Cob: Origins of Cement vs Cob

[SANCO Enterprises <Paul & Mary Salas>]

John Schinnerer wrote:

> Aloha,
>
> -----Original Message-----
> From: SANCO Enterprises <Paul & Mary Salas>
> >What you described in your test example does not correlate to
> >any ASTM test method for the material. Compression, modulus of rupture
> >and absorption are accepted test standards and should be utilized if one
> >is going to compare similarities or differences between materials.
>
> ...and neither the "homebrew" tests described nor the comparable ASTM tests
> deal with the materials as actually used in a completed structure.  Bits and
> sheets and bricks and blocks of small sizes are not a cob house, nor is a cob
> house made of these bits but rather of a relatively monolithic mass of cob
> shaped in ways that have a lot to do with the viability (or not) of the
> building.

John, I could respond in a very indepth manner to the "less than optimum"
(borrowed form John Fordice) manner in which you view accepted test practices,
however in fairness to others, I will be brief.

Unless a person has a strong civil engineering or extensive construction
background, one can be lead to believe that ASTM tests, codes and building
standards are nonsense and should be done away with. When one experiences
structural failures of every sort during a 35 year career, there is a greater
appreciation for the standards and an inner aversion for the builder who
willfully fails to install the proper materials. It becomes an analytical
process where you recognize the rationale behind the establishment of the code
or standard. It is true that sometimes an existing standard is adapted to
another material that is similar yet different. Adobe, cod, monolithic earth and
rammed earth falls into this adaptive mode. Another major issue is how to
encompass earthen materials as a whole, i.e., cob, adobe, rammed earth, puddled
earth, monolithic adobe, pneumatically applied earth, soil bags, earth ceramic
firing, soil cement and others.   The commonality is all these methods is that
they all use earth as the base material.  Is it necessary to have a different
code and a different standard for each?  I say NO !!!!

You are very incorrect in your assumption that cob and earthen materials are not
tested in the manner that they are used. Not only my work but that of Dr. Fern,
Paul G. McHenry and many, many others have documented the performance of rammed,
earth, adobe and. puddled earth (cob).

Our lab work at UNM is a precursor to full scale walls and then structures to be
SCIENTIFICALLY tested.  ASTM standards evolved as new materials were introduced
into the building industry.  If it is necessary to develop a new test procedure
or revise one that more appropriately tests a material, then a petition with
full documentation must be submitted.  Just because a stand alone code or
standards don't exist for cob, do we just complain about it and do nothing? If
someone like John Fordice doesn't take the initiative to try and make some thing
happen as far as a code is concerned or a company like SANCO Enterprises doesn't
undertake to test and document the performance characteristics od the medium,
then nothing will ever change and sustainability will continue to diminish and
all can continue to pay excessively for their stick built housing.


Paul Salas
SANCO Enterprises, LLC
Albuq., NM