travertine paver installation on a highly expansive soil

Q: I just received 3 pallets of travertine ivory swirl and plan to use them under an outdoor covered porch (no walls). The soil is highly expansive clay soil... I just had foundation repair done and am in the middle of renovation. I assumed it would be best to lay down caliche (locally quarried crushed/powdered limestone road base) then sand then the pavers...no concrete. The contractor is a little weary since the pavers are 1.25" and not 1.5" thick. I'm thinking the concrete would eventually crack and heave and would be more expensive to repair than just adjusting the pavers in the sand. If the pavers can be flexible with the change of soil moisture, that would be better, right? I'm in central Texas near Austin.

A: Yes, laying on top of crushed limestone and sand is the way to go.
There is absolutely no need for a concrete base.

Travertine pavers have higher compressive strength than brick and
cement pavers, almost double the strength. You should have no
issues. On another note, we suggest 6x12 pavers for driveways in
the same thickness (1.25 inch)

More information about travertine paver installation can be found here: http://www.travertinemart.com/travertine-installation