Around A.D. 79, Roman author Pliny the Elder wrote in his Naturalis Historia that concrete structures in harbors, exposed to the constant assault of the saltwater waves, become “a single stone mass, impregnable to the waves and every day stronger.” He wasn’t exaggerating. While modern marine concrete structures crumble within decades, 2,000-year-old Roman piers and … Continue reading How seawater strengthens ancient Roman concrete