[Cob] cob shake test info

[dhowell at pickensprogressonline.com]

Ed,
	Understood about quality control. I must point out concrete mixes  
from scratch in a wheelbarrow can also have vastly different  
strengths according to the amount of water used. Adobe bricks? New  
Mexico Earthen Building Materials code states, "each of the tests  
prescribed in this section shall be applied to sample units selected  
at random at a ratio of five units per twenty-five thousand bricks to  
be used or at the discretion of the building official." Five out of  
25,000 seems like a pretty unrepresentative number for the whole.  
Quality control can be done by performing tests at the foundation,  
sill height, and lintel height of the walls. Did you know the adobe  
code allows a psi of 250 and one out of five can have a psi less than  
that? We're talking about the same material just a different building  
procedure. Their code is a good guideline, but some things are  
questionable, such as it requires concrete stucco which is an  
accident waiting to happen according to the Devon Earth Building  
Association. A healthy topic that must be discussed, don't you think?
Damon

On May 17, 2012, at 2:09 PM, Henry Raduazo wrote:

> 	The problem might be one of quality control. When you are mixing  
> something in a large batching machine (like a concrete mixer) you  
> have large 3-5 yard batches which are perfectly uniform. When you  
> have small crews making 1/27th of a yard batches on a tarp  
> asserting quality control is a nightmare. Every crew can not make  
> every batch the same let alone getting the 5 or 6 different crews  
> to make uniform batches.
> 	I have been able to make uniform cob batches by mixing one ton  
> batches on a concrete slab with a rototiller. That might satisfy a  
> quality control person, but getting such anal persons to accept  
> hundreds of batches made by half a dozen different crews might be  
> expecting too much even if we had a code that described the  
> material in a way to differentiate acceptable cob from unacceptable  
> cob.
>
> Ed
> On May 17, 2012, at 11:29 AM, dhowell at pickensprogressonline.com wrote:
>
>> Thanks Ron,
>> 	As I mentioned; "but no paperwork which building officials will  
>> accept."
>>
>>
>> On May 16, 2012, at 8:17 PM, Henry Raduazo wrote:
>>
>>>> but no paperwork which building officials will accept.
>>
>