The Use of De-Icing Salts in Post-Tensioned Concrete Slabs and Their Effects on the Life of the Structure
, Rubén Muñoz Pavón 1 and Jaime C. Gálvez 1
Bernardino Chiaia
Round 1
Reviewer 1 Report
This paper investigated the use of de-icing salts in the corrosion of steel rebars in bridge decks and their effect on post-tensioning elements. Additionally, the paper also proposed strategies for the prevention and repair of structures. Overall, the topic is interesting, and the paper is suitable for the journal's scope. The paper can be accepted for publication after several minor comments suggested by this reviewer:
1. In the introduction, second and third paragraphs, please revise to represent a more in-depth discussion on the analysis of the salt effect on infrastructure and post-tensioned slabs.
2. Section 2, the title should be revised to be more scientific (not include parentheses).
3. Figure 13, for better interpretation, please separate and name the sub-Figs. (a) and (b)
4. The limitation of this paper should be included and suggested for further studies.
Author Response
The authors would like to sincerely thank you for your detailed comments, which have helped us to improve the quality of the paper. The comments are helpful and constructive.
Author Response File: 
Author Response.docx
Reviewer 2 Report
It is a very interesting case and allows for far-reaching reflections on areas of civil engineering that go beyond the strict field of physical sciences.
But the article requires improvement in some of its parts to strengthen the importance of the case.
- The state of the art has considerable omissions that have dealt with this issue from different positions or by indicating other variables associated with de-icing salts (see Mullapudi, R. Typical Parking Structure Problems, Repairs, and Cost Assessment. In Forensic Engineering 2022 (pp. 960-968); Skripkiūnas, G., Nagrockienė, D., Girskas, G., & Janavičius, E. (2012). Resistance of modified hardened cement paste to frost and de-icing salts. The Baltic Journal of Road and Bridge Engineering, 7(4), 269-276; Šelih, J. (2010); among others.
- The coherence between the objectives stated in the article "to highlight the importance of carrying out scheduled and systematized inspections" and the parts of the article should be strengthened. What is the meaning of paragraph 4 for this objective?
- In line with the previous criticism, the conclusions do not respond to the defined objective but to the importance of using impermeable treatment when using this type of de-icing salts. To address this issue in more depth, the results of the laboratory analysis are essential and it is clearly stated in the article that they are not yet available.
- No methodology has been specified, it is a description of a case where hypotheses have been put forward but not yet proven (lack of laboratory data). The use of qualitative methodology including participant observation is suggested as a methodology to explore and discuss ideas for academic progress, which in this case would focus on the effects of decision-making on different processes in the life span of a bridge (design, implementation, use).
Author Response
The authors would like to sincerely thank you for your detailed comments, which have helped us to improve the quality of the paper. The comments are helpful and constructive.
Author Response File: Author Response.docx
Reviewer 3 Report
In this paper the Authors describe the problem of the use of de-icing salts in the corrosion of steel rebars in bridge decks and their effect on post-tensioning elements. In particular, the paper aims to show the role of melting salts in the corroding process of steel rebars and their effects in post-tensioned elements. The manuscript pays special attention to the brittle rupture phenomenon of transversal rebars for being extraordinary as well as highlights the most likely mechanisms that gave rise to this pathology. The article focuses on one of the structures in which this process has been observed, the “Nudo de Colmenar Bridge”, a motorway junction, located near Madrid.
The Authors assess that the water presence plays a determining role in the deterioration process. In this sense, an appropriate conservation strategy involves minimizing water entry into the structure throughout its service life. For this reason, the execution of a high performance waterproof treatments during the construction phases is a key aspect to avoid the progression of the previous pathologies and their effects on structural safety.
The paper could be of a certain interest, but not in the present form. Some revisions are necessary before final publication.
As a first hint, the manuscript is written in a quite good English grammar. Some typos were found within the text, a moderate language check is necessary.
In the following a list of suggestions are given.
(1) The indication of the salt concentration used would be of great importance to better understand the corrosive action of the chlorides. The Reviewer suggests to add some information regarding the usual concentration (g/m2) of the de-icing salt used to ensure roadway safety along the Nudo de Colmenar Bridge. It is well known that the initiation corrosion time depends on various factors including the surface chloride content, the rate of penetration of chloride ions in concrete, the depth of the concrete cover, as well as the threshold chloride concentration. Typical dry salt diffusion rates up to 15 g/m2 are used as precautionary action under normal weather conditions. When conditions are expected to be very severe or when heavy snow is expected, it is possible to carry out preventive salting with a rate up to 40 g/m2. Otherwise, post-salting curative applications used to remove snow and ice from the road surface, once formed, are between 20 and 40 g/m2.
(2) On page 6 the Authors state that: “Chlorides can easily penetrate inside the concrete mass through the existing cracks in the deck upper face until they reach the reinforcement bars.”. In the case of uncracked concrete, numerous models developed from Fick's second law of diffusion have been used to predict the initiation of chloride-induced reinforcement corrosion in concrete. On the other hand, factors such as crack width, average crack spacing, crack height and the crack geometry, can strongly affect the chloride ion diffusion in the cracked concrete. In this context, there are several mathematical models that describe the diffusion of chlorides within cracked concrete. To which models did the Authors refer during their investigation and study?
(3) The Authors declare that: “It suggests that bars failure is the consequence of a corrosion-fatigue phenomenon. This phenomenon occurred as a result of chloride from the frequent use of de-icing salts go into the slab cracks and the presence of cyclic traffic loads.”. In addition, it would be interesting to have information also on how vehicular traffic influences exposure to chlorides, which is generally highest for surfaces facing towards traffic. As a matter of fact, the de-icing salt follows different pathways from the road, each of which is coupled to separate mechanisms regulated by a set of factors. The mechanisms are run-off, splash, ploughing, spray and dry crystals. In addition, a certain amount of the salt applied on the road will be lost almost instantly as “initial loss” to the surroundings. The initial loss depends on the state of the road, the salt application method, the salt application width and the intensity of the traffic. It would be appropriate for the Authors to spend a few words on this subject to clarify if, during their observations, areas with greater salt accumulation were found and therefore with the presence of more evident corrosive effects.
(4) In the reference list, the year of publication of the cited papers is missing.
The final comment of the Referee is that the manuscript is suitable for publication after the above suggestions have been implemented.
The manuscript is written in a quite good English grammar. Some typos were found within the text, a moderate language check is necessary.
Author Response
The authors would like to sincerely thank you for your detailed comments, which have helped us to improve the quality of the paper. The comments are helpful and constructive.
Author Response File: Author Response.docx
Reviewer 4 Report
This manuscript discusses the effect of de-icing salts on post-tensioned concrete slabs, with a particular focus on the Nudo de Colmenar Bridge. Although the topic is interesting, several revisions are necessary to improve the quality of the manuscript.
1. The introduction section requires a complete rewrite as the structure is poorly organized and confusing. For example, the first paragraph on page 2 starts with sentences discussing the economic optimization of post-tensioned elements, while the rest of the paragraph deals with the chloride effect on regular concrete. The second paragraph then switches back to post-tensioned elements. A clear and logical flow of ideas should be established.
2. The manuscript lacks sufficient references, and the existing studies are not clearly referenced. The research gap in the field and the significance of the study are not adequately explained. It would be beneficial to include more relevant and recent references to strengthen the paper's arguments.
3. The reviewer questions the validity of the results presented in Section 3 as no supporting references are provided for the assumptions made by the authors.
It is essential to establish a clear and logical flow of description in a manuscript. Language errors also impact the reader's comprehension of the manuscript, underscoring the need for careful proofreading.Therefore, authors are advised to conduct a thorough review and revision of their work to ensure clarity and accuracy.
Author Response
The authors would like to sincerely thank you for your detailed comments, which have helped us to improve the quality of the paper. The comments are helpful and constructive.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Dear authors,
Thank you for your attention to my comments. Many of the issues have been resolved, however, others still seem to need improvement.
A clear state-of-the-art has been incorporated, but a paragraph at the end of the section would have been desirable to identify the knowledge gap this case intends to address.
Unfortunately, the methodology section doesn't respond to what is needed in a scientific article. This section should describe the nature, the techniques that have been used and the reason for its selection to address the gap that has been identified, that is to say: To highlight the importance of carrying out the scheduled and systematized inspections. What has been written is the diagnosis that has been followed to determine the causes of the pathology of the case study.
Also, the second and third points highlighted in the previous report haven't been fixed. They require a theoretical framework addressing the importance of scheduled and systematized inspections and linking them to the research findings.
Therefore, I think the article needs further work before publishing.
Author Response
The authors would like to express again their gratitude for your meticulous feedback, which has significantly contributed to enhancing the quality of the document. Your comments have offered valuable insights and constructive suggestions.
Author Response File: Author Response.docx
Reviewer 3 Report
The paper has been improved.
Author Response
The authors would like to express again their gratitude for your meticulous feedback, which has significantly contributed to enhancing the quality of the document. Your comments have offered valuable insights and constructive suggestions.
Reviewer 4 Report
The revised version is excellent and suitable for publication.
Author Response
The authors would like to express again their gratitude for your meticulous feedback, which has significantly contributed to enhancing the quality of the document. Your comments have offered valuable insights and constructive suggestions.
Round 3
Reviewer 2 Report
Dear authors,
This case is of great interest, as it highlights the importance of regular inspection of infrastructure, to ensure its effectiveness and to achieve economic and management savings. But I believe that the theoretical framework should highlight that even if regulations exist in this regard, they still might not be carried out, resulting in the disastrous consequences demonstrated in this case. Therefore I believe that there is a social dimension which has not been explored, and which the article should include, in the elaboration of the theoretical framework and its importance to this case study.
Author Response
The authors agree with the reviewer in the social dimension of this case study. Therefore, they have included a new paragraph in the introduction section. It should also be mentioned that further analysis of cost-benefit in the use of de-icing salts remains out of the scope of this study although it is part of future studies.
Author Response File: Author Response.docx
Round 4
Reviewer 2 Report
Dear authors,
Thank you for the clarifications given.
However, I would recommend explaining in the methodology section how the case study methodology has been used in this field of engineering since it is usually used for the analysis of social phenomena.
Author Response
The authors agree with the reviewer and have updated the methodology section emphasizing the importance of infrastructure management currently and the new social dimension for civil engineering sector. The modifications are the following:
“Infrastructure management is progressively gaining importance compared with design. Guides of basic inspection of road works or main inspections of crossing works and flyover bridges [14, 15] where released on 2012, whereas the first version of the standard 3.1-IC of road layout design was released on 1939 [16]. The existence of specific regulations for infrastructure management denotes its growing importance in the Civil Engineering sector, traditionally focused on the design and construction of new projects. The great social impact of maintenance has become as important as the design of the infrastructure itself. In this sense, the referred document shows the process followed to carry out maintenance in accordance with the indications of the existing regulations.”
Consequently, the list of references has been updated too.
