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Whitetopping
Whitetopping is the covering of an existing asphalt pavement with a layer of Portland cement concrete. Whitetopping is divided into types depending on the thickness of the concrete layer and whether the layer is bonded to the asphalt substrate. Unbonded whitetopping, also called conventional whitetopping, uses concrete thicknesses of 20cm (8") or more that is not bonded to the asphalt. Bonded whitetopping uses thicknesses of 5 to 15cm (2-6") bonded to the asphalt pavement and is divided into two types, thin and ultrathin. The bond is made by texturing the asphalt. Thin whitetopping uses a bonded layer of concrete that is 10 - 15cm (4-6") thick while an ultrathin layer is 5 to 10 cm (2-4") thick. Ultrathin whitetopping is suitable for light duty uses, such as roads with low traffic volume, parking lots and small airports. Fiber reinforced concrete is used in some thin whitetopping overlays and almost all ultrathin whitetopping overlays. Whitetopping is suitable for asphalt pavement wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cool Pavement
Cool pavement is defined by the United States Environmental Protection Agency as pavement that implements technologies contributing to heat island effect reduction efforts. Most cool pavements either increase pavement albedo to reflect shortwave radiation out of the atmosphere and reduce heat transfer to the Earth’s surface, or use evaporative water cooling through the pavement to lower ambient temperatures. Newer technologies involve energy harvesting, heat storage methods, and phase change materials. Cool pavements are commonly made with reflective coatings or aggregates applied to conventional pavements or incorporation of porous or permeable materials. While pavement load capability may be reduced with more frequent maintenance requirements, cool pavements show promising results in reducing ambient temperatures and reducing energy usage. Development The United States Environmental Protection Agency defines cool pavement as pavement that implements technologies contributing t ... [...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] |
Portland Cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar (masonry), mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder (substance), powder, produced by heating limestone and clay minerals in a kiln to form Clinker (cement), clinker, and then #Cement grinding, grinding the clinker with the addition of several percent (often around 5%) gypsum. Several types of portland cement are available. The most common, historically called ordinary portland cement (OPC), is grey, but white portland cement is also available. The cement was so named by Joseph Aspdin, who obtained a patent for it in 1824, because, once hardened, it resembled the fine, pale limestone known as Portland stone, quarried from the windswept cliffs of the Isle of Portland in Dorset. Portland stone was p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactured material in the world. When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that can be poured and molded into shape. The cement reacts with the water through a process called hydration, which hardens it after several hours to form a solid matrix that binds the materials together into a durable stone-like material with various uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process is exothermic, which means that ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parking Lot
A parking lot or car park (British English), also known as a car lot, is a cleared area intended for parking vehicles. The term usually refers to an area dedicated only for parking, with a durable or semi-durable surface. In most jurisdictions where cars are the dominant mode of transportation, parking lots are a major feature of cities and suburban areas. Shopping malls, sports stadiums, and other similar venues often have immense parking lots. (See also: multistorey car park) Parking lots tend to be sources of water pollution because of their extensive impervious surfaces, and because most have limited or no facilities to control runoff. Many areas today also require minimum landscaping in parking lots to provide shade and help mitigate the extent to which their paved surfaces contribute to heat islands. Many municipalities require a minimum numbers of parking spaces for buildings such as stores (by floor area) and apartment complexes (by number of bedrooms). In th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airport
An airport is an aerodrome with extended facilities, mostly for commercial Aviation, air transport. They usually consist of a landing area, which comprises an aerially accessible open space including at least one operationally active surface such as a runway for a airplane, plane to take off and to land or a helipad, and often includes adjacent utility buildings such as Air traffic control, control towers, hangars and airport terminal, terminals, to maintain and monitor aircraft. Larger airports may have airport aprons, taxiway bridges, air traffic control centres, passenger facilities such as restaurants and Airport lounge, lounges, and emergency services. In some countries, the US in particular, airports also typically have one or more fixed-base operators, serving general aviation. Airport operations are extremely complex, with a complicated system of aircraft support services, passenger services, and aircraft control services contained within the operation. Thus airpor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber Reinforced Concrete
Fiber-reinforced concrete or fibre-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. Fibers include steel fibers, glass fibers, synthetic fibers and natural fibers – each of which lend varying properties to the concrete. In addition, the character of fiber-reinforced concrete changes with varying concretes, fiber materials, geometries, distribution, orientation, and densities. Historical perspective The concept of using fibers as reinforcement is not new. Fibers have been used as reinforcement since ancient times. Historically, horsehair was used in mortar and straw in mudbricks. In the 1900s, asbestos fibers were used in concrete. In the 1950s, the concept of composite materials came into being and fiber-reinforced concrete was one of the topics of interest. Once the health risks associated with asbestos were discovered, there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup has a higher viscosity than water. Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per metre squared, or pascal-seconds. Viscosity quantifies the internal friction, frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's center line than near its walls. Experiments show that some stress (physics), stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge
A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it. The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge, dating from the 13th century BC, in the Peloponnese is one of the oldest arch bridges in existence and use. Etymology The ''Oxford English Dictionary'' traces the origin of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Building Engineering
Architectural engineering or architecture engineering, also known as building engineering, is a Academic discipline, discipline that deals with the engineering and construction of buildings, such as environmental, structural, mechanical, electrical, computational, embeddable, and other research domains. It is related to Architecture, Mechatronics Engineering, Computer engineering, Computer Engineering, Aerospace engineering, Aerospace Engineering, and civil engineering, Civil Engineering, but distinguished from Interior design, Interior Design and architectural design, Architectural Design as an art and science of designing infrastructure through these various engineering disciplines, from which properly align with many related surrounding engineering advancements. From reduction of greenhouse gas emissions to the construction of resilient buildings, architectural engineers are at the forefront of addressing several major challenges of the 21st century. They apply the latest scie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Materials
A material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geological origin or biological function. Materials science is the study of materials, their properties and their applications. Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials. New materials can be produced from raw materials by synthesis. In industry, materials are inputs to manufacturing processes to produce products or more complex materials, and the nature and quantity of materials used may form part of the calculation for the cost of a product or delivery under contract, such as where contract costs are calculated on a " time and materials" basis. Historical elements Materials chart the history of humanity. The system of the three preh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactured material in the world. When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that can be poured and molded into shape. The cement reacts with the water through a process called hydration, which hardens it after several hours to form a solid matrix that binds the materials together into a durable stone-like material with various uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process is exothermic, which means that ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
