Scientist Search for Clues to the Formula for Roman Concrete

One of the mysteries that continue to baffle scientists and engineers is how the ancient Romans produced the strongest concrete in the world.  Typically modern concrete buildings last about 50 to 60 years while ancient Roman concrete structures have survived through 2,000 years of environmental damage.   

Historical Timeline of Concrete

The history of concrete is actually quite interesting. For example, did you know that the art and science of concrete was almost entirely lost after the fall of the Roman Empire? Concrete is, in fact, an ancient material dating back thousands of years. From the earliest use of cement some twelve million years ago to the rediscovery of cement in the early 1700s, let’s review the little-known history of cement. 

12 Million Years ago: Earliest known occurrence of cement. Deposits of cement were formed due to oil shale burning next to a bed of limestone. Although these deposits dated back millions of years, they were not discovered and researched until the 1970s. 

6500 BC: The earliest concrete structures were built by the Nabataea or Bedouins traders who, literally, built an empire in Syria and northern Jordan. 

5600 BC: Homes were being built along the Danube River (in what was formerly Yugoslavia) which used concrete floors. 

700 BC:  Kilns were being used to create mortar for the construction of homes, concrete floors, and water cisterns.  

200 BC: The Romans built an empire out of concrete. Although their concrete was very rudimentary (almost plastic-like), they were also creative and created cement from volcanic sand.  

125 AD: The Pantheon is erected. The structure has one the largest un-reinforced concrete domes ever created in history.

After the fall of the Roman Empire, the art of Concrete was lost to mankind.

1756: The building blocks of concrete begin to re-emerge and John Smeaton rediscovers hydraulic cement. 

1824: Joseph Aspdin invents Portland cement! The material was aptly named “Portland” cement because it resembled the building materials found in Portland, England. 

1825: The commercial demand for concrete begins to soar. In the United States, the Erie Canal was commissioned to be built out of cement. 

The Conco Companies one of the foremost suppliers of concrete services for the Western U.S. We got our start in 1959 in the Bay Area by offering clients the best value on a broad range of concrete services and products.  Since that time, we have taken a leading role as top concrete contractors in the region. We have four regional offices serving California, Oregon, Nevada, Colorado and Washington.

Mesopotamia’s Mud-Brick Building Material

Archaeological evidence indicates that some of the very earliest large-scale buildings were in ancient Mesopotamia; however, in many cases, the only thing that has survived is traces of their foundations.  We have better examples of the impressive buildings constructed by the later civilizations of Mesopotamia, Persia and the rest of the ancient Near East of which some of them remains partially intact. 

Since wood was scarce in the area and the climate is extremely dry and hot, the most common building material was brick formed from mud.  The bricks were easy to make as well as to use and varied from small hand-sized bricks to large slabs used for paving.  They were made from mud or clay from the river, and then mixed with sand or chopped straw to provide additional strength.  Once formed the bricks were laid in a wide variety of elaborate and sophisticated patterns. 

Although the earliest bricks were shaped by hand, Wikipedia states by 3500 BC, “fired bricks came into use and surviving records show a very complex division of labor into separate tasks and trades.”  The fired bricks were used to build walls and also used with stone to make pavement.  Sometime around 2700 BC, rectangular wooden molds were introduced that produced bricks twice as long as they were wide.  In addition during that same period the Mesopotamians started producing plano-convex bricks, which have flat bottoms and sides but tops that curve out to form a convex surface.  The plano-convex bricks were used to construct walls of buildings, which had the convex side on the exterior wall of the structure.  This type of brick lost its popularity sometime around 2400 BC and bricks makers started to make every surface a flat plane.   

The Conco Companies are one of the foremost suppliers of concrete services for the Western U.S. We got our start in 1959 in the Bay Area by offering clients the best value on a broad range of concrete services and products.  Since that time, we have taken a leading role as top concrete contractors in the region. We have four regional offices serving California, Oregon, Nevada, Colorado and Washington.

Sources: en.wikipedia.org/wiki/History_of_construction, fofweb.com/

The Ancient Mystery of the Hanging Gardens of Babylon

In our series about Architectural Wonders of the Ancient World, The Hanging Gardens of Babylon is one of the most fascinating.  It is the only ancient wonder not reliably verified that it actually existed as no definitive archaeological evidence has ever been found.  Nonetheless, there are many accounts from ancient historians who describe the magnificence gardens’ elegant terraces, elaborate water features and floating plants in detail. 

It has generally been believed that if the Gardens existed they were built in Babylon near the present-day Hillah, Babil province, in Iraq by Nebuchadnezzar II who ruled from 605 to 562 BC.  However there is a group of archeologists and historians who think they may have been built somewhere else.  Recently Dr. Stephanie Dalley of Oxford University cited evidence that the Hanging Gardens were built by King Sennacherib in the Assyrian capital of Nineveh 350 miles away from the Babylon site. 

Texts from one of the ancient Greek historians, Diodorus of Sicily, described the Hanging Gardens as a beautiful park-like structure that was 400 ft. wide by 400 ft. long and had walls 80 ft. tall.  He states that the Gardens were built in a Persia design and had sloped, split-level stone tiers that resembled a theater.  The beautiful terraces were constructed beneath galleries that carried the hanging plants.  He explains that the walls were twenty-two ft. thick with ten foot wide passageways.  Diodorus’ descriptions included the roof that had “first a layer of reeds laid in great quantities of bitumen, over this two courses of baked brick bonded by cement, and as a third layer of covering of lead, to the end that the moisture from the soil might not penetrate beneath.” 

The large amount of water needed to care for the plants is thought to have been transported using a similar principle to the Archimedes’ screw, which is a pump that scoops water in a spiral tube and carries it up.  It is estimated that the gardens would have required 8,200 gallons of water daily to survive. 

The Conco Companies’ mission is to be the best supplier of concrete services in the Western United States and to bring expertise and unsurpassed quality to each project. We have built our reputation on superior concrete formwork, reinforcing, place and finish, shotcrete and other ancillary services that benefit from our vast experience. We serve Northern and Southern California, Colorado, Oregon, Washington, and Nevada. 

Sources:

en.wikipedia.org/wiki/Hanging_Gardens_of_Babylon  

dailymail.co.uk/sciencetech/article-2513819/Mystery-missing-Hanging-Gardens-Babylon-solved-Expert-claims-elusive-wonder-world.html