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KOTI - Korea Transport institute-
Technologies and Construction Methods on the Road
# The condition of the road is as important as the engine performance is for vehicle movement.
Frictional force between the road surface and tires is necessary. The force makes the tire push away the surface of the road. Driving power, generated by the reaction of the frictional force, makes the vehicle move forward.
# Melody Coming from Highway
When passing through a certain section of highway you can hear unique sound from the bottom of your car.
The sound is generated from the grooves that are cut at regular intervals on the surface of the road which is called as ‘rumble strip’.
# Function of Rumble Strip
Rumble strips inhibit hydroplaning in rainy weather and prevent skid by improving braking power. The unique sound, coming from the surface of the road, is the output of pitch controls depending on the intervals of the grooves.
The closer the intervals are, the higher pitch becomes to alert drivers to prevent them from drowsing; If the interval is 10.6cm, you hear ‘do’ sound. If the interval is 9.5cm, you do ‘re’ sound.
# Development of Road Pavement
People laid a myriad of bricks on the ground like tiles to pave the road in Mesopotamia around BC 3000.
The Roman Empire, that constructed the longest road among the ancient countries, used stones and gravels in order to improve the stability of the road. There were about 80,000-kilometre paved roads around 100 AD.
The paved roads began to proliferate rapidly in the UK after the Industrial Revolution and John McAdam, a Scottish engineer, suggested an innovative road pavement method early 19th century.
This is so-called ‘Macadam Method of Construction’ that lays huge stones, sprinkles small stones and gravels and then covers them with tar.
This road had excellent durability to improve the speed of wagons dramatically.
The asphalt road you see today began in the US end 19th century.
The surface of the road was able to be paved with the mixture of asphalt, gravels and sand which, in particular, helped the cars using rubber tires with high-speed driving a lot.
Meanwhile, concrete road has not been constructed until 20th century.
# Asphalt Road versus Concrete Road
Today’s paved roads are broadly divided into asphalt road and concrete road.
Asphalt road has less noise and excellent drainage but is relatively less solid and more susceptible to heat.
On the contrary, concrete road is highly resistant to heat but has huge noise and gives you bad impression of riding.
As the asphalt roads have had deformations here and there due to scorching heat, Korea has preferred to the concrete pavement which is resistant to heat so we have now had more concrete-paved highways.
The asphalt road construction method is applied to most highways that are built these days.
That’s because is formed a consensus of considering drivers’ safety and convenience before durability as salinity water began being used to remove snow on the road caused damages to existing concrete roads in the 2000s
In addition, technical development has greatly improved the durability and thermal resistance of asphalt.
# A new technology to increase the life of road by mixing shredded wasted tires into asphalt used to be studied in Australia in May.
The applied mechanism is that the rubber scraps of tires serve as a sunscreen to protect asphalt from damage.
It is anticipated that new road paving technologies will be emerged in the future which are more environmentally friendly and suitable for the age of autonomous driving.
* This card news is produced by modifying and supplementing the article 'Technologies and Construction Method on the Road’ in 『Monthly Transportation』 of Korea Transport Institute issued July 2022.