Evolution of Concrete

The earliest recordings of concrete structures date back to 6500BC by the Nabataea traders in regions of Syria and Jordan. Over the period, the product and went through a lot of changes in terms of technology, material used etc. Construction Times seeks to understand the journey of Concrete.

Ancient people made discoveries about naturally occurring materials they could use it to improve fundamental parts of their infrastructure — homes, fences, wells, etc. The generations who followed them built upon that knowledge, making improvements here and there until the industrial age descended and sped up building developments to their current level.

Early Days

12 million years ago - Naturally Occurring Cement

On land that is now Israel, spontaneous combustion produced reactions between limestone and oil shale, resulting in natural deposits of “naturally occurring cement” that would make possible the future formation of concrete.

10,000 BC - Earliest Limestone Structure

Limestone — also often called “lime” — plays the earliest role in the story of concrete, as the base ingredient in cement, and it's been used for millennia. Predating another massive stone temple, Stonehenge, by 6,000 years, the GöbekliTepe in modern-day Turkey was the earliest known limestone structure. Limestone made up the T-shaped pillars of this temple, which were built and carved by prehistoric people who had not yet developed metal tools or even pottery.

6500 BC - Desert Cisterns

The first concrete-like structures, secret underground cisterns for storing scarce water, were built by Nabataea or Bedouin traders who developed a small empire in the desert oases of southern Syria and northern Jordan. Some of these cisterns still exist in those areas today.

5600 BC - Pre-concrete Floors

In the former country of Yugoslavia, in the area of LepenskiVir along the Danube River, huts were found in the mid-1960s with a semblance of concrete floors. The lime cement that was used probably came from a deposit upriver and was mixed with sand, gravel, and water to resemble concrete mixtures of our time.

3000 BC - Egyptian Pyramids

Limestone rocks or concrete blocks? Despite some hotly debated speculation about blocks in the Egyptian pyramids being formed with an early type of concrete more than 5,000 years ago, it's more widely believed across the field of archaeology that the limestone blocks were hauled from quarries nearby. To make the mortar for holding the blocks together, the builders mixed straw with mud that contained crushed limestone, gypsum, and clay.

1400-1700 BC - Minoan Structures On Crete

The Minoan society on the island of Crete, forerunners to the Greeks and credited as the first European civilization, used a building material that mixed clay and a type of volcanic ash called pozzolana for building for floors, foundations, and sewers.

1300 BC - First “Lime” Coating

Middle Eastern builders burned limestone and mixed it with water, then used the mixture to coat the outsides of their pounded-clay walls. When the mixture reacted with the air, it formed a hard, protective surface — and laid the foundations, so to speak, for modern versions of cement.

1000 BC - Grecian Tombs

The Mycenaeans used their early form of cement to build tombs. You can see some of them today in the Peloponnese in Greece.

770-476 BC - China's Great Wall

The northern Chinese used a form of cement for building boats and their section of the Great Wall. Over the centuries of the wall's construction, materials used for its entire span included reeds, willow branches, wood, compacted sand, mud, and 100 million tons of stone and brick. Where these weren't cemented by limestone mortar, they were held together by a mortar made of glutinous, sticky rice.

700 BC - Kilns, Mortar&Hydraulic Lime

The same Bedouins who pioneered underground cisterns later built kilns to produce a rudimentary kind of hydraulic lime — cement that hardens underwater — for waterproof mortar that advanced the construction of houses, floors, and newly waterproof cisterns underground.

300-500 AD - Roman architecture

The Romans started with the same raw materials as the Minoans — volcanic ash found near Pompeii and Mount Vesuvius, which they used to thicken a mixture of kilned limestone, ground-up rocks, sand, and water — allowing them to build ramps, terraces, and the roads that eventually connected the whole empire. Pouring the mixture into molds soon allowed builders to create vaults and domes, as well as the arches of the empire's iconic aqueducts and bathhouses. Roman concrete has endured earthquakes, lightning strikes, crashing sea waves, and thousands of years of weathering.

82 AD - The Colosseum

After Rome's civil war, the emperor known as Vespasian set out to build the largest theatre in the world, with more than 50,000 seats. Today we know the world's first stadium, completed 1,937 years ago, as “The Colosseum.” About a third of the structure still stands nearly two millennia later, an iconic symbol of the Roman Empire.

117-125 AD - The Pantheon — & The Loss Of Concrete

Rome's Pantheon, soon to celebrate its 1,900th birthday, is as sturdy as ever. The temple's unreinforced concrete dome was twice as wide and high as any dome ever created at the time, spanning 143 feet with its famed “oculus” in the center. Its mammoth weight is buttressed by incredibly thick concrete walls and eight-barrel vaults, all reinforced with brick — but no internal support.

Today's engineers wouldn't dare build an unreinforced dome of that size, and they may never know the secret to the Pantheon's enduring stability. We do know that Emperor Hadrian's engineers adjusted the concrete recipes, using more volcanic ash than rock to make the dome lighter, and more rock aggregate in the walls for heavier reinforcement. But when the Roman Empire fell in 476 AD, the unprecedented Roman recipe for concrete was lost to the world.

1507 - The Renaissance - Pont Notre-Dame Bridge

Just after the Dark Ages, an Italian friar named Giovanni Giocondo built the Pont Notre-Dame Bridge in Paris using remnant information from the ancient Roman cement recipe. About 250 years afterward, the structure was demolished because houses built atop the bridge added too much weight. Giocondo would go down in history as the only person to attempt building with concrete during the Renaissance.

Advancements In Concrete

16th-century improvements

A bricklayer in Andernach, Germany, tried mixing volcanic ash called trass with lime mortar. The resulting material was water-resistant and strong — and the chain reaction started by the discovery would lead to the creation of modern cement.

17th-century concrete trade

In the 17th century, the Dutch (who were already adept at building in water) sold trass to France and Britain for use on buildings that required waterproof properties. The two rival countries immediately began competing to create their own hydraulic building materials.

1793 - Modern production of hydraulic lime for cement

When British civil engineer John Smeaton was commissioned to build a new lighthouse on the Eddystone Rocks in Cornwall, England, he set about searching for the most durable and waterproof building material he could find. After finding limestone nearby with a high concentration of clay, he fired it in a kiln and turned it into clinker. He ground it into powder and mixed it with water to create a paste, with which he built the lighthouse.

In the process — and more than 1,000 years after the secrets of concrete were lost — Smeaton rediscovered how to make cement. Before long, manufacturers started marketing his discovery as “Roman cement.” And the Eddystone Lighthouse stood for nearly 130 years, outlasting the rocks that eroded out from under it.

1824 - Invention of Portland Cement

Englishman Joseph Aspdin refined the process by carefully proportioning limestone chalk with clay and burning the mixture in a kiln until the carbon dioxide was removed. He also heated alumina and silica until the materials became glass-like, then pulverized them and added them into the limestone mixture along with gypsum.

1836 - Strength testing

The first testing of concrete's tensile and compressive strength took place in Germany. Tensile strength is the ability to resist tension or pulling apart; compressive strength is the ability to resist compression, or pushing together.

1850s - Reinforcement with steel mesh patented

A French gardener, Joseph Monier, experimented successfully with pouring concrete over a steel mesh. (Concrete and steel expand at a similar rate when they heat up, making them a perfect pairing). Monier patented several variants of his invention for use with railway sleeper cars, building slabs, and pipes. Reinforced concrete is much stronger and more practical than the unreinforced stuff. It can span larger gaps, allowing concrete to soar in the form of bridges and skyscrapers.

1880s - Reinforcement with iron bars

California engineer Ernest Ransome began testing concrete and 2-inch iron rods to see if the materials would bond. When they did, Ransome went a step further by twisting the iron bars to create an armature around which he could “build” concrete into any desired shape — an experiment which also worked. Today we call this system reinforcing bar, or rebar, although modern engineers typically use steel instead of iron.

Ransome's system soon would be used in commercial buildings, roads, bridges, and even the first skyscrapers. Famed architect Frank Lloyd Wright began to implement rebar concrete technology in modern architecture. Some of Wright's most famous buildings — including Unity Temple in Oak Park, Illinois, considered the world's first modern building; and Fallingwater in Mill Run, Pennsylvania, his most celebrated work — were made of reinforced concrete.

1880s - Prestressing steel patented

The process of prestressing steel was patented to make concrete stronger and allow engineers to use less steel and concrete.

Ever since Ransome developed the use of rebar, concrete has built all types of monumental buildings and infrastructure works.

Evolution

Over the years, concrete turned into a more efficient material. From using natural substances that resembled cement to enhancing natural materials with man-made processes. As technology advanced, so did our methods of producing concrete and cement.

Today, we have a standard formula for Portland cement. It was created back in 1917 by the American Society for Testing and Materials along with the National Bureau of Standards. The standard formula created a consistent quality no matter when or where someone made the substance.

Even before we developed a formula for Portland cement, builders were using concrete in projects all over the world once again. In the early 1900s, concrete regained public acceptance as a building material, with these types of structures going up.

After these and other buildings, ready-mix concrete was developed. In 1913, the material was delivered in Baltimore, Maryland. It helped make job sites more efficient since workers no longer had to mix concrete on-site. Instead, it arrived pre-mixed from a plant in early versions of what we consider cement trucks today.

Some decades later, we discovered that producing small air bubbles, known as air entrainment, improved concrete. After the introduction of air-entrainment substances to concrete in 1930, the building material was easier to work with and less prone to freezing. Now architects in colder climates could choose the material without worrying about cracks or breakage.

Around the same time, builders developed thin-shell concrete. Roofs, domes, arches and other similar structures were made of a thin shell of concrete. Because of the strong, rounded shapes of these structures, they did not require thick layers of the material. The lighter weight of thin-shell concrete makes the rest of the building safer from collapse since it doesn't need to support a heavy material.

As we worked with concrete, we made it a stronger and more resistant building material. We discovered easier ways to make it, transport it and use it. Along with those discoveries, builders and architects constructed buildings in different styles. Brutalist, modern and other concrete structures.

Courtesy

https://www.bigrentz.com/blog/the-history-of-concrete

https://www.dcpu1.com/blog/history-of-concrete/

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