Although trackways preceded them, modern roads only really came about when the Romans started to build them in Europe in order to speed up their communications network. Since those times, modern road building technology has developed almost out of all recognition. However, the basic priorities of roads remain the same: the creation of a durable surface with good water run-off properties that makes transportation easier. Read on to take a look at how contemporary road builders get the job done.
Clearing the Way
Once a route for a new road has been surveyed and a design has been drawn up by civil engineers, it is time to prepare the ground. Buildings, pipelines and electrical installations all need to be carefully removed first. Next come natural obstacles such as trees and hills. In many cases, cuttings are made into hilly sections of the route with earthmoving machinery. Heavy duty earthmoving equipment can shift large amounts of soil to ensure that the road does not face too many steep sections once it is in use.
Roads could slip over the earth on which they sit given sufficient force, so they need to be weighed down. Just as in Roman times, this is done with stones, although the process is now mechanised. Hardcore is laid down over the road's route to create a foundation on which the surface will be constructed. It is commonplace to compact the hardcore down so that it remains in place for years to come. Either side of this section of hard material, culverts or drains are installed to make sure that rainfall can flow away from the road, helping it to remain safe.
The Road's Surface
When the foundation has been built, it is time to make the surface on which vehicles will actually drive. Roadmakers either use asphalt or concrete these days. Concrete is cheap and is simply poured out in sections, but this can lead to a noisy and uncomfortable ride for drivers. Asphalt is smoother and sometime considered to be more reliable. It is laid down when it is hot from a device known as a paver which has a hopper that is constantly fed from supply trucks. As asphalt cools on the foundation, workers spread it around so that an even road surface is created. Long sections can be fashioned using this approach.
In some cases, the upper layer of a road needs to be replaced because it has worn out. Without damaging the supporting foundation, a high-tech road profiler can remove the concrete or asphalt top. Once it has gone, a new surface can be laid down soon afterwards.