Historical Hardening: Preserving Cincinnati’s Iconic Concrete Structures

Like many innovations that become part of society for a time, concrete was forgotten about and rediscovered later. Our timeline shows how this material continued to evolve even after its rediscovery.

Archaeological discoveries at Gobekli Tepe reveal that early humans built rudimentary concrete structures for worship purposes. This marked the first time that people lived in communities centered around an activity instead of nomadic hunter-gatherers.

Ancient Egyptians

The ancient Egyptians are famous for their pyramids, mummies and hieroglyphic writing. But they also developed advanced engineering and scientific techniques.

The Egyptians used the annual flooding of the Nile River to support their farms and cities. Their astronomy allowed them to track the movement of the sun and moon and work out complex calendars.

One of their most important inventions was the process of case hardening, a surface hardening method that involves packing steel parts into a box with materials that are high in carbon like hoof and horn and then heating them together at a very high temperature. This encourages the carbon to diffuse into the surface of the steel. if you need help Go to this company’s website.

Romans

The Romans used concrete in their construction projects, including the monumental aqueducts that fed the city of Rome. Their use of concrete was a revolutionary technology that freed them from the structural limitations that plague builders of stone and brick structures.

Modern structural concrete differs from Roman concrete in two important ways. First, modern concrete mixes are in a plastic state that can be poured into molds, while Roman concrete was built by hand layering mortar over rock aggregate.

The Romans also developed case hardening, a process that is similar to our modern heat treating. This method involves immersing steel components in a solution containing carbon, such as bone meal or hoof ash.

Nabataeans

The Nabataeans were a small empire that developed in desert oases of Syria and Jordan. They controlled major trade routes and accumulated great wealth. They were distinctly different from, indeed sometimes opposed to Graeco-Roman culture and built their own unique buildings, including a theater at Petra.

One of their most important achievements was discovering how to make waterproof cement. They bonded together rock fragments with a special mixture of lime and fine silica sand using a tamping process. It is this discovery that may have allowed them to rise from a band of desert traders to a sophisticated civilization. This knowledge would later become the foundation of concrete technology in Europe.

19th Century

The 19th century saw a large number of concrete buildings built, many designed by Hannaford and his sons. Some of these iconic structures are found throughout Over-the-Rhine.

The 18th century marked the rediscovery of hydraulic lime by a man named John Smeaton who used it to rebuild his Eddystone Lighthouse in Cornwall, England. He also developed concrete using powdered brick and pebbles as aggregate.

G. A. Wayss and Francois Hennebique independently developed reinforced concrete frame construction in Germany and Austria, while Ernest L. Ransome patented the use of twisted steel bars as reinforcement for concrete (which became the norm in America). These innovations allowed builders to construct stronger and taller buildings than ever before.

20th Century

The Nabataeans built kilns to make cement, but they did not cast concrete into formwork as we do today. They used their mortar to bind stones together and for building floors and underground waterproof cisterns.

In the 19th century, Portland cement was introduced and it revolutionized concrete construction. French gardener Joseph Monier discovered that embedding iron mesh in concrete made it more resistant to tension. This became known as reinforced concrete.

The Union Central Tower was a skyscraper that stood on the southwest corner of 4th and Vine Streets for Cincinnati Gas & Electric Company. It was designed by Garber & Woodward of Cincinnati.

21st Century

While Cincinnati’s skyline continues to evolve with new high-rises and modern office towers, the city is blessed with a large stock of historic buildings that still stand throughout the downtown basin. Several of these are designed by the prolific local architect Samuel Hannaford and his architectural firm.

Case hardening is a method used on items that will be repeatedly impacted by other surfaces, such as rifle bolts and firing pins. In this process, steel is packed into a container with a carbonaceous material such as bone meal or horse hoofs and heated at a high temperature for a specified time. This causes the carbon to diffuse into the surface of the steel, rendering it harder.