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Keramický zpravodaj 27 (2) (2011)
THE PYRAMID OF KHUFU (CHEOPS)
Unlike Egyptologists, Davidovits [3] considers Khufu’s Pyra-
mid a work composed of geopolymeric (man-made)
blocks. He rather speaks about artificial mould blocks than
about blocks of quarried limestone. According to him, the
most typical geopolymers are external casings [3]. The
pyramid itself is located on the Giza Plateau together with
smaller Menkaure’s, and Khafre’s pyramids. Particularly the
pyramid of Khufu (Cheops) is considered by Davidovits as
“man-made”.
Khufu decided to build his pyramid on a bastion in the
western desert near today’s Giza. Moreover, this rocky
spur simplified and strengthened the structure of the core
[10]. The construction lasted approx. 23 years during the
ruling period of the Pharaoh Khufu.
Originally, the pyramid was composed of 210 courses,
now they are 203. The blocks are 1.5 – 1m high, and get
smaller with increasing height.
CHEMICAL METHOD OF THE “MANUFACTURE”
OF A GEOPOLYMERIC MOULD BLOCK
According to Davidovits’ theory, the in situ manufacture of
blocks was used [3]. A mixture of materials was carried to
a wooden formwork, where it quickly solidified due to
solar radiation. A detailed calculation of the number of
workers is rather complicated with respect to the more
distant sources of input raw materials for the manufactu-
re, and is a subject of controversy for many Egyptologists.
Estimates range from 20,000 to 100,000 workers (Hero-
dotos is the author who gives the highest number and
expressly points out that they were slaves). Davidovits’
theory would explain the construction of the pyramid with
a much smaller number of workers, and considers 1,500
labours. This was particularly the reason it became very
attractive for non-specialists who had not been to Egypt
and could not see clear evidence of a much more labori-
ous construction.
EVALUATING THE METHODS OF THE KHUFU
PYRAMID CONSTRUCTION
According to the traditional view [10], Khufu’s pyramid
was built of quarried blocks of stone from nearby quarri-
es. As the wheel had not yet been invented, we can exclu-
de any use of pulleys or other equipment based on the
wheel principle. Workers probably transported the stone
block by means of various ramps. These ramps were alle-
gedly made of unfired bricks and were splashed with Nile
water to improve their slippery characteristics. Very pro-
bably, these limestone blocks were placed on wood sled-
ges pulled by workers with the help of animals on the
above-mentioned ramps to the destination.
Contrary to this, Davidovits describes the formation of
blocks in situ, where the mixed mass was transported in
wicker baskets and placed in formwork the size of the
blocks in question. In the following paragraphs, I try to
specify the number of workers necessary for the transport
of this key material.
Number of workers necessary for the construction
of Khufu‘s pyramid
The construction of Khufu’s Pyramid has a number of mys-
terious aspects. These particularly comprise instruments,
for hacking the quarried limestone blocks. We could con-
sider copper instruments; nevertheless, copper has rank 3
on the Mohs scale of hardness. Another unknown aspect
is the transport of completed blocks and their placement.
The inconceivability of such work is particularly given by
the size and mass of such blocks. It was known, the Anci-
ent Egyptians did not know the wheel, therefore, wooden
sledges were very probably used for this transport.
According to geophysical surveys carried out by French sci-
entists in 1986, the structure of the pyramid core is hete-
rogeneous. It also contains spaces filled with sand, which
simplified the construction but makes calculations much
more difficult. Therefore, in the following paragraph, I will
work with experimental data.
In total, 2,500,000 blocks were used, of which 2,300,000
blocks for construction, and 115,000 - 200,000 blocks for
the external casing. In case the construction was carried
out 365 days a year, one had to place 342 blocks per day.
But in case the construction was carried out 290 days
during the year, the number of blocks to be placed increa-
ses to 431 blocks per day. On the assumption that the
shift lasted 10 hours, a block should be placed every
2 minutes (34 – 43 blocks per hour). In the case of 8-hour
shifts, 42 – 53 blocks per hour should be placed. If the
construction took 20 years, 290 days/year, and 8 hours
a day, then 500 blocks would have to be placed each day.
The numbers of workers on the construction site are diffe-
rent according to different sources – Herodotos reports up
to 100 thousand people; nevertheless, present historians
reduce the numbers to lower values (e.g. 30 thousand
according to Verner).
Number of workers necessary for the construction
of a geopolymeric Khufu’s Pyramid
Davidovits [3] presents to some extent a simpler solution
of the construction of the pyramids according to the abo-
ve-described method. The advantages of this method are
based on a much smaller labour force, and also only milli-
metres wide joints between external blocks and blocks in
the corridor inside the pyramid.
Davidovits’ lab tests show that 5kg of natron and 10 kg of
lime were necessary for 1 t of cast block. This means that
approx. 6,062,500 t of limestone, 31,250 t of natron and
62,500 t of lime were necessary for the whole pyramid. At
the same work intensity, i.e. 290 days/year and 8 h/day for
20 years, 132.68 t of materials would be needed to be
transferred during one hour. On the assumption that each
person can carry 20 kg, this amount of material would
need 6,634 people (during one hour).
CLAY
It is nearly impossible to obtain samples of original Nile
River mud existing in the Nile River bed at that time.
Nevertheless, it was possible to obtain a sample of clay
from a mud brick from the Mastaba in Dahsure from the
Egyptian Middle-era, which can be considered representa-
tive (Fig. 4). It is clear that the content of the “active com-
ponent”- kaolinite, is at a very low level, and does not
exceed 10 % by weight. The main components are plagi-
oclases, microcline, and quartz. In this case, the minor
phase is illite together with kaolinite, smectic phase
(montmorillonite?) and amphibole (Fig. 4). The question
whether sand was added to the mixture, which would
explain the higher concentration of quartz in the material,
remains open. Traditional mud bricks were prepared by
ramming clay mixed with water and straw into the form
of bricks. Sand contained in the mud brick from Dahsure
could have come from river sources or it could have been
windblown by wind laid sand from the dessert.