Posted on 12/09/2006 4:41:35 PM PST by Maelstorm
At least one Pa. university seems to be producing something worthwhile.
ping
Portland cement injects a large amount of the world's carbon dioxide into the atmosphereIs this sentence supposed to make sense?
Wonder if it was a later repair job???
No! Volcanos spew alot of CO2 into the atmosphere but no one in academe seems to care!
This looks like an answer in search of a question.
whats the agenda here? and why so long to figure out the difference between concrete and stone?
I wonder about that, too.
"Carbon dioxide emissions from a cement plant are divided into two source categories: combustion and calcination. Each accounts for about one-half the total CO2 emissions from a cement manufacturing facility. The combustion-generated CO2 emissions are related to fuel use. The calcination CO2 emissions are formed when the raw material is heated and CO2 is liberated from the limestone. Calcination is a necessary key to cement production. Therefore, the focus of reductions in CO2 emissions during cement manufacturing is on energy use, and since 1975, the cement industry has reduced GHG emissions from fuel use by 33 percent. Today, the cement industry accounts for less than 1.5 percent of U.S. CO2 emissions, well below other sources such as electric generation plants for heating and cooling (33 percent), transportation (27 percent), and industrial operations (19 percent)."
http://www.bipac.net/page.asp?g=PCA&content=issue_greenhouse&parent=PCA
Had to go look.
GGG ping
Cement manufacturing is the third largest cause of man-made carbon dioxide emissions. While fossil fuel combustion and deforestation each produce significantly more carbon dioxide (CO2), cement-making is responsible for approximately 2.5% of total worldwide emissions from industrial sources (energy plus manufacturing sectors).
Cement is a major industrial commodity. Manufactured commercially in at least 120 countries, it is mixed with sand and gravel to make concrete. Concrete is used in the construction of buildings, roads, and other structures, as well as in other products and applications. Its use as a residential building material is particularly important in countries where wood is not traditionally used for building or is in short supply. Annual CO2 emissions from cement production in nine major regions of the world are shown in Figure A below.
Large quantities of CO2 are emitted during the production of lime, the key ingredient in cement. Lime, or calcium oxide (CaO), is created by heating calcium carbonate (CaCO3) in large furnaces called kilns. Calcium carbonate is derived from limestone, chalk, and other calcium-rich materials. The process of heating calcium carbonate to yield lime is called calcination or calcining and is written chemically as:
CaCO3 + Heat -> CaO + CO2
http://www.cs.ntu.edu.au/homepages/jmitroy/sid101/uncc/fs030.html
Explains the form lines plainly visible in the cantilevered passageways. Forty years ago before polymers were kewl, my brother, a retired stonemason, said the walls were probably poured in some sections. Why not? Plenty of sand around. Add a little water and stuff, mix well, and viola! A pyramid.
Paint it white for the albedo effect. Global warming fixed!
This is nothing new. I read several articles with microphotography back in 1989 by a Professor Davidowits published in Concrete International.
I was persuaded by these articles that this was worth investigating. The type of cement used has different common names but the technical one is alkalai-activated alumino-silicate cement. This cement is quite distint and different from ordinary portland cement and has several advantages over portland cement such as durability, strength, dimensional stability (non-shrink) and rapid cure.
What doesn't make sense is this guys apparent assertion that block were cast and then dragged into place. It makes for more sense, if you are using concrete in the first place, to cast the blocks in situ.
This is not a new theory.
It appeared many years ago and was discredited.
Is this sentence supposed to make sense?
Isn't it obvious? Ancient Egyptians caused global warming!
That explains why the pyramids are in a desert!!!!!!! <;^(
Years ago, the Smithsonian proved that, with the use of only eight pieces of wood, large stone blocks could be easily moved with just a fraction of the manpower. They do this by forming two wooden "wheels", held together with pins, which turn the rectangular blocks into cylinders.
To build a pyramid, you first lay the bottom layer of stones, and then you pile dirt around them to form a dirt ramp that you can then roll the next layer up. Eventually, all but the top of the pyramid is covered with dirt. And when it is done, take away the dirt and there is your pyramid.
Dirt ramps were long since used in the region. Perhaps the most famous example was the giant dirt ramp used to attack Masada, in AD 70, by the Romans--far larger and more complex than anything the Egyptians would have needed.
Now if things were so relatively easy, compared to the traditional model, at the pyramid site, it would also explain why the quarry and stone carving cities have been found, but no equivalent giant slave city to actually build these same pyramids.
As far as the concrete blocks, I would think that when making the majority of the pyramid, the blocks could be somewhat irregularly sized. However, for the final outside layer, you would want them as regularly sized as possible--hence molded concrete blocks, for aesthetic reasons.
The reason that such blocks only seem to exist at the top of the pyramid can be explained by the fact that many of the lower blocks were long ago looted for other buildings.
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