Example Report #1
Example #1 is of a planter with a minor cosmetic problem where the owner was concerned if there was also a durability problem. Structure is a sidewalk planter subject to splashing of road salt. Photos are from various elevations, and may be roadside or not-roadside. Pictures were taken 6-8 months (one winter) after installation.
Our Description Of The Problem
Apparently scaling or flaking on some pieces of the cast stone sidewalk planters. Scaling and flaking and "popouts" are similar in that they all involve loss of mortar (cement paste and sand) that is covering aggregate (stone). In a case like this all three may be involved, though I don't think we are seeing typical popouts (which involve a stone that expands when saturated and frozen). Observed following one season of freeze-thaw.
The mortar (sand and cement paste portion or fraction of concrete) has broken off leaving a tiny crater and a visible stone. This occurs only where a stone is very near the surface and there is a weak thin mortar paste above the stone. A number of factors in both the mix and the piece can lead to this. Because it is observed only in some stones (far from a majority) we conclude that there is no inherent problem in the mix design or the material. Likely causes (and all can be operative include minor curing issues, dust on the stone, particles of deleterious material (dirt, chert, etc.) in the sand.
Anticipated Future Behavior
I expect that the majority of the problem areas have shown themselves. I would expect to see a few new ones in year 2, and a declining number of new appearances in following years. This is not likely to lead to a reduced service life or to complete deterioration of a piece..
None practical in our opinion. You can replace. Any patch will likely be as visible or more so than what you see now and will be at risk to fail as it will be very thin and weak. The stones that are exposed are "colder"in terms of color than the surface, which shows a lot of brown sand particles. You could carefully take a fine paint brush and put a matching stain on the stone. This will be a lot of work and will reduce the visibility of the affected areas. Will affect appearance, will not affect durability
Your Particular Questions/Concerns
Your main concern was whether these pieces were likely to continue scaling and crumbling over the next few years. That is not likely.
1234a1.pdf points to certain areas in one of your photos.