Asphalt concrete (commonly called asphalt , blacktop , or pavement in North America, and tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads , parking lots , airports , and the core of embankment dams . Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with bitumen (a substance also independently known as asphalt), laid in layers, and compacted.
41-546: Download coordinates as: The Bluemont Junction Trail is a 1.2-mile (1.9 km) asphalt -paved rail trail in Arlington County, Virginia , United States, that the Arlington County government constructed along a former branch of the defunct Washington and Old Dominion Railroad . The shared use path travels southwest from Ballston through Bluemont Junction Park to Bluemont Junction. The trail connects Ballston to
82-820: A 300-yard (274 m)-long connector trail travels along the westbound entrance ramp of I-66, crossing the highway to meet the Custis Trail, which travels east to Rosslyn , the Francis Scott Key Bridge and the Mount Vernon Trail . Shared use paths connecting to the Custis Trail and the Mount Vernon Trail cross the Potomac River on four bridges and provide access to Georgetown , the National Mall and downtown Washington, D.C. A northward extension of
123-436: A convex road surface. Rather, it is the economy of asphalt concrete that renders it more frequently used. Concrete is found on interstate highways where maintenance is highly crucial. Asphalt concrete generates less roadway noise than a Portland cement concrete surface, and is typically less noisy than chip seal surfaces. Because tire noise is generated through the conversion of kinetic energy to sound waves , more noise
164-510: A part of U.S. Route 29 ). The connection opened on June 30, 1912, and became a part of the railway's main passenger line. After the portion of the railway that travelled between Thrifton Junction and Great Falls closed in 1934, the former connection remained as a part of the section of the railroad that traveled between Bluemont Junction and the railroad's Rosslyn terminal. In 1960, the Virginia highway department began negotiations to purchase
205-451: A part of a planned connection between the railway's line that travelled between Alexandria and the town of Bluemont, Virginia (at the base of Blue Ridge east of Snickers Gap ) and its line that travelled between Georgetown and Great Falls . The three-mile long double-track connection traveled between a site to be named " Bluemont Junction " in the valley of Four Mile Run and a site to be named "Thrifton Junction" near Lee Highway (now
246-604: A range of strategies for incorporating waste materials into asphalt concrete. The strategies presented in the study include the use of plastics, particularly high-density polyethylene, in asphalt binders, and the use of glass, brick, ceramic, and marble quarry waste in place of traditional aggregate. Rejuvenators may also be produced from recycled materials, including waste engine oil, waste vegetable oil, and waste vegetable grease. Recently, discarded face masks have been incorporated into stone mastic. Virginia State Route 120 Too Many Requests If you report this error to
287-545: Is 207 feet (63.1 m). Views along the Bluemont Junction Trail from northeast to southwest: Asphalt concrete The process was refined and enhanced by Belgian-American inventor Edward De Smedt . Edgar Purnell Hooley further enhanced the process in the UK where the term tar macadam, shortened to tarmac was coined, after the name of his company Tar Macadam (Purnell Hooley's Patent) Syndicate Limited derived from
328-456: Is also less resilient and more vulnerable to cracking. Water trapped under the pavement softens the subbase and subgrade, making the road more vulnerable to traffic loads. Water under the road freezes and expands in cold weather, causing and enlarging cracks. In spring thaw, the ground thaws from the top down, so water is trapped between the pavement above and the still-frozen soil underneath. This layer of saturated soil provides little support for
369-451: Is produced as the speed of a vehicle increases. The notion that highway design might take into account acoustical engineering considerations, including the selection of the type of surface paving, arose in the early 1970s. With regard to structural performance, the asphalt behaviour depends on a variety of factors including the material, loading and environmental condition. Furthermore, the performance of pavement varies over time. Therefore,
410-529: Is recycled at a greater rate than any other material in the United States. Many roofing shingles also contain asphalt, and asphalt concrete mixes may contain reclaimed asphalt shingles (RAS). Research has demonstrated that RAP and RAS can replace the need for up to 100% of the virgin aggregate and asphalt binder in a mix, but this percentage is typically lower due to regulatory requirements and performance concerns. In 2019, new asphalt pavement mixtures produced in
451-543: The Washington and Old Dominion Railroad Trail (W&OD Trail) and the Four Mile Run Trail in and near Bluemont Park. The trail is part of a route to Georgetown and downtown Washington, D.C. It serves as an alternative to a portion of the more hilly Custis Trail . In 1911, the newly incorporated Washington and Old Dominion Railway purchased the property that now contains the Bluemont Junction Trail to accommodate
SECTION 10
#1732858391418492-520: The tarmacadam process. A variety of specialty asphalt concrete mixtures have been developed to meet specific needs, such as stone-matrix asphalt , which is designed to ensure a strong wearing surface, or porous asphalt pavements, which are permeable and allow water to drain through the pavement for controlling storm water. Different types of asphalt concrete have different performance characteristics in roads in terms of surface durability, tire wear, braking efficiency and roadway noise . In principle,
533-670: The Bluemont Junction Trail (by then in the County's Bluemont Junction Park) between Bluemont Junction and Fairfax Drive in August 1988 and officially with a celebration on October 8, 1988. The Bluemont Junction Trail's northeast trailhead is located on the south side of Fairfax Drive near the eastbound exit ramp of Interstate 66 (I-66) (the Custis Memorial Parkway) in Ballston. North of the Drive,
574-435: The Bluemont Junction Trail travels 388 yards (355 m) between the north side of Fairfax Drive and the south side of Washington Boulevard (Virginia State Route 237), where it connects to North Glebe Road ( Virginia State Route 120 ). The trail meets at its northeast trailhead on-street bike lanes that travel between Ballston and Rosslyn on Fairfax Drive ( Virginia State Route 237 ) and on Clarendon and Wilson Boulevards above
615-530: The Department of Transportation to incorporate crumb rubber into asphalt paving materials. Other recycled materials that are actively included in asphalt concrete mixes across the United States include steel slag, blast furnace slag, and cellulose fibers. Further research has been conducted to discover new forms of waste that may be recycled into asphalt mixes. A 2020 study conducted in Melbourne, Australia presented
656-590: The Run connects the trail to the Four Mile Run Trail in Bluemont Park. The Bluemont Junction Trail's grade is generally small except near its southwest trailhead. The trail's elevation at its northeast trailhead at Fairfax Drive is 259 feet (78.9 m). After reaching its highest elevation (275 feet (83.8 m)) at its crossing of Wilson Boulevard , the trail descends to its southeast trailhead, where its elevation
697-496: The United States contained, on average, 21.1% RAP and 0.2% RAS. Recycled asphalt components may be reclaimed and transported to an asphalt plant for processing and use in new pavements, or the entire recycling process may be conducted in-place. While in-place recycling typically occurs on roadways and is specific to RAP, recycling in asphalt plants may utilize RAP, RAS, or both. In 2019, an estimated 97.0 million tons of RAP and 1.1 million tons of RAS were accepted by asphalt plants in
738-534: The United States. RAP is typically received by plants after being milled on-site, but pavements may also be ripped out in larger sections and crushed in the plant. RAP millings are typically stockpiled at plants before being incorporated into new asphalt mixes. Prior to mixing, stockpiled millings may be dried and any that have agglomerated in storage may have to be crushed. RAS may be received by asphalt plants as post-manufacturer waste directly from shingle factories, or they may be received as post-consumer waste at
779-477: The combination of tar and Macadam gravel composite mixtures. The terms asphalt (or asphaltic ) concrete , bituminous asphalt concrete , and bituminous mixture are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation, AC , is sometimes used for asphalt concrete but can also denote asphalt content or asphalt cement , referring to
820-519: The construction of utility trenches and appurtenances that are placed in the pavement after construction. Lack of compaction in the surface of the asphalt, especially on the longitudinal joint, can reduce the life of a pavement by 30 to 40%. Service trenches in pavements after construction have been said to reduce the life of the pavement by 50%, mainly due to the lack of compaction in the trench, and also because of water intrusion through improperly sealed joints. Environmental factors include heat and cold,
861-432: The cracks with bitumen is a temporary fix, but only proper compaction and drainage can slow this process. Factors that cause asphalt concrete to deteriorate over time mostly fall into one of three categories: construction quality, environmental considerations, and traffic loads. Often, damage results from combinations of factors in all three categories. Construction quality is critical to pavement performance. This includes
SECTION 20
#1732858391418902-474: The determination of appropriate asphalt performance characteristics must take into account the volume of traffic in each vehicle category, and the performance requirements of the friction course. In general, the viscosity of asphalt allows it to conveniently form a convex surface, and a central apex to streets and roads to drain water to the edges. This is not, however, in itself an advantage over concrete, which has various grades of viscosity and can be formed into
943-508: The end of their service life. Processing of RAS includes grinding the shingles and sieving the grinds to remove oversized particles. The grinds may also be screened with a magnetic sieve to remove nails and other metal debris. The ground RAS is then dried, and the asphalt cement binder can be extracted. For further information on RAS processing, performance, and associated health and safety concerns, see Asphalt Shingles . In-place recycling methods allow roadways to be rehabilitated by reclaiming
984-691: The existing pavement, remixing, and repaving on-site. In-place recycling techniques include rubblizing , hot in-place recycling, cold in-place recycling, and full-depth reclamation . For further information on in-place methods, see Road Surface . During its service life, the asphalt cement binder, which makes up about 5–6% of a typical asphalt concrete mix, naturally hardens and becomes stiffer. This aging process primarily occurs due to oxidation, evaporation, exudation, and physical hardening. For this reason, asphalt mixes containing RAP and RAS are prone to exhibiting lower workability and increased susceptibility to fatigue cracking. These issues are avoidable if
1025-541: The highway department purchased the remainder of the railroad in 1968, the department sold to the Virginia Electric and Power Company (VEPCO) the portion of the railroad's former right-of-way that the department did not need for the construction of I-66 or for other transportation purposes. The Arlington County government subsequently acquired the portion of the railroad's former right-of-way that now lies between I-66 and Bluemont Junction. The County unofficially opened
1066-432: The liquid asphalt portion of the composite material. Mixing of asphalt and aggregate is accomplished in one of several ways: In addition to the asphalt and aggregate, additives, such as polymers , and antistripping agents may be added to improve the properties of the final product. Areas paved with asphalt concrete—especially airport aprons —have been called "the tarmac" at times, despite not being constructed using
1107-491: The long-term behaviour of asphalt pavement is different from its short-term performance. The LTPP is a research program by the FHWA , which is specifically focusing on long-term pavement behaviour. Asphalt deterioration can include crocodile cracking , potholes , upheaval, raveling , bleeding , rutting , shoving, stripping , and grade depressions. In cold climates, frost heaves can crack asphalt even in one winter. Filling
1148-498: The mix's rutting resistance while maintaining adequate fatigue cracking resistance. In mixes with higher recycled content, the addition of virgin binder becomes less effective, and rejuvenators may be used. Rejuvenators are additives that restore the physical and chemical properties of the aged binder. When conventional mixing methods are used in asphalt plants, the upper limit for RAP content before rejuvenators become necessary has been estimated at 50%. Research has demonstrated that
1189-401: The performance aspects of RAP and RAS is to combine the recycled components with virgin aggregate and virgin asphalt binder. This approach can be effective when the recycled content in the mix is relatively low, and has a tendency to work more effectively with soft virgin binders. A 2020 study found that the addition of 5% RAS to a mix with a soft, low-grade virgin binder significantly increased
1230-474: The portion of the line that traveled between Rosslyn and Washington Boulevard for the construction of a highway that was to become part of Interstate 66 (I-66). The purchase was made in July 1962 for $ 900,000. In September 1963, the railroad stopped operating east of Washington Boulevard. In 1964, the railroad stopped using the portion of the line that remained between Washington Boulevard and Bluemont Junction. After
1271-424: The presence of water in the subbase or subgrade soil underlying the pavement, and frost heaves. High temperatures soften the asphalt binder, allowing heavy tire loads to deform the pavement into ruts. Paradoxically, high heat and strong sunlight also cause the asphalt to oxidize, becoming stiffer and less resilient, leading to crack formation. Cold temperatures can cause cracks as the asphalt contracts. Cold asphalt
Bluemont Junction Trail - Misplaced Pages Continue
1312-422: The recycled components are apportioned correctly in the mix. Practicing proper storage and handling, such as by keeping RAP stockpiles out of damp areas or direct sunlight, is also important in avoiding quality issues. The binder aging process may also produce some beneficial attributes, such as by contributing to higher levels of rutting resistance in asphalts containing RAP and RAS. One approach to balancing
1353-463: The road above, leading to the formation of potholes. This is more of a problem for silty or clay soils than sandy or gravelly soils. Some jurisdictions pass frost laws to reduce the allowable weight of trucks during the spring thaw season and protect their roads. The damage a vehicle causes is roughly proportional to the axle load raised to the fourth power, so doubling the weight an axle carries actually causes 16 times as much damage. Wheels cause
1394-508: The road to flex slightly, resulting in fatigue cracking, which often leads to crocodile cracking. Vehicle speed also plays a role. Slowly moving vehicles stress the road over a longer period of time, increasing ruts, cracking, and corrugations in the asphalt pavement. Other causes of damage include heat damage from vehicle fires, or solvent action from chemical spills. The life of a road can be prolonged through good design, construction and maintenance practices. During design, engineers measure
1435-416: The roadbed, preventing it from weakening the subbase and subsoil. Sealcoating asphalt is a maintenance measure that helps keep water and petroleum products out of the pavement. Maintaining and cleaning ditches and storm drains will extend the life of the road at low cost. Sealing small cracks with bituminous crack sealer prevents water from enlarging cracks through frost weathering, or percolating down to
1476-510: The roadway. It is far less expensive to keep a road in good condition than it is to repair it once it has deteriorated. This is why some agencies place the priority on preventive maintenance of roads in good condition, rather than reconstructing roads in poor condition. Poor roads are upgraded as resources and budget allow. In terms of lifetime cost and long term pavement conditions, this will result in better system performance. Agencies that concentrate on restoring their bad roads often find that by
1517-411: The subbase and softening it. For somewhat more distressed roads, a chip seal or similar surface treatment may be applied. As the number, width and length of cracks increases, more intensive repairs are needed. In order of generally increasing expense, these include thin asphalt overlays, multicourse overlays, grinding off the top course and overlaying, in-place recycling, or full-depth reconstruction of
1558-402: The time they have repaired them all, the roads that were in good condition have deteriorated. Some agencies use a pavement management system to help prioritize maintenance and repairs. Asphalt concrete is a recyclable material that can be reclaimed and reused both on-site and in asphalt plants . The most common recycled component in asphalt concrete is reclaimed asphalt pavement (RAP). RAP
1599-416: The traffic on a road, paying special attention to the number and types of trucks. They also evaluate the subsoil to see how much load it can withstand. The pavement and subbase thicknesses are designed to withstand the wheel loads. Sometimes, geogrids are used to reinforce the subbase and further strengthen the roads. Drainage, including ditches , storm drains and underdrains are used to remove water from
1640-455: The underground routes of Washington Metro 's Orange and Silver lines. After leaving the northeast trailhead, the Bluemont Junction Trail travels 1.2 miles (1.9 km) southwest in Arlington County's Bluemont Junction Park, crossing five streets at grade. The trail reaches its southwest trailhead at an intersection with the W&;OD Trail at Bluemont Junction, near Four Mile Run . A bridge over
1681-527: The use of rejuvenators at optimal doses can allow for mixes with 100% recycled components to meet the performance requirements of conventional asphalt concrete. Beyond RAP and RAS, a range of waste materials can be re-used in place of virgin aggregate, or as rejuvenators. Crumb rubber, generated from recycled tires, has been demonstrated to improve the fatigue resistance and flexural strength of asphalt mixes that contain RAP. In California, legislative mandates require