Pavement facts for kids

A road surface is the strong material used to cover roads, sidewalks, and other areas where vehicles or people travel. In America, it's often called pavement. In Britain, "pavement" usually means a sidewalk.

Long ago, roads were often made of gravel, cobblestones, or large stone blocks. Today, most roads are built with asphalt or concrete. These materials are laid over a firm base. Road surfaces often have lines and symbols to help guide traffic safely. Newer methods like permeable paving are also being used for paths and lighter roads.

History of Road Surfaces

People have been building roads for thousands of years. Early roads were often just dirt paths. Over time, people learned to build stronger, more lasting surfaces.

In 1984, Laura Ingalls Wilder, who wrote Little House on the Prairie, described seeing pavement for the first time. She was traveling in a covered wagon with her family. She wrote:

"In the very midst of the city, the ground was covered by some dark stuff that silenced all the wheels and muffled the sound of hoofs. It was like tar, but Papa was sure it was not tar, and it was something like rubber, but it could not be rubber because rubber cost too much. We saw ladies all in silks and carrying ruffled parasols, walking with their escorts across the street. Their heels dented the street, and while we watched, these dents slowly filled up and smoothed themselves out. It was as if that stuff were alive. It was like magic."

This quote shows how amazing paved roads seemed to people who were used to dirt paths.

The first paved roads were built by the Carthaginians around 600 BC. The Romans later destroyed Carthage. However, they might have learned about paved roads from them. The Romans went on to build over 87,000 kilometres (54,000 mi) (about 54,000 miles) of roads across their huge empire. These roads helped them move armies and goods.

Two important Scottish engineers helped improve roads in the 18th and 19th centuries:

• Thomas Telford (1757–1834) designed flat roads. These roads made it easier for horses to pull wagons. His designs were strong and could support heavy loads.
• John Loudon McAdam (1756–1836) invented a process called "macadamisation". This method created smooth, hard road surfaces that drained water quickly. His roads were much stronger and less muddy than older dirt roads.

Asphalt Roads

By the 1870s, roads in the United States were being built using asphalt. Workers would spread asphalt with rakes. Then, steam rollers would press it down to make it firm.

In 1894, an American engineer named Clifford Richardson studied asphalt roads. He found that many roads did not have enough coarse gravel mixed in. He then created a detailed plan for building the strongest asphalt pavement of his time.

After 1907, less natural asphalt was used for roads. Instead, asphalt made from petroleum became more common. As cars became very popular, more and more roads were needed. This led to new ways of making asphalt. During World War II, there was a big need for even stronger pavement. This was especially true for aircraft runways, which had to support heavy planes.

Concrete Roads

The ancient Romans were the first to use concrete on a large scale. However, after the Western Roman Empire fell, concrete was rarely used for many centuries. Concrete as a building material was rediscovered and improved in the mid-18th century.

One of the most important uses of concrete pavement happened in the 1950s. This was when the Interstate Highway System began in the US. This system includes about 45,000 miles of highways across the US. About 60 percent of these highways are made of concrete.