Asphalt is used as a surface paving material for roads, driveways, parking lots, sidewalks, bike paths and more. It is a good material for surface paving because placing a smooth layer of asphalt is possible. It is also relatively inexpensive, yet durable. Here are some scientific asphalt facts and some facts about how asphalt paving is built and used.
Asphalt is a natural occurring material also known a bitumen. It is a tar-like petroleum substance that is a lot like hard dried pancake syrup. For many years ancient people found the asphalt and used it for waterproofing their boats and things they wanted to store water inside. They also used asphalt to help keep water out of their buildings.
Separately, people like the Romans and other ancient civilizations built roads by laying down large stones. This allowed people, horses and goods to pass, even when the ground was very soft. The large stones, however, were very heavy and required intensive labor to build so this type of road was not practical for long distances. In the late 1700’s a man named John Loudon McAdam realized that smaller stones held together well if they had a certain percent of large stone, smaller stone and tiny fine stones. He developed a surface paving known as water-bound macadam. In this case, water was used to bind together all of the stones. This was a huge advancement in pavement technology and allowed construction of many more roads because they were easier to build and cost much less.
In 1824, in Paris France the first recorded road was built that replaced water-binding with asphalt binding. It was understood that water was a problem with the water-bound macadam. The stone could not hold together. Since asphalt had been used form many years as a waterproofing material, it was a natural fit in keeping the water out of the road paving.
Since this time engineers, scientists and researchers have learned more about the science of how the asphalt binder performs. Many different advancements in materials are been made to allow people to produce the millions of miles of asphalt roads used throughout the world.