[Cob] burnt mud

[dirtcheapbuilder-Charmaine Taylor]

Hi Copper I looked at the text of that site.  It was common for Romans 
to burn field mud, to mix with lime to make cements   ie Roman 
Cements... the dung and straw would be fuel to change the chemistry of 
the burned field clay.

Once burned he clay is now reactive with lime and when added to it sets 
quickly with water and makes hydraulic   material.  Clays are burned 
now by Mfgs of OPC to make cement   so it is a common process, well 
refined in commercial use.

   Used bric dust yourself, or finding a sticky 'gumbo'clay when mixed 
with limes gives a faster set...but not as good as burned clays.


Natural hydraulic lime has high clay content naturally, which is why 
the evil OPC makers bought up all the mines in the US  back in the 
50-60s  and it is now imported at great cost by Transmineral USA,-- the 
   St. Austier French lime.

it is a great product when you need the lime to set fast... but  for  
plasters and general use regular lime with a fine silica clay added can 
do as well for strong plasters/mortars.

>  Charmaine Taylor Publishing    books at dirtcheapbuilder.com
PO Box 375 Cutten CA  95534 USA  -- 707-441-1632
www.dirtcheapbuilder.com  &  www.papercrete.com

On Sep 19, 2004, at 6:09 PM, Copper Harding wrote:

> This was all I could find on the internet.  I am
> wondering if anyone has any experience with this
> stuff.  Do you know the ratio of mud/hay/manure?  any
> ideas on temperature or method of "burning for a few
> days"
>
> The fact that it turned water-resistant says that
> something chemical is changing?
>
>
>>  http://www.aiys.org/webdate/kearev.html
>
> =====
> _________________________
> Ms. Copper Harding