Hemp Cement

[Janosh]

http://www.brasschecktv.com/page/491.html
Check this out! Hemp cement, stronger than Portland cement.

[c-ray]

yeah mon
fine ground hemp hurds + fly ash + lime + sand in the right proportions = hemp pozzolan
the key is to soak the lime for a while like a month or more
and ideally make the ash from hemp stalks

[Landry]

That's pretty cool

[Janosh]

Hey C-Ray,
You got that exactly right! I have been researching pozzolons for about 8 years. I even have a stucco pump for spraying mortar. I haven't used it yet, but fibered mortar can be sprayed over anything. You can pile up snow. cover it with a tarp, plastic, hemp bags, etc. and spray it, bury it, plant bushes on top.....
Mortars can be light weight and insulative or heavy dense thin and flexible.
Maybe we can trade database info. I have a bunch.
Now that the greenhouse is up its time to build tanks for heat storage and battery cases and other usefull containers.

[c-ray]

sorry that's all the info I have
I was fortunate to find out about pozzolan from an environmentalist in '96 ...and in 2000 while hiking randomly came across a house coated in hemp pozzolan based stucco
the owner had commercial aspirations at the time so I did not get the exact recipe just the ingredient list that I posted above
he claimed it was very water resistant, while a standard concrete will actually absorb moisture
the pozzolan reaction is a complete chemical reaction while portland cement is incomplete and will continue to react for aeons
the stucco was about 1/2" thick as I recall and also another interesting benefit was that no stucco wire was required...I guess it reacted and fused with the preceding layer quite well (which was regular plywood if I recall correctly)
it might make for an excellent roof coating, or could be made into roof tiles
polishing would probably make it waterproof

also I should mention the type of lime was calcium hydroxide aka hydrated lime

here is the wikipedia page on pozzolan (http://en.wikipedia.org/wiki/Pozzolan)

[c-ray]

I am thinking also that other plants like switchgrass, big bluestem, bamboo, rice and flax would work too
needs to be tested though

[Janosh]

There is a plant called Horstail around here that grows in sandy gravely areas nothing else does and it is high in silicone. What I understand is that the ash contains reactive silicone that combines with minerals in other soils and constituents. Fiber on the other hand lends reinforcement to the mortar giving it strength and resilience aided by fines in clays, and lime in the presence of water. keeping water ratio as low as is workable increases strength and decreases permeability. Permeability allows moisture to absorb into the matrix which can cause damage during freeze thaw cycles.

[c-ray]

ahh yes horsetail...the highest plant source of silica

[c-ray]

I have seen references to algae, polygonum (http://en.wikipedia.org/wiki/Polygonum) and casuarina (http://en.wikipedia.org/wiki/Casuarina) being high in silica as well
the casuarina is like a horsetail tree, for the tropics and subtropics

[c-ray]

from http://cat.inist.fr/?aModele=afficheN&cpsidt=1861194
[QUOTE]Titre du document / Document title
Study of pozzolanic properties of wheat straw ash

Auteur(s) / Author(s)
BIRICIK H. (1) ; AK

[Janosh]

I think coal ash can be used as cement additive though consistency may be a limiting factor. Even lacking pozzolons characteristics it makes a good aggregate to a mortar mix and in refractories.

[c-ray]

from http://www.citypaper.net/articles/2009/01/22/drexel-michel-barsoum-egyptian-pyramids
Pyramid Scheme
A Drexel professor has some concrete answers about how the pyramids were built.

by Patrick Rapa
Published: Jan 21, 2009

"Right now everybody thinks the Romans invented concrete," says Michel Barsoum. "Well, I've got bad news for the Romans. The Egyptians did it 2,000 years earlier."

Barsoum, a Cairo-born professor in the Department of Materials Science and Engineering at Drexel University for the past 20 years, says the theories that modern science have devised to explain the construction of Egypt's Great Pyramids are wrong.

He believes that some of the blocks (weighing as much as 15 tons each) which make up the three largest pyramids on the Giza Necropolis weren't quarried, hauled and carved as most scientists believe.

They were made to order via reconstituted limestone. An early, super-strong version of concrete. Barsoum's theory, naturally, has been treated as heresy in the world of Egyptology.

It's a simple formula; see How to Make Barsoum's Blocks . That's the recipe Barsoum and his students have been cooking up in a dusty, spacious lab in the basement of Drexel's Lebow building at 31st and Chestnut.

Actually, cooking isn't the right word. This stuff is so environmentally friendly it requires no heat, beyond the creation of lime, to create. It's strong, too. Today's construction standard, Portland cement, breaks down after 150 years and leaves a considerable carbon footprint. The pyramids, built without the luxury of mixers or dump trucks (not to mention the wheel), are some 4,500 years old. If some of the blocks are made of concrete, as Barsoum's research shows, it's not just archaeologists and historians but engineers, environmentalists and humanitarians who should take notice.

"The only CO2 this will produce is [in] transportation," marvels Barsoum, opening up a Tupperware container of 1-inch pyramid models. He and his students have founded a company to develop the concrete. (He's also part of an international team working on another recipe, one that incorporates slag, the molten byproduct of steelmaking — mountains of which are accumulating at industrial sites around the world.)

But it's this simple Egyptian concrete, he says, which not only provides the answer to one of the greatest mysteries of all time, but will help people in struggling countries today. "If they could build something like this 4,500 years ago, there's no reason why a poor African farmer can't. You just tell him, take some of this dirt, some of this dirt, grind it up, put it together, make yourself a brick and build yourself a house that should, in principle, last 2,000 years."

Science has never been able to prove its consensus conclusion on how the pyramids were built. There are about 100 of these burial structures in the Giza area, but none of the immense ramps or copper chisels researchers theorize were used in their construction have ever been found.

Some blocks are placed so tightly next to each other that you can't slide a human hair in the crack between them. And the Great Pyramid of Khufu, constructed of 2.3 million limestone blocks, was apparently assembled in about 20 years. Nobody's quite sure how, even with a crew of slave laborers, the ancient Egyptians could pull that off.

That said, new discoveries are still out there to be made. The 4,300-year-old mummified remains of Queen Seshseshet were dug up earlier this month, in a pyramid that went unnoticed until a month before.

In 2006, Barsoum published a paper called "Microstructural Evidence for Reconstituted Limestone Blocks in the Great Pyramids of Egypt." Some of the findings contained within can be a little tricky for a layman (like this reporter) to grasp. Basically, samples from various parts of the pyramids were compared with each other, as well as limestone from elsewhere in the region, and microstructural inconsistencies were found. The quarried ones, he said, differed from the reconstituted ones.

The paper also cited the visible differences in certain kinds of blocks. In the 1800s, a British Egyptologist blasted his way into the southern face of the Great Pyramid with gun powder. The remaining hole allows one to view the smooth uniform arrangement of the outer blocks alongside the rounded, irregular stones further in. Barsoum postulates that the smoother stones — the ones that make up the outer and inner casing and possibly a large portion of the pyramid top — are the ones made of concrete. The rough stones, about 80 percent, then, are the ones quarried and hauled into place.

Barsoum's theory allows for imprecise chisels and far fewer ramps, and requires only materials available in ancient Egypt. Some Egyptologists admit he makes a strong case. Others are not convinced.

Barsoum thought about quitting several times during his eight years of research on the project. "I did not want to be the guy to demystify the pyramids," he says. "Mysteries are good for the soul, as long as you don't take them too far. As long as you don't go into conspiracy theories and all that."

There's always the little problem of getting lumped in with the non-scientific theories ancient Egypt seems to attract. There's the idea that the pyramids were nuclear reactors, giant batteries or alien outposts, for instance.

"So many kooks, so many theories. Everybody and his brother has a theory about how they were made. And most of them are crackpots," says Barsoum.

By comparison, his "concrete" concept should be a much easier sell to the science establishment, but he has certainly been met with resistance. When he gives his presentation at schools and conferences, he estimates he can convince 80 percent of an audience of the merits of his research. The remaining skeptics, he notes, sometimes become very angry. His blog, pyramids.blog.com, and inbox have seen their share of venomous comments. "You should see this one guy how he lays into me. It's fascinating," he says.

"I have to be very careful giving this talk because you could very easily destroy your career. That's a risk I did take."

Barsoum did not invent the concrete theory, and he freely admits he laughed the first time he heard it. Joseph Davidovits of France broached the subject in 1988 in a book called The Pyramids: An Enigma Solved. Twenty years on, he's a successful pioneer of geopolymer research, but utterly unrespected by mainstream archaeology.

Barsoum, whose recipe differs from Davidovits', never intended to devote so much time and effort to the pyramids. He has a day job. After hearing about the concrete theory from the friend of a friend, he figured he could disprove it quickly with an electron microscope. No such luck.

Penn-educated archaeologist Zahi Hawass, secretary general of the Egyptian Supreme Council of Antiquities and director of the Giza Pyramids Excavation — aka the curator of the pyramids, the Sphinx, and everything else — seems particularly incensed by the notion. Attempts to reach him were unsuccessful, but Hawass told the Mirror of London in April of 2006 that the book was closed on how the pyramids were built. "They're made from solid blocks of quarried limestone. To suggest otherwise is idiotic and insulting."

"He is not amused," smiles Barsoum, who is still hopeful he and Hawass will cooperate on research in the future, despite Hawass' vitriolic reaction.

"The mystery sells, that's part of it."

Some people, he figures, believe the sheer brawn required for the chisel-and-ramps scenario is somehow better than the brilliance of inventing a concrete stronger than people are making today.

"I've had people get up at the end of my talk, look at me and say, 'This is bullshit!' and walk out."

But ... insulting?

"People take the pyramids personally," says Barsoum. "It's strange. Of all the monuments in the world. ... If I was talking about the Parthenon or the Taj Mahal or whatever, nobody would really give a damn."



[B]How to Make Barsoum's Blocks

Mix the following items:

water
lime (made by heating limestone)
diatomaceous earth (a crumbly, porous rock made of fossilized algae)
limestone rubble (ground to powder)

Let it evaporate for a few days until it's got the clumpy consistency of wet sand. Pour it into a mold. Stamp it down. Let it sit. Once it's hard, move the mold over and make another block alongside the first one, thus ensuring a tight fit. Repeat.

[c-ray]

from http://www.edie.net/news/news_story.asp?id=16265&channel=0&title=How+good+is+hemp+and+lime%3F+Study+pins+down +performance
How good is hemp and lime? Study pins down performance
April 9, 2009

The environmental potential of hemp as a building material has never really been in doubt - it absorbs carbon as it grows and can be grown almost anywhere, cutting down on the need for energy-intensive transportation.

But is it any good?

A study underway at the BRE Centre for Innovative Construction Materials at the University of Bath is attempting to clear up any doubts.

"The idea of using hemp and lime has been around in the UK for ten or 12 years now and there have been a number of applications but there's still relatively little scientific information on the performance of the materials," Prof Pete Walker, director of the centre, told edie.

"We've identified this as a significant barrier to market uptake."

He said that mainstream engineers, architects and buyers were shying away from a potential tool in the fight against climate change due to the absence of reliable independent information on its characteristics.

The research project is providing concrete answers to the questions of the construction industry and also experimenting with different ratios of hemp to lime in an effort to maximise its carbon cutting potential.

"The lime has all the embodied carbon and energy and, if we're honest, the cost," said Prof Walker.

"The hemp offsets this. Using renewable crops to make building materials makes real sense - it only takes an area the size of a rugby pitch four months to grow enough hemp to build a typical three bedroom house.

"Growing crops such as hemp can also provide economic and social benefits to rural economies through new agricultural markets for farmers and associated industries."

Hemp-lime is a lightweight composite building material made of fibres from the fast growing plant, bound together using a lime-based adhesive making it better-than-carbon neutral.