Scientists study concrete to make it 'greener'
The interior of the Pantheon, Rome, by Giovanni Paolo Panini. The Roman Pantheon was built around 125 AD. The 4,535 metric ton (5,000 tn) dome is made of concrete. The exact composition of the Roman concrete used in the dome remains a mystery. An unreinforced dome in these proportions made of modern concrete would hardly stand the load of its own weight.
A team of researchers is working to make concrete “greener.”
Using nanotechnology, they’re exploring the possibility of creating a new type of concrete – eventually replacing some of the cement in concrete with industrial waste materials, like blast furnace slag, which would otherwise end up in a landfill.
Today, cement is concrete’s main ingredient. The process that makes it burns large amounts of fossil fuels, releasing greenhouse gases and contributing to global warming.
Hamlin Jennings: It’s not like automobiles or home heating. I think that in the United States, it’s on the order of about eight or ten percent. Even 5% is an amount, which when it’s attributed to one thing, it’s noteworthy.
That was Hamlin Jennings of Northwestern University. He’s part of a team of researchers working to understand the atomic structure of cement, with the goal of eventually creating a new kind of concrete that doesn’t require so much energy to produce. He said that within the past five years – thanks to the tools of nanotechnology – scientists have come to understand the details of how the atoms in concrete are put together.
He couldn’t say exactly when we can expect to see sidewalks and building foundations made with the new type of concrete. But he predicted it would be years, not decades.
Jennings told Earth & Sky that the first step toward reducing the amount of energy it takes to create cement is learning more about the composition of cement. His research has shown that, at the atomic level, cement paste is composed of tiny particles arranged like marbles packed into a container.
He said, “The way those marbles pack together can be dependent on whether I put in one marble at a time and they all pile up in neat stacks or if I throw a handful in at a time in a more random structure.”
How the marbles pack together and the structures they form, Jennings said, are what gives cement its special glue-like ability to hold together the ingredients that make up concrete. The next step, Jennings said, is to investigate how to manipulate cement’s marble-like particles to create a material that consumes fewer fossil fuels and thereby results in fewer CO2 emissions.
Thanks to the National Science Foundation.
As long as this new concrete will be just as strong, this is great news.
The Romans made concrete with formidable holding power. The Pont de Gard has stood fpr 2.000 years, withstanding storms and floods that have washed away bridges built with modern technology.
Question: How much energy did the Romans require in order to make their concrete? Maybe the engineers struggling with the problem could learn something from the past.
I can’t help but wonder if the Romans even knew how they made their concrete so strong.
I imagine that when we finally figure it out, it’ll be just like Damascus steel. Not even the people who originally made it knew why it was so strong, they just knew it was. It’s secret turned out to be nanotechnology, too. It was tempered with clay that had carbon nanotubes in it.
I hope we do find greener concrete technologies, seeing as it’s everywhere all around us.
The romans were smart. People made batteries a long time ago similar to ours. It is no surprise that the romans could build something better then us in this modern world. The history channel teaches you a lot of stuff!
Engineers should build dams with greener materials. However useful dams may be, I find them physically disgusting because of the large amounts of concrete imposed on nature.