I love listening to Podcasts. I listen to one almost every morning when I walk. Today I listened to a Ted Talk about concrete. Sounds boring, but it was pretty interesting
Thousands of years ago, the Romans invented concrete. Pliny the Elder praised an imposing sea wall made from what we would call concrete. He said it was as "impregnable to the waves and every day stronger." He was right. It still stands.
Today, our roads, sidewalks, bridges and skyscrapers are made of similar, though less durable material concrete. There are three tons of concrete on earth for every person. And over the next 40 years, we'll use enough concrete to build the equivalent of the New York City every MONTH!
Concrete has changed our world, but not always in a good way. It has played a large role in rising global temperatures. Concrete, steel, plastic, glass, and aluminum account for 31% of greenhouse gas emissions. Concrete alone is responsible for 8% of all carbon emissions worldwide.
The problem is cement, one of the four ingredients in concrete. (gravel, sand and water being the other three). It's impossible to make cement without generating carbon dioxide. For every ton of cement we produce we release one ton of carbon dioxide.
If we could find a way to produce concrete by eliminating greenhouse gases we could change the world for a third time. Right now, there is no 100% clean concrete, but we're getting close. Many scientists have been looking for ways to continue to use concrete, but make it more environmentally friendly. Others have been working to uncover and replicate the secrets of Roman concrete. They found that Pliny's remark is literally true. The Romans used volcanic ash in their cement. When the ash interacted with seawater it was strengthened by the seawater making the concrete more durable and long lasting than what we have today. Hopefully, with all this research we can replicate the success of the Romans, and produce a concrete that is both strong, long lasting, eco friendly.
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