Oren wrote in
:


The soil here is heavy with salt. It leeches up through concrete and
block walls. The water if full of Calcium and *stuff*.


I never thought of that. You get very little water from the sky compared to
the north-east (where I live), so it would be expected that the salt
content of your soil would be high.

However, that salt can't go anywhere without water as the transport agent.
Somehow water is getting under the OP's slab and your driveway, and is
pushing the salt up and out. Or your concrete is really, really porous.


--
Tegger