A. Kantautas, G. Vaickelionis. Modified sawdust concrete // STATYBA (Civil
Engineering). Vilnius: Technika, 2000, Vol VI, No 2. P. 113–119.
Wood-cement materials are widely produced and applied in many developed
countries. In this case special prepared wood aggregates are employed. Wood
sawdust practically is not employed. Extracts, present in wood, slow down
the cement hydration. The influence of mineral additives on this process was
determined. The efficiency of mineral additives depends on their hydraulic
activity. It has been found that the mineral components (additives) of
sawdust concrete have a positive effect on cement setting and hardening due
to two reasons: 1) hydraulic and other mineral additives absorb wood
extracts from liquid phase which inhibit and retard setting of cement and
reduce their concentration in solution; 2) reduce pH of liquid phase so the
hemicellulose which is in sawdust or other wood aggregates, less
disintegrate lightly soluable sugars.
When sawdust amounts are different, the optimum cement and rottenstone
relation is not constant: y = 1,29x-0,66, where y is cement and rottenstone
mass relation, x is sawdust and binding material (cement+rottenstone) volume
relation. The influence of sawdust concrete humidity on its strength was
found: , where y is concrete compressive strength (MPa), when its humidity X
(%), R is concrete compressive strength (MPa), when its humidity W (%).
The possibility of accelerating the hardening process of concrete mixes of
cement-rottenstone (gaize)-sawdust system by means of steaming at 80 °C was
studied, too. It is impossible when producing ordinary wood-cement
materials. The physical and technical properties of sawdust concrete such as
shrinkage strain, expansion deformations and elastic modulus were
determined. Sawdust concrete contraction deformation depending on concrete
density may vary by 8…14 mm/m and expansion (in humid conditions) by 1,1…2,5
mm/m. Deformation decreases when quartz sand additive is used. When the
concrete gets dry repeatedly, deformations are smaller.
The sawdust concrete elasticity modulus is similar to that of light concrete
with inorganic additives having the same density.
Its frost resistance depends on the concrete structure and cement quantity.
When the concrete with a small amount of sawdust is used
(cement+additive:sawdust=5:1), the samples endure 75 freezing cycles. The
heat conductivity of sawdust concrete is low.
The experimental data have shown that structural thermoinsulated small
blocks can be produced from these concrete mixes.
* * * * * * *
----- Original Message -----
From: "Rex Tarr" <rex420@hotmail.com>
To: <ferro-users@ferrocement.net>
Sent: Tuesday, October 01, 2002 2:04 PM
Subject: [Ferro Cement] Re: Solar House Competition and ESSA archive link
> Keith,
> try a Google search on the phrase "sawdust concrete" (with the quotes). I
> got 108 hits, some from engineering journals.
> I recommend whitewashing your sawdust prior to using it in mortar mixes,
to
> neutralize acidity. After hearing that organic materials in the mortar can
> help concrete hold colors longer, sawdust concrete is back on the map for
> me.
> :)Rex
>
>
> ----Original Message Follows----
> From: Keith B <ferroist@comcast.net>
> Subject: [Ferro Cement] Solar House Competition and ESSA archive link
> Date: Mon, 30 Sep 2002 17:33:54 -0400
> Hi Richard,
> Familiar names indeed. I keep hitting those achives while looking for
> things relevant to this list, recently while searching for
woodcrete/sawdust
> cement references. There was a good U.S. article on that which I found in
> '00, and there's supposed to be a big report in Australia circa 1997, but
I
> can't find either. Any help in the general area? - kb
>
-----Original Message-----
From: papercreters@yahoogroups.com [mailto:papercreters@yahoogroups.com] On Behalf Of lebarongroup
Sent: Sunday, April 03, 2011 9:20 AM
To: papercreters@yahoogroups.com
Subject: [papercreters] Bark Mulch Crete?
Hi All,
I just picked up a yard of long fiber 0-4" by 1/16th to 1/4 wide green douglas fir chips from a pole yard for garden mulch.
As I was unloading it hit me... for $25 I could have more shredded "paper" than I could make in a week of chopping with my mixer.
Could one skip all or most of the paper chopping and use these long cellulose chips to make a similar material to light clay straw infill.
My studio is going to be post and beam with infill so load bearing isn't a problem.
I know this wouldn't technically be papercrete anymore but has anyone tried it? Or heard of any results of testing?
Mainly wondering if the resins would somehow interfere with the portland adhering to the material.
Thoughts, advice and real world experience would be appreciated!
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