Because we may attempt to publish this data in the near future, I will only give the bare bones of our findings. Although iron was a valuable commodity in antiquity, it would have been more cost efficient to pour liquid iron in the street rather than to replace every pavement stone. Iron tangs could be wedged between pavements stones to create tension while liquid iron could be poured to create both tension and adhesion, solidifying the street. Additionally, iron and other materials, such as broken terracotta and pieces of limestone, could be used as a filler in areas where the pavement stones had either broken or had been worn down by cart wheels. These measures assured that the streets were sturdy and flat enough to permit cart traffic.
Because the Naples area is low in iron deposits, the iron could have arrived in Pompeii in the ballast of ships as nontaxable slag. The only questions this research cannot answer is how they did it. Once the iron arrived in the bay, how was it melted down and transported throughout the streets to be poured? The technology available at the time did not permit iron to be melted completely—instead when slag was put into a furnace, the iron would form a “sponge-y” material which would later be hammered into shape. Cast iron technology would not be around in Europe until the Middle Ages. Once the material is melted, how did they transport it? The cooling rate of iron would make transporting this material in liquid form very difficult on the length of road it would have to travel. These questions are incredibly interesting to us and we continue to explore them.