Road surface
Road surface
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Road surface

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Road surface

A road surface (British English) or pavement (North American English) is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, macadam, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads or dirt roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.

Today, permeable paving methods are beginning to be used for low-impact roadways and walkways to prevent flooding. Pavements are crucial to countries such as United States and Canada, which heavily depend on road transportation. Therefore, research projects such as Long-Term Pavement Performance have been launched to optimize the life cycle of different road surfaces.

Pavement, in construction, is an outdoor floor or superficial surface covering. Paving materials include asphalt, concrete, stones such as flagstone, cobblestone, and setts, artificial stone, bricks, tiles, and sometimes wood. In landscape architecture, pavements are part of the hardscape and are used on sidewalks, road surfaces, patios, and courtyards, among others.

The term pavement comes from Latin pavimentum, meaning a floor beaten or rammed down, through Old French pavement. The meaning of a beaten-down floor was obsolete before the word entered English.

Pavement, in the form of beaten gravel, dates back before the emergence of anatomically modern humans. Pavement laid in patterns like mosaics were commonly used by the Romans.

The bearing capacity and service life of a pavement can be raised significantly by arranging good drainage by an open ditch or covered drains to reduce moisture content in the pavements subbase and subgrade.

Wheeled transport created the need for better roads. Generally, natural materials cannot be both soft enough to form well-graded surfaces and strong enough to bear wheeled vehicles, especially when wet, and stay intact. In urban areas it was worthwhile to build stone-paved streets and, in fact, the first paved streets appear to have been built in Ur in 4000 BC. Corduroy roads were built in Glastonbury, England, in 3300 BC, and brick-paved roads were built in the Indus Valley Civilisation on the Indian subcontinent from around the same time. Improvements in metallurgy meant that by 2000 BC stone-cutting tools were generally available in the Middle East and Greece allowing local streets to be paved. Notably, in about 2000 BC, the Minoans built a 50 km paved road from Knossos in northern Crete through the mountains to Gortyn and Lebena, a port on the south coast of the island, which had side drains, a 200 mm thick pavement of sandstone blocks bound with clay-gypsum mortar, covered by a layer of basaltic flagstones and had separate shoulders. This road could be considered superior to any Roman road. Roman roads varied from simple corduroy roads to paved roads using deep roadbeds of tamped rubble as an underlying layer to ensure that they kept dry, as the water would flow out from between the stones and fragments of rubble, instead of becoming mud in clay soils.

Although there were attempts to rediscover Roman methods, there was little useful innovation in road building before the 18th century. The first professional road builder to emerge during the Industrial Revolution was John Metcalf, who constructed about 290 kilometres (180 mi) of turnpike road, mainly in the north of England, from 1765, when Parliament passed an act authorising the creation of turnpike trusts to build toll funded roads in the Knaresborough area.

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