[Geof]

... On the other hand high frequencies could sink larger aggregates or prevent them from penetrating as the smaller particle fill more effectively....

I think it is possible you have it sort of backwards here. I would expect that low frequencies could excite bulk movement of the constituents of the mix and maybe encourage separation and settling; high frequencies could be expected to cause vibration within the particles promoting release of the air bubbles adhering to the surfaces. Whether the particle tended to move as one unit, the bulk movement, or just vibrate, would depend on the wavelength of the vibration in the mix and this depends on the speed of sound in the mix.

[jsage]

Geof,

Thanks. I was just wondering b/c From concrete work I recollect that larger aggregates will move to the bottom if hit with mallets for too long of period. At the same time, there is a subthread where the large aggregates came to the top when a vibrating sander was used.

Liquefaction from earthquakes. People caught in avalanches. Ultra long landslide runouts ; ) Just trying to relate to this application. Obviously, I am taking a non physics approach and asking the question ; )

Thanks again.

Mike.

[Geof]

Geof,

Thanks. I was just wondering b/c From concrete work I recollect that larger aggregates will move to the bottom if hit with mallets for too long of period. At the same time, there is a subthread where the large aggregates came to the top when a vibrating sander was used.

Liquefaction from earthquakes. People caught in avalanches. Ultra long landslide runouts ; ) Just trying to relate to this application. Obviously, I am taking a non physics approach and asking the question ; )

Thanks again.

Mike.

All low frequency, some ultra-low frequency...except for the ultra long landslide runout.

I have read a couple of proposals for explaining long runouts:
One is that air gets entrained in the rubble and both decreases the bulk density and acts an an air cushion because it can't get squeezed out quickly.

The other explanation, which I favor, is that the particles in the landslide are vibratin; ringing like bells you could say. This means that they do not reside in contact with each other for friction to take effect; they constantly bounce off each other and thus keep running down even a small slope or out onto flat just from their own momentum.

This is not directly applicable to the behaviour of aggregate/epoxy under vibration but is partly why I suspect there would be a frequency dependence because things vibrating internally can behave differently to things that are simply moving in one direction or oscillating as a single unit.