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RE: Rammed earth construction

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I'm curious on how you get anchor values (epoxy anchor I assume), say in
a ledger condition.


From: Thor Tandy [mailto:vicpeng(--nospam--at)] 
Sent: Friday, October 31, 2008 9:39 AM
To: seaint(--nospam--at)
Subject: RE: Rammed earth construction

I do RE in BC, Canada.  If I can help ...
1)  Get lab tests done on the available material - material is
site-specific and needs care in selection.
2)  Generate several particle-size gradings of the material and develop
"mixes" that when tested give the "best" behaviour.
3)  Decide what, if any, admixtures you might want to add.  Eg: cement,
flyash, other pozzolans etc that may be beneficial to the final working
4)  If you decide to go reinforced RE and cement stabilized RE then make
sure that you are comfortable using the masonry block design standards.
Most engineers use masonry or concrete.  While masonry approximates what
is essentially a cement-stabilized aggregate, I'm not convinced yet.
5)  For further information on material choice, SIREWall Inc here on
Saltspring Island, BC has over 15 years of aggregate sampling
experience, design of RE structures, and has a fund of knowledge on the
behaviours of RE material in Canada, China and the US.  I am one of
their structural consultants so we familiar with their work.
6)  I don't know Rwandan climates but while RE does perform well in wet
and cold climes, it is prudent to design with reasonably large overhangs
of the roof.  Verandahs are an excellent way to protect.
7)  If you go with cement-stabilized RE then curing is as important as
in conc. construction.
8)  There is a lot of info on the internet.  Peter Walker of Bath
University, UK has done much research on un-reinforced RE and Kepa
Morgan of Auckland University, NZ and done a lot of work with
fibre-reinforced RE.  If you go with unreinforced and no-additive RE
then I recommend those 2 Profs will be of great help.
Hope this helps you get started.  If you need any further assistance
then please contact me privately.

Thor A. Tandy P.Eng, C.Eng, Struct.Eng, MIStructE
UNISOL Engineering Ltd
Unit 7 - 625 Hillside Ave
Victoria, BC, V8T 1Z1
Tel/Fax: (250) 382-9115
Email: vicpeng(--nospam--at)

	-----Original Message-----
	From: Michael Hemstad [mailto:mhemstad(--nospam--at)]
	Sent: Friday, October 31, 2008 10:17 AM
	To: seaint(--nospam--at)
	Subject: Rammed earth construction
	I have a project in Rwanda on which my client wants to try some
alternative means of construction.  Rammed earth and straw bale
construction have come up.
	(For those who haven't heard of these, rammed earth is made by
building wall forms, placing soil in them, and pounding it until it
rings.  It makes a durable, fireproof wall with local materials and
labor.  Straw-bale construction involves stacking straw bales, often
dowelling them together with wood dowels, then applying thick parging to
each side.   This apparently results in a strong, fireproof, relatively
durable wall too, although I know less about it than rammed earth.)  
	Does anyone have information on either of these?  I am
specifically looking for information on what soil properties are needed
for a successful rammed-earth installation (e.g. clay content, sand
content, moisture content).  I don't yet know whether a geotechnical
engineer is available to the project; so information of the "holds
together as a ball when dropped" type is also appreciated.
	I appreciate any help, or alternate suggestions.
	Mike Hemstad, P.E., S.E.
	Minneapolis, Minnesota