How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues

# Summary Scientists studying a 1,900-year-old latrine at Hadrian's Villa in Italy discovered that Roman concrete's exceptional durability stems from two chemical processes: the previously known pozzolanic reaction and an additional process called carbonation, where atmospheric carbon dioxide reacts with calcium compounds to form calcite that fills cracks and strengthens the material over time. This finding, published in *Science Advances*, could help researchers develop more sustainable and long-lasting concrete alternatives, as modern concrete typically deteriorates within 100 years while Roman structures have survived for approximately 2,000 years.