Reading your post, you may want to reconsider the use of sand under a slab on grade. While its well drained, it can be difficult or impossible to get optimum compaction because the fines or small aggregate is all the same size, you need a composite material such as gravel, which has an array of sieve size aggregate, along with optimum moisture to obtain suitable compaction. Ideally you want to excavate all topsoil, organics out, to undisturbed, suitable bearing soil, then build up the sub base in 12" lifts compacted 95% or better, so that it does not settle under the slab.
Even where there is no slab, you may not get the stability you need or expect, I'd just build it up with crusher run, run of bank gravel, or similar, it would likely perform as you need, instead of displacing. Under a roof, that sand will likely dry out and even if you had optimum moisture when placed, and it did compact, when it drys it could be like driving on sugar.