Frost Heaving and Induced Pressure of Unsaturated Interfacial Zone between Gravel Ballast and Subgrade

Round 1

Reviewer 1 Report

2. Comments to Author:

Manuscript Number: applsci-1624151

Title: Frost Heaving and Induced Pressure of Unsaturated Interfacial Zone between Gravel Ballast and Subgrade.

General remarks

Through laboratory tests, the frost height and induced pressure of gravel ballast soil mixtures were examined. Frost studies were affected by various mixing ratios and saturation levels. In general, gravelly soil is not considered a geomaterials susceptible to frost damage; however, the frost potential of gravel ballast increases with the increase in the degree of saturation and the mixing fraction of the subgrade soil.

Specific remarks

• Line 95-96: 63.5– 95 125 mm (30%), 25.4–63.5 mm (23%), 9.52–25.4 mm (3%), 2.5–9.52 mm (14%), and 0.15–2.5 96 mm (20%). Why are these ratios used and what are the specifications?
• Line 112-113, M (e.g., mass_subgrade/mass_total×100%) of 0%, 5%, 10%, 15%, 20%,and 25%. Please add Ref.

Author Response

Dear reviewer

The author summarizes responses in a single file as attached. Please find the attached. Appreciate the reviewer's efforts to review.

Author Response File: Author Response.docx

Reviewer 2 Report

APPLIED SCIENCES

Author: Jinung Do

Comments for author:

Abstract: The objective of the work is not clearly defined. The author has to specify what is the purpose of the research that has been carried out. Check.

It is recommended that the author mention the name of the tests carried out from where it says: "through Laboratory tests". Check.

At the end of the Abstract a small paragraph should be included where the author indicates in which field the results obtained could be used. Check.

Lines 7 to 14: This paragraph is too long to be taken into account in the Abstract; the author's description should be removed to the Introduction. Check.

Introduction: Lines 25 to 80. The arguments provided by the author are conceptual and academic. The Introduction should provide a state of the art on the research related to the line of this work, where the authors make a logical interpretation of the advances achieved. Please, it is recommended to rewrite it.

From line 70 to 74. The definition of soil sizes is not adequate and does not correspond to detrital rock classification systems.

In the introduction section the chemical composition of the grains is not taken into account. It only differentiates between gravel and precast ballast. No mention is made of the type of gravel.

Line 93: The way the reference is made is incorrect. Check.

Line 95: Write "Figure 1" instead of "Fig. 1". Check throughout the text.

Line 99: Write "Figure 2" instead of "Fig. 2". Check throughout the text.

Table 1. It is recommended to delete this table. It plays no role in the work and is merely conceptual. Check.

Line 103: the units of measurement of "2.67" and "2.70" are missing. Check.

Figure 4: This Figure does not play any role in this work, therefore, it should be deleted. The author should keep in mind that a scientific paper should not contain too much information from other authors. Check.

Lines 272 and 273: At least two references should be added after the sentence: "Several previous studies have evaluated frost heaving in various soil types". Check.

Lines 273 and 274: On what basis does the author use this classification? Justify in each case and also mention the standards used. Check.

Lines 277 to 281: I ask the same question: On what basis does the author use this classification? Check.

Lines 281 and 282: Bibliographic references must be introduced, it is not enough to mention previous studies. Check.

Line 289: The way of making the bibliographic citation is incorrect. Please check this error throughout the paper. Check.

Conclusions: The author does not provide any data on where and how the results obtained could be used.

In general, the number of trials used in this work is considered insufficient. The author has used only 2 tests: "Frost heaving" and "Frost heaving pressure".

In no part of the work is a deep characterization of the material used and no reference is made to the name of the rock used as ballast in this research. This research lacks the following parameters:

1. petrographic characteristics of the ballast to know the name of the rock, mineralogy and alterations.
2. Shape factor
3. Fracture
4. Surface texture
5. Pore volume, size and distribution
6. Water absorption
7. Size
8. Wear resistance

Comments for author File: Comments.docx

Author Response

Dear reviewer

The author summarizes responses in a single file as attached. Please find the attached. Appreciate the reviewer's efforts to review.

Author Response File: Author Response.docx

Reviewer 3 Report

1. Line 84-85: Please explain the reasons for measuring frost heaving without confinement, measuring the frost heaving pressure under confined conditions.
2. Line 95-96: Please explain why choose the reconstituted ratio of gravel ballast, and will this cause discrepancy between laboratory and field results?
3. Line 102-104: Are the values of specific gravity, maximum dry weight, and optimum water content measured in laboratory tests or the values of the cited references? What is the purpose of citing the values of the references [22] and [23]?
4. Figure 3: please explain why the trend γd–M and n-M are exhibited in this figure. There is no clear rule from the picture. What may be the reason?
5. Line 161-162: Supplementing frost heaving pressure tests with M=10%, 20%, and S=80% recommended.
6. Line 175-176: for h-M0-S70/80/90, the authors explain the occurrence of the downward trend of h-value at the beginning of h-M0-S70 by water shrinking at 4 °C and expanding below 4 °C. The h-M0-S70/80/90 should be tested under the same temperature conditions. Then why does not the h value of h-M0-S80/90 decrease at the beginning?

Author Response

Dear reviewer

The author summarizes responses in a single file as attached. Please find the attached. Appreciate the reviewer's efforts to review.

Author Response File: Author Response.docx