History of Highways || civil door

:: Difference b/w Highway & Roadway :: 

Nowadays, we are using the term Highway instead using the term Roadway because we refer to construct the roads over an embankment. Hence, the term highway is used. 

:: History of Highways :: 

The development of highway can be dated from the time of Romans advancement of technology from carriages pulled by two horses to vehicles with power equivalent to 100 horses, road development had to follow suit. The construction of modern highways did not begin until the late 19th to the early 20th century. The development of highways in chronological order can be defined further by civil door:

:: Roman Roads :: 

They provided efficient means for the overland movement of armies, officials, and civilians, and the inland carriage of official communications and trade goods. 

Roman roads were of several kinds, ranging from small local roads to broad, long-distance highways built to connect cities, major towns and military bases. These major roads were often stone-paved and metaled, cambered for drainage, and were flanked by footpaths, bridleways and drainage ditches. They were laid along accurately surveyed courses, and some were cut through hills or conducted over rivers and ravines on bridgework. Sections could be supported over the marshy ground on rafted or piled foundations.

Main features of Roman Roads:

• They built straight regardless of gradients.
• They offer the soft soil was removed & hard stratum was added to the roads.
• The thickness of the construction was 0.75M to 1.2M at some places.
• They provide the larger stone slabs to the roads at the top thickness of the stone slabs is 10cm to 15cm.
• The thickness of subgrade stones was 10cm to 20cm.
• They excavate the softer part of the soil surface until they find the harder soil strata.
• They used heavy foundation stones at the bottom.
• They mixed lime and volcanic pozzolana to make mortar & after that, they added the gravels to this mortar to make concrete.
• Concrete was a major Roman road making innovation.
• They also used the kerbstones on both sides of the road.

:: Tresaguet Roads :: 

Pierre-Marie-Jérôme Trésaguet was a French engineer. He is widely credited with establishing the first scientific approach to road building about the year 1764. Among his innovations was the use of a base layer of large stone covered with a thin layer of smaller stone. The advantage of this two-layer configuration was that when rammed or rolled by traffic the stones jammed into one another forming a strong wear resistant surface which offered less obstruction to traffic.

Trésaguet was born in Nevers, the youngest son from a family of engineers. He began his career as a sub-inspector in the Corps des Ponts et Chaussées (Bridges and Highways Corps), in Paris. He later moved to Limoges, Haute-Vienne as chief engineer in 1764. In 1775 he was appointed inspector general of roads and bridges for all of France. He published a paper describing his road building methods.

:: Main features of the Tresaguet Roads :: 

Cross-section of Tresaguet Roads

• They also provide the large size stones on the foundation of the road.
• They thought "larger stone is not compulsory to provide on the top of the road".
• The thickness of road was around 30cm only.
• They used compaction techniques to compact the subgrade and subbase soil.
• The transverse slope has been provided to the roads to take off the drain from the road surface.
• They gave importance to soil subgrade moisture content.

:: Telford Roads ::

Thomas Telford was a Scottish civil engineer, architect and stonemason, and a noted road, bridge and canal builder. After establishing himself as an engineer of road and canal projects in Shropshire, he designed numerous infrastructure projects in his native Scotland, as well as harbors and tunnels. Such was his reputation as a prolific designer of highways and related bridges, he was dubbed The Colossus of Roads (a pun on the Colossus of Rhodes), and, reflecting his command of all types of civil engineering in the early 19th century, he was elected as the first President of the Institution of Civil Engineers, a post he retained for 14 years until his death.

:: Main features of Telford Roads ::

• They used the horizontal subgrade. 

• Telford provided level subgrade of 9m width. 

• A binding layer of wearing course with the thickness of 4cm was provided with cross-slope of 1in45. 

:: Macadam Roads :: 

Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which single-sized crushed stone layers of small angular stones are placed in shallow lifts and compacted thoroughly. 
A binding layer of stone dust (crushed stone from the original material) may form; it may also, after rolling, be covered with a binder to keep dust and stones together. The method simplified what had been considered state of the art at that point.

:: Main features of Macadam Roads :: 

                         Cross-section of McAdam Roads

• McAdam was the first person who suggested that heavy foundation stones are not at all required to be placed at the subgrade layer.
• He realized the importance of subgrade drainage and compaction. So, the subgrade was compacted and prepared with the cross slope of 1in36.
• In present time the Macadam road is classified by the two types i.e. WBM & BM.