|
Stone Mastic Asphalt
Stone mastic asphalt (SMA), also called stone-matrix asphalt, was developed in Germany in the 1960s with the first SMA pavements being placed in 1968 near Kiel. It provides a deformation-resistant, durable surfacing material, suitable for heavily trafficked roads. SMA has found use in Europe, Australia, the United States, and Canada as a durable asphalt surfacing option for residential streets and highways. SMA has a high coarse aggregate content that interlocks to form a stone skeleton that resists permanent deformation. The stone skeleton is filled with a mastic of bitumen and filler to which fibres are added to provide adequate stability of bitumen and to prevent drainage of binder during transport and placement. Typical SMA composition consists of 70−80% coarse aggregate, 8−12% filler, 6.0−7.0% binder, and 0.3% fibre. The deformation resistant capacity of SMA stems from a coarse stone skeleton providing more stone-on-stone contact than with conventional dense graded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kiel
Kiel ( ; ) is the capital and most populous city in the northern Germany, German state of Schleswig-Holstein. With a population of around 250,000, it is Germany's largest city on the Baltic Sea. It is located on the Kieler Förde inlet of the Bay of Kiel and lies in the southeast of the Jutland Peninsula, on the mouth of the Schwentine River, approximately northeast of Hamburg. The world's busiest artificial waterway, the Kiel Canal, has a terminus in Kiel's Holtenau district. This canal connects the Baltic to the North Sea, with its other end in Brunsbüttel. Most of Kiel is part of Holstein. The boroughs north of the Schwentine also belong to Wagria, while those north of the Kiel Canal are historically part of Southern Schleswig. Kiel is one of Germany's major maritime centres, known for a variety of international sailing events, including the annual Kiel Week, which is the biggest sailing event in the world. Kiel is also known for the Kiel mutiny, Kiel Mutiny, when sailors re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Workability
{{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Armour
Plastic armour (also known as plastic protection) was a type of vehicle armour originally developed for merchant ships by Edward Terrell of the British Admiralty in 1940. It consisted of small, evenly sized aggregate in a matrix of bitumen, similar to asphalt concrete. It was typically applied as a casting ''in situ'' in a layer about thick on to existing ship structures made from mild steel or formed in equally thick sections on a steel plate for mounting as gun shields and the like. Plastic armour replaced the use of concrete slabs, which although expected to provide protection, were prone to cracking and breaking up when struck by armour-piercing bullets. Plastic armour was effective because the very hard particles would deflect bullets, which would then lodge between the plastic armour and the steel backing plate. Plastic armour could be applied by pouring it into a cavity formed by the steel backing plate and a temporary wooden form. Production of the armour was by road c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permeable Paving
Permeable paving surfaces are made of either a porous material that enables stormwater to flow through it or nonporous blocks spaced so that water can flow between the gaps. Permeable paving can also include a variety of surfacing techniques for roads, parking lots, and pedestrian walkways. Permeable pavement surfaces may be composed of; pervious concrete, porous asphalt, paving stones, or interlocking pavers. Unlike traditional impervious paving materials such as concrete and asphalt, permeable paving systems allow stormwater to percolate and infiltrate through the pavement and into the aggregate layers and/or soil below. In addition to reducing surface runoff, permeable paving systems can trap suspended solids, thereby filtering pollutants from stormwater. Permeable pavement is commonly used on roads, paths and parking lots subject to light vehicular traffic, such as cycle-paths, service or emergency access lanes, road and airport shoulders, and residential sidewalks and ... [...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] |
Skid Resistance
Road slipperiness is a condition of low skid resistance due to insufficient road friction. It is a result of snow, ice, water, loose material and the texture of the road surface on the traction produced by the wheels of a vehicle. Road slipperiness can be measured either in terms of the friction between a freely-spinning wheel and the ground, or the braking distance of a braking vehicle, and is related to the coefficient of friction between the tyre and the road surface. Public works agencies spend a sizeable portion of their budget measuring and reducing road slipperiness. Even a small increase in slipperiness of a section of road can increase the accident rate of the section of road tenfold. Maintenance activities affecting slipperiness include drainage repair, snow removal and street sweeping. More intensive measures may include grinding or milling a surface that has worn smooth, a surface treatment such as a chipseal, or overlaying a new layer of asphalt. A specific road ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitumen
Bitumen ( , ) is an immensely viscosity, viscous constituent of petroleum. Depending on its exact composition, it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American English, the material is commonly referred to as asphalt or tar. Whether found in natural deposits or refined from petroleum, the substance is classed as a pitch (resin), pitch. Prior to the 20th century, the term asphaltum was in general use. The word derives from the Ancient Greek word (), which referred to natural bitumen or pitch. The largest natural deposit of bitumen in the world is the Pitch Lake of southwest Trinidad, which is estimated to contain 10 million tons. About 70% of annual bitumen production is destined for road surface, road construction, its primary use. In this application, bitumen is used to bind construction aggregate, aggregate particles like gravel and forms a substance referred to as asphalt concrete, which is collo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highway Engineering
Highway engineering (also known as roadway engineering and street engineering) is a professional engineering discipline branching from the civil engineering subdiscipline of transportation engineering that involves the planning, design, construction, operation, and maintenance of roads, highways, streets, bridges, and tunnels to ensure safe and effective transportation of people and goods."Highway engineering." McGraw-Hill Concise Encyclopedia of Science and Technology. New York: McGraw-Hill, 2006. Credo Reference. Web. 13 February 2013. Highway engineering became prominent towards the latter half of the 20th century after World War II. Standards of highway engineering are continuously being improved. Highway engineers must take into account future traffic flows, design of highway intersections/interchanges, geometric alignment and design, highway pavement materials and design, structural design of pavement thickness, and pavement maintenance. History The beginning of road const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wearing Course
The wearing course, also known as a friction course or surface course, is the upper layer in roadway, airfield, and dockyard construction. The term 'surface course' is sometimes used slightly different, to describe very thin surface layers such as chip seal. In rigid pavements the upper layer is a portland cement concrete slab. In flexible pavements, the upper layer consists of asphalt concrete, that is a construction aggregate with a bituminous binder. The wearing course is typically placed on the binder course which is then laid on the base course, which is normally placed on the subbase, which rests on the subgrade. There are various different types of flexible pavement wearing course, suitable for different situations. Stone mastic asphalt is a type of flexible pavement wearing course which is typically used for heavily trafficked roads. See also * Highway engineering * Road construction *Road surface A road surface (British English) or pavement (North American Eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wool
Wool is the textile fiber obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have some properties similar to animal wool. As an animal fiber, wool consists of protein together with a small percentage of lipids. This makes it chemically quite distinct from cotton and other plant fibers, which are mainly cellulose. Characteristics Wool is produced by follicles which are small cells located in the skin. These follicles are located in the upper layer of the skin called the epidermis and push down into the second skin layer called the dermis as the wool fibers grow. Follicles can be classed as either primary or secondary follicles. Primary follicles produce three types of fiber: kemp, medullated fibers, and true wool fibers. Secondary follicles only produce true wool fibers. Medullated fibers share nearly identical characteristics to hair and are long but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyester
Polyester is a category of polymers that contain one or two ester linkages in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include some naturally occurring chemicals, such as those found in plants and insects. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing. Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends can be strong, wrinkle- and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind, and environmental resistance compared to plant-derived fibers. They are less Fireproofing, fire-resistant and can melt when ignited. Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are used for their mechanical propert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
