Romans made sure that their architecture would pass the test of time by creating the most durable concrete in the world. Even after two millennia, Roman piers survived the daily collision with water in an almost ideal state. Today’s scientists took a closer look at Roman concrete to reveal its secrets.
Roman Concrete Developed Crystals to Fill in Empty Spaces
Ancient harbors along the former Roman Empire seem to be even more indestructible than they were in their day one. These 2,000-year-old structures are of concrete made of lime and volcanic ash. It turns out that this composition went through an organic evolution on its own. This is a chemical reaction that lent the material some incredible properties.
A team of scientists from the United States found the answer to this Roman mystery. It appears that the combination of lime and volcanic ash needs seawater to grow stronger. The minerals in water trigger an interlocking effect which covers the material with an impenetrable organic layer. The lead author of the study, Prof Marie Jackson, is a geology research professor at the University of Utah. She stated that this composition might sound counterproductive for its purpose of building constructions at first.
“We’re looking at a system that thrives in open chemical exchange with seawater.”
More exactly, the combination of lime, volcanic ash, and seawater causes a pozzolanic reaction. This chemical effect grows crystals inside the mixture which leads to the elimination of any gaps in the composition. This mineralization process makes even construction in waters defy the brutal forces of erosions and waves.
Scientists Intend to Replicate the Roman Recipe
Today’s concrete recipes dictate people to finish up their mixture of various elements such as ash, limestone, iron, chalk, and others with crushed stone or sand. This final process hinders the composition to start the mineralization effect when in contact with saltwater. This discovery can add much value to the industry. As a consequence, scientists have already started to find a similar recipe for Roman concrete.
Image source: 1