Concrete Pyramids

By Isabel R. Harris and Matthew W. A. Bruder V



Over four thousand years ago, modern man built one of the greatest construction marvels of all time, the great pyramids of Giza.  The awesome technology to create these structures developed in a few hundred years and disappeared just as fast, never to be duplicated.  By about 500 B.C., during Herodotus’ visit to Egypt, the methods of construction were obscure, even to the Egyptian priests consulting their records[1].  Conventional wisdom states that the three great pyramids are made of stone blocks quarried, hauled over the Nile, and maneuvered up great ramps to their present positions.  It is becoming clear, however, that the great pyramids are actually made of concrete.  Even today with mounting evidence, people still cling to conventional ideas as to their construction. 

The pyramids were constructed during the reigns of three pharaohs about 2500 BC.  The great pyramid was built for a pharaoh named Khnumu-Khufu during his 20-year reign. The pharaoh ruled over an essentially agrarian society.  This society was entirely dependent on the fall inundation (flood) of the Nile annually to fertilize the flood plain, on which they grew their crops.  Various major construction tasks were undertaken only during these three months of the year, starting relatively small, reaching its zenith with the great pyramids, and dying away by about 500 BC.  Although large constructions were undertaken, after the building of the great pyramids, none equaled them in magnitude and quality.  The Egyptian priests told Herodotus that the great pyramid was completed during the reign of the pharaoh, 20 years[2].  

To complete a pyramid within the lifetime of the reigning pharaoh was a monumental task.  Masons designed the structure, selected and cleared the site, and laid out the orientation.  As the site was being prepared, other groups of masons quarried stone blocks at twenty quarries throughout Egypt[3].   These blocks were then hauled to the Nile, floated to the construction site, hauled up a ramp, and put in place.  The pharaoh, to complete the pyramid being constructed, drafted one hundred thousand laborers, including slaves for labor, an impressive mental picture.  For most people, thousands of labors and its associated stone theory are easy to conceptualize.  A child’s blocks can be used to mimic the operation on a small but deceptive scale.

At the same time as the pyramids were being constructed, another intriguing development occurred.  Fine alabaster vases with delicate, narrow throats and other artifacts were created in the same meticulous precision as the casing stones[4].  How could the Egyptians hollow out the bottom of the vases through the narrow throat without a highly advanced technology, which has disappeared in the mist of time?  Little if any indication of their manufacture remains.

There is evidence, in the quarries, of incomplete stone blocks and stele (obelisks) in various stages of completion, from later eras, abandoned for one reason or another.  Also, there are chisel marks left from the era when the pyramid blocks were being extracted from the quarries.  The marks vary considerably from era to era as the tools used to quarry changed[5].  Clearly, the stone was removed from the quarry.

Various authors including Herodotus, talking to Egyptian priests thousands of years after the completion, spoke of machines for raising the blocks[6].  It stands to reason, if you did not have a stone block, you would not have to raise it.  Later construction by the Egyptians themselves, Greeks, Romans, the masons of medieval Europe, and including the masons of today used the same basic method of cutting the blocks at the quarries and hauling them into place.  The blocks are rough-cut with tools on site, the rough ashlar (rough cut stone) is removed, finished, and it is hauled to the structure location and is installed, a simple enough procedure to understand.

Each of these arguments support the concept that the blocks were; as is commonly thought; cut, hauled, floated, hauled, and placed.  They are simple and straightforward, but there are certain problems with this theory. 

Another theory has been put forward periodically since the 18th century.  That is the pyramids were constructed of concrete.  Le Chatelier (a French chemist) did some serious investigation into the matter but failed to answer all of the questions.  His failure to determine the chemistry being used, coupled with the fact that hieroglyphics could not be read at the time created gaps, brought the theory into question.

As the climate changed different construction materials had to be developed.  Egypt was fairly moist until historic times (about 4000 BC). Wood all but disappeared and from pre-dynastic times had to be imported from Lebanon.  Mud brick held together by straw and baked in the sun fell apart during the infrequent rains and could not support the weight of very large structures.  All of their structures crumbled in a few years, nothing was permanent

Around their campfires, Egyptians noticed that the heat caused some of the rocks to melt and form colorful beads.  A small select group of laborers initially started making the beads and experimented by mixing and heating various combinations of minerals and ores.  They also found that some of the rocks powered to dust when heated; but when water was spilled on them, they resolidified.  Additionally, they found the powder could be mixed with water and before it hardened, could be placed in a container (a mold) and the rock, when hardened, assumed the shape of the container.  The cast rocks, when placed in water, did not fall apart.  Instead of structures that would fall apart in the periodic rains, buildings of these materials would last forever.

The Egyptians continued development of this process next making fine alabaster vases.  To this day no one conventionally can figure out how they were made.   They were molded, using concrete.  An inner mold of wax was made and positioned in a plywood outer mold.  (The Egyptians knew how to make plywood from the earliest times[7].)  After the concrete set but before it hardened, the wax inner mold was melted and removed, the outer mold was separated, the seams smoothed, and the vase became an enigma. 

The Egyptians, with an eye to the practical and each succeeding pharaoh wanting to outdo his predecessor, transformed the accidental diminutive beads into ever-larger blocks and experiments with basic pyramid designs begun.

If the small beads are kept distinct from the casing stones, another question arises.  How were the stones cut so precisely without scrap?  The era when the great pyramids were constructed was before the Bronze Age (The Bronze Age started about 800 B.C. in Egypt).  The Egyptians had only sticks, stones, and copper tools with which to quarry the blocks[8]. Nevertheless, given enough time, a block could be quarried and finished. The remaining pyramid casing stones are so precisely shaped that a piece of paper cannot be slid between the blocks[9].  Incredibly careful cutting or was the wall of the adjacent block also used as a wall of the mold?  A lot of time would be necessary to cut blocks this precisely, even today.  In 1984, Joseph Davidovits measured very precisely thousands of blocks on a pyramid where the casing stones had been removed 150 years ago.  Why are there only ten sizes, within two thousandths of an inch[10]?  Was it careful cutting or only a limited number of molds to cast the blocks?  Obviously if the blocks, some 30 feet in length, had to be cut and shaped to within two thousandths of an inch two new dimensions are added to the problems associated with carving stone blocks, how were they measured and additional time would be required for the increase in precision.  If laborers were cutting the stones, where is the scrap from the trimming, bad blocks, and the blocks that fractured or were damaged in transit?  There are not any[11].  With concrete, the rocks were beaten to a powder, hauled to the site, burned, mixed, and cast.  Everything is consumed and can be reused by powdering and heating it again.

To move the size of blocks used in the pyramids, some weighing 500 tons[12], in one piece, ramps with ample foundations would be required.  Where are the ramps to transport the blocks or where are their foundations?  There are not any.  The causeway, which according to Herodotus took 10 years to build and ran from the mortuary temple at the river’s edge to the pyramid itself, was built of polished stone, engraved, and covered[13].  The causeway, even when completed, would not support large blocks, but would support labors carrying buckets of concrete.  It can be simply handed up the pyramid, a bucket at a time, until the mold is filled. Concrete doesn’t require ramps. 

Herodotus says the priests told him the great pyramid was completed in 20 years[14].  With 2,500,000 blocks in the pyramid[15] this is no small undertaking.  If you are cutting discreet blocks and moving them, a focused infrastructure, well beyond the resources of today let alone the ancient Egyptians, would have been required.  The construction infrastructure shrinks substantially, to a manageable size of about 1,400 people, if a concrete process is used[16].  Since the work was carried out during the 20 years for only three months of the year (Thirty Egyptian calendar days.  The temples were closed and the Egyptians did not even get the traditional tenth day to rest.[17]).  The Egyptians worked only eight hours a day, therefore a stone block had to be placed every 3.5 minutes.  With ten molds, they only had to cast one block every half-hour.

In a microscopic study a human hair was found in a piece of a block taken from one of the pyramids[18].  How did a hair get into a rock?  It could have easily fallen from a worker into the concrete slurry.

Today, rocks and concrete can be easily distinguished from one another.  Concrete contains microscopic air bubbles from the slurry preparation and pouring.  A certified sample from one of the pyramid blocks was examined and the bubbles were found[19].  Granite does not contain air bubbles, concrete formulated similar to granite would.

If the Egyptians came up with this marvelous process, why did the Egyptians stop making concrete, start carving blocks of relatively softer stone, and lose the technology?  The answer is they simply ran out of known deposits of minerals and ores to form the high quality concrete.  From hieroglyphs and chemical analysis, the composition of the minerals and ores required were determined.  Locations of these ores were examined throughout Egypt.  It was found that some of the minerals and ores necessary for the process were completely consumed.  In one particular location, in the Sinai Peninsula were the mineral changed but the color of the rock did not, the miners stopped extracting the mineral precisely at the point where it changed[20].  After the great pyramids, very soft-core blocks were mined since they could easily be cut with the tools at hand.  The casing blocks were made from destroying earlier structures and reprocessing them.  Since the Egyptians worshiped the dead and long dead pharaohs continued to have large numbers of priests, only a limited number of structures could be consumed.  As iron tools developed, it was easier culturally and practically to cut softer rock than to reprocess the old and the craft died out.

We have two theories with significantly different technologies and similar results.  The conventional theory suggests a fantastic technology, which was lost as fast as it was developed and even with modern methods, many facts cannot be adequately explained or duplicated.  The concrete theory simply explains all of the observations and allows the eclectic craftsmen to complete the job in the time allotted.  As their raw materials were consumed, the workmen adapted and developed different technologies to carry on their tasks, the old practices disappeared, and their results became an enigma.


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[1] Herodotus, The Histories, Oxford University Press, 1998, p145

[2] Herodotus, The Histories, Oxford University Press, 1998, p145

[3] Davidovits, D. and Morris, M., The pyramids, Dorset Press, 1988, p18-19

[4] Davidovits, J. and Morris, M, The Pyramids, Dorset Press, 1988, p124

[5] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, p55

[6] Herodotus, The Histories, Oxford University Press, 1998, p145

[7] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p72

[8] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p10

[9] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p 11

[10] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p 12

[11] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p12

[12] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p51

[13] Herodotus, The Histories, Oxford University Press, 1998, p145

[14] Herodotus, The Histories, Oxford University Press, 1998, p 145

[15] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p10

[16] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p 80-81

[17] Herodotus, The Histories, Oxford University Press, 1998, p144

[18] Davidovits, J. and Morris, M., The Pyramids, Dorset Press, 1988, p 90-91

[19] Wenskus, J., ”Did the Pharaohs Cheat with Concrete?” R&D Magazine, Dec 1990, p5

[20] Davidovits, J. and Morris, M. The Pyramids, Dorset Press, 1988, p 76