Message #51571

[hulagrub]

Alvin, I am thinking that the freeze thaw cracks happen mostly while they are still in the ground. All rocks will absorb a certain amount of moisture, (if they didn't absorb water, we would never be able to get a specific gravity) and while in the ground and dirt, they are probably closer to their saturation point. 
Then, lets say the frost line goes down 30 inches, those ice crystals gotta go somewhere. I imagine that as a rock gets closer to the surface it goes through more and more freezing and thawing cycles, therefore they are most likely to be to their ultimate damage point, before they get into our oily, grubby rock cutting and grinding hands. It's a wonder how all those surface collected rocks, are as solid as they are, but we still have fun with them!