We might poor stained concrete floors every day, but even we have to stop sometimes to think about how amazing concrete is as a material. After all, it’s the most-used product in the world and has been used for thousands of years. And during that time, humanity has made some absolutely amazing structures from it. Today we’re going to take a look at some of the famous structures that have been created from concrete over the millennia, and also discuss how they’re holding up the elements after so many years.
Christ the Redeemer, Rio de Janeiro, Brazil
This statue of Jesus certainly isn’t the tallest or heaviest statue in the world, but it’s location certainly makes it one of the most impressive. Perched atop the Corcovado mountain overlooking Rio de Janeiro, this statue of Christ stands 98 feet tall without its base (with the base it’s 125 feet tall) and weighs 635 metric tons.
Christ the Redeemer is made from reinforced concrete and soapstone and was built between 1922 and 1931. Because it is constantly being exposed to the elements from every angle, and due to lighting strikes, the statue requires constant upkeep.
Here are two interesting side notes. First, the statue is considerably thinner than most people imagine (take a look at these side views). Second, the statute is considered one of the New7Wonders of the World, along with the Great Wall of China, Petra, Chichen Itza, Machu Picchu, the Taj Mahal, and The Colosseum.
And hey, speaking of The Colosseum…
The Colosseum, Rome, Italy
The Colosseum is the largest amphitheater ever built, able to hold between 50,000 to 80,000 people. Construction began in 72AD and was complete eight years later. One of the most popular uses for it was as an arena for gladiatorial combat, but it was also used for animal hunts, executions, and theatrical dramas. In addition, it was used as a theater to recreate mock sea battles and reenactments of famous battles.
If it hadn’t been for earthquakes in 443 and 1339, it would probably be in much better condition than it is today. The fact that The Colosseum is still standing at all after nearly 2,000 years despite those quakes is a testament to the staying power of concrete.
The Hoover Dam, Nevada-Arizona border
If you’ve never been to the Hoover Dam, you really should. It’s truly a modern marvel, especially considering how large it is, how much pressure is behind it, and when they built it.
1931 was a good year for concrete, because the year Christ the Redeemer was finished The Hoover Dam started and was completed in 1936 (and finished two years ahead of schedule). It was built during the Great Depression and became the largest concrete structure in the world. It holds back the Colorado River as a way of controlling floods and providing hydroelectric power. In doing so it created Lake Mead, the largest reservoir in the United States in total water volume.
The Hoover Dam is an arch-gravity dam, meaning that the backward-facing arch transfers the water’s force to the canyon walls. As much concrete as you see, there’s considerably more that you can’t see. The bottom of Hoover Dam is 660 feet thick at the bottom but only 45 feet thick at the top.
Now let’s talk about the concrete! The Hoover Dam isn’t one continuous pour of concrete. Concrete heats and contracts as it cures, which means that uneven cooling (remember that’s it’s strangely-shaped wedge standing out in the sun) would cause it to crack. Oh, and it would take 125 years to cure! Putting water behind that would lead to an immediate breaking of the dam.
Because the country wasn’t going to wait 125 years for a dam that was just going to break anyway, new techniques were developed. The concrete was poured in large blocks, some as large as 50 square feet by 5 feet high. Pipes were inserted into the concrete, through which river water was pumped. This cooled the concrete and helped it cure faster. To cool it down even faster, a refrigeration plant was built nearby. There are over 3,250,000 cubic yards of concrete in the Hoover Dam, enough to pave a two-lane concrete highway from New York to San Francisco. Oh, and it weighs over 6 million tons.
Over 100 people died during the construction of the Hoover Dam, but it helped thousands more weather the Great Depression. Most of the deaths were due to falling from great heights, and while it makes a good horror story, no workers were entombed in the concrete. When you’re dealing with a lake full of water to hold back, you can’t have weak spots, and a human body certainly doesn’t let the concrete cure correctly.
Sixty years after the Hoover Dam was dedicated, core sample were taken in order to gauge the integrity of the dam. What they found is that it is still curing, which means that it’s actually getting stronger as the years go by.
While your stamped concrete patio or driveway will never be as well-known as a 98-foot tall Jesus, we’re going to make it look great all the same! You might not be able to charge admission to get close to your concrete pool deck, but you’ll certainly be proud to invite friends to your backyard and enjoy the stamped concrete underneath. When you’ve got that special concrete in mind, contact Marrocco’s to get the project started!