Any shore structure erodes and eventually creeps into the water below. That’s the way it works. Or at least that’s how they are usually work. Scientists say that the ancient Romans were looking for a way to build sea walls that became harder over time. They published their findings in the magazine American miner.
The incredible stability of the walls, itself, is not news. In the 1st century CE, Pliny the Elder described the wonder of it Naturalis Historia, writes that the concrete walls with a swell battle became “one big stone, incredible for the waves and stronger every day.”
We know that Roman concrete consisted of a mixture of volcanic ash, lime, seawater, and lumps of volcanic rock – and that the combination of these ingredients produces a chemical reaction. pozzolanic which makes the concrete stronger. But today ‘s cement is undergoing a similar reaction, and our sea walls are falling apart like nothing else under the ram of the ocean’ s corrosive impact.
Something else was clearly going on.
To find out what it was, geologists examined samples from walls built between 55 BCE and 115 CE. They used high-power microscopes and X-ray scanners to peer into the underlying structure of the concrete, and a method called raman spectroscopy to identify its particles.
Their results showed that the pozzolanic reaction at the time of formation of the walls was just one stage of the concrete process. The real magic happened when the walls were built, and they sat soft in the sea. The salt water actually contaminated elements of the concrete – but in doing so, it allowed new crystals to grow, creating even stronger bonds.
“We are looking at a system that opposes all that one would not want in cement-based concrete,” lead author Marie Jackson, of the University of Utah, said in a statement. ” which thrives in open chemical exchange with seawater. “
The goal now, Jackson says, is to reproduce the exact recipe and strengthen our own building materials. But that could be harder than it sounds.
“The Romans were lucky with the kind of rock they had to work with,” she says. “They saw volcanic ash grow cement to produce the tuff. We don’t have those rocks in much of the world, so substitutes have to be made.”
We still have a lot to learn from the ancient walls and architects of yesteryear. Jackson and her colleagues continue to pore through Roman texts and their own concrete, looking for clues for its incredible strength.
“The Romans were worried about this,” Jackson says. “If we’re going to build in the sea, we should be concerned about it as well.”