After about a week, this piece should have reached 80% of it’s 10,500 psi. compressive strength. It easily supports (8) 50lb. bags of concrete mix (400 lbs.) and will continue to get stronger. The actual weight it can support is unknown, but the mix is quite strong even at only 3/4″ thick!
With a flexural strength of 1500 psi. after a few days of curing, this piece will actually bend before it breaks.