Thursday, January 26, 2006

Later That Month

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.

1 comment:

jeremy said...

That's fascinating stuff. Pardon my limited knowledge, but why should it strengthen over time?

I'm a student of the Univeristy of Nottingham (UK) and I'm currently reading for my dissertation- final year project. The title for my dissertation is: "Review of the Potential for Rammed Earth Buildings in the Communities of Developed and Developing Countries" and so I am particularly interested in the social impact of rammed earth construction in the 21st century- in both developed and lesser economically developed countries (Morrocco;Burber dwellings China;Hakka housing and modern day France). I want to focus on the attitudes of people towards earthen construction in regards to cultural importance, and in relation to economic and technological developement (ie questions like, does the idea of earth in construction seem like a step back?)... you get the picture.

Do you have any knowledge in this area? Any opinion? Any papers or articles that could shed light on these issues? Any help would be greatly appreciated.