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A road surface (
British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial codification of grammar and usage and is employed by a populatio ...
), or pavement (
American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American English is the most influential form of ...
), is the durable surface material laid down on an area intended to sustain vehicular or foot
traffic Traffic on roads A road is a thoroughfare, route, or way on land between two places that has been paved or otherwise improved to allow travel by foot or by some form of conveyance (including a motor vehicle Electric bicycles parked i ...

traffic
, such as a
road A road is a wide way leading from one place to another, typically one with a specially prepared surface which vehicles and bikes can use. Roads consist of one or two roadways (British English: carriageways), each with one or more lanes and any ...

road
or
walkwayImage:Legaransegget.jpg, left, The Legaran Segget walkway in Johor Bahru, Malaysia. In American English, walkway is a composite or umbrella term for all engineered surfaces or structures which support the use of trails. ''The New Oxford American Di ...

walkway
. In the past,
gravel road A gravel road is a type of unpaved road A road is a thoroughfare, route, or way on land between two Location (geography), places that has been Pavement (material), paved or otherwise improved to allow travel by foot or by some form of wikt:con ...

gravel road
surfaces,
cobblestone Cobblestone is a natural building material Building material is material used for construction Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def ...

cobblestone
and
granite setts Granite () is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools ...
were extensively used, but these have mostly been replaced by
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

asphalt
or
concrete Concrete is a composed of fine and coarse bonded together with a fluid (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its ...

concrete
laid on a compacted
base course Layers in the construction of a mortarless pavement:A. Subbase In topology s, which have only one surface and one edge, are a kind of object studied in topology. In mathematics, topology (from the Greek language, Greek words , and ) is concer ...
. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled roads 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, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic. Today,
permeable paving''See pervious concrete for pervious slab pavement surfaces.'' Permeable paving includes a variety of surfacing techniques for roads, parking lots, and pedestrian walkways, unified under the common goal to allow for infiltration of stormwater r ...
methods are beginning to be used for low-impact roadways and walkways. Pavements are crucial to countries such as
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country in . It consists of 50 , a , five major , 326 , and some . At , it is the world's . The United States shares significan ...

United States
and
Canada Canada is a country in the northern part of . Its extend from the to the and northward into the , covering , making it the world's . Its southern and western , stretching , is the world's longest bi-national land border. Canada's capital ...

Canada
, which heavily depend on road transportation. Therefore, research projects such as
Long-Term Pavement Performance Long-Term Pavement Performance Program, known as LTPP, is a research project supported by Federal Highway Administration (FHWA) to collect and analyze road surface, pavement data in the United States and Canada. Currently, the LTPP acquires the larg ...
have been launched to optimize the life cycle of different road surfaces.


Development of road surfaces

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 began to be worthwhile to build stone-paved streets and, in fact, the first paved streets appear to have been built in
Ur
Ur
in 4000 BC.
Corduroy road A corduroy road or log road is a type of road or timber trackway Historic roads (historic trails in USA and Canada) are paths or routes that have historical importance due to their use over a period of time. Examples exist from prehistori ...

Corduroy road
s were built in
Glastonbury Glastonbury (, ) is a town and civil parish In England, a civil parish is a type of Parish (administrative division), administrative parish used for Local government in England, local government. It is a territorial designation which is the ...

Glastonbury
,
England England is a that is part of the . It shares land borders with to its west and to its north. The lies northwest of England and the to the southwest. England is separated from by the to the east and the to the south. The country cover ...

England
in 3300 BC and brick-paved roads were built in the
Indus Valley Civilization , c. 2500 BCE. Terracotta Terracotta, terra cotta, or terra-cotta (; Italian language, Italian: "baked earth", from the Latin ''terra cocta''), a type of earthenware, is a clay-based ceramic glaze, unglazed or glazed ceramic, where the ...

Indus Valley Civilization
on the Indian subcontinent from around the same time. Improvements in
metallurgy Metallurgy is a domain of Materials science, materials science and engineering that studies the physical and chemical behavior of metallic Chemical element, elements, their Inter-metallic alloy, inter-metallic compounds, and their mixtures, which ...
meant that by 2000 BC stone-cutting tools were generally available in the Middle East and
Greece Greece ( el, Ελλάδα, Elláda, ), officially the Hellenic Republic, is a country located in . Its population is approximately 10.7 million as of 2021; is its largest and capital city, followed by . Situated on the southern tip of the , ...

Greece
allowing local streets to be paved. Notably, in about 2000 BC, the Minoans built a 50 km paved road from
Knossos Knossos (also Cnossos, both pronounced ; grc, Κνωσός, Knōsós, ; Linear B Linear B is a syllabic script that was used for writing Mycenaean Greek, the earliest attested form of Greek. The script predates the Greek alphabet ...

Knossos
in North
Crete Crete ( el, Κρήτη, translit=, : , : '','' ) is the largest and most populous of the , the largest island in the world and the largest island in the , after , , , and . Crete rests approximately south of the Greek mainland. It has an ar ...

Crete
through the mountains to
Gortyn Gortyn, Gortys or Gortyna ( el, Γόρτυν, , or , ) is a , and an site, on the island of away from the island's capital, . The seat of the municipality is the village . Gortyn was the capital of . The area was first inhabited around 7000 ...

Gortyn
and Lebena, a port on the south coast of the island, which had side drains, a 200 mm thick pavement of
sandstone Sandstone is a clastic sedimentary rock of a clast (sand grain), derived from a basalt Basalt (, ) is a fine-grained extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron ('' mafic ' ...

sandstone
blocks bound with
clay Clay is a type of fine-grained natural soil File:Stagnogley.JPG, Surface-water-Gley soil, gley developed in glacial till, Northern Ireland. Soil is a mixture of organic matter, minerals, gases, liquids, and organisms that together support ...

clay
-
gypsum Gypsum is a soft sulfate mineralThe sulfate minerals are a class of mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the ...

gypsum
mortar Mortar may refer to: * Mortar (weapon), an indirect-fire infantry weapon * Mortar (masonry), a material used to fill the gaps between blocks and bind them together * Mortar and pestle, a tool pair used to crush or grind * Mortar, Bihar, a village in ...
, covered by a layer of
basalt Basalt (, ) is a fine-grained extrusive A volcanic rock from Italy with a relatively large six-sided phenocryst (diameter about 1 mm) surrounded by a fine-grained groundmass, as seen in thin section under a petrographic microscope Extrusi ...

basalt
ic
flagstone Flagstone (flag) is a generic flat stone A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed. R ...
s and had separate
shoulders The human shoulder is made up of three bones: the clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the scapula, shoulder blade and the sternum (brea ...
. This road could be considered superior to any
Roman road Roman roads ( la, viae Romanae ; singular: ; meaning "Roman way") were physical infrastructure vital to the maintenance and development of the Roman state, and were built from about 300 BC through the expansion and consolidation of the Roman Rep ...

Roman road
. Roman roads varied from simple
corduroy road A corduroy road or log road is a type of road or timber trackway Historic roads (historic trails in USA and Canada) are paths or routes that have historical importance due to their use over a period of time. Examples exist from prehistori ...

corduroy road
s 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 The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmasse ...
was John Metcalf, who constructed about of
turnpike road Turnpike often refers to: * A type of gate, another word for a turnstile * In the United States, a toll road Turnpike may also refer to: Roads United Kingdom * Turnpike trust, a body set up by an Act of Parliament, with powers to collect road tol ...

turnpike road
, mainly in the north of England, from 1765, when
Parliament In modern politics and history, a parliament is a legislative body of government. Generally, a modern parliament has three functions: Representation (politics), representing the Election#Suffrage, electorate, making laws and overseeing the ...
passed an act authorising the creation of
turnpike trust Turnpike trusts were bodies set up by individual acts of Parliament Acts of parliament, sometimes referred to as primary legislation In parliamentary systems and presidential systems of government, primary legislation and secondary legislati ...
s to build new
toll Toll may refer to: Transportation * Toll (fee) A toll is a fee A fee is the price A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for one unit of goods or services ...
funded roads in the Knaresborough area. Pierre-Marie-Jérôme Trésaguet is widely credited with establishing the first
scientific approach The scientific method is an Empirical evidence, empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century. It involves careful observation, applying rigorous skepticism about what ...

scientific approach
to
road building A road is a thoroughfare A thoroughfare is a primary passage or way as a transit route through regularly trafficked areas whether by road A road is a thoroughfare, route, or way on land between two Location (geography), places that has been ...
in France at the same time as Metcalf. He wrote a memorandum on his method in 1775, which became general practice in France. It involved a layer of large rocks, covered by a layer of smaller gravel. By the late 18th and early 19th centuries, new methods of highway construction had been pioneered by the work of two British engineers:
Thomas Telford Thomas Telford FRS FRS may also refer to: Government and politics * Facility Registry System, a centrally managed Environmental Protection Agency database that identifies places of environmental interest in the United States * Family Resources ...
and
John Loudon McAdam John Loudon McAdam (23 September 1756https://familysearch.org/ark:/61903/1:1:XY88-68G – 26 November 1836) was a Scottish civil engineer and road-builder. He was the inventor of "macadam Macadam is a type of road construction, pio ...

John Loudon McAdam
. Telford's method of road building involved the digging of a large trench in which a foundation of heavy rock was set. He also designed his roads so that they sloped downwards from the centre, allowing drainage to take place, a major improvement on the work of Trésaguet. The surface of his roads consisted of broken stone. McAdam developed an inexpensive paving material of soil and stone aggregate (known as
macadam Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which single-sized crushed stone layers of small angular stones are placed in shallow lifts and compacted thoroughly. A binding layer of st ...

macadam
). His road building method was simpler than Telford's, yet more effective at protecting roadways: he discovered that massive foundations of rock upon rock were unnecessary, and asserted that native soil alone would support the road and traffic upon it, as long as it was covered by a road crust that would protect the soil underneath from water and wear. Size of stones was central to McAdam's road building theory. The lower road thickness was restricted to stones no larger than . Modern tarmac was patented by British civil engineer
Edgar Purnell Hooley Edgar Purnell Hooley (5 June 1860 – 26 January 1942) was a Welsh inventor. After inventing tarmac in 1902, he founded Tar Macadam Syndicate Ltd the following year and registered tarmac as a trademark. Following a merger in 2013 the business bec ...
, who noticed that spilled tar on the roadway kept the dust down and created a smooth surface.. (Details of this story vary a bit, but the essence of is the same, as are the basic facts). He took out a patent in 1901 for tarmac.
Hooley Hooley is a village in the borough of Reigate and Banstead Reigate and Banstead is a Non-metropolitan district, local government district with borough status in east Surrey, England. It includes the towns of Reigate, Surrey, Reigate, Redhill, Sur ...
's 1901
patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of years in exchange for publishing an sufficiency of disclosure, enabling disclo ...

patent
for Tarmac involved mechanically mixing tar and aggregate prior to lay-down, and then compacting the mixture with a
steamroller A steamroller (or steam roller) is a form of road roller – a type of heavy construction machinery used for leveling surfaces, such as roads or airfields – that is powered by a steam engine from Stott Park Bobbin Mill, Cumbria, Englan ...

steamroller
. The tar was modified by adding small amounts of
Portland cement Portland cement is the most common type of in general use around the world as a basic ingredient of , , , and non-specialty . It was developed from other types of in England in the early 19th century by , and is usually made from . It is a f ...

Portland cement
,
resin In polymer chemistry and materials science, resin is a solid or highly Viscosity, viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focus ...

resin
, and
pitch Pitch may refer to: Acoustic frequency * Pitch (music), the perceived frequency of sound including "definite pitch" and "indefinite pitch" ** Absolute pitch or "perfect pitch" ** Pitch class, a set of all pitches that are a whole number of octaves ...
.


Asphalt

Asphalt (specifically,
asphalt concrete Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac, bitumen macadam, or rolled asphalt in the United Kingdom and the Republic of Ireland) is a composite material A composite material (also called a c ...
), sometimes called
flexible pavementHighway engineering is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effective transportation of people and go ...
due to the nature in which it distributes loads, has been widely used since the 1920s. The viscous nature of the
bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external ...

bitumen
binder allows asphalt concrete to sustain significant
plastic deformation In engineering, deformation refers to the change in size or shape of an object. ''Displacements'' are the ''absolute'' change in position of a point on the object. Deflection (engineering) , Deflection is the relative change in external displace ...
, although
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
from repeated loading over time is the most common failure mechanism. Most asphalt surfaces are laid on a gravel base, which is generally at least as thick as the asphalt layer, although some 'full depth' asphalt surfaces are laid directly on the native
subgrade Layers in the construction of a mortarless pavement: A.) Subgrade B.) Subbase C.) Pavers_F.)_Fine-grained_sand.html" ;"title="Paver_(flooring).html" ;"title="Paver_base.html" ;"title="Base course D.) Paver base">Base course D.) Paver base E.) Pave ...
. In areas with very soft or expansive subgrades such as
clay Clay is a type of fine-grained natural soil File:Stagnogley.JPG, Surface-water-Gley soil, gley developed in glacial till, Northern Ireland. Soil is a mixture of organic matter, minerals, gases, liquids, and organisms that together support ...

clay
or
peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation Vegetation is an assemblage of plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the ...
, thick gravel bases or stabilization of the subgrade with
Portland cement Portland cement is the most common type of in general use around the world as a basic ingredient of , , , and non-specialty . It was developed from other types of in England in the early 19th century by , and is usually made from . It is a f ...

Portland cement
or
lime Lime refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany * Austra ...
may be required. Polypropylene and polyester
geosynthetic File:Mega sand container.jpg, upright=1.1, Geotextile sandbags can be ca. 20 m long, such as those used for the artificial reef at Narrow Neck, Queensland. Geosynthetics are synthetic products used to stabilize terrain. They are generally polymeric ...
s have also been used for this purpose and in some northern countries, a layer of
polystyrene Polystyrene (PS) is a synthetic aromatic forms of benzene (top) combine to produce an average structure (bottom) In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, com ...

polystyrene
boards have been used to delay and minimize frost penetration into the subgrade. Depending on the temperature at which it is applied, asphalt is categorized as hot mix, warm mix, half warm mix, or cold mix. Hot mix asphalt is applied at temperatures over 300 °F (150 °C) with a
free floating screedThe free floating screed is a device pioneered in the 1930s that revolutionized the asphalt Pavement (material), paving process. The device is designed to flatten the material (e.g. concrete or asphalt) below it, which is also known as screed. Desc ...
. Warm mix asphalt is applied at temperatures of 200–250 °F (95–120 °C), resulting in reduced energy usage and emissions of
volatile organic compounds Volatile organic compounds (VOC) are organic chemicals , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bond, bonds. Due to carbon's abilit ...

volatile organic compounds
. Cold mix asphalt is often used on lower-volume rural roads, where hot mix asphalt would cool too much on the long trip from the
asphalt plant An asphalt plant is a plant used for the manufacture of asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined produ ...

asphalt plant
to the construction site. An asphalt concrete surface will generally be constructed for high-volume primary highways having an average annual daily traffic load greater than 1200 vehicles per day. Advantages of asphalt roadways include relatively low noise, relatively low cost compared with other paving methods, and perceived ease of repair. Disadvantages include less durability than other paving methods, less tensile strength than concrete, the tendency to become slick and soft in hot weather and a certain amount of
hydrocarbon In , a hydrocarbon is an consisting entirely of and . Hydrocarbons are examples of s. Hydrocarbons are generally colourless and hydrophobic with only weak odours. Because of their diverse molecular structures, it is difficult to generalize furth ...
pollution to soil and
groundwater Groundwater is the water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

groundwater
or
waterway A waterway is any navigable A body of water ( Lysefjord) in Norway Norway ( nb, ; nn, ; se, Norga; smj, Vuodna; sma, Nöörje), officially the Kingdom of Norway, is a Nordic countries, Nordic country in Northern Europe whose ...

waterway
s. In the mid-1960s,
rubberized asphalt Rubberized asphalt concrete (RAC), also known as asphalt rubber or just rubberized asphalt, is noise reducing pavement material that consists of regular asphalt concrete Asphalt concrete (commonly called asphalt, blacktop, or pavement in Nort ...
was used for the first time, mixing crumb rubber from used tires with asphalt. While a potential use for tires that would otherwise fill landfills and present a fire hazard, rubberized asphalt has shown greater incidence of wear in freeze-thaw cycles in temperate zones due to non-homogeneous expansion and contraction with non-rubber components. The application of rubberized asphalt is more temperature-sensitive, and in many locations can only be applied at certain times of the year. Study results of the long-term acoustic benefits of rubberized asphalt are inconclusive. Initial application of rubberized asphalt may provide a reduction of 3–5 decibels (dB) in tire-pavement-source noise emissions; however, this translates to only 1–3 decibels (dB) in total traffic-noise reduction (due to the other components of traffic noise). Compared to traditional passive attenuating measures (e.g., noise walls and earth berms), rubberized asphalt provides shorter-lasting and lesser acoustic benefits at typically much greater expense.


Concrete

Concrete surfaces (specifically,
Portland cement Portland cement is the most common type of in general use around the world as a basic ingredient of , , , and non-specialty . It was developed from other types of in England in the early 19th century by , and is usually made from . It is a f ...

Portland cement
concrete) are created using a concrete mix of Portland cement, coarse aggregate,
sand Sand is a granular Granularity (also called graininess), the condition of existing in granules or grains A grain is a small, hard, dry seed A seed is an embryonic plant enclosed in a protective outer covering. The formation of th ...

sand
, and water. In virtually all modern mixes there will also be various admixtures added to increase workability, reduce the required amount of water, mitigate harmful chemical reactions and for other beneficial purposes. In many cases there will also be Portland cement substitutes added, such as
fly ash Fly ash, flue ash, coal ash, or pulverised fuel ash (in the UK) plurale tantum: coal combustion residuals (CCRs)is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired bo ...
. This can reduce the cost of the concrete and improve its physical properties. The material is applied in a freshly mixed slurry, and worked mechanically to compact the interior and force some of the cement slurry to the surface to produce a smoother, denser surface free from honeycombing. The water allows the mix to combine molecularly in a chemical reaction called hydration. Concrete surfaces have been classified into three common types: jointed plain (JPCP), jointed reinforced (JRCP) and continuously reinforced (CRCP). The one item that distinguishes each type is the jointing system used to control crack development. One of the major advantages of concrete pavements is they are typically stronger and more durable than asphalt roadways. They also can be grooved to provide a durable skid-resistant surface. A previous disadvantage was that they had a higher initial cost, and could be more time-consuming to construct. This cost can typically be offset through the long life cycle of the pavement and the higher cost of bitumen. Concrete pavement can be maintained over time utilizing a series of methods known as concrete pavement restoration which include
diamond grinding Diamond grinding is a Grinding (abrasive cutting), grinding process that can be applied to a variety of surfaces including floors, stones, and engineering ceramics. It takes advantage of the fact that diamond has the highest hardness of any bulk ma ...
, dowel bar retrofits, joint and crack sealing, cross-stitching, etc. Diamond grinding is also useful in reducing noise and restoring skid resistance in older concrete pavement. The first street in the United States to be paved with concrete was
Court Avenue Court Avenue is a small street in downtown Bellefontaine, Ohio Ohio is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty states, it ...
in
Bellefontaine, Ohio Bellefontaine ( ) is a city in and the county seat A county seat is an administrative center, seat of government, or capital city of a county or Parish (administrative division), civil parish. The term is used in Canada, China, Romania, Hungary a ...
in 1893. The first mile of concrete pavement in the United States was on
Woodward Avenue A woodward is a Game warden, warden of a wood. Woodward may also refer to: Places ;United States * Woodward, Iowa * Woodward, Oklahoma * Woodward, Pennsylvania, a census-designated place * Woodward Avenue, a street in Tallahassee, Florida, which b ...
in
Detroit, Michigan (strait A strait is a naturally formed, narrowing, typically navigable waterway that connects two larger bodies of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Mo ...

Detroit, Michigan
in 1909. Following these pioneering uses, the
Lincoln Highway Association The Lincoln Highway is one of the earliest transcontinental highway routes for automobiles across the United States of America. Conceived in 1912 by Indiana Indiana () is a U.S. state in the Midwestern United States The United ...
, established in October 1913 to oversee the creation of one of the United States' earliest east-west transcontinental highways for the then-new automobile, began to establish "seedling miles" of specifically concrete-paved roadbed in various places in the American Midwest, starting in 1914 west of
Malta, Illinois Malta is a village in DeKalb County, Illinois, DeKalb County, Illinois, United States. The population was 1,164 at the 2010 census, up from 969 in 2000. History Malta was founded in 1855, under the name of Milton. Shortly afterwards, the name was c ...
, while using concrete with the specified concrete "ideal section" for the Lincoln Highway in
Lake County, Indiana Lake County is a county (United States), county located in the U.S. state of Indiana. In 2020, its population was 498,700, making it Indiana's List of counties in Indiana, second-most populous county. The county seat is Crown Point, Indiana, Cro ...
during 1922 and 1923. Concrete roadways may produce more noise than asphalt, due to tire noise on cracks and expansion joints. A concrete pavement composed of multiple slabs of uniform size will produce a periodic sound and vibration in each vehicle as its tires pass over each expansion joint. These monotonous repeated sounds and vibrations can cause a fatiguing or hypnotic effect upon the driver over the course of a long journey.


Composite pavement

Composite pavements combine a Portland cement concrete sublayer with an asphalt overlay. They are usually used to rehabilitate existing roadways rather than in new construction. Asphalt overlays are sometimes laid over distressed concrete to restore a smooth wearing surface. A disadvantage of this method is that movement in the joints between the underlying concrete slabs, whether from thermal expansion and contraction, or from deflection of the concrete slabs from truck
axle loadThe axle load of a wheeled vehicle A vehicle (from la, vehiculum) is a machine A machine is a man-made device that uses power to apply forces and control movement to perform an action. Machines can be driven by animals and people ...
s, usually causes ''s'' in the asphalt. To decrease reflective cracking, concrete pavement is broken apart through a ''break and seat,'' ''crack and seat'', or ''
rubblization Rubblization is a construction and engineering technique that involves saving time and transportation costs by reducing existing concrete into rubble at its current location rather than hauling it to another location. Rubblization has two primary ap ...
'' process. Geosynthetics can be used for reflective crack control. With break and seat and crack and seat processes, a heavy weight is dropped on the concrete to induce cracking, then a heavy roller is used to seat the resultant pieces into the subbase. The main difference between the two processes is the equipment used to break the concrete pavement and the size of the resulting pieces. The theory is that frequent small cracks will spread thermal stress over a wider area than infrequent large joints, reducing the stress on the overlying asphalt pavement. "Rubblization" is a more complete fracturing of the old, worn-out concrete, effectively converting the old pavement into an aggregate base for a new asphalt road. The whitetopping process uses Portland cement concrete to resurface a distressed asphalt road.


Recycling

Distressed pavement can be reused when rehabilitating a roadway. The existing pavement is broken up, and may be ground on-site through a process called
milling Milling may refer to: * Milling (grinding), breaking solid materials into smaller pieces by grinding, crushing, or cutting in a mill * Milling (machining), a process of using rotary cutters to remove material from a workpiece * Milling (military tra ...
. This pavement is commonly referred to as reclaimed asphalt pavement (RAP). RAP can be transported to an asphalt plant, where it will be stockpiled for use in new pavement mixes, or it may be recycled in-place using the techniques described below. For further information on asphalt mixes containing RAP and other recycled materials, see
Asphalt Concrete Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac, bitumen macadam, or rolled asphalt in the United Kingdom and the Republic of Ireland) is a composite material A composite material (also called a c ...

Asphalt Concrete
.


In-Place Recycling Methods

* of pavement: Existing concrete pavement is milled into gravel-sized particles. Any steel reinforcing is removed, and the ground pavement is compacted to form the base and/or sub-base layers for new asphalt pavement. Ground pavement may also be compacted for use on gravel roads.   *Cold in-place recycling: Bituminous pavement is ground or milled into small particles. The asphalt millings are blended with asphalt emulsion, foamed bitumen, or soft bitumen to rejuvenate the aged asphalt binder. New aggregate may also be added. The resulting asphalt mix is paved and compacted. It may serve as the top pavement layer, or it may be overlaid with new asphalt after curing. *Hot in-place recycling: Bituminous pavement is heated to 250 - 300 °F (120 - 150 °C), milled, combined with a rejuvenating agent and/or virgin asphalt binder, and compacted. It may then be overlaid with new asphalt concrete. This process typically recycles the top two inches (50 mm) or less, and may be used to correct surface defects, such as rutting or polishing. To preserve the condition of the asphalt binder and avoid excessive hydrocarbon emissions, heating is typically achieved gradually through the use of infrared or hot air heaters. * Full depth reclamation: The full thickness of the asphalt pavement and underlying material is pulverized to provide a uniform blend of material. A binding agent or stabilizing material may be mixed in to form a base course for the new pavement, or it may be left unbound to form a sub-base course. Common binding agents include asphalt emulsion, fly ash, hydrated lime,
Portland cement Portland cement is the most common type of in general use around the world as a basic ingredient of , , , and non-specialty . It was developed from other types of in England in the early 19th century by , and is usually made from . It is a f ...

Portland cement
, and calcium chloride. Virgin aggregate, RAP, or crushed Portland cement may also be added to improve the
gradation Gradation may refer to: * Gradation (music), gradual change within one parameter, or an overlapping of two blocks of sound * Gradation (album), ''Gradation'' (album), 1988 pop album by Shizuka Kudo * Gradation (art), visual technique of gradually ...
and mechanical properties of the mix. This technique is typically used to address structural failures in the pavement, such as alligator cracking, deep rutting, and shoulder drop-off.


Bituminous surface

Bituminous surface treatment (BST) or chipseal is used mainly on low-traffic roads, but also as a sealing coat to rejuvenate an asphalt concrete pavement. It generally consists of aggregate spread over a sprayed-on asphalt emulsion or cut-back asphalt cement. The aggregate is then embedded into the asphalt by rolling it, typically with a rubber-tired road roller, roller. This type of surface is described by a wide variety of regional terms including "chip seal", "tar and chip", "oil and stone", "seal coat", "sprayed seal", "surface dressing", "microsurfacing" or as simply "bitumen." BST is used on hundreds of miles of the Alaska Highway and other similar roadways in Alaska, the Yukon Territory, and northern British Columbia. The ease of application of BST is one reason for its popularity, but another is its flexibility, which is important when roadways are laid down over unstable terrain that thaws and softens in the spring. Other types of BSTs include micropaving, slurry seals and Novachip. These are laid down using specialized and proprietary equipment. They are most often used in urban areas where the roughness and loose stone associated with chip seals is considered undesirable.


Thin membrane surface

A thin membrane surface (TMS) is an oil-treated aggregate which is laid down upon a
gravel road A gravel road is a type of unpaved road A road is a thoroughfare, route, or way on land between two Location (geography), places that has been Pavement (material), paved or otherwise improved to allow travel by foot or by some form of wikt:con ...

gravel road
bed, producing a dust-free road. A TMS road reduces mud problems and provides stone-free roads for local residents where loaded truck traffic is negligible. The TMS layer adds no significant structural strength, and so is used on secondary highways with low traffic volume and minimal weight loading. Construction involves minimal subgrade preparation, following by covering with a cold mix
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or externa ...

asphalt
aggregate. The Operation Division of the Ministry of Highways and Infrastructure (Saskatchewan), Ministry of Highways and Infrastructure in Saskatchewan has the responsibility of maintaining of thin membrane surface (TMS) highways.


Otta seal

Otta seal is a low-cost road surface using a thick mixture of
bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external ...

bitumen
and crushed rock.


Gravel surface

Gravel is known to have been used extensively in the construction of roads by soldiers of the Roman Empire (see
Roman road Roman roads ( la, viae Romanae ; singular: ; meaning "Roman way") were physical infrastructure vital to the maintenance and development of the Roman state, and were built from about 300 BC through the expansion and consolidation of the Roman Rep ...

Roman road
) but in 1998 a limestone-surfaced road, thought to date back to the Bronze Age, was found at Yarnton in Oxfordshire, Britain. Applying gravel, or "metalling", has had two distinct usages in road surfacing. The term road metal refers to the broken Rock (geology), stone or cinders used in the Road#Construction, construction or repair of roads or Rail track, railways, and is derived from the Latin ''metallum'', which means both "Mining, mine" and "quarry". The term originally referred to the process of creating a gravel roadway. The route of the roadway would first be dug down several feet and, depending on local conditions, French drains may or may not have been added. Next, large stones were placed and compacted, followed by successive layers of smaller stones, until the road surface was composed of small stones compacted into a hard, durable surface. "Road metal" later became the name of Rock (geology), stone chippings mixed with tar to form the road-surfacing material Tarmacadam, tarmac. A road of such material is called a "metalled road" in Britain, a "paved road" in Canada and the US, or a "sealed road" in parts of Canada, Australia and New Zealand. A granular surface can be used with a traffic volume where the annual average daily traffic is 1,200 vehicles per day or less. There is some structural strength if the road surface combines a sub base and base and is topped with a double-graded seal aggregate with emulsion. Besides the of granular pavements maintained in Saskatchewan, around 40% of New Zealand roads are unbound granular pavement structures. The decision whether to pave a gravel road or not often hinges on traffic volume. It has been found that maintenance costs for gravel roads often exceed the maintenance costs for paved or surface-treated roads when traffic volumes exceed 200 vehicles per day. Some communities are finding it makes sense to convert their low-volume paved roads to aggregate surfaces.


Other surfaces

Pavers (or paviours), generally in the form of pre-cast concrete blocks, are often used for aesthetic purposes, or sometimes at harbor, port facilities that see long-duration pavement loading. Block paving, Pavers are rarely used in areas that see high-speed vehicle traffic. Brick,
cobblestone Cobblestone is a natural building material Building material is material used for construction Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def ...

cobblestone
, Sett (paving), sett, Plank road, wood plank, and wood block pavements such as Nicolson pavement, were once common in urban areas throughout the world, but fell out of fashion in most countries, due to the high cost of labor required to lay and maintain them, and are typically only kept for historical or aesthetic reasons. In some countries, however, they are still common in local streets. In the Netherlands, brick paving has made something of a comeback since the adoption of a major nationwide traffic safety program in 1997. From 1998 through 2007, more than 41,000 km of city streets were converted to local access roads with a speed limit of 30 km/h, for the purpose of traffic calming. One popular measure is to use brick paving - the noise and vibration slows motorists down. At the same time, it is not uncommon for cycle paths alongside a road to have a smoother surface than the road itself. Likewise,
macadam Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which single-sized crushed stone layers of small angular stones are placed in shallow lifts and compacted thoroughly. A binding layer of st ...

macadam
and Tarmacadam, tarmac pavements can still sometimes be found buried underneath asphalt concrete or Portland cement concrete pavements, but are rarely constructed today. There are also other methods and materials to create pavements that have appearance of brick pavements. The first method to create brick texture is to heat an asphalt pavement and use metal wires to imprint a brick pattern using a compactor to create stamped asphalt. A similar method is to use rubber imprinting tools to press over a thin layer of cement to create decorative concrete. Another method is to use a brick pattern stencil and apply a surfacing material over the stencil. Materials that can be applied to give the color of the brick and skid resistance can be in many forms. An example is to use colored polymer concrete, polymer-modified concrete slurry which can be applied by screeding or spraying. Another material is aggregate-reinforced thermoplastic which can be heat applied to the top layer of the brick-pattern surface. Other coating materials over stamped asphalt are paints and two-part epoxy coating. File:Brick sidewalk in Chicago.JPG, Concrete pavers File:Paving in Haikou 02.jpg, Replacing the old road with concrete blocks in Bo'ao Road area, Haikou City, Hainan, China File:Construction of a crosswalk using polymer modified cement slurry.jpg, Polymer cement overlaying to change asphalt pavement to brick texture and color to create decorative crosswalk


Acoustical implications

Roadway surfacing choices are known to affect the intensity and spectrum of sound emanating from the tire/surface interaction. Initial applications of noise studies occurred in the early 1970s. Noise phenomena are highly influenced by vehicle speed. Roadway surface types contribute differential noise effects of up to 4 decibel, dB, with chip seal type and grooved roads being the loudest, and Road surface#Concrete, concrete surfaces without spacers being the quietest. Asphaltic surfaces perform intermediately relative to concrete and chip seal. Rubberized asphalt has been shown to give a marginal 3–5 dB reduction in tire-pavement noise emissions, and a marginally discernible 1–3 dB reduction in total road noise emissions when compared to conventional asphalt applications. File:Small cobbles.jpg, Cobbles File:Wallpaper group-cmm-1.jpg, Rectangles File:Rambla waves IMG 2089.JPG, Decorative wavy pattern on La Rambla, Barcelona, La Rambla File:Wallpaper group-pgg-2.jpg, Decorative mock-brick pattern File:Wallpaper group-p3-1.jpg, More decorative brickwork patterns


Surface deterioration

As pavement systems primarily fail due to
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
(in a manner similar to metals), the damage done to pavement increases with the fourth power of the
axle loadThe axle load of a wheeled vehicle A vehicle (from la, vehiculum) is a machine A machine is a man-made device that uses power to apply forces and control movement to perform an action. Machines can be driven by animals and people ...
of the vehicles traveling on it. According to the AASHO Road Test, heavily loaded trucks can do more than 10,000 times the damage done by a normal passenger car. Tax rates for trucks are higher than those for cars in most countries for this reason, though they are not levied in proportion to the damage done. Passenger cars are considered to have little practical effect on a pavement's service life, from a materials fatigue perspective. Other failure modes include aging and surface abrasion. As years go by, the binder in a bituminous wearing course gets stiffer and less flexible. When it gets "old" enough, the surface will start losing aggregates, and macrotexture depth increases dramatically. If no maintenance action is done quickly on the wearing course, potholes will form. The freeze-thaw cycle in cold climates will dramatically accelerate pavement deterioration, once water can penetrate the surface. Clay and fumed silica nanoparticles may potentially be used as efficient UV-anti aging coatings in asphalt pavements. If the road is still structurally sound, a bituminous surface treatment, such as a chipseal or surface dressing can prolong the life of the road at low cost. In areas with cold climate, studded tires may be allowed on passenger cars. In Sweden and Finland, studded passenger car tires account for a very large share of pavement Rut (roads), rutting. The physical properties of a stretch of pavement can be tested using a falling weight deflectometer. Several design methods have been developed to determine the thickness and composition of road surfaces required to carry predicted traffic loads for a given period of time. Pavement design methods are continuously evolving. Among these are the Shell Pavement design method, and the American Association of State Highway and Transportation Officials (AASHTO) 1993/98 "Guide for Design of Pavement Structures". A mechanistic-empirical design guide was developed through the NCHRP process, resulting in the Mechanistic Empirical Pavement Design Guide (MEPDG), which was adopted by AASHTO in 2008, although MEPDG implementation by state departments of transportation has been slow. Further research by University College London into pavements has led to the development of an indoor, 80-sq-metre artificial pavement at a research centre called Pedestrian Accessibility and Movement Environment Laboratory (PAMELA). It is used to simulate everyday scenarios, from different pavement users to varying pavement conditions. There also exists a research facility near Auburn University, the NCAT Pavement Test Track, that is used to test experimental asphalt pavements for durability. In addition to repair costs, the condition of a road surface has economic effects for road users. Rolling resistance increases on rough pavement, as does wear and tear of vehicle components. It has been estimated that poor road surfaces cost the average US driver $324 per year in vehicle repairs, or a total of $67 billion. Also, it has been estimated that small improvements in road surface conditions can decrease fuel consumption between 1.8 and 4.7%.


Markings

Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. It can be in the form of mechanical markers such as Cat's eye (road), cat's eyes, botts' dots and rumble strips, or non-mechanical markers such as paints, thermoplastic, plastic and epoxy.


See also

* Asphalt * Cobblestone * Diamond grinding of pavement * Ecogrid * Good Roads Movement * List of road types by features * Pavement management * Plastic armour * Portuguese pavement (mosaic-like) * Road construction * Road slipperiness * Sealcoat * Sett (paving)


References


External links


PaveShare - Concrete Paver Education"Pavements" website of the US Department of Transportation's Federal Highway Administration
* {{DEFAULTSORT:Road Surface Pavements Road hazards, Surface Articles containing video clips