[Strawbale] Hydraulic vs. Hydrated Lime

[Mark Piepkorn]

At 11:28 AM 2/21/2007, Andrew deGruchy wrote:
>... 12" x 18" masonite board (1/4" thick) which I had previously
>applied a 1 white Portland cement, 2 Type S hydrated lime and
>9 sand mixture to as a demonstration of what is considered a
>"high (type s) lime content" mortar gauged for strength and
>durability with a little Portland cement and bent it to an arc ...
>the plaster cracked every inch or two along the whole board
>as would be expected.
>
>Then I took out another identical board with a pure 1:1 lime and
>fine sand mix previously placed on the board weeks earlier, at
>the same time I made the lime/cement/sand board. I bent it to
>an arc compressing it as far as I could bend it without breaking
>the board. No cracks. It flexed beautifully.


         I was already a lime fan (and am an even bigger fan of 
clay-based plasters)... but this was something I hadn't seen before. 
It happened exactly as he described.

         A plaster-thick hunk of the stuff would, of course, have 
cracked. But it was an impressive demonstration that made a strong point.



Mark Piepkorn
www.potkettleblack.com

... the fully trained artistic eye is the smaller
half of the journey; the principal thing is the
beginning, the opening of the eyes.
   - Herman Hesse