Dan and Bex are on a road trip. Whilst driving though some roadworks, it gets them thinking about how roads are constructed today.
Roads today are constructed using all sorts of amazing gadgets and machinery – some of them you probably recognise, but some you might not!
Let’s check them out and the different jobs they do!
Before any digging can begin, the site has to be ‘set out’ – that means putting markers to make sure everyone knows where the repairs or construction will be, and guides to check that everything is level.
No one wants a wobbly road!
When that’s done, bring on the diggers for the earthworks!
Whether repairing or constructing, the old road surface, vegetation and topsoil are scraped away. Huge earth-moving machines, like diggers and bulldozers, create a solid foundation for the road to be built.
Without a solid foundation, road, will fail before long.
Dump trucks bring aggregates such as gravel and sand to the site to be spread around by bulldozers and graders to create a level surface.
Drains are also installed so that water will drain away from the road surface and make it safer for vehicles to travel in storms.
Rumbling rollers make sure it’s all nice and flat, and then construction workers will check their markers and take measurements to make sure everything’s fine!
Pavers are really clever! They help to finish the job with the top layer of the road – which is known as the Pavement.
It might be concrete, sticky black asphalt, tarmac or a mixture of different things, depending on where the road is, how hot it might get, and how much traffic it’ll carry.
You might be wondering what asphalt is…
It’s a sticky oily substance called bitumen which is mixed with sand and crushed rock. It’s then heated to very high temperatures before it is laid down. Once cold, it makes a very smooth and strong black surface.
Some roads are made using concrete rather than asphalt. Liquid concrete is poured into special steel moulds and as it dries, a special machine vibrates it to make it settle evenly and then trims it to the correct height.
To prevent cracks, joints are cut between the concrete slabs. These joints allow the slabs to expand and contract with changes in temperature without breaking – which you can hear as a melodic sound as you drive over them.
Part of the M25 motorway is concrete – if you listen out when you’re travelling on it, you’ll be able to hear the clicks as you move over the sections.