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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 bes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asphalt Concrete
Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and Tarmacadam, tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface road surface, roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the nineteenth century. It consists of Construction aggregate, mineral aggregate Binder (material), bound together with bitumen (a substance also independently known as asphalt, Pitch (resin), pitch, or tar), laid in layers, and compacted. The American English 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 denot ... [...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 Wash ... (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. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of the processes involved is called tribology, and has a history of more than 2000 years. Friction can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire. Another important consequence of many types of friction can be wear, which may lead to performance degradation or damage to components. It is known that frictional energy losses account for about 20% of the total energy expenditure of the world. As briefly discussed later, there are many different contributors to the retarding force in friction, ranging from asperity deformation to the generation of charges and changes in local structure. When two bodies in contact move relative to each other, due to these variou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environmental Issues
Environmental issues are disruptions in the usual function of ecosystems. Further, these issues can be caused by humans (human impact on the environment) or they can be natural. These issues are considered serious when the ecosystem cannot recover in the present situation, and catastrophic if the ecosystem is projected to certainly collapse. 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. Some scholars believe that the projected peak global population of roughly 9-10 billion people could live sustainably within the earth's ecosystems if humans worked to live sustainably wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March 3, 1879, to study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The agency also makes maps of planets and moons, based on data from U.S. space probes. The sole scientific agency of the U.S. Department of the Interior, USGS is a fact-finding research organization with no regulatory responsibility. It is headquartered in Reston, Virginia, with major offices near Lakewood, Colorado; at the Denver Federal Center; and in NASA Research Park in California. In 2009, it employed about 8,670 people. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on its hundredth anniversary, was "Earth Science in the Pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Aromatic Hydrocarbon
A Polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, or when biomass burns at lower temperatures as in forest fires. 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 also found in fossil fuel deposits such as coal and in petroleum. Exposure to PAHs can lead to different types of cancer, to fetal development complications, and to cardiovascular issues. 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 hydro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pavements
Pavement(s) or paving may refer to: Surfacing * Road surface, the durable surfacing of roads and walkways * Sidewalk, a walkway along the side of a road, called a pavement in British English * Asphalt concrete, a common form of road surface * Cool pavement, pavement that delivers higher solar reflectance than conventional dark pavement * Crazy paving, a means of hard-surfacing used outdoors * Nicolson pavement, a road surface material consisting of wooden blocks * Pavers (flooring), an outdoor floor done in blocks * Permeable paving, paving that enables stormwater to flow through it or between gaps * Portuguese pavement, the traditional paving used in most pedestrian areas in Portugal * Resin-bound paving, a mixture of aggregate stones and resin used to pave footpaths, driveways, etc. * Tactile paving, textured ground surface indicators to assist vision-impaired pedestrians * Whitetopping, the covering of an existing asphalt pavement with a layer of Portland cement concret ... [...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. Most petroleum is converted into petroleum products, which include 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 petroleum o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
