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Sealcoat
Sealcoating, or pavement sealing, is the process of applying a protective coating to asphalt-based pavements to provide a layer of protection from the elements: water, oils, and U.V. damage. The effects of asphalt sealers have been debated. Asphalt sealing is marketed as increasing the life of the asphalt, but there is no independent research that proves these claims. Asphalt sealing can also make the asphalt more slippery and impact the environment. Detriments to Sealcoat Pavement sealcoat products come in a variety of standards. For example, refined tar-based sealer offers the best protecting against water penetration and chemical resistance. Asphalt-based sealer typically offers poor protection against environmental chemical and harsher climates (salt water). Petroleum-based sealer offer protection against water and chemicals somewhere between the other two sealers. Another difference between coatings is in terms of wear. Again, refined tar-based sealer offers the best ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 asphalt, laid in layers, and compacted. The process was refined and enhanced by Belgian-American inventor Edward De Smedt. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road Surface
A road surface (British English), or pavement (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, 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, 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. Pavements are crucial to countries such as United States and Canada, which heavily depend on road tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NAVFAC Hawaii Personnel Train With New Pavement Sealing Machine (25170426478)
NAVFAC is an abbreviation for Naval Facility. The term may refer to: * Naval Facilities Engineering Systems Command The Naval Facilities Engineering Systems Command (NAVFAC) is the United States Navy's engineering systems command, providing the Navy and United States Marine Corps with facilities and expeditionary expertise. NAVFAC is headquartered at the Washi ... (NAVFAC), the engineering command and its subordinate organizations * Naval Facility (NAVFAC), cover name for one of the classified shore terminal/processing facilities for the U.S. Navy's Sound Surveillance System {{dab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into ''static friction'' ("stiction") between non-moving surfaces, and ''kinetic friction'' between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities (see Figure 1). *Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. *Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. *Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. *Internal friction is the force resisting motion between the elements making up a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environmental Issues
Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on the individual, organizational or governmental levels, for the benefit of both the environment and humans. Environmentalism is a social and environmental movement that addresses environmental issues through advocacy, legislation education, and activism. Environment destruction caused by humans is a global, ongoing problem. Water pollution also cause problems to marine life. Most scholars think that the project peak global world population of between 9-10 billion people, could live sustainably within the earth's ecosystems if human society worked to live sustainably within planetary boundaries. The bulk of environmental impacts are caused by the most wealthy populations in the globe consuming too much industrial goods. The UN Environmenta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Aromatic Hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are found in coal and in oil deposits, and are also produced by the combustion of organic matter—for example, in engines and incinerators or when biomass burns in forest fires. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life. Nomenclature and structure The terms polyaromatic hydrocarbon or polynuclear aromatic hydrocarbon are also used for this concept. By definition, polycyclic aromatic hydrocarbons have multiple rings, precluding benzene from being considered a PAH. Some sources, such as the US EPA and CDC, consider naphthalene to be the simplest PAH. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pavements
Pavement may refer to: * Pavement (architecture), an outdoor floor or superficial surface covering * Road surface, the durable surfacing of roads and walkways ** Asphalt concrete, a common form of road surface * Sidewalk or pavement, a walkway along the side of a road * Cool pavement, is pavement that delivers higher solar reflectance than conventional dark pavement. * Pavement (York), a street in York, in England Geology * Limestone pavement, a naturally occurring landform that resembles an artificial pavement * Desert pavement, a desert ground surface covered with closely packed rock fragments of pebble and cobble size * Tessellated pavement, a rare sedimentary rock formation that occurs on some ocean shores * Glacial striation Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them w .. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum Products
Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. Unlike petrochemicals, which are a collection of well-defined usually pure organic compounds, petroleum products are complex mixtures. The majority of petroleum is converted to petroleum products, which includes several classes of fuels. According to the composition of the crude oil and depending on the demands of the market, refineries can produce different shares of petroleum products. The largest share of oil products is used as "energy carriers", i.e. various grades of fuel oil and gasoline. These fuels include or can be blended to give gasoline, jet fuel, diesel fuel, heating oil, and heavier fuel oils. Heavier (less volatile) fractions can also be used to produce asphalt, tar, paraffin wax, lubricating and other heavy oils. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials. Since petro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
