Not long ago we shared with you the news that these humble blocks made of 1 part 3/4 minus, 1 part sand, 1 part limestone tailings and 5% cement earned a compressive strength test rating of 10.25 MPA (1525 PSI) after 14 days. (They like to break them every few weeks to see how strong they get after time.)
14 days later (28 days total) the compressive strength is 12.51 MPA (1814 PSI)
That's an increase of 2.26 MPA (or 327 PSI) in 14 days.
(Hey, aren't there some walls out there where 327 PSI is the total compressive strength?)
This good news was enough to inspire test cylinders made with 3% cement--just like Rick Joy's 2 story Convent Avenue studios in Tucson Arizona.
We'll let you know when we get them crushed.