Evolution of road construction

EVOLUTION OF ROAD CONSTRUCTION CONSTRUCTION AHERD EVOLUTION OF ROAD CONSTRUCTION ACROSS THE GLOBE Dating back to between 2600 and 2200 BC, one of the world's first paved roads was discovered in Egypt. It was seven-and-half-miles long Walking track and covered with slabs of sandstone and limestone, probably to facilitate the movement of human-drawn sleds loaded with basalt stone'. Running southwest out of Rome, to Capua, then to Tarentum and then stretching over to the Straits of Messina, the Via Appia was begun in 312 BC and was one of the first and In the 8th century, the most sophisticated roads in the Arab world could be found in most famous Roman military roads?. Baghdad. These were paved with tar. In the 18th century, Scottish road engineer John Loudon McAdam invented the process of “macadamisation", which still reflects the techniques In the 15th century, the Incas established a 14,000 mile-long road and bridge system in South America, spanning high Andean mountain passest and containing giant flights of stairs. As the Incas didn't used in modern road construction. Using a sloped subgrade surface, making the road slightly convex, his method of pavement design ensured rainwater rapidly drained off the road instead of have wheeled vehicles, the roads were mainly used by traders and messengers, walking by foot and using llamas to carry goods. penetrating and damaging the road's foundations. The introduction of the rock crusher led to much smoother surfaces and dense graded base materials. MODERN ROAD CONSTRUCTION 4 SURFACE COURSE ASPHALTIC CONCRETE Asphalt or bitumen mixed with aggregate particles. CEMENT CONCRETE Cement mixed with water and aggregate particles SUBBASE Unbound granular materials, gravel 3 BASE COURSE Non-erosive (bound) granular materials, fine gravel SUBGRADE Existing soil MODERN ROAD CONSTRUCTION TAKES SEVERAL FACTORS INTO CONSIDERATION Traffic volume over Rainfall/evaporation pattern Depth of water table Pavement type Permeability of pavement layers Whether shoulders the design life of the pavement are sealed or not Approximately ALL ROADS A 80,000km LEAD TO ROME of roads spanned the Roman Empire Roman roads were originally designed for the military. Construction was primarily organised by the legions themselves as they stretched the frontiers. FLAT STONES The Romans built their roads on foundations of clay, chalk and gravel with bigger flat stones GRAVEL laid on top. Their roads were also sloped so that rain water drained off to the ditches on either side'. CHALK On heavily travelled roads, the Romans used CLAY additional layers that included six sided pavers in order to reduce dust raised by wheels. 1 The New York Times, World's oldest paved road found in Egypt, 1994, http://www.nytimes.com/1994/05/08/world/world-s-oldest-paved-road-found-in-egypt.html 2 UNRV History, Roman Roads, http://www.unrv.com/culture/roman-roads.php 3 Transport: Anniversary Special Issue, Google books, http://books.google.com.au/books?id=3jyDjmWNWwQC&printsec=frontcover&dq=Transport:+Anniversary+Special+Issue&source=bl&ots=78-ONQ4NPN&sig=ACacrO011 mGh?rmwodqZeDoloCo&hl=en&sa=X&ei=UIFuUJb8F6KgigtkiYCgAg&ved=0CDEQ6AEWAA p. 101 4 PBS, The Lost Inca Empire, http://www.pbs.org/wgbh/nova/ancient/lost-inca-empire.html 5 Peru Cultural Society, Inca Roads and Chasquis, http://www.discover-peru.org/inca-roads-chasqui/ 6 Pavement Interactive, Pavement History, http://www.pavementinteractive.org/article/pavement-history/ 7 UNRV History, Roman Roads, http://www.unrv.com/culture/roman-roads.php 8 Transport: Anniversary Special Issue, Google books, http://books.google.com.au/books?id=3jyDjmWNWwQC&printsec=frontcoverådq-Transport:+Anniversary+Special+Issue&source=bl&ots=78-onQ4NPN&sig=ACqcrO011 mGh9rmw0dqZeDoloCO&hl=en&sa=X&ei=UlFuUJb8F6KgigtkiYCgAgåved=OCDEQ6AEWAA p. 101 Allianz (M BROUGHT TO YOU BY ALLIANZ AUSTRALIA Search for "Allianz infographics" for more!