Pavement facts for kids

Road surface or pavement (American English) is the durable surface material laid down on an area intended for vehicle or foot traffic. It is used primarily as a road surface. Pavement, (British English) generally refers to a sidewalk or walkway. In the past, gravel road surfaces, cobblestone and granite setts were extensively used. These surfaces have mostly been replaced by asphalt or concrete laid on a compacted base course. Road surfaces are frequently marked to guide traffic. Today, permeable paving methods are beginning to be used for low-impact roadways and walkways.

History

In 1984 Laura Ingalls Wilder, author of Little House on the Prairie, while traveling in a wagon with her parents, wrote about the first time she saw pavement:

"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."

The first paved roads were created by the Carthaginians about 600 BC. The ancient Romeand destroyed Carthage but may have borrowed the idea of paved roads. They went on to build over 87,000 kilometres (54,000 mi) of roads throughout their empire.

Thomas Telford (1757–1834) was a Scottish civil engineer. He is noted for building flat roads that required fewer horses to pull the wagons. His roads were well designed and supported heavy loads. John Loudon McAdam (1756–1836), was a Scottish engineer and road-builder. He invented a new process, "macadamisation", for building roads with a smooth hard surface that drained quickly. His roads were more durable and less muddy than soil-based roads.

Asphalt

By 1870, in the United States roads were being built using asphalt spread with rakes and made compact by steam rollers. In 1894, Clifford Richardson, an American engineer, determined that roads paved with asphalt did not contain enough coarse gravel. He produced a specification for the most durable pavement of the time.

By 1907, 1907 natural asphalt was being used less than petroleum-based asphalt for roads. Automobiles became more popular and more roads were needed. This created new methods of producing asphalt. World War II created a need for better and stronger pavement on which to land heavy aircraft.

Concrete

The ancient Romans were the earliest large-scale users of concrete. But after the collapse of the Western Roman Empire, concrete was only used rarely. Concrete as a building material was redeveloped in the mid-18th century. One of the most significant uses of concrete pavement came about in the 1950s with the start of the Interstate Highway System in the US. There are about 45,000 miles of interstate highway in the US. About 60 percent is concrete.