For those interested in the health effects of portland cement, below is an exerpt from a paper by Bau-biologist George Swanson. I am currently locating the actual German study of the cellular effects of various floor types on production and will post when located.
Properties of Concrete Made with Portland Cement:
Let us now turn to concrete made with Portland cement. As a further indication as to
why ceramic cement got ‘lost’ in the shuffle, when a convenient produce such as
Portland cement becomes a fixed paradigm within the largest industry in the world, bar
none, it stands to order it would take an exceedingly better and easily assimilated
alternative to even be considered. When something that successful isn’t perceived to
be broken, why on earth do anything else but improve it!
Let’s start by looking at its health-related properties and performance characteristics of
the readily available choices. Portland cement has the tendency to take on moisture
and hold it for prolonged periods of time. This is a serious drawback from a Building
Biology standpoint. Furthermore, modern polymer additives in Portland cement often
further clod its pours causing it to be even less breathable. The most deleterious health
effects of concrete occur however, when it’s wet: it continuously outgases, and this
promotes mold growth, and also becomes a conductor of heat, cold and electricity.
It is now widely recognized that the production of concrete made with Portland cement
is a major contributor, up to 12%, to the worldwide global warming crisis. What is less
widely recognized is that the immense amount of energy that it takes to bake a Portland
cement “clinker,” amounting to roughly 3000 degrees F. for many hours, is routinely
purchased at less than 10% of what the average consumer pays for the same amount
of energy, and is thus, hugely and outrageously subsidized by the public sector.
A vivid example of this type of subsidy was revealed when Alcoa Aluminum closed
several of its plants in California for two years, paying full wages to send home
employees. Yet the company had its highest profit years in history these two years by
selling its “energy “ futures back to the people of California at an average cost of over
twenty times what they paid for it.
When building with Portland cement you must use a bonding material to enable
cellulose to adhere to it. The lime in Portland cement repels any sugars and acids such
as normally found in cellulose. Therefore you need to neutralize the sugars and acids in
wood or cellulose before binding them to concrete. This requires the use of an often
toxic adhesive, to accomplish. With magnesium oxide and clay-treated wood chips, on
the other hand, cellulose will bond to clay without having to go through the expensive
patented European neutralization process used to create products such as Durisol,
Hardiboard and Wonderboard.
In many buildings today, 50% to 90% of a solid concrete envelope (by weight) is
involved in holding up its own “dead weight”. This is a very inefficient use of resources.
Instead the wise builder should consider using a light insulative exoskeleton filling only
about 30% (or less) of the block mass with conventional concrete. Products such as
Durisol and AAC can achieve this light exoskeleton while creating enough thermal
mass in the inside of the block to provide all the benefits of documented thermal
performance, breathability and hygroscopicity discussed in previous chapters. In the
future the use of ultra high strength MgO cements could reduce the use of structural
cement materials to even less than 10%.
Harmful Health Effects of Concrete Made with Portland Cement:
Making the "clinker" in Portland cement at 3000 degrees creates a missing unstable
isotope which gives it an unbalanced charge. Concrete made from Portland cement is
therefore very electrically unstable causing these isotopes to always seek electrons in
neighboring objects in order to stabilize themselves electrically.
These isotopes created in the manufacture of Portland cement draw electrons out of
anything with an opposite charge in close proximity to a concrete slab or wall, including
people, animals or the cellulose in plants. This causes fatigue and other health
problems in people who stand or work near concrete over prolonged periods of time.
Concrete will also drain a standard car battery placed on it over a period of time. If you
place that same battery on magnesium oxide cement, however, it does not drain
electrically. The same is true with the human body; that is, magnesium oxide used as a
building material will not drain the electrical charge out of a person standing over floors
made with it, and you therefore do not feel fatigued. You can put this benefit of
magnesium oxide to use as part of your slab protocol as you will see in the next section.
Some of the most harmful effects of concrete made with Portland cement come when it
is “enhanced” with plastics. The concrete never cures, or does so extremely slowly,
which may enhance the strength of the concrete but is not healthy for the occupants of
the building. Furthermore concrete outgases and is toxic, particularly when it mixes with
mold. (The use of concrete inside clay-treated wood chip wall forms is an exception
because they allow the concrete contained within them to cure fully, drying out all their
initial moisture and any new moisture that enters later through wicking by capillary
action or through water leaks.)
The high temperatures used in the making of Portland cement makes it extremely
hydrophilic, causing a number of problems including the promotion of mold growth.
Helmut Ziehe, Founder and former Director of the International Institute of Bau-biologie
and Ecology, explains this in a recent email correspondence:
“When cement is made they use very high temperatures which in turn gets rid of the crystal water
in the limestone molecule. In making concrete, water is added and comes in contact with that
cement. Now the cement has the tendency of holding on to that water. This is an explanation for
the long drying out time of concrete. The health effect is connected to living in wet conditions
(promoted by the continual wetness of concrete) with the possibility of mold growth.”
Studies in Germany have shown that factory workers standing on concrete for more
than one hour develop a condition whereby the communication of information between
cells is interrupted in the body of the worker. This appears to cause the information
exchange from cell to cell to reduce by 30-50%. Also the “wetness” of the human cells
decreases and they become dehydrated. As a result the cells do not function properly
leaving the worker feeling fatigued.
As a remedy to this employers in Germany have made cut outs in the concrete floor of
assembly lines and replaced them with cork covered clay-treated wood chip over direct
earth for workers to stand on. By doing this the workers have been shown to increase
their productivity and decrease their absenteeism and medical expenditures. For this
reason industrial laws now exist in Germany limiting the amount of time workers can
stand on concrete to no more than one hour per day.
To remedy this in our own homes in North America we must avoid these harmful effects
and simulate the natural relationship that exists between bone and tissue by replacing
concrete with natural mineral enhanced clay and cellulose wherever possible. Our cells
know what is going on behind walls or below floors in the houses we build and much of
our general lack of health in society shows it.
Clay-treated wood chip is much closer to the ideal as a building material and has none
of the deleterious effects seen with concrete alone. This is because electron-hungry
concrete contained within a clay-treated wood chip wall draws electrons from the clay
and wood chip encasing it rather than pulling electrons from the bodies of people
standing, sitting or sleeping nearby.
The same holds true if you place pieces of crushed Durisol or Faswall under a concrete
slab. The concrete in the slab will pull electrons out of the crushed Durisol below it
rather than from the feet of occupants standing above it, as you will see in the next
section, Clay-treated Wood Chip Under Concrete Slab. This is a significant way to
reduce fatigue produced by living on a concrete slab in a home built slab-on-grade or
spending much time in a finished basement.
On 1/31/10 7:34 PM, "Robert Riversong" <[log in to unmask]> wrote:
--- On Sun, 1/31/10, Peter Nazarenko <[log in to unmask]> wrote:
An obvious fundamental: the production and transportation of concrete consumes enormous energy generating enormous pollution.
Don't confuse Portland cement with concrete. Almost all the environmental impact of concrete production comes from the mining, milling and high-temperature kilning of limestone into cement. While concrete requires sand, stone and water, they're produced locally to the end use and batch mixing plants are scattered around the county to reduce transportation costs and setting time of the finished (heavy) product.
The impact of concrete is vast because it is the second most used substance after water (3.5 tons annually for every person on earth). Its use contributes 7%-10% of the global CO2 production (about 631 lbs/cubic yard), but the 40% of that which is caused by the decarbonation of limestone during kilning is reabsorbed into the concrete over its useful life or after demolition. Because we use it by the ton, it often contributes the majority of embodied energy to a building project (1.7 million Btus per cubic yard), but much of both the embodied energy and CO2 can be reduced by using fly ash or other substitute pozzolans for the Portland cement. I am not an advocate of the use of concrete, but rather of the drastically reduced use of it in residential construction. For that reason, I do not build full basement foundations, but shallow frost-protected or rubble-trench grade beams. Eliminating the basement walls and moving the cellar slab up to grade for a thermal mass, radiant, finished floor allows a reduction of 80% of concrete volume. I would far prefer to substitute an earthen floor for the concrete slab. It's far more ecological and sustainable, far more comfortable on the feet, has about the same IR emissivity of concrete, and offers 70% of the thermal mass index of concrete and more than 80% of its thermal effusivity (ability to transfer heat to other materials). But this is a very labor-intensive process and alien enough to most people that it's a hard sell except to earth-friendly DIYers (I helped install one for the Arch Druid of Vermont in his cordwood masonry home – picture attached). Earthen floors have been used since the beginning of human habitation, the materials can be locally sourced and mixed by hand or with minimal equipment, have close to zero pollution impact and about 90% less embodied energy than concrete, are suitable for self-help construction (or community building parties), can use binders of anything from chopped straw to cellulose insulation, can be stabilized with starch paste, milk casein, glues, lime or portland cement, can have potter's oxides or stone dust mixed in for color and sheen, and can be finished with raw or boiled linseed oil or other natural oxidizing oils and waxed for a hard, durable finish that can be swept and mopped. There are few floors as beautiful and comfortable as an earthen floor, and they are amenable to radiant in-floor heating.
They are also easily maintained with occasional resealing or patching with clay, but can go 10 years between refinishing except in high-traffic areas where they should be protected.
Those who give up freedom for safety, deserve neither.
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