That's pretty crazy, and is exactly the opposite of what happens in modern concrete, which erodes as saltwater rusts the steel reinforcements and washes away the compounds that hold the material together. 'The Romans created a rock-like concrete that thrives in open chemical exchange with seawater,' says Jackson. Jackson was particularly interested in the presence of aluminous tobermorite, a hardy silica-based mineral that's actually pretty rare and difficult to make in the lab, yet is abundant in the ancient concrete.ДЄs it turns out, aluminous tobermorite and a related mineral called phillipsite actually grows in the concrete thanks to the sea water sloshing around it, slowly dissolving the volcanic ash within and giving it space to develop a reinforced structure from these interlocking crystals. 'It's been astounding what we've been able to find.' 'We can go into the tiny natural laboratories in the concrete, map the minerals that are present, the succession of the crystals that occur, and their crystallographic properties,' says Jackson. With these advanced techniques they could identify all the mineral grains produced in the ancient concrete over centuries. Now the researchers mapped the samples using an electron microscope, before drilling down to an extremely high resolution with X-ray microdiffraction and Raman spectroscopy. In a previous research project led by Jackson, the team had already gathered samples of Roman marine concrete from several ports along the Italian coast.Дrilling for Roman concrete samples in Tuscany, 2003. Mixed in with the volcanic ash mortar was more volcanic rock as aggregate, which would then continue to react with the material, ultimately making Roman cement far more durable than you'd think it should be.

Theirs was created with volcanic ash, lime and seawater, taking advantage of a chemical reaction Romans may have observed in naturally cemented volcanic ash deposits called tuff rocks. This is why concrete doesn't have the longevity of natural rocks. This aggregate has to be inert, because any unwanted chemical reaction can cause cracks in the concrete, leading to erosion and crumbling of the structures. In concrete, this paste binds 'aggregate' - chunks of rock and sand. Modern concrete is typically made with portland cement, a mixture of silica sand, limestone, clay, chalk and other ingredients melted together at blistering temperatures. Researchers led by geologist Marie Jackson from the University of Utah have been chipping away at the mysteries of Roman concrete for years, and now they have mapped its crystalline structure, figuring out precisely how this ancient material solidifies over time. As it turns out, not only is Roman concrete more durable than what we can make today, but it actually gets stronger over time. Now scientists have uncovered the incredible chemistry behind this phenomenon, getting closer to unlocking its long-lost recipe.

Rome 2 4 turns per year