Building Roads in the UK
Ancient history tells us of the origins of travel and communications, of how, thousands of years ago, artefacts crafted from far distant lands arrived in ancient Britain.
Trade routes, such as the Silk Road, or the Amber Road brought goods from far East to far West, but the idea of “road” is something of a misconception.
Stoney, dusty tracks in the summer, mud and flood in the winter, these ancient trails were roads by name only.
The first recorded engineered roads are from some 1,100 B.C. as the Assyrian Empire grew, they levelled and drained tracks across their territories from Mesopotamia to Syria.
The greatest road builders of all, until modern times, were of course, the Romans, as they expanded their empire from the Middle East to the Iberian Peninsula, and from North Africa to Northern Europe.
All across these lands there were built networks of straight, engineered paved roads.
Surveyors used a tool called a “groma” which was basically, a wooden cross with plumb bobs on the cross members, which when lined up with each other, gave the surveyor a straight line.
The roads were built by the military, primarily to allow the legions to access all parts of the Empire relatively quickly.
The process, after the surveyors had marked the route, was to dig two trenches parallel to each other. These were the drainage channels. The spoil built up the centre or the road to give an angle for run-off.
Kerb stones on both sides supported the courses of sand, rubble, sand and gravel, and where possible, and certainly on major roads, cut, flat stones to allow a smooth surface.
Roman engineers excelled in bridge building, and many examples remain today, as do breath-taking viaducts and drainage systems.
The roads of Britain had no serious attention paid to them until the seventeen hundreds, when two engineers began to construct roads, each developing different techniques, Thomas Telford and John McAdam.
Telford’s system was to begin with a trench, and base it with a foundation of heavy rock with a raised centre, and a six inch (150mm) layer of gravel as surface. This gave a substantial road, but needed resurfacing frequently.
McAdams roads were constructed using around a foot of broken stone of about one inch in diameter straight onto the subsoil, again, with a raised crown for drainage, and a layer of fine grained stone that was cemented by powder produced by traffic, which was used to compact it, and gravel layers added.
McAdams method, for economy and speed, became widely accepted across Europe, but the advent of the motor car proved too much for it, and Telford’s method accepted until the construction of today’s modern asphalt and concrete highways.