Papercreters: [papercreters] Re: Heat curing papercrete appears to improve tensile strength.

Wednesday, June 24, 2009

[papercreters] Re: Heat curing papercrete appears to improve tensile strength.

Thanks for this testing information Slurryguy. I want to test some of the blocks I've been making to see the differnces, if any, in the different mixes I've used. I really like the blocks I've made out of the clay that I have here. They shrink more than with cement in the mix but the price is right. They also dry agonizingly slow but are very hard and solid once they do dry. Anyway, the temperature hit 110 today in the AZ Outback and the temp tonight is still over 90 so the drying will speed up considerably. 115 to 118 is common from here til the end of August, ideal for drying blocks,....... and sweating.

--- In papercreters@yahoogroups.com, "slurryguy" <slurryguy@...> wrote:
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>
> I don't use a fish scale to compression test at all. For compression testing I use a piece of scrap steel as a second class lever to get a mechanical advantage, a hydraulic bottle jack, and a bathroom scale. Keeping the sample size as small as possible is very helpful to prevent the forces from getting too crazy large. The beauty of the lever is that you can adjust the fulcrum, load, and jack locations to prevent overloading the bathroom scales. Of course, accurate fulcrum, load, and pressure point distance measurements are important so that you can calculate the amount of mechanical advantage the lever is providing from the scales and jack to the sample. Of course, the larger the mechanical advantage of the lever, the greater the margin of error is in the measurement.
>
> A fish scale can be used for tensile tests if the sample is small enough also. It's a fairly straight forward process. Clamp the sample on both ends, hang it up with the scale, pull on it until the sample tears apart. Read the maximum force applied to the scales.
>
> ***WARNING*** Be prepared for the sample to rip apart rapidly. Don't just pull on it directly with your hands because when it lets go it will snap toward your hands, and maybe other body parts (face, eyes, head) and can easily injure you. Looping your pull cable around a pully is a good safety tip. Then the flying loose end will fly toward the pully, and not toward you. TRUST ME. I've learned this very painful lesson through the school of "hard knocks."
>
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> Professional laboratories would scoff at such poorly calibrated techniques, but you'd be surprised what you can learn by these crude experiments.
>
>
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> --- In papercreters@yahoogroups.com, Evelyn Vollmer <evelynanne8@> wrote:
> >
> > How do you use a fish scale for testing the compressive and tensile strength
> > of blocks?
> >
> > On Tue, Jun 23, 2009 at 9:27 AM, donald1miller <donald1miller@>wrote:
> >
> > >
> > >
> > >
> > >
> > > Given the water absorbency of PC, how will you be able to use them as
> > > shingles or siding? Not being sarcastic, just playing devil's advocate. I
> > > also think from my use of heavy cardboard for pulp that it may have more
> > > tensile strength than PC made with newsprint. Do you have a simple home
> > > based method of testing the compressive and tensile strength of blocks? I
> > > think you mentioned using a big fish scale. I haven't done any testing so
> > > any help here would be appreciated.
> > >
> > > --- In papercreters@yahoogroups.com <papercreters%40yahoogroups.com>,
> > > "slurryguy" <slurryguy@> wrote:
> > > >
> > > > With your arid location, I don't see a practical benefit in trying to
> > > pour a slipform wall of papercrete and heat cure it. You won't be needing
> > > the papercrete to have a lot of tensile strength the way you are using it.
> > > >
> > > > If my initial discovery is confirmed by further testing, I think the
> > > concept has applicatons in other areas. For example:
> > > >
> > > > Fibercement Shingles
> > > > Fibercement Clapboards
> > > > Fibercement Window Trim
> > > > Fibercement Mouldings
> > > > Papecrete Panels
> > > > Papercrete Structural Inslating Panels
> > > > Perhaps even fibercement wallboard
> > > >
> > > > Stuff like that. Those items require a certain amount of tensile stregth
> > > or they don't work well.
> > > >
> > > >
> > > > Take shingles. I can imagine compressing damp slurry into shingles in a
> > > device constructed similarly to a Tortilla Press, but more rectangular, and
> > > then curing them in a solar oven.
> > > >
> > > > I can imagine creating something like an oversized Pasta Roller that
> > > could roll-compress a long flat board as a clapboard. A layer of slurry
> > > could be spread evenly on a long piece of window screen and compressed
> > > through the roller. The press might also have a wood grain texture in the
> > > top roller to give the clapboard an attractive surface texture. Heat curing
> > > them in a large solar wood kiln type structure might work well.
> > > >
> > > >
> > > > Of course... more experimentation is needed to confirm my suspicions
> > > about improved tensile strength. Even if there is improvement by heat
> > > curing, will it be enough additional strength to perform well in any of the
> > > above applications?
> > > >
> > > > I don't know. I'm just questioning aloud at this point.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --- In papercreters@yahoogroups.com <papercreters%40yahoogroups.com>,
> > > JUDITH WILLIAMS <williams_judith@> wrote:
> > > > >
> > > > >
> > > > > That's very interesting. I'm already wondering........"How can I pour
> > > my slurry into a mold that is actually a solar oven?" Then they would be dry
> > > in no time, and stronger as well. What about a slip form wall with some sort
> > > of solar reflector and good ventilation?
> > > > >
> > > > > As far as what I learned over the weekend? It's OK to lounge on a sofa
> > > bed outdoors under a large beach umbrella and watch other people work.
> > > > >
> > > > > Sincerely, Judith
> > > > > Visit my new website at http://www.papercretebyjudith.com
> > > > >
> > > > > More info at www.judith-l-williams.com
> > > > >
> > > >
> > >
> > >
> > >
> >
> >
> >
> > --
> > Chinese herbals for the Western Mind
> > www.ozbotanicals.com
> > Skype~eve8mon
> >
>