What Are Roads Made out Of?
Have you ever wondered what roads are made out of? There are millions of miles of roads in the world, and most of them fall into four categories. In this article I will tell you what the four main types of roads are in the world, and what they are made out of.
Chip seal is by far the most common type of road in western countries like the USA, Australia and New Zealand. Now-days Chip seal is not used for motorways or very busy roads. It is mainly used for moderately busy roads, residential streets, industrial streets, country roads and highways. Chip seal roads are made by pouring a layer of tar onto a road, then dropping moderately fine gravel onto the tar. A steamroller will then proceed to drive over the gravel, setting it into the tar. Any excess gravel is brushed to the side by road workers.
When your driving on newly sealed Chip-seal roads you must drive slowly and carefully, because there may still be loose gravel on the road. This gravel can flick up and crack you or others windscreens if you drive over it too fast. Chip-seal roads are probably the most popular type of road in the world. It has been around for a very long time, and is going to continue to be used well into the future.
Asphalt roads are quite a new development, and have become popular in the last decade or so. Used mainly in western countries, Asphalt roads are great for busy roads, motorways, urban commercial areas, and the main streets of towns. Unlike Chip-seal roads, Asphalt roads do not wear smooth after heavy use. This is why they are ideal for very busy streets, where vehicles stop and start a lot.
Asphalt roads are made out of tar-seal mixed with very fine gravel. It is mixed before-hand , and the whole mixture is poured onto the road. It is then smoothed and left to dry. This makes a very strong, durable, smooth road. The only downside to Asphalt roads is the fact that it loses grip when wet.
Gravel roads are usually used in very rural areas, where there is not enough traffic for a sealed road to be worthwhile. Gravel roads are very cheap to make, and need little or no maintenance. To make a gravel road the ground the road will be made on must be leveled, then gravel poured onto it. And thats all there is to it!
Dirt roads are often just muddy 4x4 tracks in the bush, through paddocks or around rivers. unlike gravel roads, dirt roads are often not suitable for regular cars. Especially in the winter when the dirt turns to mud. It would be wise to use a four wheel drive vehicle to travel on unmaintained dirt roads.
Dirt roads are not often planned. Many are just cleared bush or foliage that is made smooth by vehicles driving over it. Most of these roads are not on maps either, because instead of being made by road workers, they are made by farmers (or other civilians).