Friday Fun Fact: Concrete was used as a building material in ancient Rome. They mixed lime, water and a volcanic ash from Mount Vesuvius, mixed in fragments of volcanic rock and called it “Pozzolana”.  The Roman civil engineer Vitruvius wrote of 4 types of pozzolana – Black, Grey, Red and White.  Roman concrete was forgotten about during the dark ages.  In 1796 the English discovered a natural deposit of cement rock and sold it as Roman Cement. Concrete is used more than any other manmade material on the planet.