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Crushed Rock
Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from naturally occurring gravel, which is produced by natural processes of weathering and erosion and typically has a more rounded shape. Use * Angular crushed stone is the key material for macadam road construction, which depends on the interlocking of the individual stones' angular faces for its strength. * As riprap * As railroad track ballast * As filter stone. * As composite material (with a binder) in concrete, tarmac, and asphalt concrete. * In landscaping as a groundcover, walkway and driveway pavement, and infill for permeable pavers. As a mineral groundcover its benefits include erosion control, water conservation, weed suppression, and aesthetics. It is often seen used in rock gardens and cactus gardens. Background Crushed stone is a major basic raw material use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walkway
In American English, walkway is a composite or umbrella term for all engineered surfaces or structures which support the use of trails. ''The New Oxford American Dictionary'' also defines a walkway as "a passage or path for walking along, esp. a raised passageway connecting different sections of a building or a wide path in a park or garden." The word is used to describe a footpath in New Zealand, where "walkways vary enormously in nature, from short urban strolls, to moderate coastal locations, to challenging tramps ikesin the high country ountains. Similarly in St. John's, Newfoundland, Canada the " Grand Concourse", is an integrated walkway system that has over of walkways, which link every major park, river, pond, and green space in six municipalities. In Toronto, Ontario, Canada, the SkyWalk is an approximately enclosed and elevated walkway (skyway) connecting Union Station to the CN Tower and the Rogers Centre (SkyDome). It is part of the PATH network. The SkyWalk passe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sintered
Clinker nodules produced by sintering Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms in the materials diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece. Because the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points such as tungsten and molybdenum. The study of sintering in metallurgical powder-related processes is known as powder metallurgy. An example of sintering can be observed when ice cubes in a glass of water adhere to each other, which is driven by the temperature difference between the water and the ice. Examples of pressure-driven sintering are the compact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slag
Slag is a by-product of smelting (pyrometallurgical) ores and used metals. Broadly, it can be classified as ferrous (by-products of processing iron and steel), ferroalloy (by-product of ferroalloy production) or non-ferrous/base metals (by-products of recovering non-ferrous materials like copper, nickel, zinc and phosphorus). Within these general categories, slags can be further categorized by their precursor and processing conditions (e.g., Blast furnace (BF) slags, air-cooled blast furnace (ACBF) slag, basic oxygen furnace (BOF) slag, and electric arc furnace (EAF) slag) . Due to the large demand for these materials, slag production has also significantly increased throughout the years despite recycling (most notably in the iron and steelmaking industries) and upcycling efforts. The World Steel Association (WSA) estimates that 600 kg of by-products (~90 wt% is slags) are generated per tonne of steel produced. Composition Slag is usually a mixture of metal oxides and sili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand, for example, aragonite, which has mostly been created, over the past 500million years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Somewhat more rarely, sand may be composed of calciu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roadbuilding
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of roads, including parkways, avenues, controlled-access highways (freeways, motorways, and expressways), tollways, interstates, highways, thoroughfares, and local roads. The primary features of roads include lanes, sidewalks (pavement), roadways (carriageways), medians, shoulders, verges, bike paths (cycle paths), and shared-use paths. Definitions Historically many roads were simply recognizable routes without any formal construction or some maintenance. The Organization for Economic Co-operation and Development (OECD) defines a road as "a line of communication (travelled way) using a stabilized base other than rails or air strips open to public traffic, primarily for the use of road motor vehicles running on their own wheels", which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolomite (rock)
Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. It occurs widely, often in association with limestone and evaporites, though it is less abundant than limestone and rare in Cenozoic rock beds (beds less than about 66 million years in age). The first geologist to distinguish dolomite rock from limestone was Belsazar Hacquet in 1778. Most dolomite was formed as a magnesium replacement of limestone or of lime mud before lithification. The geological process of conversion of calcite to dolomite is known as dolomitization and any intermediate product is known as dolomitic limestone. The "dolomite problem" refers to the vast worldwide depositions of dolomite in the past geologic record in contrast to the limited amounts of dolomite formed in modern times. Recent research has revealed sulfate-reducing bacteria living in anoxic conditions precipitate dolomite which ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measures Of National Income And Output
A variety of measures of national income and output are used in economics to estimate total economic activity in a country or region, including gross domestic product (GDP), gross national product (GNP), net national income (NNI), and adjusted national income (NNI adjusted for natural resource depletion – also called as NNI at factor cost). All are specially concerned with counting the total amount of goods and services produced within the economy and by various sectors. The boundary is usually defined by geography or citizenship, and it is also defined as the total income of the nation and also restrict the goods and services that are counted. For instance, some measures count only goods & services that are exchanged for money, excluding bartered goods, while other measures may attempt to include bartered goods by ''imputing'' monetary values to them. National accounts Arriving at a figure for the total production of goods and services in a large region like a country entails a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Construction
Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and comes from Latin ''constructio'' (from ''com-'' "together" and ''struere'' "to pile up") and Old French ''construction''. To construct is the verb: the act of building, and the noun is construction: how something is built, the nature of its structure. In its most widely used context, construction covers the processes involved in delivering buildings, infrastructure, industrial facilities and associated activities through to the end of their life. It typically starts with planning, financing, and design, and continues until the asset is built and ready for use; construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual demolition, dismantling or decommissioning. The constructio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raw Material
A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedstock, the term connotes these materials are bottleneck assets and are required to produce other products. The term ''raw material'' denotes materials in unprocessed or minimally processed states; e.g., raw latex, crude oil, cotton, coal, raw biomass, iron ore, air, lumber, logs, water, or "any product of agriculture, forestry, fishing or mineral in its natural form or which has undergone the transformation required to prepare it for international marketing in substantial volumes". The term ''secondary raw material'' denotes waste material which has been recycled and injected back into use as productive material. Ceramic While pottery originated in many different points around the world, it is certain that it was brought to light mostly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cactus Garden
A cactarium or cactuario (from Latin, ''cactarium'') is a garden dedicated to the planting of cacti. While they generally specialize in collecting cacti, they can also include other desert plants such as sabla, agaves or Crassulaceae, although this would better be termed "xeriscaping''"''. Cacti are succulent plants native to the American continent, typical of arid environments. They require dry conditions and therefore, in many countries, the collections are kept in greenhouses that protect from rain. Due to their low need for water, they are a sustainable landscaping option. Cactariums also tend to host plants from other botanical families, native to the desert regions of the world. History A cactus garden is a garden for the cultivation and display with many types of cacti. Cacti, due to their unusual appearance for Europeans, attracted the attention of the first European colonizers of Americas and were brought to Europe as ornamental plants already in the 16th century. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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