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#161435 - 03/03/05 09:27 PM
Re: Heavy Lifting and Ancient Stonework
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Member
Registered: 04/01/04
Posts: 1059
Loc: Dubai, UAE
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quote:
Originally posted by Wallis:
What happened to that theory that the Egyptians did use some sort of cement?
They didn't, if they did no one has found it. Their gypsum mortar wasn't particularly strong. Lime based mortars were invented by the Romans although it was also invented and lost for a brief time in Mesopotamia.
You may be remembering a theory that the Egyptians "poured" their stones. Unfortunately all Egyptian stone work found so far doesn't reflect this theory and it has fallen to the way side.
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#161436 - 03/03/05 09:56 PM
Re: Heavy Lifting and Ancient Stonework
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Member
Registered: 04/01/04
Posts: 1059
Loc: Dubai, UAE
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I stand corrected
Sorry made an error, the Egyptians did know about lime based concretes but no surviving building seems to have used it. In the few instances where it has been found it was used as a fill mixed with rubble. Egyptians used calcinated gypsum to give brick or stone structures a smooth coating and to seal and join the cut edges
Concrete has evolved over the centuries. The oldest concrete ever discovered dates from around 7000 BC and was discovered in Galilee, Israel, where it was used as an infill material rather than as a building material in its own right. This material was lime concrete, which was made by mixing burnt limestone with water and stone. Its use spread around the eastern Mediterranean and concrete was being used in Ancient Greece by 500 BC.
Possibly copying and developing the ideas that the Ancient Greeks had, the Romans started using concrete around 300 BC. In fact, more than 200 Roman bridges are still around today. The Romans discovered a pink volcanic ash and, thinking it was sand, mixed it with lime. The mixture produced a much stronger product known as pozzolanic cement, which was used in building and engineering for the next 400 years. The Romans also developed lightweight concrete by using pumice, a very lightweight rock, as an aggregate. Aggregates, made of stone or sand, are the main raw material used in the making of concrete.
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#161441 - 03/05/05 03:29 AM
Re: Heavy Lifting and Ancient Stonework
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outcast
Member
Registered: 11/13/01
Posts: 1768
Loc: Portugal
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quote:
Originally posted by JohnWayne:
Egyptians didn't use that method for large scale cutting, they used driving wedges or hammer percussion. The drilling method was for cutting selective holes.
quote:
The forms of the tools were straight saws, circular saws, tubular drills, and lathes.
The straight saws varied from .03 to .2 inch thick, according to the work; the largest were 8 feet or more in length... ...No. 6, a slice of diorite bearing equidistant and regular grooves of circular arcs, parallel to one another; these grooves have been nearly polished out by cross grinding, but are still visible. The only feasible explanation of this piece is that it was produced by a circular saw.
quote:
These tubular drills vary in thickness from 1/4 inch to 5 inches in diameter, and from 1/30 to 1/5 inch thick. The smallest hole yet found in granite is 2 inch diameter.
At El Bersheh... there is a still larger example, where a platform of limestone rock has been dressed down, by cutting it away with tube drills about 18 inches diameter; the circular grooves occasionally intersecting, prove that it was done merely to remove the rock.
Sir William Matthew Flinders Petrie
quote:
The ancient builders used a tube drill to hollow out the sarcophagus in the King's chamber of the Great Pyramid - they drilled off course and left a tube drill mark on the top inside of the box on the east side. They did some extra polishing to fix it up a bit but if you go to the King's chamber you can still see it if you look carefully.
Looking at the radius of the cut in the sarcophagus (less than 2") it is obvious that in this one piece alone the masons made thousands of holes - each several inches deep. The craftsmen who did this had mastery of the principles of drilling round hollow holes in any material, soft or hard: wood, stone, or metal, and could have drilled virtually any naturally occuring material on this planet.
Robert Francis
_________________________
"There is no adequate defense, except stupidity, against the impact of a new idea."
Percy Williams Bridgman (1882-1961)
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#161444 - 03/05/05 09:57 AM
Re: Heavy Lifting and Ancient Stonework
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Member
Registered: 04/01/04
Posts: 1059
Loc: Dubai, UAE
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Egyptian stone quarries
As one would expect, extracting materials from hard stone quarries was significantly more difficult for ancient Egyptians than from their soft stone counterparts. The tools necessary to remove and shape blocks from bedrock had to be as strong or stronger than the rock being cut, and for this reason metal tools could not be used. Instead, workers would chip away at hard stone with tools made from comparatively harder types of stone. Such is the case with the extraction of granite, where dolerite balls were pounded against the rock's surface in order to cut into it.
Granite was used as a building material by the Egyptians throughout most of the dynastic period. Djoser's funerary complex at Saqqara marks the first time it was used extensively, but by the 18th and 19th dynasties it had become the third most used architectural material after limestone and sandstone. Initially, builders obtained granite by simply working large, loose boulders that dotted the outskirts of the upper Nile valley near Aswan. Obviously, the supply of these boulders quickly ran out as architects began to fully utilize the stone for its structural and aesthetic properties. It became apparent that granite would have to be quarried from bedrock, and no place could provide this more easily or abundantly than the source of the early boulders, Aswan. Marked by its magnificent cataracts(the northernmost in Egypt), the Aswan region would be able to supply ancient builders with all the granite they could ever use.
In order to see how granite was extracted from Aswan by the ancient Egyptians, it is best to look at abandoned quarries such as the famous unfinished obelisk. This massive site was originally intended to become the source for the largest obelisk ever made (when erected, it would have been 42 meters high). Work on this colossal feat was halted late in its development because of the discovery of cracks in the rock that would threaten the obelisk's structural integrity. Though its size was abnormal, it is evident from remains at the site that the unfinished obelisk was cut out of bedrock using the method suspected to have been implemented at other granite quarries. Workers would cut away a trench of about 75 cms all the way around the block intended for removal by pounding at the surrounding bedrock with the dolerite balls mentioned previously. Each worker would have his own quadrant in which he would chip the rock in one corner until told to change position and work another corner. After the trench had reached its desired depth (a bit deeper than the depth of the block being quarried), workers had to cut out enough rock from underneath the block so that it could be broken free by massive wooden levers.
The incessant noise of dolerite balls pounding, knee damage due to kneeling all the time, and other factors led to what would seem to be a rather miserable existence for quarry workers. It was not necessary for these to be skilled laborers, so it is often theorized that prisoners of war or other people in unfortunate situations did most of the work. Most studies of ancient Egyptian quarrying techniques for hard stone have focused on granite, but we know that quartzite at least was not obtained by pounding around it with dolerite balls. Instead of having relatively vertical walled trenches, quarries of this rock featured walls stepped in one foot increments. These steps were cut by creating a crack in the rock with huge diorite chisels and then breaking off the remainder
http://www.duke.edu/~jpw5/quarries/hardstone.html
Aside from mud brick, soft stone was the most frequently used long-term building material in ancient Egypt. Within this rather vague category, the limestone and sandstone dominated Egyptian architecture. Though the characteristics of different types of these stones varied greatly, the manner in which they were quaried did not. Limestone was used as a building material from the third Dynasty and was a constant in Dynastic architecture ever after. It was quarried throughout the east bank of the Nile near Cairo and the rest of the Delta region. Sandstone was not introduced as a building material until the eleventh Dynasty and was found between Esna and Gebel Barkal in Upper Egypt.
Both of these types of stone were extracted mainly in the open quarry fashion. In this situation, masons and engineers would look for a sloped area in which the bedrock was easily accessible. After clearing any dirt, sand, and rubble from the rock face, workers would cut a grid whose cells were separated by narrow working channels. Because of this, many blocks could be worked at the same time. To remove a block, workers would dig out about half of its underside and place blocks of wood in the newly created spaces. Then channels would be flooded and the wood would be expanded, thus breaking free the stone block. When combined with the shear size of some of the quarries (notably that at Beni Hasan, which extended for miles), this system allowed ancient Egypt to be able to produce soft stone in extremely high voloume and at a relatively low cost.
Another factor that led to soft stone's high volume was the development of new tools used to cut it. In order to cut a stone block from the bedrock, one would use both metal and stone tools. As Rosemary Klemm showed in Stein und Steinbruche im alten Agyptem, metals tools went through a significant evolution at the beginning of the New Kingdom, when the copper that chisels were made from was replaced by significantly more durable bronze.
When compared to hard stones like granite, it is easy to see why soft stones such as limestone were used to most often in construction. The production speed and costs of hard stones could not compare with those described above, and innovation in the techniques of their quarrying were almost nonexistent. In special cirucumstances, however, the quarrying of soft stones could be as expensive, time consuming, and dangerous as that of granite. Often a builder would want to use only the best limestone, such as that of Tura near Cairo. Any supplies near the surface of this extremely high-grade stone quickly dissapeared, but instead of looking for another source, quarrymen often decided to construct covered quarries. Covered quarries were esentially man-made caves that when fully exhausted could be hundreds of meters long. The process by which these caves were extended (and thus stone was extracted) was quite tedious. Workers would cut a small passage at the top of the back wall and then cut down behind the block intended for removal, as in the diagram in this page. To remove the block, the water and expanded wood system was used.
http://www.duke.edu/~jpw5/quarries/softstone.html
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