.1, 3.2.2, 3.2.3, 3.2.4: Mention the number of measurements taken to see the repeatability of the tests.

Author Response

Comments are addressed in the document.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript "Chloride-induced corrosion and carbonation in 3D-printed concrete" is interesting to publish, provided corrections are carried out by the authors:

a) Manuscript citation mode is not used by the journal, authors must correct this. There are numerous errors in the reference list;
b) In the introduction, the literature review regarding the durability of cementitious materials is limited, suggesting the insertion of the following manuscripts: 10.1111 / ijac.13634; 10.1016 / j.cscm.2021.e00814; 10.1016 / j.cscm.2021.e00794.
c) Authors should deepen and answer questions related to the porosity of these materials, such as porisity due to mercury intrusion and its consequences in this type of material;
d) The dosing process should be better discussed, which water-cement ratio? Plasticity and viscosity concepts of mixtures should be discussed for 3D printing;
e) The process of removing circular samples for durability must be thought of by the authors and better shown;
f) The carbonation front and its images must be standardized;
g) Authors should use scanning electron microscopy and other microstructural characterization techniques;
h) The conclusion is very long, authors should make it more concise for readers.

Author Response

Comments are addressed in the document.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have addressed the comments of the reviewer.

Reviewer 3 Report

Manuscript may be accepted for publication.