A: 568 psi (removed after 3 days)
B: 460 psi (removed after 6 days)
C: 599 psi (removed after 9 days)
D: 386 psi (removed after 1 day)
All of these are within the expected 300 - 700 psi range, so this was a great success! 599 psi means the press had to apply 7,527 pounds of force to crush a 4" diameter cylinder. That's a lot!
Surprisingly the one with the worst compaction was the strongest. Looking back at my records, I see that I left it in the form for 9 days (it was still damp when I removed it). It appears that curing time is a very important factor.
Curing in the form for 9 days presents a challenge for construction, as I'd like to move on to the next wall section sooner than 9 days. I think I need another test comparing curing in the form vs. periodic watering for a few days to see how well that fully hydrates the cement.
#RammedEarth #StopBuildingCrapHouses
