22 upvotes, 2 direct replies (showing 2)
View submission: How strong can ice be as a bonding adhesive?
This answer is pretty good. To add to it, it also depends on the nature of force being applied. This idea of tensile strength is correct, but the method of applying stress should also be considered. As mentioned, you would have to factor in the wettability of the surface, as concrete is a porous rough surface. This would function to effectively increase the adhesive strength as compared to a smooth surface, so you'd have to subtract a correcting factor. This is discussed in this paper[1] by L. E. Raraty and David Tabor, and indeed when water is able to completely wet a surface, it is significantly more adhesive.
1: https://royalsocietypublishing.org/doi/abs/10.1098/rspa.1958.0076
To maybe help explain the above answer a bit more thoroughly, tensile strength is a material function. u/ECatPlay, I'm going to go with your definition of tensile strength here and note that it refers to the maximum amount of extensional force that can be applied. This force is applied normal to the surface (by pulling the two blocks apart). If you want to understand more about material fracture, this site[2] does a relatively good job at explaining how this works in a way that is easy to digest.
2: https://www.xometry.com/resources/materials/fracture-strength/
Another method of fracture would be achieved by applying a shear stress. If you applied a torque by twisting the blocks or pushing one down and pulling one up, you could also break them apart. The differences between how tensile versus shear strength is defined actually does vary a bit by field but the idea is discussed here[3] by John M. Horeth (this paper is old though, so keep that in mind since setups were more difficult to control back then). In this case, the two values seem to be similar, but they don't always have to be the same, and can depend greatly on microstructural differences between materials. Since ice is a brittle crystal, that means it isn't ductile and doesn't bend easily, similar to a material like glass or ceramic. Interestingly enough, because of this brittle materials often actually do not have a dependence on temperature if enough force is applied. Pure ice at 0 degrees C and -50 degrees C will actually have almost identical responses to the same stress. This is supported by data presented in the aforementioned papers by Horeth and Raraty & Tabor.
3: https://deepblue.lib.umich.edu/bitstream/handle/2027.42/106369/39015003264192.pdf?sequence=2
Edit: my comment is about tensile strength and resistance to axial shear, it doesn't include compressive strength, which is different for water as mentioned here https://www.researchgate.net/publication/227158247%5C_Review%5C_Mechanical%5C_properties%5C_of%5C_ice%5C_and%5C_snow[4][5] (source provided originally by /u/MaleficentCaptain114 as an additional comment in this thread)
5: https://www.researchgate.net/publication/227158247_Review_Mechanical_properties_of_ice_and_snow
Comment by SaltCityDude at 19/01/2024 at 01:53 UTC
10 upvotes, 1 direct replies
It seems to me that the weak point that should be of the most concern is not the tensile strength of the ice, but rather the boundary layer between the ice and the concrete blocks. This seems to be the location most likely to fail, far more likely than the ice itself breaking in from shear stress.
Comment by racinreaver at 19/01/2024 at 21:42 UTC
2 upvotes, 0 direct replies
Pure ice at 0 degrees C and -50 degrees C will actually have almost identical responses to the same stress.
Interestingly enough if you get a bit colder you'll hit cryo ice which has properties much closer to rock. "Warm" ice will flow under modest loads under laboratory timescales, while really cold ice needs more of geologic pressures and timescales.