Roman street in Pompeii, with still well-preserved cobblestones. The construction of Roman roads was a true masterpiece of Roman engineering. The road-building technique was taken over by the Etruscans and initially closely imitated. Over time, new technologies began to be adopted.
The first layer was sand, which was compacted and profiled. 1 or 2 layers of flat stones were placed on the prepared substrate and covered with cement mortar or clay. Volcanic ash (pozzolana) was also used instead of mortar. This is how the lower layer of the road, statumen, was created, 20-30 cm thick, sometimes up to 0.5 m thick. The Statumen was framed with curbs weighing from 10, 15 kg to 50 kg, this was to strengthen the edges of the road. The next layer called rudus or ruderatio 20-30 cm thick consisted of crushed sandstone, crushed brick or crushed stone. They were beaten with carefully forged wooden beaters. All this was poured with mortar with a ratio of crushed brick and limestone – 3:1.
Then the foundation began to be laid, the first layer of which was nucleus, i.e. cement with small stone fragments, slag, clay and sand. The whole thing formed a layer of water-impermeable, tight fine-grained concrete. The approximate composition of this half-meter-long layer was 3 parts of brick flour and 2 parts of calcium.
The upper layer, summum dorsum, consisted of gravels with a grain size of up to 6 cm called gloren strata or polygonal stone tiles, silicea strata.
The profiled and carefully leveled surface, parimentum, was made of 5 cm thick stone slabs with a slope of 1:60 and an area of 30 to 100 cm.
