How it all began …
We don’t have to look far in today’s world to find concrete … it is all around … quite understandably as it is one of the most widely used building materials.
The word “concrete” can be traced back to the Latin verb “concrescere” which literally means “to grow together”. This reflects two or more different materials combining together to form a new and unique compound with its own properties.
The use of different forms of concrete dates back to ancient times.
Around 6,500 BCE concrete like structures were build underground to store scarce water near oases in what is now Syria and Jordan. In Egypt around 3,000 BCE, mud and straw were combined to form a building material to bind bricks together during construction.
Later on in Egypt, around 2,500 BCE, there was a significant step forwards toward the concrete we know today.
A material containing burnt gypsum (or lime) was used to create a more advanced form of concrete. Lime and gypsum were mixed with sand and water to create a strong material that could withstand the harsh desert climate.
They used it to build their pyramids, notably the Great Pyramid at Giza which still stands today, a real testament to the durability of their concrete.
The Romans also made significant advancements in concrete technology. They used a mixture of lime, volcanic ash, and water to create a strong and durable material that could be poured into molds and used for a variety of applications. They also found that using sea water significantly increased the strength and durability of the mortar.
They used concrete to build their famous aqueducts, temples, and even their famous Colosseum which was built around 80 CE.
The recipe for concrete continued to advance.
Rome’s Pantheon, almost 2,000 years old, is as sturdy as ever. The temple’s spectacular 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 Roman 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 CE, the unprecedented Roman recipe for concrete was lost to the world.
During the Middle Ages, the use of concrete declined as building techniques shifted towards stone and brick.
However, around 1,700, methods for making concrete that was water resistant were developed using different volcanic ashes.
This led eventually to John Smeaton developing “hydraulic lime” which allowed the construction of the Eddystone Lighthouse in 1759.
In 1824, Joseph Aspdin created his patented Portland cement when he heated clay and limestone together and then let it cool.
The invention of Portland cement in the 19th century revolutionized the use of concrete once again. Portland cement allowed for the production of high-quality concrete that was strong, durable, and versatile.
The construction of the Thames Tunnel, led by William Aspdin, Joseph Aspdin’s son, civil engineer Isambard Kingdom Brunel, and Brunel’s father, used Portland cement in its first large-scale application. This major engineering project encountered many issues during its construction but was completed and open to the public in 1843.
The tunnel measured 35 feet wide and was 20 feet high. It was 1,300 feet in length. It is currently used as a railway tunnel.
Since then, the use of iron and steel rods to reinforce concrete has enabled it to be used in countless applications which has expanded our world as we know it.
In the 1930s the Hoover dam was completed. Between 1956 and 1992 the US Interstate Highway system was built. From buildings and bridges to roads and dams. Its versatility and durability have made it a popular choice for construction projects around the world.
In recent years, advancements in technology have allowed for the development of new types of concrete that are even more sustainable and eco-friendly, ensuring that this ancient building material will continue to be used for generations to come.